Devi Ramesh

A simple, rapid, and precise RP-HPLC method for simultaneous analysis of Amlodipine besylate and Glimepiride in bulk and its pharmaceutical formulations has been developed and validated. Amlodipine besylate was separated from Glimepiride by using Grace Smart Altima C8 column (25 cm × 4.6 mm, 5-μm) with a mobile phase consisting of acetonitrile: 20mM phosphate buffer (55:45 (v/v), pH 3.5) a flow rate of 1 mL/min and detection wavelength at 230 nm.  Amlodipine besylate and Glimepiride were eluted with retention times of 5.47 min and 14.17 min respectively. The method was validated for accuracy, precision, linearity, specificity and sensitivity in accordance with ICH (Q2B) guidelines. The results of all the validation parameters were found to be within the acceptable limits. The calibration plots were linear over the concentration ranges from 70-3000ng/mL for Amlodipine besylate and 100-3000ng/mL for glimepiride. The limit of detection and limit of quantification were found to be 19.4ng/mL and 58.8ng/mL for amlodipine besylate, 25.6ng/mL and 76.2ng/mL for glimepiride respectively for both the drugs. From the results it is suggested that the method is simple, reproducible, accurate and precise. The method was successfully applied for the determination of content and the dissolution profile of the combined bilayer tablet dosage form.

The emerging new fixed dose combination of Glipizide (GLZ) as sustained release and Telmisartan (TEL) as immediate release were formulated as a bilayer matrix tablet using guggul. Guggul used as a binding agent with three different concentrations (70%, 80%, and 90%; F1-F6) was used for the preparation of first layer of tablet containing glipizide. The conventional tablet of telmisartan was prepared as a second layer. Prepared bilayer tablets were studied for the in vitro release study carried out at pH 1.2 for first two hours and then at pH 6.8 for 6 hours using USP dissolution apparatus II (Basket). All the evaluation tests were found to be within the acceptance limits specified in Indian Pharmacopeia. The assay and dissolution study of tablets were done by HPLC which was developed and validated according to the ICH Q2 (B) guidelines. The contents of assay of the tablets were found to be 90.92% - 103.84% for F2-F5. The release of glipizide from the tablet was extended up to 8 h. Tablet containing 2.5 mg of glipizide with 80% of guggul release of drug after 8 h was found to be 82.36% and tablet containing 5 mg of glipizide with 90% guggul release of glipizide after 8 h was found to be 74.67%. The release pattern of each formulation (F2-F5) was fitted into the dissolution kinetics models and all the formulations were best fitted in the Higuchi model kinetic. From the results, we have concluded that the guggul act as a binding agent as well as rate retarding agent.

A simple, rapid, and precise RP-HPLC method for simultaneous analysis of Losartan potassium and Atorvastatin calcium in bulk and its pharmaceutical formulations has been developed and validated. Atorvastatin was separated from losartan by using Grace Smart Altima C-18 column (25 cm × 4.6 mm, 5-μm) with a mobile phase consisting of acetonitrile: 10mM phosphate buffer (55:45 %v/v, pH 3.0) a flow rate of 1mL/min and detection wavelength at 240 nm. Aceclofenac was used as an internal standard in this method. Losartan, atorvastatin and aceclofenac were eluted with retention times of 4.85 min, 8.31min and 9.51 min respectively. The method was validated for accuracy, precision, linearity and sensitivity in accordance with ICH (Q2B) guidelines and the results of all the validation parameters were found to be within the acceptable limits. The calibration plots were linear over the concentration ranges from 200-30000ng/mL (r2 = 0.999) for both the drugs. Accuracy and precision were determined by QC sample covering low, medium, and high concentration levels. Intra and inert-day accuracy were found to be 97.16-102.57% for losartan and 97.01-103.05% for atorvastatin. The limit of quantification was found to be166ng/mL and 179ng/mL for losartan and atorvastain respectively. The method was successfully applied for the assay of the dosage form, recovery of the individual drugs from the combined tablet dosage was found to be >97% for both the drugs. From the results it is suggested that the proposed method is simple, reproducible, accurate and precise.