Analytical Qbd Approach For Development And Validation Of Rp-High Performance Liquid Chromatography Method For Determination Of Tofisopam In Pure Form And Tablets

A novel, simple, optimized reversed-phase chromatography method for assay of Tofisopam in pure and tablet form is developed. The experimental trial was by Box Behnken design using the Design Expert® software 10 version. The attributes selected were peak symmetry, number of theoretical, and peak purity. The predicted data satisfied with actual experimental data. The optimized chromatographic conditions required a quaternary pump with a mobile phase of Water: Acetonitrile 25:75 v/v at 1 mL/min, oven temperature at 25oC at 310 nm using C18(250 × 4.6 mm Id, 5μm) column and PDA detector with a run time of 5 min. The method was validated for linearity, precision, accuracy, and specificity. The method produced a linear response over a concentration range of 4–24 ppm with an overall average accuracy of 99.98%. The method was robust, reproducible, and specific with respect to the retention time of tofisopam.

Improvement of detection method for acetonitrile in workplace air / 中国职业医学

OBJECTIVE: To improve the standard detection method for acetonitrile in workplace air. METHODS: Acetonitrile in the air of workplace was collected by silica gel, eluted with methanol, separated and determined by gas chromatography with flame ionization detection. RESULTS: After the improvement of the method, the linear range of acetonitrile was 1.57-1 574.00 mg/L, and the correlation coefficient was 0.999 98. The detection limit was 0.29 mg/L and the minimum detection concentration was 0.19 mg/m~(3 )(collected sample volume was 1.5 L). The average desorption efficiency was 93.1%-98.9%. The within-run and between-run precision was 2.6%-3.3% and 1.7%-3.6%, respectively. The samples could be stored at room temperature for at least 10 days. CONCLUSION: The improved method is precisied, accurate and simple to operate, which is suitable for determination of acetonitrile in workplace air.

Bioengineered miR-328-3p modulates GLUT1-mediated glucose uptake and metabolism to exert synergistic antiproliferative effects with chemotherapeutics

MicroRNAs (miRNAs or miRs) are small noncoding RNAs derived from genome to control target gene expression. Recently we have developed a novel platform permitting high-yield production of bioengineered miRNA agents (BERA). This study is to produce and utilize novel fully-humanized BERA/miR-328-3p molecule (hBERA/miR-328) to delineate the role of miR-328-3p in controlling nutrient uptake essential for cell metabolism. We first demonstrated successful high-level expression of hBERA/miR-328 in bacteria and purification to high degree of homogeneity (>98%). Biologic miR-328-3p prodrug was selectively processed to miR-328-3p to suppress the growth of highly-proliferative human osteosarcoma (OS) cells. Besides glucose transporter protein type 1, gene symbol solute carrier family 2 member 1 (GLUT1/), we identified and verified large neutral amino acid transporter 1, gene symbol solute carrier family 7 member 5 (LAT1/) as a direct target for miR-328-3p. While reduction of LAT1 protein levels by miR-328-3p did not alter homeostasis of amino acids within OS cells, suppression of GLUT1 led to a significantly lower glucose uptake and decline in intracellular levels of glucose and glycolytic metabolite lactate. Moreover, combination treatment with hBERA/miR-328 and cisplatin or doxorubicin exerted a strong synergism in the inhibition of OS cell proliferation. These findings support the utility of novel bioengineered RNA molecules and establish an important role of miR-328-3p in the control of nutrient transport and homeostasis behind cancer metabolism.

