Comparative Dissolution Profiling of Norfloxacin 400 mg Tablets Using USP Apparatus I (Basket) and USP Apparatus II (Paddle)

Abstract

Dissolution testing is an essential quality control tool used to evaluate the rate and extent of drug release from oral solid dosage forms and to predict their in vivo performance. The present study was conducted to compare the dissolution behavior of Norfloxacin 400 mg tablets using USP Apparatus I (Basket) and USP Apparatus II (Paddle) under optimized experimental conditions. Norfloxacin, a second-generation fluoroquinolone antibiotic, exhibits pH-dependent solubility, making dissolution profiling an important parameter for assessing its pharmaceutical performance. The dissolution studies were performed using acetate buffer (pH 4.0) as the dissolution medium maintained at 37 ± 0.5°C. USP Apparatus I was operated at 100 rpm, whereas USP Apparatus II was operated at 50 rpm. Samples were collected at predetermined time intervals (5, 10, 15, 20, 30, 45, and 60 minutes) and analyzed using a validated UV–Visible spectrophotometric method at 278 nm. The cumulative percentage drug release obtained from both apparatuses was compared to evaluate the effect of hydrodynamic conditions on dissolution performance.The results demonstrated that both apparatuses provided satisfactory dissolution profiles and complied with pharmacopeial requirements. However, USP Apparatus II exhibited a comparatively faster drug release than USP Apparatus I. At 30 minutes, cumulative drug release was 89.76% for the Paddle apparatus and 82.94% for the Basket apparatus. At 60 minutes, the Paddle apparatus achieved 99.85% drug release, while the Basket apparatus showed 97.28% release. The enhanced dissolution observed with the Paddle apparatus may be attributed to improved mixing efficiency and hydrodynamic conditions around the dosage form. In conclusion, both USP Apparatus I and USP Apparatus II are suitable for dissolution testing of Norfloxacin tablets; however, USP Apparatus II demonstrated superior dissolution efficiency and may be considered the preferred method for routine quality control evaluation of immediate-release Norfloxacin formulations.