A rapid, straightforward, sensitive, efficient, and cost-effective reverse-phase high-performance liquid chromatographic method was employed for the simultaneous determination of Sorbitol, Sodium Lactate, and Chloride...A rapid, straightforward, sensitive, efficient, and cost-effective reverse-phase high-performance liquid chromatographic method was employed for the simultaneous determination of Sorbitol, Sodium Lactate, and Chlorides in a drug solution for infusion. Sorbitol, Sodium lactate, and Chloride are all officially recognized in the USP monograph. Assay methods are provided through various techniques, with titrations being ineffective for trace-level quantification. Alternatively, IC, AAS, and ICP-MS, though highly accurate, are costly and often unavailable to most testing facilities. When considering methods, it’s important to prioritize both quality control requirements and user-friendly techniques. A simple HPLC simultaneous method was developed for the quantification of Chlorides, Sorbitol, and Sodium Lactate with a shorter run time. The separation utilized a Shimpack SCR-102(H) ion exclusion analytical column (7.9 mm × 300 mm, 7 μm), with a flow rate of 0.6 mL per min. The column compartment temperature was maintained at 40°C, and the injection volume was set at 10 μL, with detection at 200 nm. All measurements were conducted in a 0.1% solution of phosphoric acid. The analytical curves demonstrated linearity (r > 0.9999) in the concentration range of 0.79 to 3.8 mg per mL for Sodium Lactate (SL), 0.16 to 0.79 mg per mL for Sodium Chloride (SC), and 1.5 to 7.2 mg per mL for Sorbitol. Validation of the developed method followed the guidelines of the International Conference on Harmonization (ICH Q2B) and USP. The method exhibited precision, robustness, accuracy, and selectivity. In accelerated stability testing over 6 months, no significant variations were observed in organoleptic analysis and pH. Consequently, the developed method is deemed suitable for routine quality control analyses, enabling the simultaneous determination of Sodium Lactate, Sodium Chloride, and Sorbitol in pharmaceutical formulations and infusions.展开更多
COVID-19,a disease caused by the novel coronavirus SARS-Co V-2,has produced a serious emergency for global public health,placing enormous stress on national health systems in many countries.Several studies suggest tha...COVID-19,a disease caused by the novel coronavirus SARS-Co V-2,has produced a serious emergency for global public health,placing enormous stress on national health systems in many countries.Several studies suggest that cytokine storms(interleukins)may play an important role in severe cases of COVID-19.Neutralizing key inflammatory factors in cytokine release syndrome(CRS)could therefore be of great value in reducing the mortality rate.Tocilizumab(TCZ)in its intravenous(IV)form of administration-Ro Actemra?20 mg/m L(Roche)-is indicated for treatment of severe CRS patients.Preliminary investigations have concluded that inhibition of IL-6 with TCZ appears to be efficacious and safe,with several ongoing clinical trials.This has led to a huge increase in demand for IV TCZ for treating severe COVID-19 patients in hospitals,which has resulted in drug shortages.Here,we present a comparability study assessing the main critical physicochemical attributes of TCZ solutions used for infusion,at 6 mg/m L and 4 mg/m L,prepared from Ro Actemra?20 mg/m L(IV form)and from Ro Actemra?162 mg(0.9 m L solution pre-filled syringe,subcutaneous(SC)form),to evaluate the use of the latter for preparing clinical solutions required for IV administration,so that in a situation of shortage of the IV medicine,the SC form could be used to prepare the solutions for IV delivery of TCZ.It is important to remember that during the current pandemic all the medicines are used off-label,since none of them has yet been approved for the treatment of COVID-19.展开更多
This work presents a software tool for modeling of mass transfer physicochemical processes occurring in the atmosphere. The implemented algorithms provide an efficient theoretical frame for the interpretation of the r...This work presents a software tool for modeling of mass transfer physicochemical processes occurring in the atmosphere. The implemented algorithms provide an efficient theoretical frame for the interpretation of the results obtained from Coated Wall Flow Tube (CWFT) reactor experiments, which is one of the most adequate techniques to study heterogeneous kinetics. The numerical simulations are based on the fundamental Langmuir adsorption theory by ordinary differential equations and the second Fick’s law described by partial differential equations. The main application of the system is to estimate the basic parameters that characterize the processes. The best parameter estimation is found by minimizing the difference between experimental signals from the CWFT reactors and the obtained numerical simulations. A numerical example for an experimental data fit is given.展开更多
The endocannabinoid system(ECS),particularly its signaling pathways and ligands,has garnered considerable interest in recent years.Along with clinical work investigating the ECS’functions,including its role in the de...The endocannabinoid system(ECS),particularly its signaling pathways and ligands,has garnered considerable interest in recent years.Along with clinical work investigating the ECS’functions,including its role in the development of neurological and inflammatory conditions,much research has focused on developing analytical protocols enabling the precise monitoring of the levels and metabolism of the most potent ECS ligands:exogenous phytocannabinoids(PCs)and endogenous cannabinoids(endocannabinoids,ECs).Solid-phase microextraction(SPME)is an advanced,non-exhaustive sample-preparation technique that facilitates the precise and efficient isolation of trace amounts of analytes,thus making it appealing for the analysis of PCs and ECs in complex matrices of plant and animal/human origin.In this paper,we review recent forensic medicine and toxicological studies wherein SPME has been applied to monitor levels of PCs and ECs in complex matrices,determine their effects on organism physiology,and assess their role in the development of several diseases.展开更多
Dietary flavonoids are abundant in natural plants and possess multiple pharmacological and nutritional activities.In this study,apigenin,luteolin,and baicalein were chosen to evaluate their anti-diabetic effect in hig...Dietary flavonoids are abundant in natural plants and possess multiple pharmacological and nutritional activities.In this study,apigenin,luteolin,and baicalein were chosen to evaluate their anti-diabetic effect in high-glucose and dexamethasone induced insulin-resistant(IR)HepG2 cells.All flavonoids improves the glucose consumption and glycogen synthesis abilities in IR-HepG2 cells via activating glucose transporter protein 4(GLUT4)and phosphor-glycogen synthase kinase(GSK-3β).These fl avonoids signifi cantly inhibited the production of reactive oxygen species(ROS)and advanced glycation end-products(AGEs),which were closely related to the suppression of the phosphorylation form of NF-κB and P65.The expression levels of insulin receptor substrate-1(IRS-1),insulin receptor substrate-2(IRS-2)and phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)pathway in IR-HepG2 cells were all partially activated by the fl avonoids,with variable effects.Furthermore,the intracellular metabolic conditions of the fl avonoids were also evaluated.展开更多