Nitrogenous Chemical Constituents from Brassica campestris Seeds / 中国实验方剂学杂志

Objective:To study nitrogenous chemical constituents from the seeds of Brassica campestris. Method:The aerial parts of nonfat seeds were extracted with 75% ethanol heat refluxing method,then suspended in H2O and separated with ligarine and ethyl acetate to obtain respective fractions.Chemical constituents were isolated and purified by various chromatographic methods and identified by physicochemical characters and spectroscopic analysis or comparison with standard compounds. Result:Thirteen nitrogenous chemical compounds were isolated and identified as coixspirolactam C (1),indole-3-acetonitrile (2),2-β-D-glucopyranosylsulfanyl-1H-indole-3-acetonitrile (3),nicotinic acid (4),adenosine (5), 1H-indole-3-carbaldehyde (6),4-hydroxy-1H-indole-3-carbaldehyde (7),6-hydroxy-1H-indole-3-carboxylic acid (8),ethyl 2-oxo-1,2,3,4-tetrahydroquinoline-4-carboxylate (9),5-hydroxy-4(1H)-quinazolinone (10),4-hydroxy-2-quinazolinone (11),5-hydroxy-quinazoline-2(1H),4(3H)-dione (12),5-allyloxazolidin-2-one (13). Conclusion:All of the compounds were isolated from this plant for the first time, and compounds 1,3 and 13 were isolated from Brassica for the first time.

Application of flash nanoprecipitation to fabricate poorly water-soluble drug nanoparticles

Nanoparticles are considered to be a powerful approach for the delivery of poorly water-soluble drugs. One of the main challenges is developing an appropriate method for preparation of drug nanoparticles. As a simple, rapid and scalable method, the flash nanoprecipitation (FNP) has been widely used to fabricate these drug nanoparticles, including pure drug nanocrystals, polymeric micelles, polymeric nanoparticles, solid lipid nanoparticles, and polyelectrolyte complexes. This review introduces the application of FNP to produce poorly water-soluble drug nanoparticles by controllable mixing devices, such as confined impinging jets mixer (CIJM), multi-inlet vortex mixer (MIVM) and many other microfluidic mixer systems. The formation mechanisms and processes of drug nanoparticles by FNP are described in detail. Then, the controlling of supersaturation level and mixing rate during the FNP process to tailor the ultrafine drug nanoparticles as well as the influence of drugs, solvent, anti-solvent, stabilizers and temperature on the fabrication are discussed. The ultrafine and uniform nanoparticles of poorly water-soluble drug nanoparticles prepared by CIJM, MIVM and microfluidic mixer systems are reviewed briefly. We believe that the application of microfluidic mixing devices in laboratory with continuous process control and good reproducibility will be benefit for industrial formulation scale-up.

Hypocrellin A-based photodynamic action induces apoptosis in A549 cells through ROS-mediated mitochondrial signaling pathway

Over recent decades, many studies have reported that hypocrellin A (HA) can eliminate cancer cells with proper irradiation in several cancer cell lines. However, the precise molecular mechanism underlying its anticancer effect has not been fully defined. HA-mediated cytotoxicity and apoptosis in human lung adenocarcinoma A549 cells were evaluated after photodynamic therapy (PDT). A temporal quantitative proteomics approach by isobaric tag for relative and absolute quantitation (iTRAQ) 2D liquid chromatography with tandem mass spectrometric (LC-MS/MS) was introduced to help clarify molecular cytotoxic mechanisms and identify candidate targets of HA-induced apoptotic cell death. Specific caspase inhibitors were used to further elucidate the molecular pathway underlying apoptosis in PDT-treated A549 cells. Finally, down-stream apoptosis-related protein was evaluated. Apoptosis induced by HA was associated with cell shrinkage, externalization of cell membrane phosphatidylserine, DNA fragmentation, and mitochondrial disruption, which were preceded by increased intracellular reactive oxygen species (ROS) generations. Further studies showed that PDT treatment with 0.08 µmol/L HA resulted in mitochondrial disruption, pronounced release of cytochrome , and activation of caspase-3, -9, and -7. Together, HA may be a possible therapeutic agent directed toward mitochondria and a promising photodynamic anticancer candidate for further evaluation.

