Simultaneous Quantitation and Monitoring of Gemifloxacin and Rosuvastatin by Liquid Chromatography with UV-detection

Rapid, sensitive and economical liquid chromatographic methods have been developed for simultaneous quantitation of gemifloxacin and rosuvastatin in Active Pharmaceutical Ingredients (API), pharmaceutical formulations and in human serum. At first, method was developed with chromatographic system consisting methanol and water in the ratio of 90:10 as mobile phase (pH adjusted 3 with o-phosphoric acid) passing through stationary phase of prepacked Purospher Star ® C18 (5?µm, 25?×?0.46?cm) column at 1.0 mLmin-1. Drug analytes eluted at 1.9 and 3.042 minutes simultaneously at isosbestic point of 263 nm. Linear calibration curves were obtained for 0.125-7.5 µgmL-1 gemifloxacin and 0.25-15 µgmL-1 rosuvastatin with r2 > 0.998. Inter and intra day precision studies were within 2%. Accuracy of method from recovery studies were within 97.62-102.44%. The method was further optimized and validated for the same chromatographic conditions at individual ?max of each drug at 346 nm for 0-2.8 min for gemifloxacin and 243 nm for 2.9-3.6 min for rosuvastatin by programming the detector to match maximum absorbance of individual chromophores. The method followed linearity over a range of 0.03125-7.5 µgmL-1 gemifloxacin and 0.0625-15 µgmL-1 rosuvastatin for which the LOQ values shifted to more sensitive level of 05 from 16 ngmL-1 rosuvastatin and 06 from 09 ngmL-1 gemifloxacin as compared to prior method. LOD values also shifted from 5 to 2 ngmL-1 rosuvastatin and 3 to 2 ngmL-1 gemifloxacin. Precision was less than 2% RSD and accuracy of method was 99.21-103.21 % for both drugs. Robustness and ruggedness parameters were also carried out for validation of methods. Both methods were applied on tablet formulations and human serum samples and followed ICH guidelines. The methods are applicable to pharmacokinetic and pharmacodynamic drug-drug interactions studies, can be utilized in clinical, forensic and drug research centres. Use of conventional UV detectors for sensitive determination of compounds will help in valuable research in developing countries.