Investigation and greenness profiling of ethanol-based mobile phases for analysis of different ciprofloxacin formulations

Replacing toxic solvents with greener alternatives such as ethanol is a strategy that aims to reduce the hazardous organic solvent consumption. Two new green HPLC methods were developed for the determination of four different binary mixtures containing ciprofloxacin (CIP) as an important therapeutic agent. The first method was used for separation of three binary mixtures of ciprofloxacin (CIP) with either ornidazole (ORZ) or tinidazole (TNZ) or metronidazole (MEZ), while the second one was used for separation of CIP and hydrocortisone (HCZ). In method I, good separation was accomplished within 10 min on Cyano column using ethanol and water in a ratio of 65:35, v/v containing 0.3% glacial acetic acid at pH 3.0 and flowing with the rate of 0.9 mL/min. Using time programing technique, UV detection was adjusted at 310, 313 and 316 nm for ORZ, TNZ and MEZ, respectively, in the first 6 min then at 276 nm for CIP determination. Method II was used for separation of CIP and HCZ, the separation was achieved within 5 min on Shim-pack CLC-C8 column. Ethanol and water were used in a ratio of 60:40 v/v, containing 0.4% glacial acetic acid at pH 4.6 as a mobile phase. The analysis was carried out at a flow rate of 0.7 mL/min with UV detection at 265 nm. The two methods were validated by referring to the pharmacopoeial guidelines. Moreover, the proposed methods were assessed regarding their greenness to indicate the eco-friendly character of the methods.