Simultaneous Determination of Seven Residual Solvents in Nilethylenol Raw Material by GC / 中国药房

OBJECTIVE： To establish a method for simultaneous determination of residual methanol， ethanol， acetonitrile， isopropanol， methylbenzene， tetrahydrofuran and ethyl acetate in Nilethylenol raw material. METHODS： GC was performed. The determination was performed on DB-WAX capillary column. The detector was hydrogen flame ionization detector with split ratio of 5 ∶ 1. The carrier gas was nitrogen （purity： 99.999％） at the flow rate of 1.0 mL/min. The sample size was 1 μL， directly sampling with bonded crosslinked polyethylene glycol as stationary phase. The initial temperature was 40 ℃ and was maintained for 5 min， increased to 90 ℃ at 10 ℃/min， and then increased to 200 ℃ at 5 ℃/min. The temperature of injector was 220 ℃， and detector temperature was 230 ℃. RESULTS： The linear range was 0.24-12.00 μg/mL for methanol （r＝0.999 7）， 0.40-20.00 μg/mL for ethanol （r＝0.999 5）， 0.033-1.64 μg/mL for acetonitrile （r＝0.999 8）， 0.40-20.00 μg/mL for isopropanol （r＝0.999 5）， 0.071-3.56 μg/mL for methylbenzene （r＝0.999 6）， 0.058-2.88 μg/mL for tetrahydrofuran （r＝0.999 8）， 0.40-20.00 μg/mL for ethyl acetate （r＝0.999 7）， respectively. The limits of quantitation were 0.24， 0.40， 0.033， 0.40， 0.071， 0.058， 0.40 μg/mL， respectively. The limits of detection were 0.08， 0.10， 0.01， 0.13， 0.02， 0.02， 0.13 μg/mL， respectively. RSDs of precision， stability and reproducibility tests were all lower than 2％. The recoveries were 98.17％-100.48％ （RSD＝0.92％，n＝9）， 97.77％-101.30％（RSD＝1.32％，n＝9）， 97.56％-100.85％（RSD＝1.20％，n＝9）， 98.64％-100.92％（RSD＝0.87％，n＝9）， 98.54％-100.62％（RSD＝0.76％，n＝9），98.26％-100.00％（RSD＝0.74％，n＝9）， 98.30％-100.59％（RSD＝0.76％，n＝9）， respectively. CONCLUSIONS： The method has high sensitivity and good accuracy， and can be used for the simultaneous determination of residual methanol， ethanol， acetonitrile， isopropane， methylbenzene， tetrahydrofuran and ethyl acetate in Nilethylenol raw material.

Nematode resistance to five anthelmintic classes in naturally infected sheep herds in Northeastern Brazil / Resistência de nematódeos a cinco classes de anti-helmínticos em rebanhos de ovinos naturalmente infectados no Nordeste do Brasil

Abstract This study aimed to evaluate the occurrence of nematode resistance to anthelmintics on sheep herds from the semi-arid region of Paraíba, Northeastern Brazil. Fecal Egg Count Reduction Test (FECRT) was carried out on 20 properties. In each herd, 30 animals were divided into five groups containing six animals each: group I, treated with albendazole 10%, 4 mg/kg; group II, ivermectin 0.08%, 0.2 mg/kg; group III, closantel 10%, 10 mg/kg; group IV, levamisole hydrochloride 5%, 5 mg/kg; and group V, monepantel 2.5%, 2.5 mg/kg. All treatments were administered orally as a single dose. Fecal samples were collected on days zero and 10 after treatment, to perform FECRT and coprocultures. Multiresistance was observed in all the properties; 95% had high resistance to albendazole, 85% to ivermectin, 80% to closantel, 40% to levamisole, and 45% to monepantel. On property 15, where monepantel was ineffective, a second FECRT for this anthelmintic was carried out 4 months after the first, resulting in 75% efficacy. Immediately after the FECRT result, two ewes were euthanized and necropsied, and Haemonchus contortus, Trichostrongylus axei, Trichostrongylus colubriformis, Oesophagostomum columbianum, and Trichuris ovis were recovered. It was concluded that the resistance of sheep gastrointestinal nematodes to antthelmintic, including monepantel, is high.

