Validated HPLC Method for Determining Related Substances in Compatibility Studies and Novel Extended Release Formulation for Ranolazine

HPLC method has been developed for determination of Ranolazine together with its related substances in a laboratory mixture for drug and excipient compatibility studies as well as in a novel extended release tablet developed in-house. Efficient chromatographic separation was achieved on a Supelcosil C 18, (250×4.6 mm, 5 μm) column with mobile phase containing combination of Phosphate buffer pH 7.0 and Methanol in ratio of 350:650 at flow rate of 1.0 ml/minute and eluent was monitored at 220 nm. Linearity, regression value, recovey, % RSD of method precision, LOD and LOQ values were found with in the limits. In this method impurities were well seperated from the main peak. This method was found to be satisfactory. Limits for reporting threshold and total impurities were 0.1% and 2.0%, respectively, as per Q3B(R) Impurities in New drug Products. Compatibility studies are essential for preformulation studies of formulation development. In the present study, the possible interactions between Ranolazine and some excipients (Hypromellose phthalate grade HP-55, Ethocel 7 FP premium, Natrosol type 250 HHX, Klucel HF pharm, Avicel PH 101 and Magnesium Stearate) were evaluated by examining the pure drug or drug-excipient powder mixtures which were stored under different conditions (55°C after 15 days and 40°C/75% RH after 30 days) using High Performance Liquid Chromatography (HPLC). The results demonstrate the suitability of Ranolazine with Hypromellose phthalate grade HP55, Ethocel7FP premium, Natrosol type 250 HHX, Klucel HF pharm, Avicel PH101 and Magnesium Stearate. Same method also used in novel extended release tablet for determination of related substances. Based upon obtained results shows developed formulation was stable at 40°C/75% RH for 3 months.