Bioequivalence of allopurinol-containing tablet preparations

Area of Science:

• Pharmacokinetics and Drug Bioequivalence
• Clinical Pharmacology
• Gout Management Therapeutics

Background:

• Allopurinol is a key medication for managing hyperuricemia and gout.
• Ensuring bioequivalence between different allopurinol formulations is crucial for therapeutic consistency.
• Uribenz and Zyloric 300 are two distinct allopurinol tablet preparations requiring comparative analysis.

Purpose of the Study:

• To establish the bioequivalence of Uribenz allopurinol tablets compared to Zyloric 300.
• To assess the relative bioavailability of allopurinol and its active metabolite, oxypurinol.
• To confirm comparable efficacy in reducing uric acid levels between the two preparations.

Main Methods:

• An open-label, randomized crossover study involving 18 healthy volunteers.
• Administration of single doses of Uribenz and Zyloric 300 allopurinol tablets at a two-week interval.
• Quantification of plasma allopurinol and oxypurinol concentrations via High-Performance Liquid Chromatography (HPLC) over 72 hours.

Main Results:

• Mean Area Under the Curve (AUC) values for both allopurinol and oxypurinol were virtually identical between Uribenz and Zyloric 300.
• Peak plasma concentration (Cmax) values showed minor variations within acceptable bioequivalence ranges.
• Both preparations induced an equivalent maximum reduction of 18% in volunteer uric acid levels.

Conclusions:

• The study successfully demonstrated bioequivalence between Uribenz and Zyloric 300 allopurinol tablet preparations.
• The findings support the interchangeable use of these two allopurinol formulations.
• Bioequivalence ensures consistent therapeutic outcomes for patients requiring allopurinol treatment.