Resumo O objetivo deste estudo foi avaliar a ocorrência de resistência de nematódeos a anti-helmínticos em rebanhos ovinos do semiárido da Paraíba, Nordeste do Brasil. Testes de Redução na Contagem de Ovos Fecais (TRCOF) foram conduzidos em 20 propriedades. Em cada rebanho, 30 animais foram selecionados e foram divididos em cinco grupos contendo seis animais cada: grupo I, tratado com albendazol 10%, 10 mg/kg; grupo II, ivermectina 0,08%, 0,2 mg/kg; grupo III, closantel 10%, 10 mg/kg; grupo IV, cloridrato de levamisol 5%, 5 mg/kg; grupo V, monepantel 2,5%, 2,5 mg/kg. Todos os tratamentos foram administrados via oral, em dose única. Amostras fecais foram coletadas nos dias zero e 10 após os tratamentos, para a realização do TRCOF e coproculturas. Multirresistência foi observada em todas as propriedades; 95% dos rebanhos obtiveram alta resistência ao albendazole, 85% a ivermectina, 80% ao closantel, 40% ao levamisole, e 45% a monepantel. Na propriedade 15, onde o monepantel foi ineficaz, um segundo TRCOF foi conduzido para este fármaco 4 meses após o primeiro, resultando em 75% de eficácia. Imediatamente após o resultado do TRCOF, duas ovelhas foram eutanaziadas e necropsiadas, e Haemonchus contortus, Trichostrongylus axei, Trichostrongylus colubriformis, Oesophagostomum columbianum, e Trichuris ovis foram recuperados. Concluiu-se que a resistência dos nematódeos gastrintestinais de ovinos aos anti-helmínticos, incluindo o monepantel, é alta.

A simple method for the(7-methoxy-1-naphthyl)acetonitrile synthesis / 国际药学研究杂志

Objective To research and optimize the synthesis process of(7-methoxy-1-naphthyl)acetonitrile for industrial production.Methods(7-Methoxy-1-naphthyl)acetonitrile was synthesized from industrial grade 1-amino-7-naphthol,by diazotiza?tion,Sandmeyer reaction and coupled reaction.Factors such as the reaction temperature,the reaction time and the ratio of the raw ma?terial were optimized to make the reaction conditions mild.The total yield was 53.9%.Results and Conclusion The structures of in?termediate and target compounds were confirmed by MS and 1H NMR.The new method is suitable for industrial production.

Simultaneous Determination of 6 Residual Organic Solvents in Xingnaojing Injection by Headspace GC / 中国药房

OBJECTIVE:To establish the method for simultaneous determination of 6 residual organic solvents in Xingnaojing injection,such as methanol,ethanol,isopropanol,n-butanol,ethyl acetate and acetonitrile.METHODS:Headspace GC method was adopted.The determination was performed on DB-624 capillary column by temperature programming with the injector temperature of 200 ℃;flame ionization detector was adopted with the temperature of 250 ℃;carrier gas was nitrogen with flow rate of 25 mL/min and split ratio of 35 ∶ 1;headspace sampling size was 1 mL,and heating temperature of headspace sampling was 80 ℃;equilibrium time was 15 min.RESULTS:The linear ranges of methanol,ethanol,isopropanol,n-butanol,ethyl acetate and acetonitrile were 15.00-240.00 μg/mL (r =0.999 9),25.00-400.00 μg/mL (r =0.999 9),25.00-400.00 μg/mL (r =0.999 9),25.00-399.99 μg/mL(r=0.999 9),25.00-399.99 μg/mL(r=0.999 8) and 5.00-80.00 μg/mL(r=0.999 9).The LOQ were 5.98,3.94,2.05,2.13,1.39,1.24 μg/mL,and the LOD were 2.01,2.11,1.18,1.56,1.15,0.01 μg/mL,respectively.RSDs of precision tests were all less than 2.0％,stability and repetitive tests only ethyl acetate was detected,RSD＜2.0％;the recoveries were 93.59％-99.02％ (RSD=2.62％,n=6),92.42％-98.40％ (RSD=2.43％,n=6),94.81％-104.64％ (RSD=3.47 ％,n=6),94.56％-106.73％ (RSD=4.21％,n=6),97.04％-106.33％(RSD=3.50％,n=6)and 98.40％-107.97％ (RSD=3.37％,n=6).CONCLUSIONS:The method is specific,rapid,simple and accurate,and can be used for simultaneous determination of 6 residual organic solvents in Xingnaojing injection.

