method validation

This study describes the development and validation of stability indicating HPLC method for moprolol, an antihypertensive drug. The drug was subjected to stress degradation under different conditions recommended by International Conference on Harmonization. The sample so generated was used to develop a stability-indicating high performance liquid chromatographic method for moprolol. The peak for was well resolved from peaks of degradation products, phenomenex C18 column (250 mm ×4.6 mm, 5 μ) at 370C, using an isocratic mobile phase consisting of mixture of 10 mM potassium dihydrogen phosphate buffer with 0.1% V/V TEA in Milli-Q water (pH 3, adjusted with OPA): ACN: Methanol (50:40:10 %V/V/V) at a flow rate of 1 mL minute-1. The retention times were found to be 3.3 min, respectively. Detection was carried out using photodiode array detector. A linear response (r > 0.99) was observed in the range of 0-40μg/mL. The method was found to be specific and stability-indicating as no interfering peaks of degradants and excipients were observed. The method showed good recoveries (average 99.5%) and relative standard deviation for intra and inter-day were ≤ 2 %. The method was validated for specificity and robustness also.The proposed method is hence suitable for application of degradation kinetics of moprolol under different stress conditions employed. Degradation followed a pseudo-first-order kinetics, and rate constant (k), time left for 50% potency (t1/2) and time left for 90% potency (t90) were calculated. This method can also be applied in quality-control laboratories for quantitative analysis of both the drugs individually and in combination, since it is simple and rapid with good accuracy and precision.

A modest, fast, precise, and accurate, stability-indicating reversed phase high performance liquid chromatographic method was developed and validated for vierodt’s method of analysis  of rosuvastatin calcium(RSTC) and fenofibrate (FBT). The  volume of injection sample was 20 μl and the quantification was obtained by UV-VISIBLE detector at 240nm.The chromatographic separation was achieved on X bridge C18, 250 x 4.6 mm, 5 µm particle column, by an gradient mobile phase comprising of acetonitrile: 10 mM potassium dihydrogen phosphate buffer solutions of pH 5.5 in the ratio of 90:10 v/v at a flow rate of 1.5 ml/ min. The retention times for RSTC and FBT were found to be 4.35min and 7.75 min, respectively. The drugs were shown to thermal, photolytic, hydrolytic, and oxidative stress conditions and the stressed samples were evaluated by the suggested method. Validation of the method was approved as per International Conference on Harmonization (ICH) guidelines. Linearity was accepted for RSTC and FBT in the range of 0.040-0.120 mg/ ml and 0.016-0.048 mg/ ml, respectively. The limits of detection were 0.02 μg/ ml and 0.05 μg/ ml, respectively and the LOQ value 0.1 μg/ ml and 0.09 μg/ ml, for RSTC and FBT, respectively. The developed method was profound to be accurate, precise and stability-indicating as no interfering peaks of degradants and excipients were identified. The suggested method is hence appropriate for application in quality-control laboratories for quantitative determination of both the drugs individually and in combination, since it is simple and rapid with good accuracy and precision.

A specific and sensitive liquid chromatography-electrospray ionization tandem mass spectrometry method was developed for the determination of zolmitriptan in human plasma. Zolmitriptan and the internal standard (IS) rizatriptan were extracted by liquid–liquid extraction and were separated on a sunfire C18 column (100 x 2.1mm and 3.5µm) with isocratic elution of mobile phase consisting of 10mM ammonium formate containing 0.1% formic acid and acetonitrile. Electrospray ionization in multiple reaction monitoring mode was used to monitor the parent and the daughter ions of the analyte and the internal standard. The response is linear over a range of 0.5 to 100.0 ng/ml concentration with a correlation coefficient (r2) greater than 0.99 and an extraction efficiency of about 95%. The validated method can be applied to pharmacokinetic, toxicokinetic and bioequivalence studies.

Accurate, precise, rapid and economical first order derivative spectroscopic method was developed and validated for the estimation of Cefixime and levofloxacin in tablet. The wavelengths selected for quantitation were 289.45 nm for levofloxacin (zero cross for cefixime) and 317.0 nm for cefixime (zero cross for levofloxacin). Linearity for detector response was observed in the concentration range of 2-12 μg/ml for both Cefixime and Levofloxacin using methanol as a solvent with correlation coefficient 0.991 and 0.993 respectively. The proposed method was successfully applied for the simultaneous estimation of both drugs in tablet.