Objective:To assess the acute and subacute toxicity as well as the phytochemical composition of two extracts and three fractions of Ammi majus L.Methods:The aqueous extracts were prepared separately by maceration for ...Objective:To assess the acute and subacute toxicity as well as the phytochemical composition of two extracts and three fractions of Ammi majus L.Methods:The aqueous extracts were prepared separately by maceration for 48 h and by infusion for 1 h,while the fractions were prepared by the Soxhlet extractor,successively employing cyclohexane,ethyl acetate,and ethanol.The acute toxicity study was carried out in accordance with the OECD N°423 guideline at a single dose(2000 mg/kg)in mice for 14 days.The subacute toxicity study was performed by a daily oral administration of 250 mg/kg 2 for 10 d and 100 mg/kg doses for 28 d.Phytochemical screening was performed using staining and precipitation reactions,while the chemical characterization of some analytes was detected by HPLC-MS/MS analysis.Results:In the acute toxicity study,no signs of toxicity such as convulsion,salivation,diarrhea,sleep and coma were observed during 30 minutes and 14 days,so the lethal dose was higher than 2000 mg/kg for each extract and fraction.The subacute toxicity results showed that at a dose of 250 mg/kg,61.10%of the animals died and the rest developed morbidity.On the other hand,at a dose of 100 mg/kg,all the animals were still alive after 28 days,with no morbidity and the biochemical parameters were normal with no abnormalities in the liver,kidneys and pancreas.Phytochemical screening indicated the presence of flavonoids,tannins,coumarins,and free quinones and the absence of alkaloids and anthocyanins.Conclusions:The extracts and fractions of Ammi majus L.are not toxic in the short and long term with a varied chemical composition.Toxicological tests on animals other than rodents and in the long term(more than 28 days)are needed to further confirm the safety of Ammi majus extracts.展开更多
AIM: Proteolytic degradation of the extracellular matrix facilitates cancer invasion and promotes metastasis. The study aims at evaluation of preoperative and postoperative serum cathepsins B and D levels in correlati...AIM: Proteolytic degradation of the extracellular matrix facilitates cancer invasion and promotes metastasis. The study aims at evaluation of preoperative and postoperative serum cathepsins B and D levels in correlation with selected anatomoclinical features of colorectal cancer.METHODS: Blood samples were collected from 63colorectal cancer patients before curative operation of the tumor 10 d later. Blood that was obtained from 20healthy volunteers, served as a control. The activity of cathepsin B was measured with Bz-DL-arginine-pNA as a substrate at pH 6.0, while cathepsin D activity was determined with urea-denatured hemoglobin (pH 4.0).RESULTS: The preoperative and postoperative activities of cathepsin B were significantly (P＜0.00001) lower in serum of colorectal cancer patients than in control group.However, postoperative values of this protease were significantly increased in comparison with preoperative ones (P = 0.031). Activity of cathepsin D appeared to be significantly higher in colorectal cancer sera (P＜0.00001)compared with controls. No statistically significant differences between preoperative and postoperative activity of cathepsin D were noted (P = 0.09). We revealed a strong linkage of cathepsins' levels with lymph node status and pT stage of colorectal cancer.CONCLUSION: Blood serum activities of cathepsin B and D depend on the time of sampling, tumor size and lymph node involvement. Significantly, increased activity of cathepsin D could indicate a malignant condition of the large intestine. In our work, the serum postoperative decrease of cathepsin B activity appears as an obvious concomitant of local lymph node metastasis-the wellknown clinicopathological feature of poor prognosis.展开更多
A carbon paste electrode (CPE) modified with ferrocene carboxylic acid (FcCA) and TiO2 nanoparticles was constructed by incorporating TiO2 nanoparticles and ferrocene carboxylic acid into the carbon paste matrix. The ...A carbon paste electrode (CPE) modified with ferrocene carboxylic acid (FcCA) and TiO2 nanoparticles was constructed by incorporating TiO2 nanoparticles and ferrocene carboxylic acid into the carbon paste matrix. The electrochemical behavior of captopril (CAP) at the surface of the modified electrode was investigated using electroanalytical methods. The modified electrode showed excellent electrocatalytic activity for the oxidation of CAP in aqueous solutions at physiological pH values. Cyclic voltammetric curves showed that the oxidation of CAP at the surface of the modified electrode reduced its overpotential by more than 290 mV. The modified electrode was used for detecting captopril using cyclic voltammetry and square wave voltammetry techniques. A calibration curve in the range of 0.03 to 2400 μmol/L was obtained that had a detection limit of 0.0096 μmol/L (3?) under the optimized conditions. The modified electrode was successfully used for the determination of captopril in pharmaceutical and biological samples.展开更多
Extract of oven dried leaves of Pongamia pinnata(L) Pierre was used for the synthesis of silver nanoparticles. Stable and crystalline silver nanoparticles were formed by the treatment of aqueous solution of AgNO_3(1m ...Extract of oven dried leaves of Pongamia pinnata(L) Pierre was used for the synthesis of silver nanoparticles. Stable and crystalline silver nanoparticles were formed by the treatment of aqueous solution of AgNO_3(1m M) with dried leaf extract of Pongamia pinnata(L) Pierre. UV-visible spectroscopy studies were carried out to quantify the formation of silver nanoparticles. Transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy were used to characterize the silver nanoparticles. TEM image divulges that silver nanoparticles are quite polydispersed, the size ranging from 20 nm to 50 nm with an average of 38 nm. Water soluble heterocyclic compounds such as flavones were mainly responsible for the reduction and stabilization of the nanoparticles. Silver nanoparticles were effective against Escherichia coli(ATCC 8739), Staphylococcus aureus(ATCC 6538p), Pseudomonas aeruginosa(ATCC 9027) and Klebsiella pneumoniae(clinical isolate). The move towards extracellular synthesis using dried biomass appears to be cost effective, eco-friendly to the conventional methods of nanoparticles synthesis.展开更多
Understanding the effects of elevation and related factors(climate,vegetation) on the physical and chemical soil properties can help to predict changes in response to future climate or afforestation forcings.This work...Understanding the effects of elevation and related factors(climate,vegetation) on the physical and chemical soil properties can help to predict changes in response to future climate or afforestation forcings.This work aims to contribute to the knowledge of soil evolution and the classification of forest soils in relation to elevation in the montane stage,with special attention to podzolization and humus forms.The northern flank of the Moncayo Massif(Iberian Range,SW Europe) provides a unique opportunity to study a forest soils catena within a consistent quartzitic parent material over a relatively steep elevation gradient.With increasing elevation,pH,base saturation,exchangeable potassium,and fine silt-sized particles decrease significantly,while organic matter,the C/N ratio,soil aggregate stability,water repellency and coarse sand-sized particles increase significantly.The soil profiles shared a set of properties in all horizons:loamy-skeletal particle-size,extreme acidity(pH-H_2O<5.6) and low base saturation(<50%).The most prevalent soil forming processes in the catena include topsoil organic matter accumulation and even podzolization,which increases with elevation.From the upper to lower landscape positions of wooded montane stage of the Moncayo Massif,mull-moder-mor humus and an UmbrisolCambisol-Podzol soil unit sequences were found.展开更多
