Objective: A bioanalytical quantification method was developed for the simultaneous estimation of simvastatin (SIM) and ezetimibe (EZE) from the human plasma. Methods: The technique was developed and equipped with reverse-phase (RP) high-performance liquid chromatography, using RP-C18 column with an ultraviolet detector. For the estimation of SIM and EZE, the mobile phase (acetonitrile:acetate buffer pH 4.0, pH adjusted with acetic acid) was pumped at a flow rate of 0.8 ml/min in the ratio of 85:15% v/v and the eluents were monitored at 234 nm. A calibration graph to study linearity of the SIM and EZE in biological matrix was carried out in the concentration range of 400–4000 ng/ml for both these drugs SIM and EZE. Results: The developed method was validated according to the US FDA and European Medicines Agency guidelines for sensitivity, accuracy, precision, and stability. The obtained statistical data of validation were found to be within prescribed limit assures rigidity of the method. Both the drugs in combined form were estimated in human plasma by the proposed method. Conclusions: The developed method is free from solid-phase extraction so it becomes simple and economical. The method is efficient for precise and accurate quantification of SIM and EZE in plasma and hence applied for bioequivalence, bioavailability study in real clinical samples.

Objective: A reverse-phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated for the simultaneous estimation of amlodipine besylate (AD) and valsartan (VAL) in pharmaceutical dosage form, and rosuvastatin (RV) and VAL from the bulk mixture. Method: Chromatographic separation was performed on RP-C18 column. The optimized unique mobile phase (acetonitrile:water and pH adjusted to 4.8 with acetic acid) was pumped at a flow rate of 0.8 ml/min in the ratio of 75:25% v/v, and the eluents were monitored at 245 nm. Results: The assay was performed with tablet and percentage of assay was found to 101.39 for AD and 100.05 for VAL, respectively, and with bulk mixture, percentage of assay was found to 99.58 for RV and 100.32 for VAL, respectively. Linearity was obtained in the concentration range of 1–12 μg/ml for AD, 5–50 μg/mL for VAL, and 2–20 μg/ml for RV. The method was statistically validated and RSD was found to be <2%, indicating high degree of accuracy and precision of the proposed RP-HPLC method. Conclusions: The method suggests usefulness of unique mobile phase during the estimation of two or more multicomponent dosage forms. Due to its simplicity, rapidness, high precision, and accuracy, the proposed RP-HPLC method can be applied for simultaneous determination of AD and VAL in pharmaceutical dosage form, and RV and VAL in bulk mixture.