Spectrophotometric Estimation of Abacavir Sulphate in Pharmaceutical Formulations

Two simple, accurate, rapid and sensitive methods (A and B) have been developed for the estimation of abacavir sulphate in its pharmaceutical dosage form. The method A and B are based on the formation of chloroform extractable complex of abacavir sulphate with bromophenol blue (method A) and bromocresol green (method B), which shows absorbance maxima at 460 nm and 469 nm respectively. The absorbance-concentration plot is linear over the range of 1-10 mcg/mL for method A and B respectively. Results of analysis for all the methods were validated statistically and by recovery studies. The proposed methods are economical and sensitive for the estimation of abacavir sulphate in bulk drug and in its tablet dosage form

Synthesis, Anticonvulsant Activity and In silco Studies of Schiff Bases of 2-Aminothiophenes via Guanidine- Catalyzed Gewald Reaction

Purpose: To synthesize Schiff bases of 2-aminothiophenes and evaluate their anticonvulsant activity and in silco propertiesMethods: 2-Amino-N-o-tolyl-5,6-dihydro-4H-cylcopenta[b]thiophene-3-carboxamide was synthesized using 1,1,3,3-tetramethylguanidine lactate as a basic catalyst and by microwave irradiation. 2- substitued-o-tolyl-5,6-dihyro-4H-cylcopenta[b]thiophene-3-carboxamide was prepared by reacting with different substituted aromatic aldehydes. The synthesized compounds were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (1H NMR) and mass spectrometry (MS) while their anticonvulsant activity was screened against maximum electroshockinduced seizure (MES), and pentylenetetrazole-induced seizure (PTZ) against phenytoin and diazepam as reference standards. Molecular docking (in silico) studies were performed using 4-aminobutyrateaminotransferase in order to predict possible protein-ligand interactions.Results: Among the 21 synthesized compounds, 2b, 2d, 2f, 2k, 2m, 2n and 2o showed good to moderate activity against MES and PTZ-induced convulsions. Compounds 2b, 2d, 2f, 2k and 2m exhibited lower activity against PTZ than against MES model while compounds 2n and 2o afforded greater protection against PTZ than against MES model. In silico results also revealed maximum binding affinity to GABA-AT protein which was higher than other compoundsConclusion: The synthesized compounds showed potent anticonvulsant activity. Molecular docking results should give an insight into how further modification of lead compound can be carried out for higher inhibitory activity.Keywords: Ionic liquid, 2-Aminothiophenes, Anticonvulsant, In silco studies, Molecular docking

A Rapid and Selective LC-MS/MS Method for Quantification of Quetiapine in Human Plasma and its Application to Pharmacokinetic Study on Indian Schizophrenia Patients

A rapid, robust and selective high pressure liquid chromatography–positive electrospray ionization tandem mass spectrometry method has been developed and validated for the quantification of quetiapine (QUE) in human plasma with K2EDTA using oxcarbazepine (IS) as an internal standard. Analyte and internal standard were extracted from human plasma by solid-phase extraction using acetonitrile. The eluted samples were chromatographed on a C18 column by using a 10:75:15v/v mixture of ammonium formate buffer (5 mM, pH 4.50) and acetonitrile and methanol as an isocratic mobile phase at a flow rate of 0.4 mL/min and analyzed by mass spectrometry in the multiple reaction monitoring mode using the respective [M+H]+ ions, m/z 384.3/253.2 for Quetiapine and m/z 253.1/208.1 for the internal standard. The assay exhibited a linear dynamic range of 5.01 - 2501.04 ng/mL for quetiapine in human plasma. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 2.5 min for each sample made it possible to analyze 300 patient plasma samples per day. The validated method has been successfully used for the estimation of quetiapine in real time schizophrenia patient’s plasma samples for pharmacokinetic study

Detection, Isolation and Characterization of Principal Synthetic Route Indicative Impurity in Lansoprazole