S-Nitrosothiols or thionitrites with the general formula RSNO are formally composed of the nitrosyl cation(NOt) and a thiolate(RSà), the base of the corresponding acids RSH. The smallest S-nitrosothiol is HSNO an...S-Nitrosothiols or thionitrites with the general formula RSNO are formally composed of the nitrosyl cation(NOt) and a thiolate(RSà), the base of the corresponding acids RSH. The smallest S-nitrosothiol is HSNO and derives from hydrogen sulfide(HSH, H_2S). The most common physiological S-nitrosothiols are derived from the amino acid L-cysteine(Cys SH). Thus, the simplest S-nitrosothiol is S-nitroso-L-cysteine(Cys SNO). Cys SNO is a spontaneous potent donor of nitric oxide(NO) which activates soluble guanylyl cyclase to form cyclic guanosine monophosphate(c GMP). This activation is associated with multiple biological actions that include relaxation of smooth muscle cells and inhibition of platelet aggregation.Like NO, Cys SNO is a short-lived species and occurs physiologically at concentrations around 1 n M in human blood. Cys SNO can be formed from Cys SH and higher oxides of NO including nitrous acid(HONO)and its anhydride(N_2O_3). The most characteristic feature of RSNO is the S-transnitrosation reaction by which the NOtgroup is reversibly transferred to another thiolate. By this way numerous RSNO can be formed such as the low-molecular-mass S-nitroso-N-acetyl-L-cysteine(SNAC) and S-nitroso-glutathione(GSNO), and the high-molecular-mass S-nitrosol-L-cysteine hemoglobin(Hb Cys SNO) present in erythrocytes and S-nitrosol-L-cysteine albumin(Alb Cys SNO) present in plasma at concentrations of the order of 200 n M. All above mentioned RSNO exert NO-related biological activity, but they must be administered intravenously. This important drawback can be overcome by lipophilic charge-free RSNO.Thus, we prepared the ethyl ester of SNAC, the S-nitroso-N-acetyl-L-cysteine ethyl ester(SNACET), from synthetic N-acetyl-L-cysteine ethyl ester(NACET). Both NACET and SNACET have improved pharmacological features over N-acetyl-L-cysteine(NAC) and S-nitroso-N-acetyl-L-cysteine(SNAC), respectively,including higher oral bioavailability. SNACET exerts NO-related activities which can be utilized in the urogenital tract and in the cardiovascular system. NACET, with high oral bioavailability, is a strong antioxidant and abundant precursor of GSH, unlike its free acid N-acetyl-L-cysteine(NAC). Here, we review the chemical and pharmacological properties of SNACET and NACET as well as their analytical chemistry.We also report new results from the ingestion of S-[^(15) N]nitroso-N-acetyl-L-cysteine ethyl ester(S^(15) NACET) demonstrating the favorable pharmacological profile of SNACET.展开更多
Here, Pd Ru nanoparticle networks(NPNs) with various compositions were synthesized through an inexpensive method in water as a green solvent, at different ratios of the H_2PdCl_4 and RuCl_3 precursors. This is a fast,...Here, Pd Ru nanoparticle networks(NPNs) with various compositions were synthesized through an inexpensive method in water as a green solvent, at different ratios of the H_2PdCl_4 and RuCl_3 precursors. This is a fast, room temperature and surfactant free strategy which is able to form high surface area metal nanosponges with a three-dimensional(3D) porous structure. The structure of as-prepared nanosponges was characterized using the techniques of field emission scanning electron microscopy(FESEM), energy dispersive spectroscopy(EDS) and cyclic voltammetry(CV). Then, the electrocatalytic activities of Pd Ru NPNs towards formic acid oxidation were examined by electrochemical measurements including CV,chronoamperometry, and electrochemical impedance spectroscopy(EIS). Based on studies, it was found that the current density of formic acid oxidation(FAO) is strongly dependent on the composition of Pd Ru NPNs. The best performance was realized for Pd_4Ru_1 NPNs compared to monometallic Pd counterpart and other bimetallic NPNs which might be ascribed to the role of Ru in the decrease of CO adsorption strength on the catalyst and consequently the priority of formic acid oxidation through the direct pathway. The Pd_4Ru_1 NPNs also showed the maximum current density and stability in chronoamperometric measurements. In addition, comparative studies were performed between as-prepared NPNs and CNTs-supported Pd nanoparticles(Pd NPs/CNTs). The present results demonstrated the unique structural advantages of NPNs compared to individual Pd NPs supported on the CNT which leads to the promising performance of NPNs as supportless catalysts for the oxidation of formic acid.展开更多
An amperometric hydrogen peroxide biosensor using a nanobiocomposite based on neutral red modified carbon nanotubes and co-immobilized glucose oxidase and horseradish peroxidase is reported. Modification of the nanobi...An amperometric hydrogen peroxide biosensor using a nanobiocomposite based on neutral red modified carbon nanotubes and co-immobilized glucose oxidase and horseradish peroxidase is reported. Modification of the nanobiocomposite electrode with neutral red resulted in a sensitive, low-cost and reliable H_2O_2 sensor. The use of carbon nanotubes, as the conductive part of the composite, facilitated fast electron transfer rates. The biosensor was characterized for the influence of p H, potential and temperature. A remarkable feature of the biosensor is the detection of H_2O_2 at low applied potentials where the noise level and interferences are minimal. The sensor has a fast steady-state measuring time of 10 s with a quick response(2 s). The biosensor showed a linear range from 15 n M to 45 m M of H_2O_2 and a detection limit of 5 n M. Nafion, which is used as a binder, makes the determination free from other electroactive substances. The repeatability, reproducibility,stability and analytical performance of the sensor are very good.展开更多
