Two Validated Chromatographic Methods for Determination of Ciprofloxacin HCl, One of its Specified Impurities and Fluocinolone Acetonide in Newly Approved Otic Solution

Abstract

Abstract Two sensitive, selective and precise chromatographic methods have been established for concomitant quantification of ciprofloxacin HCl (CIP), fluocinolone acetonide (FLU) along with ciprofloxacin impurity A (CIP-imp A). The first method was thin-layer chromatography (TLC-densitometry) where separation was accomplished using TLC silica plates 60 G.F254 as a stationary phase and chloroform–methanol–33%ammonia (4.6:4.4:1, by volume) as a developing system. The obtained plates were scanned at 260 nm over concentration ranges of 1.0–40.0, 0.6–20.0 and 1.0–40.0 μg band−1 for CIP, FLU and CIP-imp A, respectively. The second method was based on high-performance liquid chromatography using a Zorbax ODS column (5 μm, 150 × 4.6 mm i.d.) where adequate separation was achieved through a mobile phase composed of phosphate buffer pH 3.6–acetonitrile (45:55, v/v) at flow rate 1.0 mL min−1 with ultraviolet detection at 254 nm. Linear regressions were obtained in the range of 1.0–40.0 μg mL−1 for CIP, 0.6–20.0 μg mL−1 for FLU and 1.0–40.0 μg mL−1 for CIP-imp A. The suggested methods were validated in compliance with the International Conference on Harmonization guidelines and were successfully applied for determination of CIP and FLU in bulk powder and newly marketed otic solution.