Comparative evaluation of moxifloxacin MDR-TB drug; as microspheres with respect to pure drug in lung tissue

A novel moxifloxacin (MOX)-loaded poly (DL-lactide-co-glycolide) (PLGA) microspheres (MPs) suitable for oral administration was prepared by double emulsification solvent evaporation (w/o/w) method. To investigate the pharmacokinetic of MOX-MPs, a simple and rapid high performance liquid chromatographic method was developed for the quantification of MOX in plasma and lung tissue of rats treated with MOX-MPs. Gatifloxacin (0.2µg/ml) was used as an internal standard (IS). The chromatographic separation was achieved on a reversed phase C18 column using isocratic elution with (0.01% Triethanolamine in distilled water): Acetonitrile in the ratio 70:30 v/v pH 2 adjusted with ortho-phosphoric acid, at flow rate of 1 ml/min with a total run time of 6 min. The column effluent was monitored by UV detector at 290 nm. The assay was found to be linear and validated over the concentration range 0.025 to 3.2 µg/ml for MOX in plasma and 0.1 to 2.5 µg/g of lung tissue with correlation coefficient of r2 0.9998 and r2 0.9997 respectively. The system was found to construct sharp peaks for MOX and IS with retention times of 4.08 (±0.012) and 5.84 (±0.026) min for plasma, and 4.17 (±0.016) and 5.84 (±0.022) for lung tissue, respectively. The method exhibited accuracy, precision (inter-day relative standard deviation (RSD) and intra-day RSD values < 15.0 %. The method was applied for determining MOX concentration in plasma and lung after oral administration of 10mg/kg of free MOX and MOX MPs to rats. Results established selectivity and suitability of the method for pharmacokinetic studies of MOX from MOX-MPs