Simultaneous Determination of 6 Residual Organic Solvents in Xingnaojing Injection by Headspace GC / 中国药房

OBJECTIVE:To establish the method for simultaneous determination of 6 residual organic solvents in Xingnaojing injection,such as methanol,ethanol,isopropanol,n-butanol,ethyl acetate and acetonitrile.METHODS:Headspace GC method was adopted.The determination was performed on DB-624 capillary column by temperature programming with the injector temperature of 200 ℃;flame ionization detector was adopted with the temperature of 250 ℃;carrier gas was nitrogen with flow rate of 25 mL/min and split ratio of 35 ∶ 1;headspace sampling size was 1 mL,and heating temperature of headspace sampling was 80 ℃;equilibrium time was 15 min.RESULTS:The linear ranges of methanol,ethanol,isopropanol,n-butanol,ethyl acetate and acetonitrile were 15.00-240.00 μg/mL (r =0.999 9),25.00-400.00 μg/mL (r =0.999 9),25.00-400.00 μg/mL (r =0.999 9),25.00-399.99 μg/mL(r=0.999 9),25.00-399.99 μg/mL(r=0.999 8) and 5.00-80.00 μg/mL(r=0.999 9).The LOQ were 5.98,3.94,2.05,2.13,1.39,1.24 μg/mL,and the LOD were 2.01,2.11,1.18,1.56,1.15,0.01 μg/mL,respectively.RSDs of precision tests were all less than 2.0％,stability and repetitive tests only ethyl acetate was detected,RSD＜2.0％;the recoveries were 93.59％-99.02％ (RSD=2.62％,n=6),92.42％-98.40％ (RSD=2.43％,n=6),94.81％-104.64％ (RSD=3.47 ％,n=6),94.56％-106.73％ (RSD=4.21％,n=6),97.04％-106.33％(RSD=3.50％,n=6)and 98.40％-107.97％ (RSD=3.37％,n=6).CONCLUSIONS:The method is specific,rapid,simple and accurate,and can be used for simultaneous determination of 6 residual organic solvents in Xingnaojing injection.

Simultaneous Determination of 6 Residual Organic Solvents in Omeprazole Magnesium by Headspace GC / 中国药房