Heavy metal contamination of soils is a widespread problem in Zanjan province located in North West Iran due to natural pedo geochemical background and anthropogenic sources. The province is highly polluted by some he...Heavy metal contamination of soils is a widespread problem in Zanjan province located in North West Iran due to natural pedo geochemical background and anthropogenic sources. The province is highly polluted by some heavy metals due to the presence of mineral resources notably Lead and Zinc, their improper utilization, and also the development of a number of related industries. Bonab district was selected for detail study and the objectives of the study were set to evaluate the total as well as bioavailable fraction of heavy metals in surficial soils within the studied area. 72 soil samples were collected and analyzed for heavy metal contamination by Atomic Absorption Spectrometry (AAS). The obtained results when compared with WHO and USEPA standards show a very high concentration of some toxic metals. Soils were basically polluted by Pb, Zn, Cu, and Cd. Bioavailable fraction of studied metals were also measured with formation of metal complex with Diethylene tri amine penta acetic acid (DTPA) agent. To find the share of the anthropogenic sources in the contamination of soils, the Enrichment factor (EF) and Geological Accumulation Index were measured and the distribution maps were drawn using Arc GIS (9.3). Highest concentrations of some toxic metals were found as isolated patches around the Bonab Industrial Town as well as within and around the most populated areas of the district notably Zanjan city indicating its anthropogenic origin.展开更多
Chemical composition,physico-chemical properties and fatty acid composition of breast and drumstick meat from capons(castrated male cockerels) fed cereals were studied.Three groups of capons were reared.One group was ...Chemical composition,physico-chemical properties and fatty acid composition of breast and drumstick meat from capons(castrated male cockerels) fed cereals were studied.Three groups of capons were reared.One group was fed ad libitum the same commercial diet until the 4th mon of life.The last month of its life,the capons of this group were fed corn.The second and third group of capons were fed the same diet from caponization.The second group was fed mixture of corn(50%) and wheat(50%).The third group of capons was fed 2/3 corn and 1/3 mixture of corn(50%) and barley(50%).Capons were reared under free-range conditions and slaughtered at 150 d of age.Caponization was performed at 48 d.No significant effects of feeding in chemical composition,pH,water holding capacity,drip and cooking losses and texture of the meat were observed.The meat of the third group(capons fed 83%corn) was more yellow and showed higher content of C18:2 than that of the other capons.展开更多
The objective of this paper was to evaluate the sugar and water content in sugar cane samples by means of twonon-destructive techniques in comparison with conventional methods. One non-destructive technique is the Bio...The objective of this paper was to evaluate the sugar and water content in sugar cane samples by means of twonon-destructive techniques in comparison with conventional methods. One non-destructive technique is the Biospeckle, aninteraction between the laser and the biological material which provides information about the material. The other technique is thenear infrared spectroscopy （NIR）. The Biospeckle technique has been constantly used in agricultural engineering. In this paper, therelation between the water and the sugar contents were obtained. The results for the Biospeckle were acquired through the moment ofinertia （MI）. The data acquired through already consolidated methodologies were used to quantify the samples＇ water and sugarcontents, correlating to the spectroscopy results and also to the Biospeckle. It was obtained a high determination coefficient （R^2 =0.9287） between the predicted Brix by the model generated by NIR spectroscopy and Brix measured by refractometer. It was alsopossible to differentiate the water contents of the sugar cane samples both externally lit （husk） and internally lit （cut） by Biospeckleanalysis through the calculation of MI. It is possible to evaluate the water content and the sugar content in samples combiningBiospeckle and NIR spectroscopy, which are non-invasive and non-destructive methods.展开更多
Cetuximab(CTX) is a potent chimeric mouse/human monoclonal antibody(mAb) approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses performed for full study on...Cetuximab(CTX) is a potent chimeric mouse/human monoclonal antibody(mAb) approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses performed for full study on this biopharmaceutic, the determination of the concentration preparations throughout manufacturing and subsequent handling in hospital is particularly relevant. In the present work, the study and validation of a method for quantifying intact CTX by reverse-phase high-performance liquid chromatography with diode array detection((RP)HPLC/DAD) is presented. With that end,we checked the performance of a chromatographic method for quantifying CTX and conducted a study to validate the method as stability-indicating in accordance with the International Conference on Harmonization guidelines(ICH) for biotechnological drugs; therefore, we evaluated linearity, accuracy, precision, detection and quanti fication limits, robustness and system suitability. The speci ficity of the method and the robustness of the mAb formulation against external stress factors were estimated by comprehensive chromatographic analysis by subjecting CTX to several informative stress conditions. As demonstrated, the method is rapid, accurate, and reproducible for CTX quantification. It was also successfully used to quantify CTX in a long-term stability study performed under hospital conditions.展开更多
Two simple, accurate, precise and economic spectrophotometric methods have been developed for simultaneous determination of Atorvastatin calcium (ATR) and Ezetimibe (EZ) in their bulk powder and pharmaceutical dosage ...Two simple, accurate, precise and economic spectrophotometric methods have been developed for simultaneous determination of Atorvastatin calcium (ATR) and Ezetimibe (EZ) in their bulk powder and pharmaceutical dosage form. Method (I) is based on dual wavelength analysis while method (II) is the mean centering of ratio spectra spectrophotometric (MCR) method. In method (I), two wavelengths were selected for each drug in such a way that the difference in absorbance was zero for the second drug. At wavelengths 226.6 and 244 nm EZ had equal absorbance values; therefore, these two wavelengths have been used to determine ATR; on a similar basis 228.6 and 262.8 nm were selected to determine EZ in their binary mixtures. In method II, the absorption spectra of both ATR and EZ with different concentrations were recorded over the range 200-350, divided by the spectrum of suitable divisor of both ATR and EZ and then the obtained ratio spectra were mean centered. The concentrations of active components were then determined from the calibration graphs obtained by measuring the amplitudes at 215-260 nm (peak to peak) for both ATR and EZ. Accuracy and precision of the developed methods have been tested; in addition recovery studies have been carried out in order to confirm their accuracy. On the other hand, selectivities of the methods were tested by application for determination of different synthetic mixtures containing different ratios of the studied drugs. The developed methods have been successfully used for determination of ATR and EZ in their combined dosage form and statistical comparison of the developed methods with the reported spectrophotometric one using F and Student's t-tests showed no significant difference regarding both accuracy and precision.展开更多
