QUALITY AND IN-VITRO BIOEQUIVALENCE EVALUATION OF COMMERCIAL ASCORBIC ACID TABLETS IN ZARIA METROPOLIS, KADUNA STATE, NIGERIA
Ascorbic acid (vitamin C) is an essential nutrient widely used as a dietary supplement. With the increasing availability of multiple generic brands in the market, assessing their quality and therapeutic equivalence is crucial to ensure patient safety and efficacy. This study aimed to assess the in-vitro bioequivalence of eight commercial brands of ascorbic acid tablets (coded VC01–VC08) available in Zaria, Nigeria. Physicochemical properties were analyzed using UV-Visible spectrophotometry, and dissolution studies were conducted in simulated physiological media (pH 1.2, 4.5, and 6.8) using USP Apparatus II (paddle method) at 100 rpm and 900 mL media volume, maintained at 37±0.5 °C. The dissolution profiles were compared using model-independent approaches: difference factor (f1) and similarity factor (f2). Results showed that brands VC02 and VC07 met the bioequivalence criteria with f2 > 50 and f1 < 15 across all three media. Brands VC03, VC05, VC06, and VC08 failed to meet these criteria, while VC04 had variable results depending on pH. Dissolution efficiencies (D.E %) and assay results also supported the findings, with only VC02 and VC07 showing acceptable drug release and content within official limits. The study concludes that VC02 and VC07 are bioequivalent to the comparator brand VC01 and may be used interchangeably.
Keywords: Ascorbic acid, dissolution, fit factors, generic, in-vitro bioequivalence, innovator brand, physicochemical parameters
*Correspondence: samailashamsuddeen@gmail.com, 08069566963
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