OBJECTIVE:To establish a method for the simultaneous determination of 6 kinds of residual organic solvents in Omeprazole magnesium,such as methanol,isopropanol,acetonitrile,dichloromethane,ethyl acetate and toluenein. METHODS:Headspace GC was adopted. The determination was performed on the column of DB-624 column by temperature programming. The inlet temperature was 200 ℃,and hydrogen flame ionization detector was adopted with the temperature of 250 ℃;nitrogen gas was used as carrier gas with flow rate of 2.0 mL/min;the splitting-radio was 5 : 1,and sample size was 1 mL;the headspace tem-perature was 80 ℃ and the equilibrium time was 20 min. RESULTS:The linear range were 12.56-628.00 μg/mL for methanol(r=0.9997),20.22-1011.20 μg/mL for isopropanol(r=0.9999),1.96-97.76 μg/mL for acetonitrile(r=0.9997),3.10-154.88 μg/mL for dichloromethane(r=0.9998),20.69-1034.56 μg/mL for ethyl acetate(r=0.9998),and 3.53-176.72 μg/mL for toluene(r=0.9998);the limits of quantitation were 1.00,0.91,0.47,0.93,0.41 and 0.35 μg/mL respectively;the limits of detection were 0.31,0.30,0.14,0.31,0.12 and 0.11 μg/mL respectively;RSDs of precision,stability and reproducibility tests were lower than 3%;the recoveries were 94.53%-101.29%(RSD=2.15%,n=9),97.78%-103.42%(RSD=1.77%,n=9),96.99%-105.76%(RSD=2.59%,n=9),96.83%-102.05%(RSD=1.86%,n=9),97.98%-101.13%(RSD=0.88%,n=9)and 97.80%-102.40%(RSD=1.41%,n=9). CONCLUSIONS:The method is sensitive and accurate,can be used for the simultaneous determination of 6 kinds of residual organic solvents in Omeprazole magnesium,such as methanol,isopropanol,acetonitrile,dichloromethane,eth-yl acetate and toluenein.

Amino-functionalized poloxamer 407 with both mucoadhesive and thermosensitive properties: preparation, characterization and application in a vaginal drug delivery system

Lack of mucoadhesive properties is the major drawback to poloxamer 407 (F127)-basedhydrogels for mucosal administration. The objective of the present study was to construct a novel mucoadhesive and thermosensitivehydrogel drug delivery system based on an amino-functionalized poloxamer for vaginal administration. First, amino-functionalized poloxamer 407 (F127-NH) was synthesized and characterized with respect to its micellization behavior and interaction with mucin. Then using acetate gossypol (AG) as model drug, AG-loaded F127-NH-basedhydrogels (NFGs) were evaluated with respect to rheology, drug release,vaginal mucosal adhesion,intravaginal retention and local irritation after vaginal administration to healthy female mice. The results show that F127-NHis capable of forming a thermosensitivehydrogel with sustained drug release properties. An interaction between positively charged F127-NHand negatively charged mucin was revealed by changes in the particle size and zeta potential of mucin particles as well as an increase in the complex modulus of NFG caused by mucin.andfluorescence imaging and quantitative analysis of the amount of AG remaining in mouse vaginal lavage all demonstrated greater intravaginal retention of NFG than that of an unmodified F127-basedhydrogel. In conclusion, amino group functionalization confers valuable mucoadhesive properties on poloxamer 407.

An approach for validated RP-HPLC method for the analysis of paclitaxel in rat plasma.

This report describes analysis of paclitaxel, which is an antineoplastic drug used in the treatment of kaposi's sarcoma and cancer of the lung by isocratic high performace liquid chromatography with UV detection in pure form and rat plasma. The analysis was carried out using phenomenex C18 (250 x 4.6 mm, 5 μm particle size) column with a mobile phase consisting of acetonitrile and phosphate buffer (pH 5) in the ratio of 80:20%, v/v. Paclitaxel was eluted at the retention time of 5.3 min when operated at the flow rate of 1 ml/min and monitored by UV at 227 nm. Paclitaxel was extracted from rat plasma by simple LLE method using non- toxic ethyl acetate as extraction solvent. The linearity was accessed in the concentration range of 100-600 μg/mL with correlation coefficient of 0.9999 and percentage recovery of 99.86. The liquid chromatography method was extensively validated for linearity, accuracy, precision, LOD, LOQ and robustness. All these analytical validation parameters were observed to be satisfactory, which indicates the usefulness of method for determination of paclitaxel in pure form and rat plasma. No interfering peaks were observed during the analysis.