In this work a new method is presented for simultaneous colorimetric determination of morphine(MOR) and ibuprofen(IBU) based on the aggregation of citrate-capped gold nanoparticles(AuNPs). Citrate-capped AuNPs were ag...In this work a new method is presented for simultaneous colorimetric determination of morphine(MOR) and ibuprofen(IBU) based on the aggregation of citrate-capped gold nanoparticles(AuNPs). Citrate-capped AuNPs were aggregated in the presence of MOR and IBU. The difference in kinetics of AuNPs aggregation in the presence of MOR/IBU was used for simultaneous analysis of MOR and IBU. The formation and size of synthesized AuNPs and the aggregated forms were monitored by infra-red(IR) spectroscopy and transmission electron microscopy(TEM), respectively. By adding MOR or IBU the absorbance was decreased at 520 nm and increased at 620 nm. The difference in kinetic profiles of aggregation was applied for simultaneous analysis of MOR and IBU using partial least square(PLS) regression as an efficient multivariate calibration method. The number of PLS latent variables was optimized by leave-one-out cross-validation method using predicted residual error sum of square. The proposed model exhibited a high capability in simultaneous prediction of MOR and IBU concentrations in real samples. The results showed linear ranges of 1.33–33.29 μg/mL(R^2=0.9904) and 0.28–6.9 μg/mL(R^2=0.9902) for MOR and IBU respectively with low detection limits of 0.15 and 0.03 μg/mL(S/N=5).展开更多
文摘A rapid, straightforward, sensitive, efficient, and cost-effective reverse-phase high-performance liquid chromatographic method was employed for the simultaneous determination of Sorbitol, Sodium Lactate, and Chlorides in a drug solution for infusion. Sorbitol, Sodium lactate, and Chloride are all officially recognized in the USP monograph. Assay methods are provided through various techniques, with titrations being ineffective for trace-level quantification. Alternatively, IC, AAS, and ICP-MS, though highly accurate, are costly and often unavailable to most testing facilities. When considering methods, it’s important to prioritize both quality control requirements and user-friendly techniques. A simple HPLC simultaneous method was developed for the quantification of Chlorides, Sorbitol, and Sodium Lactate with a shorter run time. The separation utilized a Shimpack SCR-102(H) ion exclusion analytical column (7.9 mm × 300 mm, 7 μm), with a flow rate of 0.6 mL per min. The column compartment temperature was maintained at 40°C, and the injection volume was set at 10 μL, with detection at 200 nm. All measurements were conducted in a 0.1% solution of phosphoric acid. The analytical curves demonstrated linearity (r > 0.9999) in the concentration range of 0.79 to 3.8 mg per mL for Sodium Lactate (SL), 0.16 to 0.79 mg per mL for Sodium Chloride (SC), and 1.5 to 7.2 mg per mL for Sorbitol. Validation of the developed method followed the guidelines of the International Conference on Harmonization (ICH Q2B) and USP. The method exhibited precision, robustness, accuracy, and selectivity. In accelerated stability testing over 6 months, no significant variations were observed in organoleptic analysis and pH. Consequently, the developed method is deemed suitable for routine quality control analyses, enabling the simultaneous determination of Sodium Lactate, Sodium Chloride, and Sorbitol in pharmaceutical formulations and infusions.
基金Project FIS PI-17/00547(Instituto CarlosⅢ,Ministerio de Economía y Competitividad,Spain),which means that it was also partially supported by European Regional Development Funds(ERDF)the University of Granada(Spain)for the support。
文摘COVID-19,a disease caused by the novel coronavirus SARS-Co V-2,has produced a serious emergency for global public health,placing enormous stress on national health systems in many countries.Several studies suggest that cytokine storms(interleukins)may play an important role in severe cases of COVID-19.Neutralizing key inflammatory factors in cytokine release syndrome(CRS)could therefore be of great value in reducing the mortality rate.Tocilizumab(TCZ)in its intravenous(IV)form of administration-Ro Actemra?20 mg/m L(Roche)-is indicated for treatment of severe CRS patients.Preliminary investigations have concluded that inhibition of IL-6 with TCZ appears to be efficacious and safe,with several ongoing clinical trials.This has led to a huge increase in demand for IV TCZ for treating severe COVID-19 patients in hospitals,which has resulted in drug shortages.Here,we present a comparability study assessing the main critical physicochemical attributes of TCZ solutions used for infusion,at 6 mg/m L and 4 mg/m L,prepared from Ro Actemra?20 mg/m L(IV form)and from Ro Actemra?162 mg(0.9 m L solution pre-filled syringe,subcutaneous(SC)form),to evaluate the use of the latter for preparing clinical solutions required for IV administration,so that in a situation of shortage of the IV medicine,the SC form could be used to prepare the solutions for IV delivery of TCZ.It is important to remember that during the current pandemic all the medicines are used off-label,since none of them has yet been approved for the treatment of COVID-19.
文摘This work presents a software tool for modeling of mass transfer physicochemical processes occurring in the atmosphere. The implemented algorithms provide an efficient theoretical frame for the interpretation of the results obtained from Coated Wall Flow Tube (CWFT) reactor experiments, which is one of the most adequate techniques to study heterogeneous kinetics. The numerical simulations are based on the fundamental Langmuir adsorption theory by ordinary differential equations and the second Fick’s law described by partial differential equations. The main application of the system is to estimate the basic parameters that characterize the processes. The best parameter estimation is found by minimizing the difference between experimental signals from the CWFT reactors and the obtained numerical simulations. A numerical example for an experimental data fit is given.
文摘The endocannabinoid system(ECS),particularly its signaling pathways and ligands,has garnered considerable interest in recent years.Along with clinical work investigating the ECS’functions,including its role in the development of neurological and inflammatory conditions,much research has focused on developing analytical protocols enabling the precise monitoring of the levels and metabolism of the most potent ECS ligands:exogenous phytocannabinoids(PCs)and endogenous cannabinoids(endocannabinoids,ECs).Solid-phase microextraction(SPME)is an advanced,non-exhaustive sample-preparation technique that facilitates the precise and efficient isolation of trace amounts of analytes,thus making it appealing for the analysis of PCs and ECs in complex matrices of plant and animal/human origin.In this paper,we review recent forensic medicine and toxicological studies wherein SPME has been applied to monitor levels of PCs and ECs in complex matrices,determine their effects on organism physiology,and assess their role in the development of several diseases.
基金supported by National Natural Science Foundation of China(32072212)Multi-Year Research Grant of University of Macao(MYRG2018-00169-ICMS)+5 种基金Science and Technology Development Fund of Macao(FDCT)(0098/2020/A)MICINN supporting the Ramón y Cajal grant for M.A.Prieto(RYC-201722891)Jianbo Xiao(RYC2020-030365-I)Xunta de Galicia supporting the Axudas Conecta Peme,the IN852A 2018/58 Neuro Food Project,the program EXCELENCIA-ED431F 2020/12the pre-doctoral grants of P.García-Oliveira(ED481A-2019/295)to Ibero-American Program on Science and Technology(CYTED-AQUA-CIBUS,P317RT0003).
