Comparative In Vitro Quality Evaluation of Six Commercial Ciprofloxacin 500 mg Tablet Brands Marketed in Libya

Abstract

Ciprofloxacin hydrochloride is a widely prescribed fluoroquinolone antibiotic in Libya, with several generic formulations representative of the broader Libyan pharmaceutical market. As generic substitution is common, evaluating pharmaceutical quality and in vitro performance is essential to verify compliance with pharmacopeial standards and therapeutic equivalence. Six commercially available brands of ciprofloxacin hydrochloride 500 mg tablets (Sarf, Ciprofloxacin (Combitic), Ladinin, Ciproquin, Quinox, Ciprofloxacin (Bristol), coded as A–F respectively, were evaluated using pharmacopeial quality control tests, including identification, weight variation, hardness, friability, disintegration, and dissolution. Dissolution testing was performed using USP Apparatus II, and drug release was quantified by UV spectrophotometry at 276 nm using a validated calibration curve (R² = 0.9945). Dissolution profiles were analyzed using kinetic models and model-independent parameters. All brands complied with pharmacopeial requirements for weight variation, friability, and disintegration. Tablet hardness ranged from 5.33 to 10.98 kg/cm², with higher hardness associated with prolonged disintegration. Only four brands met the USP acceptance criterion of ≥75% drug release at 45 min, while two brands B and D showed slower dissolution behavior. Five products followed the Higuchi model, indicating diffusion-controlled release, whereas one followed first-order kinetics. Similarity analysis showed that three brands (A, C and E) were dissolution-equivalent to the reference product Brand F (Ciprofloxacin Bristol, UK) (f₂ = 62.25–74.47), while brands (B and D) exhibited non-equivalent profiles (f₂ = 47.1 and 48.77). Differences were also observed in DE (68.49–79.34%) and MDT (5.43–10.30 min). All products met pharmacopeial requirements for physical quality; however, variations in dissolution performance were observed among the evaluated brands. Routine post-marketing dissolution surveillance is recommended to monitor product quality and support the assessment of generic ciprofloxacin hydrochloride tablet interchangeability.