Simultaneous estimation of rosuvastatin and amlodipine in pharmaceutical formulations using stability indicating HPLC method

A viable cost-effective and isocratic approach employing C-18 column (250 mm × 4.6 mm, 5 µm) based HPLC has been utilized to separate and estimate the drugs, rosuvastatin, amlodipine and their stress induced degradation products, simultaneously in pharmaceutical formulations. Focused on ICH guideline parameters, the efficient separation of both drugs and their degradation products was achieved by optimizing a 30:70 (v/v) solvent mixture of acetonitrile and 0.1 M ammonium acetate buffer (pH 5) as mobile phase. The flow rate of the mobile phase was 1.5 mL/min and all the detections were carried out at 240 nm using UV detector. The method was linear in the concentration range of 1-200 µg/mL for rosuvastatin with 0.996 coefficient of determination value. For amlodipine, linearity was in the range of 0.5-100 µg/ml with 0.994 coefficient of determination value. Both the drugs along with their degradation products were separated in less than twenty minutes. The results of within-day and between-day precision were varied from 0.72 to 1.81% for rosuvastatin and 0.83 to 1.88% for amlodipine. The results show that this ICH validated method can be employed successfully for the routine as well as stability quantification of both the active ingredients simultaneously in pharmaceutical formulations.

Utilizou-se abordagem de viabilidade custo-efetividade e isocrática, baseada em CLAE, empregando coluna C-18 (250 mm x 4,6 mm, 5 µm) para separar e avaliar os fármacos, rosuvastatina, anlodipino e seus produtos de degradação induzida por estresse, simultaneamente, em formulações farmacêuticas. Focada nos parâmetros das diretrizes da ICH, a separação eficiente de ambos os fármacos e de seus produtos de degradação foi obtida por meio da otimização da fase móvel com mistura de solventes 30:70 (v/v), respectivamente, acetonitrila e tampão acetato de amônio O,1 M (pH 5). A velocidade de fluxo da fase móvel foi de 1,5 mL/min e todas as detecções foram realizadas em 240 nm, utilizando detector de UV. O método foi linear no intervalo de concentração de 1-200 µg/mL para a rosuvastatina com coeficiente de determinação 0,996. Para o anlodipino, a linearidade ficou na faixa de 0.5-100 µg/mL, com coeficiente de determinação 0,994. Ambos os fármacos, junto com seus produtos de degradação, foram separados em menos de vinte minutos. Os resultados de precisão intra-dia e inter-dia variaram de 0,72 a 1,81% para a rosuvastatina e de 0,83 a 1,88%, para o anlodipino. Os resultados mostram que este método validado pelo ICH pode ser empregado com sucesso tanto para a rotina quanto para a quantificação simultânea da estabilidade de ambos os ingredientes ativos em formulações farmacêuticas.

Validated stability indicating gradient RP-HPLC method for the estimation of antihypertensive drugs in bulk and pharmaceutical dosage forms.

A rapid and precise RP-HPLC method for determination of Olmesartan medoxomil and Hydrochlorothiazide in bulk and pharmaceutical dosage forms. Olmesartan medoxomil & Hydrochlorothiazide are found to be degraded together under different set of conditions as followed according to ICH guidelines and the degradants so formed along with olmesartan & hydrochlorothiazide are separated by using INERTSIL ODS C18 3V (150 x 4.6, 5μ) using mobile phase 1ml triethanolamine in one litre water and the pH was adjusted to 2.5 with orthophosphoric acid and acetonitrile using a gradient program with a flow rate of 1ml/min, throughout the gradient program with a detection wavelength of 225nm for both the compounds with a injection volume of 10μl. The method was validated for selectivity, linearity, accuracy, robustness, precision and specificity. The results were indicating the method was selective in analysis of both olmesartan medoxomil and hydrochlorothiazide in the presence of degradation products formed under various stress conditions.

Development and validation of an RP-HPLC method for the simultaneous determination of Escitalopram Oxalate and Clonazepam in bulk and its pharmaceutical formulations.