文摘Dietary flavonoids are abundant in natural plants and possess multiple pharmacological and nutritional activities.In this study,apigenin,luteolin,and baicalein were chosen to evaluate their anti-diabetic effect in high-glucose and dexamethasone induced insulin-resistant(IR)HepG2 cells.All flavonoids improves the glucose consumption and glycogen synthesis abilities in IR-HepG2 cells via activating glucose transporter protein 4(GLUT4)and phosphor-glycogen synthase kinase(GSK-3β).These fl avonoids signifi cantly inhibited the production of reactive oxygen species(ROS)and advanced glycation end-products(AGEs),which were closely related to the suppression of the phosphorylation form of NF-κB and P65.The expression levels of insulin receptor substrate-1(IRS-1),insulin receptor substrate-2(IRS-2)and phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)pathway in IR-HepG2 cells were all partially activated by the fl avonoids,with variable effects.Furthermore,the intracellular metabolic conditions of the fl avonoids were also evaluated.
文摘Objective:To assess the acute and subacute toxicity as well as the phytochemical composition of two extracts and three fractions of Ammi majus L.Methods:The aqueous extracts were prepared separately by maceration for 48 h and by infusion for 1 h,while the fractions were prepared by the Soxhlet extractor,successively employing cyclohexane,ethyl acetate,and ethanol.The acute toxicity study was carried out in accordance with the OECD N°423 guideline at a single dose(2000 mg/kg)in mice for 14 days.The subacute toxicity study was performed by a daily oral administration of 250 mg/kg 2 for 10 d and 100 mg/kg doses for 28 d.Phytochemical screening was performed using staining and precipitation reactions,while the chemical characterization of some analytes was detected by HPLC-MS/MS analysis.Results:In the acute toxicity study,no signs of toxicity such as convulsion,salivation,diarrhea,sleep and coma were observed during 30 minutes and 14 days,so the lethal dose was higher than 2000 mg/kg for each extract and fraction.The subacute toxicity results showed that at a dose of 250 mg/kg,61.10%of the animals died and the rest developed morbidity.On the other hand,at a dose of 100 mg/kg,all the animals were still alive after 28 days,with no morbidity and the biochemical parameters were normal with no abnormalities in the liver,kidneys and pancreas.Phytochemical screening indicated the presence of flavonoids,tannins,coumarins,and free quinones and the absence of alkaloids and anthocyanins.Conclusions:The extracts and fractions of Ammi majus L.are not toxic in the short and long term with a varied chemical composition.Toxicological tests on animals other than rodents and in the long term(more than 28 days)are needed to further confirm the safety of Ammi majus extracts.
基金Supported by the Polish State Committee for Scientific Research, No. 3 PO5B 07922
文摘AIM: Proteolytic degradation of the extracellular matrix facilitates cancer invasion and promotes metastasis. The study aims at evaluation of preoperative and postoperative serum cathepsins B and D levels in correlation with selected anatomoclinical features of colorectal cancer.METHODS: Blood samples were collected from 63colorectal cancer patients before curative operation of the tumor 10 d later. Blood that was obtained from 20healthy volunteers, served as a control. The activity of cathepsin B was measured with Bz-DL-arginine-pNA as a substrate at pH 6.0, while cathepsin D activity was determined with urea-denatured hemoglobin (pH 4.0).RESULTS: The preoperative and postoperative activities of cathepsin B were significantly (P＜0.00001) lower in serum of colorectal cancer patients than in control group.However, postoperative values of this protease were significantly increased in comparison with preoperative ones (P = 0.031). Activity of cathepsin D appeared to be significantly higher in colorectal cancer sera (P＜0.00001)compared with controls. No statistically significant differences between preoperative and postoperative activity of cathepsin D were noted (P = 0.09). We revealed a strong linkage of cathepsins' levels with lymph node status and pT stage of colorectal cancer.CONCLUSION: Blood serum activities of cathepsin B and D depend on the time of sampling, tumor size and lymph node involvement. Significantly, increased activity of cathepsin D could indicate a malignant condition of the large intestine. In our work, the serum postoperative decrease of cathepsin B activity appears as an obvious concomitant of local lymph node metastasis-the wellknown clinicopathological feature of poor prognosis.
文摘A carbon paste electrode (CPE) modified with ferrocene carboxylic acid (FcCA) and TiO2 nanoparticles was constructed by incorporating TiO2 nanoparticles and ferrocene carboxylic acid into the carbon paste matrix. The electrochemical behavior of captopril (CAP) at the surface of the modified electrode was investigated using electroanalytical methods. The modified electrode showed excellent electrocatalytic activity for the oxidation of CAP in aqueous solutions at physiological pH values. Cyclic voltammetric curves showed that the oxidation of CAP at the surface of the modified electrode reduced its overpotential by more than 290 mV. The modified electrode was used for detecting captopril using cyclic voltammetry and square wave voltammetry techniques. A calibration curve in the range of 0.03 to 2400 μmol/L was obtained that had a detection limit of 0.0096 μmol/L (3?) under the optimized conditions. The modified electrode was successfully used for the determination of captopril in pharmaceutical and biological samples.
文摘Extract of oven dried leaves of Pongamia pinnata(L) Pierre was used for the synthesis of silver nanoparticles. Stable and crystalline silver nanoparticles were formed by the treatment of aqueous solution of AgNO_3(1m M) with dried leaf extract of Pongamia pinnata(L) Pierre. UV-visible spectroscopy studies were carried out to quantify the formation of silver nanoparticles. Transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy were used to characterize the silver nanoparticles. TEM image divulges that silver nanoparticles are quite polydispersed, the size ranging from 20 nm to 50 nm with an average of 38 nm. Water soluble heterocyclic compounds such as flavones were mainly responsible for the reduction and stabilization of the nanoparticles. Silver nanoparticles were effective against Escherichia coli(ATCC 8739), Staphylococcus aureus(ATCC 6538p), Pseudomonas aeruginosa(ATCC 9027) and Klebsiella pneumoniae(clinical isolate). The move towards extracellular synthesis using dried biomass appears to be cost effective, eco-friendly to the conventional methods of nanoparticles synthesis.
