title: Stability-indicating RP-HPLC Method for the Simultaneous Determination of Sitagliptin and Simvastatin in Tablets.
abstract: A new stability-indicating high-performance liquid chromatographic method for simultaneous analysis of sitagliptin and simvastatin in pharmaceutical dosage form was developed and validated. The mobile phase consisted of methanol and water (70:30, v/v) with 0.2 % of n-heptane sulfonic acid adjusted to pH 3.0 with ortho phosphoric acid was used. Retentions of sitagliptin and simvastatin were 4.3 min and 30.4 min, respectively with a flow rate of 1 ml/min on C8 (Qualisil BDS, 250×4.6 mm, 5 μ). Eluents were detected at 253 nm using photodiode diode array detector. The linear regression analysis data for the linearity plot showed correlation coefficient values of 0.9998 and 0.9993 for sitagliptin and simvastatin, with respective concentration ranges of 20-150 μg/ml and 8-60 μg/ml. The relative standard deviation for inter-day precision was lower than 2.0%. The assay of sitagliptin and simvastatin was determined in tablet dosage form was found to be within limits. Both drugs were subjected to a variety of stress conditions such as acidic, basic, oxidation, photolytic, neutral and thermal stress in order to achieve adequate degradation. Results revealed that considerable degradation was found in all stress conditions except oxidative degradations. The method has proven specificity for stability indicating assay method.
authors.affiliation: College of Pharmacy, Gulf medical University, Ajman, UAE.
authors.forename: P
authors.initials: P
authors.lastname: Ramalingam
authors.affiliation: Division of Pharmaceutical Analysis and Quality Assurance, Raghavendra Institute of Pharmaceutical Education and Research, Anantapur-522 721, India.
authors.forename: V Udaya
authors.initials: VU
authors.lastname: Bhaskar
authors.affiliation: Division of Pharmaceutical Analysis and Quality Assurance, Raghavendra Institute of Pharmaceutical Education and Research, Anantapur-522 721, India.
authors.forename: Y Padmanabha
authors.initials: YP
authors.lastname: Reddy
authors.affiliation: Division of Pharmaceutical Analysis and Quality Assurance, Raghavendra Institute of Pharmaceutical Education and Research, Anantapur-522 721, India.
authors.forename: K Vinod
authors.initials: KV
authors.lastname: Kumar
keywords: Sitagliptin; reverse phase liquid chromatography; simvastatin