A Simple, efficient and reproducible reverse phase high performance liquid chromatographic method was developed and validated for the Simultaneous determination of Escitalopram oxalate and Clonazepam in combined dosage form. The separation was effected on a Hypersil ODS C18 column (250mm X 4.6mm; 5μ) using a mobile phase mixture of buffer and acetonitrile in a ratio of 50:50 v/v at a flow rate of 1.0ml/min. The detection was made at 240nm. The retention time of Escitalopram oxalate and Clonazepam was found to be 2.840± 0.007min and 4.007±0.006 min. Calibration curve was linear over the concentration range of 20-120μg/ml and 1-6μg/ml for Escitalopram oxalate and Clonazepam. All the analytical validation parameters were determined and found in the limit as per ICH guidelines, which indicates the validity of the method. The developed method is also found to be precise, accurate, specific, robust and rapid for the simultaneous determination of Escitalopram oxalate and Clonazepam in tablet dosage forms.

Action of acid chlorides on benzaldehyde di-n-butylacetal at low temperature.

The benzaldehyde di-n-butylacetal has been synthesized and its reactions with acid chlorides, viz., acetylchloride, benzoylchloride, benzylchloride, perchloricacid, sodiumperchlorate, zirconiumoxychloride and calciumoxychloride have been studied at -20oC. The acetal generates esters with acetylchloride, benzoylchloride and perchloricacid while produced ether with benzylchloride, but only aldehyde with sodiumperchlorate. Interestingly, acetal yields substituted aldehyde alone with zirconiumoxychloride and calciumoxychloride. Acid chlorides are synthetically very useful reagents and vary widely in their acceptor synthon character and reactivity; hence their application in the present work on the action of acid chlorides on benzaldehyde di-n-butylacetal is a new venture.

Validated stability indicating gradient RP-HPLC method for the estimation of antihypertensive drugs in bulk and pharmaceutical dosage forms.

A rapid and precise RP-HPLC method for determination of Olmesartan medoxomil and Hydrochlorothiazide in bulk and pharmaceutical dosage forms. Olmesartan medoxomil & Hydrochlorothiazide are found to be degraded together under different set of conditions as followed according to ICH guidelines and the degradants so formed along with olmesartan & hydrochlorothiazide are separated by using INERTSIL ODS C18 3V (150 x 4.6, 5μ) using mobile phase 1ml triethanolamine in one litre water and the pH was adjusted to 2.5 with orthophosphoric acid and acetonitrile using a gradient program with a flow rate of 1ml/min, throughout the gradient program with a detection wavelength of 225nm for both the compounds with a injection volume of 10μl. The method was validated for selectivity, linearity, accuracy, robustness, precision and specificity. The results were indicating the method was selective in analysis of both olmesartan medoxomil and hydrochlorothiazide in the presence of degradation products formed under various stress conditions.

Development and validation of an RP-HPLC method for the simultaneous determination of Escitalopram Oxalate and Clonazepam in bulk and its pharmaceutical formulations.

A Simple, efficient and reproducible reverse phase high performance liquid chromatographic method was developed and validated for the Simultaneous determination of Escitalopram oxalate and Clonazepam in combined dosage form. The separation was effected on a Hypersil ODS C18 column (250mm X 4.6mm; 5μ) using a mobile phase mixture of buffer and acetonitrile in a ratio of 50:50 v/v at a flow rate of 1.0ml/min. The detection was made at 240nm. The retention time of Escitalopram oxalate and Clonazepam was found to be 2.840± 0.007min and 4.007±0.006 min. Calibration curve was linear over the concentration range of 20-120μg/ml and 1-6μg/ml for Escitalopram oxalate and Clonazepam. All the analytical validation parameters were determined and found in the limit as per ICH guidelines, which indicates the validity of the method. The developed method is also found to be precise, accurate, specific, robust and rapid for the simultaneous determination of Escitalopram oxalate and Clonazepam in tablet dosage forms.