基金supported by project CGL2013-43440-R,funded by the Ministerio de Economiay Competitividad of Spain
文摘Understanding the effects of elevation and related factors(climate,vegetation) on the physical and chemical soil properties can help to predict changes in response to future climate or afforestation forcings.This work aims to contribute to the knowledge of soil evolution and the classification of forest soils in relation to elevation in the montane stage,with special attention to podzolization and humus forms.The northern flank of the Moncayo Massif(Iberian Range,SW Europe) provides a unique opportunity to study a forest soils catena within a consistent quartzitic parent material over a relatively steep elevation gradient.With increasing elevation,pH,base saturation,exchangeable potassium,and fine silt-sized particles decrease significantly,while organic matter,the C/N ratio,soil aggregate stability,water repellency and coarse sand-sized particles increase significantly.The soil profiles shared a set of properties in all horizons:loamy-skeletal particle-size,extreme acidity(pH-H_2O<5.6) and low base saturation(<50%).The most prevalent soil forming processes in the catena include topsoil organic matter accumulation and even podzolization,which increases with elevation.From the upper to lower landscape positions of wooded montane stage of the Moncayo Massif,mull-moder-mor humus and an UmbrisolCambisol-Podzol soil unit sequences were found.
文摘S-Nitrosothiols or thionitrites with the general formula RSNO are formally composed of the nitrosyl cation(NOt) and a thiolate(RSà), the base of the corresponding acids RSH. The smallest S-nitrosothiol is HSNO and derives from hydrogen sulfide(HSH, H_2S). The most common physiological S-nitrosothiols are derived from the amino acid L-cysteine(Cys SH). Thus, the simplest S-nitrosothiol is S-nitroso-L-cysteine(Cys SNO). Cys SNO is a spontaneous potent donor of nitric oxide(NO) which activates soluble guanylyl cyclase to form cyclic guanosine monophosphate(c GMP). This activation is associated with multiple biological actions that include relaxation of smooth muscle cells and inhibition of platelet aggregation.Like NO, Cys SNO is a short-lived species and occurs physiologically at concentrations around 1 n M in human blood. Cys SNO can be formed from Cys SH and higher oxides of NO including nitrous acid(HONO)and its anhydride(N_2O_3). The most characteristic feature of RSNO is the S-transnitrosation reaction by which the NOtgroup is reversibly transferred to another thiolate. By this way numerous RSNO can be formed such as the low-molecular-mass S-nitroso-N-acetyl-L-cysteine(SNAC) and S-nitroso-glutathione(GSNO), and the high-molecular-mass S-nitrosol-L-cysteine hemoglobin(Hb Cys SNO) present in erythrocytes and S-nitrosol-L-cysteine albumin(Alb Cys SNO) present in plasma at concentrations of the order of 200 n M. All above mentioned RSNO exert NO-related biological activity, but they must be administered intravenously. This important drawback can be overcome by lipophilic charge-free RSNO.Thus, we prepared the ethyl ester of SNAC, the S-nitroso-N-acetyl-L-cysteine ethyl ester(SNACET), from synthetic N-acetyl-L-cysteine ethyl ester(NACET). Both NACET and SNACET have improved pharmacological features over N-acetyl-L-cysteine(NAC) and S-nitroso-N-acetyl-L-cysteine(SNAC), respectively,including higher oral bioavailability. SNACET exerts NO-related activities which can be utilized in the urogenital tract and in the cardiovascular system. NACET, with high oral bioavailability, is a strong antioxidant and abundant precursor of GSH, unlike its free acid N-acetyl-L-cysteine(NAC). Here, we review the chemical and pharmacological properties of SNACET and NACET as well as their analytical chemistry.We also report new results from the ingestion of S-[^(15) N]nitroso-N-acetyl-L-cysteine ethyl ester(S^(15) NACET) demonstrating the favorable pharmacological profile of SNACET.
文摘Here, Pd Ru nanoparticle networks(NPNs) with various compositions were synthesized through an inexpensive method in water as a green solvent, at different ratios of the H_2PdCl_4 and RuCl_3 precursors. This is a fast, room temperature and surfactant free strategy which is able to form high surface area metal nanosponges with a three-dimensional(3D) porous structure. The structure of as-prepared nanosponges was characterized using the techniques of field emission scanning electron microscopy(FESEM), energy dispersive spectroscopy(EDS) and cyclic voltammetry(CV). Then, the electrocatalytic activities of Pd Ru NPNs towards formic acid oxidation were examined by electrochemical measurements including CV,chronoamperometry, and electrochemical impedance spectroscopy(EIS). Based on studies, it was found that the current density of formic acid oxidation(FAO) is strongly dependent on the composition of Pd Ru NPNs. The best performance was realized for Pd_4Ru_1 NPNs compared to monometallic Pd counterpart and other bimetallic NPNs which might be ascribed to the role of Ru in the decrease of CO adsorption strength on the catalyst and consequently the priority of formic acid oxidation through the direct pathway. The Pd_4Ru_1 NPNs also showed the maximum current density and stability in chronoamperometric measurements. In addition, comparative studies were performed between as-prepared NPNs and CNTs-supported Pd nanoparticles(Pd NPs/CNTs). The present results demonstrated the unique structural advantages of NPNs compared to individual Pd NPs supported on the CNT which leads to the promising performance of NPNs as supportless catalysts for the oxidation of formic acid.
基金Department of Science and Technology(DST)Government of India,for sanctioning financial assistance for executing this programme under Nanomaterials Science and Technology Initiative Programmethe Council of Scientific and Industrial Research(CSIR),Government of India,for granting her fellowship for executing this programme
文摘An amperometric hydrogen peroxide biosensor using a nanobiocomposite based on neutral red modified carbon nanotubes and co-immobilized glucose oxidase and horseradish peroxidase is reported. Modification of the nanobiocomposite electrode with neutral red resulted in a sensitive, low-cost and reliable H_2O_2 sensor. The use of carbon nanotubes, as the conductive part of the composite, facilitated fast electron transfer rates. The biosensor was characterized for the influence of p H, potential and temperature. A remarkable feature of the biosensor is the detection of H_2O_2 at low applied potentials where the noise level and interferences are minimal. The sensor has a fast steady-state measuring time of 10 s with a quick response(2 s). The biosensor showed a linear range from 15 n M to 45 m M of H_2O_2 and a detection limit of 5 n M. Nafion, which is used as a binder, makes the determination free from other electroactive substances. The repeatability, reproducibility,stability and analytical performance of the sensor are very good.
