Development and validation of Spectrophotometry methods for estimation of linezolid in bulk and in pharmaceutical Dosage formulation

Abstract

A simple, precise and economical, and rapid Spectrophotometric methods for the quantification of Linezolid in bulk material and in tablets. Further, this study is designed to validate the developed methods as per ICH guidelines. Material & methods: In Methods A and B, a stock standard solution was prepared by dissolving 10 mg of Linezolid in 100 mL of phosphate buffer pH 7.4 to obtain a concentration of 100 μg/mL. After suitable dilution, 10 μg/mL of  Linezolid was prepared and scanned in the UV-visible range 400 –200 nm;  In method A zero order spectrum Linezolid showed a maximum absorbance at 251 nm. while in Method B  area under curve (AUC) zero-order spectrum was recorded between 245 and 268 nm. For a linearity study, series of dilutions were prepared from stock solutions. Results: In Method A and B, Linezolid followed linearity in the concentration range of 3 – 18 μg/mL with (r2 = 0.9978) (r2 = 0.9981). The accuracy of the method was checked by recovery experiment performed at three different levels i.e., 80%, 100% and 120%. The % recovery was found to be in the range 96.15% – 99.32% for method A, while in method B range is 99.16 % - 100.20 %. The low values of % RSD are indicative of the accuracy and reproducibility of the method. The precision of the method was studied as an intra-day, inter-day variations and repeatability. The % R.S.D. value less than 2 indicate that the method was precise. Ruggedness of the proposed method was studied with the help of two analysts. The proposed method of pharmaceutical formulation the amounts of Linezolid estimated by both these methods (A and B) were found to be 96.25 ± 0.44 and 99.48 ± 1.05, respectively. Conclusion: The developed methods are simple, precise, rugged, and economical. Both these methods can be used for routine analysis of Linezolid from its tablet formulation. Keywords: Linezolid, UV-Spectrophotometric methods, area under curve, zero order spectrum