Comparison of generic furosemide products by in vitro release studies using usp apparatus 2 and 4

Abstract

Dissolution studies are essential for comparing the quality of generic drugs to their reference products. The objective of this work was to evaluate the in vitro release of furosemide in tablets under official dissolution conditions and using the flow-through cell method. To this end, two USP apparatus were used: apparatus 2 (paddle at 50 rpm) containing 900 mL of phosphate buffer solution pH 5.8, and apparatus 4 (flow-through cell at 16 mL/min) with the same medium. The dissolved drug was quantified by UV spectrophotometry at 274 nm for 60 min. Although the results at a single time point met the acceptance criterion of Q = 80% at 60 min, the dissolution profiles of generic drugs were not similar to the reference product. The similarity factor (f2 < 50), mean dissolution time, dissolution efficiency, t50%, t80%, and Td values corroborate the difference between the profiles (p < 0.05). In vitro release testing demonstrates that, for furosemide tablets available in Mexico, the generic formulations perform differently from the reference products. These differences could affect in vivo absorption, which could yield different therapeutic effects. More evaluation of generic furosemide tablets manufactured in Mexico is needed.