文摘Heavy metal contamination of soils is a widespread problem in Zanjan province located in North West Iran due to natural pedo geochemical background and anthropogenic sources. The province is highly polluted by some heavy metals due to the presence of mineral resources notably Lead and Zinc, their improper utilization, and also the development of a number of related industries. Bonab district was selected for detail study and the objectives of the study were set to evaluate the total as well as bioavailable fraction of heavy metals in surficial soils within the studied area. 72 soil samples were collected and analyzed for heavy metal contamination by Atomic Absorption Spectrometry (AAS). The obtained results when compared with WHO and USEPA standards show a very high concentration of some toxic metals. Soils were basically polluted by Pb, Zn, Cu, and Cd. Bioavailable fraction of studied metals were also measured with formation of metal complex with Diethylene tri amine penta acetic acid (DTPA) agent. To find the share of the anthropogenic sources in the contamination of soils, the Enrichment factor (EF) and Geological Accumulation Index were measured and the distribution maps were drawn using Arc GIS (9.3). Highest concentrations of some toxic metals were found as isolated patches around the Bonab Industrial Town as well as within and around the most populated areas of the district notably Zanjan city indicating its anthropogenic origin.
基金financially supported by project PGIDIT04RAG012E(Consellería de InnovaciónIndustria e Comercio da Xunta de Galicia and Asociación de Criadores de Capón de VilalbaSpain)
文摘Chemical composition,physico-chemical properties and fatty acid composition of breast and drumstick meat from capons(castrated male cockerels) fed cereals were studied.Three groups of capons were reared.One group was fed ad libitum the same commercial diet until the 4th mon of life.The last month of its life,the capons of this group were fed corn.The second and third group of capons were fed the same diet from caponization.The second group was fed mixture of corn(50%) and wheat(50%).The third group of capons was fed 2/3 corn and 1/3 mixture of corn(50%) and barley(50%).Capons were reared under free-range conditions and slaughtered at 150 d of age.Caponization was performed at 48 d.No significant effects of feeding in chemical composition,pH,water holding capacity,drip and cooking losses and texture of the meat were observed.The meat of the third group(capons fed 83%corn) was more yellow and showed higher content of C18:2 than that of the other capons.
文摘The objective of this paper was to evaluate the sugar and water content in sugar cane samples by means of twonon-destructive techniques in comparison with conventional methods. One non-destructive technique is the Biospeckle, aninteraction between the laser and the biological material which provides information about the material. The other technique is thenear infrared spectroscopy （NIR）. The Biospeckle technique has been constantly used in agricultural engineering. In this paper, therelation between the water and the sugar contents were obtained. The results for the Biospeckle were acquired through the moment ofinertia （MI）. The data acquired through already consolidated methodologies were used to quantify the samples＇ water and sugarcontents, correlating to the spectroscopy results and also to the Biospeckle. It was obtained a high determination coefficient （R^2 =0.9287） between the predicted Brix by the model generated by NIR spectroscopy and Brix measured by refractometer. It was alsopossible to differentiate the water contents of the sugar cane samples both externally lit （husk） and internally lit （cut） by Biospeckleanalysis through the calculation of MI. It is possible to evaluate the water content and the sugar content in samples combiningBiospeckle and NIR spectroscopy, which are non-invasive and non-destructive methods.
基金funded by Project FIS:PI10/00201 (Instituto Carlos III, Ministerio de Economía y Competitividad, Spain)partially supported by European Regional Development Funds (ERDF)
文摘Cetuximab(CTX) is a potent chimeric mouse/human monoclonal antibody(mAb) approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses performed for full study on this biopharmaceutic, the determination of the concentration preparations throughout manufacturing and subsequent handling in hospital is particularly relevant. In the present work, the study and validation of a method for quantifying intact CTX by reverse-phase high-performance liquid chromatography with diode array detection((RP)HPLC/DAD) is presented. With that end,we checked the performance of a chromatographic method for quantifying CTX and conducted a study to validate the method as stability-indicating in accordance with the International Conference on Harmonization guidelines(ICH) for biotechnological drugs; therefore, we evaluated linearity, accuracy, precision, detection and quanti fication limits, robustness and system suitability. The speci ficity of the method and the robustness of the mAb formulation against external stress factors were estimated by comprehensive chromatographic analysis by subjecting CTX to several informative stress conditions. As demonstrated, the method is rapid, accurate, and reproducible for CTX quantification. It was also successfully used to quantify CTX in a long-term stability study performed under hospital conditions.
文摘Two simple, accurate, precise and economic spectrophotometric methods have been developed for simultaneous determination of Atorvastatin calcium (ATR) and Ezetimibe (EZ) in their bulk powder and pharmaceutical dosage form. Method (I) is based on dual wavelength analysis while method (II) is the mean centering of ratio spectra spectrophotometric (MCR) method. In method (I), two wavelengths were selected for each drug in such a way that the difference in absorbance was zero for the second drug. At wavelengths 226.6 and 244 nm EZ had equal absorbance values; therefore, these two wavelengths have been used to determine ATR; on a similar basis 228.6 and 262.8 nm were selected to determine EZ in their binary mixtures. In method II, the absorption spectra of both ATR and EZ with different concentrations were recorded over the range 200-350, divided by the spectrum of suitable divisor of both ATR and EZ and then the obtained ratio spectra were mean centered. The concentrations of active components were then determined from the calibration graphs obtained by measuring the amplitudes at 215-260 nm (peak to peak) for both ATR and EZ. Accuracy and precision of the developed methods have been tested; in addition recovery studies have been carried out in order to confirm their accuracy. On the other hand, selectivities of the methods were tested by application for determination of different synthetic mixtures containing different ratios of the studied drugs. The developed methods have been successfully used for determination of ATR and EZ in their combined dosage form and statistical comparison of the developed methods with the reported spectrophotometric one using F and Student's t-tests showed no significant difference regarding both accuracy and precision.
文摘In this work a new method is presented for simultaneous colorimetric determination of morphine(MOR) and ibuprofen(IBU) based on the aggregation of citrate-capped gold nanoparticles(AuNPs). Citrate-capped AuNPs were aggregated in the presence of MOR and IBU. The difference in kinetics of AuNPs aggregation in the presence of MOR/IBU was used for simultaneous analysis of MOR and IBU. The formation and size of synthesized AuNPs and the aggregated forms were monitored by infra-red(IR) spectroscopy and transmission electron microscopy(TEM), respectively. By adding MOR or IBU the absorbance was decreased at 520 nm and increased at 620 nm. The difference in kinetic profiles of aggregation was applied for simultaneous analysis of MOR and IBU using partial least square(PLS) regression as an efficient multivariate calibration method. The number of PLS latent variables was optimized by leave-one-out cross-validation method using predicted residual error sum of square. The proposed model exhibited a high capability in simultaneous prediction of MOR and IBU concentrations in real samples. The results showed linear ranges of 1.33–33.29 μg/mL(R^2=0.9904) and 0.28–6.9 μg/mL(R^2=0.9902) for MOR and IBU respectively with low detection limits of 0.15 and 0.03 μg/mL(S/N=5).
