Atorvastatin 1) is a synthetic lipid lowering agent which inhibits HMG-CoA reductase and amlodipine 2) is a calcium antagonist drug effective in hypertension and angina pectoris. The combination drug product of atorvastatin (ATV) and amlodipine (AML) has recently been introduced in the market; co-administration of AML with ATV demonstrated statistically significant dose-related reductions in systolic blood pressure (SBP), diastolic blood pressure (DBP) and LDL-C in patients with co-morbid hypertension and dyslipidemia. 3)Chemically ATV is [R-(R*,R*)]-2-(4-fluorophenyl)-b, dihydroxy-5-(1-methylethyl)-3-phenyl-4-[(phenylamino) carbonyl]-1H-pyrrole-1-heptanoic acid, calcium salt (2 : 1) trihydrate 4) and AML is 2-[(2-Aminoethoxy)-methyl]-4-(2-chlorophenyl)-1,4-dihydro-6-methyl-3,5-pyridinedicarboxylic acid 3-ethyl 5-methyl ester. 5)Stability testing forms an important part of the process of drug product development. The purpose of stability testing is to provide evidence on how the quality of a drug substance or drug product varies with time under the influence of a variety of environmental factors such as temperature, humidity, and light, and enables recommendation of storage conditions, retest periods, and shelf lives to be established. The two main aspects of drug product that play an important role in shelf life determination are assay of active drug, and degradation products generated, during the stability study. The assay of drug product in stability test sample needs to be determined using stability indicating method, as recommended by the International Conference on Harmonization (ICH) guidelines 6) and USP-26. 7) Although stability indicating methods have been reported for assay of various drugs in drug products, most of them describe assay procedures for drug products containing only one active drug substance. Only few stability indicating methods are reported for assay of combination drug products containing two or more active drug substances. The objective of this work was to develop a simple, precise and rapid analytical LC procedure, which would serve as stability indicating assay method for combination drug product of ATV and AML.Both methods have been reported for simultaneous determination of ATV and AML, but these methods lack stability indicating nature. None of the reported analytical procedures describe a stability indicating method for simultaneous determination of ATV and AML in presence of their degradation products. This manuscript describes the development and validation of a stability indicating isocratic reversed-phase HPLC method for simultaneous determination of ATV and AML in presence of their degradation products as per ICH guidelines. The study describes development and subsequent validation of a stability indicating reverse-phase HPLC method for the simultaneous estimation of atorvastatin (ATV), and amlodipine (AML) from their combination drug product. The proposed RP-HPLC method utilizes a Lichrospher ® 100 C 18 , 5 m mm, 250 mm؋4.0 mm i.d. column, at ambient temperature, optimum ...

A simple, precise, and rapid stability-indicating reversed-phase column liquid chromatographic (RP-LC) method has been developed and subsequently validated for simultaneous estimation of simvastatin (SIM) and ezetimibe (EZE) from their combination drug product. The proposed RP-LC method utilizes a LiChrospher 100 C18, 5 m, 250 4.0 mm id column at ambient temperature; optimum mobile phase consisting of acetonitrilewatermethanol (60 + 25 + 15, v/v/v) with apparent pH adjusted to 4.0 0.1; mobile phase flow rate of 1.5 mL/min; and ultraviolet detection at 238 nm. SIM, EZE, and their combination drug product were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. There were no other coeluting, interfering peaks from excipients, impurities, or degradation products due to variable stress conditions, and the method is specific for the estimation of SIM and EZE in the presence of degradation products. The described method was linear over the range of 180 and 380 g/mL for SIM and EZE, respectively. The mean recoveries were 99.17 and 100.43 for SIM and EZE, respectively. The intermediate precision data were obtained under different experimental conditions, and the calculated value of the coefficient of variation was found to be less than the critical value. The proposed method can be useful in the quality control of bulk manufacturing and pharmaceutical dosage forms.

A simple, precise and rapid reverse-phase HPLC method has been developed and subsequently validated for the simultaneous estimation of Amlodipine besylate and Enalapril maleate from their combination drug product. The proposed RP-HPLC method utilizes a Phenomenex C18, 5 µm, 250 mm × 4.6 mm i.d. column, at ambient temperature, optimum mobile phase consisted of Methanol: Acetonitrile : Water (40:50:10, v/v/v), effluent flow rate monitored at 1.0 mL min -1 , and detection using PDA detector. The described method was linear over the range of 0.5-6.0 g/ml and 0.5-8.0 g/ml for Enalapril maleate and Amlodipine besylate, respectively. The mean recovery was found to be 100.06 ± 0.49 % and 99.98 ± 0.63 % for Enalapril maleate and Amlodipine besylate, respectively. The intermediate precision data obtained under different experimental setup, the calculated value of coefficient of variation (CV, %) was found to be less than critical value. The proposed method can be useful in the quality control of bulk manufacturing and pharmaceutical dosage forms.

Two simple spectrophotometric methods have been developed for simultaneous estimation of Thiocolchicoside and Dexketoprofen trometemol from pharmaceutical dosage form. Method-I involved simultaneous equation method and Method-II is the Q-absorbance method. For simultaneous equation method, the absorbances of the standard solutions were taken at two wavelengths 368 nm (λ-max of Thiocolchicoside) and 258 nm (λ-max of dexketoprofen trometamol). For Q-absorbance method, the absorbances of the standard solutions were taken at two wavelengths 258 nm (λ-max of dexketoprofen trometamol) and 281 nm (Isoabsorptive point), in methanol. Linearity range was found to be 2-24 μg/ml for dexketoprofen trometamol and Thiocolchicoside in both methods based on the ratio of the two drugs in combined dosage form. The accuracy and precision of the methods were determined and validated statistically. Both methods showed good reproducibility and recovery with RSD less than 2. Proposed methods were found to be rapid, specific, precise and accurate and can be successfully applied for the routine analysis of dexketoprofen trometamol and Thiocolchicoside in pharmaceutical dosage form.