An unknown impurity in lansoprazole (2-[[[3-methyl-4-(2, 2, 2-trifluoroethoxy)-2-pyridyl] methyl] sulfinyl] benzimidazole) was detected by HPLC and was identified as des-(trifluoroethoxy) lansoprazole, an principal synthetic route indicative impurity of lansoprazole. Lansoprazole was subjected to different ICH prescribed stress conditions like hydrolysis, oxidation, photolysis and thermal degradation conditions to enrich the impurity. The impurity was enriched by using acid catalytic degradation, isolated by using preparative HPLC and characterized (FTIR, MS and NMR). Limit of Detection (LOD) and Limit of Quantification (LOQ) are found to be 0.014% and 0.035% respectively

Enantioselective Synthesis of Antiepileptic Drug: (-)-Levetiracetam-Synthetic Applications of the Versatile New Chiral N-Sul�nimine

We report an asymmetric synthesis of (-)-Levetiracetam (1) in six steps starting from versatile new chiral N-sul�nimine (3). e key step, stereoselective 1,2-addition of ethylmagnesium bromide (EtMgBr) to chiral N-sul�nimine derived from (R)-glyceraldehyde acetonide and (S)-t-BSA, gave the corresponding sulfonamide (2) in high diastereoselectivity. Simultaneous deprotection and deacetylation followed by NaIO 4 cleavage and reduction gave -amino alcohol (6). Subsequent reactions yielded the targeted compound levetiracetam (1)

Synthesis of N-(3-arylprop-2-ynyl)substituted olanzapine derivatives as potential inhibitors of PDE4B

The linkage between dopamine D2 receptors and PDE activity via cAMP prompted us to design a series of novel N-(3-arylprop-2-ynyl)substituted olanzapine derivatives as potential inhibitors of PDE4B. The target compounds were conveniently prepared by using a simple and inexpensive method involving Pd/C-mediated CC bond forming reaction under Sonogashira conditions. A number of compounds were synthesized by using this strategy in good yields. Some of the compounds showed promising inhibition of PDE4B when tested in vitro that was supported by the docking studies

A Validated RP-HPLC Method for the Determination of Impurities in Montelukast Sodium

Abstract: The present paper describes the development of a reverse phase chromatographic (RPLC) method for montelukast sodium in the presence of its impurities and degradation products generated from forced degradation studies. The drug substance was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. The degradation of montelukast sodium was observed under acid and oxidative environment. The drug was found to be stable in other stress conditions studied. Successful separation of the drug from the process impurities and degradation products formed under stress conditions were achieved on an Atlantis dC18 (250 x 4.6 mm) 5 µm column. The gradient LC method employs solution A and solution B as mobile phase. The solution A contains aqueous 0.1% OPA and solution B contains a mixture of water, acetonitrile (5:95 v/v). The HPLC method was developed and validated with respect to linearity, accuracy, precision, specificity and ruggedness

GASTRO-FLOATING TABLETS OF REPAGLINIDE: PREPARATION AND IN VIVO EVALUATION

Objective: Current research concerns the expansion of repaglinide matrix floating tablets, which are designed to prolong the gastric residence time, increase the drug bioavailability, and diminish the side effects.Methods: Different formulations of repaglinide floating tablets were prepared with different grades of hydroxypropyl methylcellulose (HPMC) and other agents. Evaluation parameters and in vivo bioavailability studies were conducted in the suitable model.Results: Among all the formulations, F21 containing HPMC K1500 PH PRM, Polyox WSR 303, and sodium bicarbonate, as gas generating agent was selected as optimized formulation based on physicochemical properties, floating lag time (36 s), and total floating time (>24 h). From in vitro dissolution studies, the optimized formulation F21 showed drug release of 98.92±5.19% within 24 h whereas 95.09±5.01% of the drug was released from the marketed product within 1 h.Conclusion: From in vitro and in vivo bioavailability studies repaglinide floating tablets expected to give a new choice for safe, economical, and increased bioavailability for effective management of diabetes mellitus