Bioavailability of Chinese rifapentine during a clinical trial in Hong Kong

Abstract

Setting: A clinical trial of rifapentine in Hong Kong.

Objective: Assessment of the bioavailability of the Chinese rifapentine used in the trial.

Design: The content of rifapentine in serum samples taken from 287 patients during the administration of four batches of the drug was measured by microbiological assay.

Results: An initial comparison of areas under curve obtained in a random allocation to 40 patients of rifapentine either of Western or Chinese origin indicated that the bioavailability of the Chinese drug was 74% of the Western drug. The bioavailability of the second batch was found to be about 66% of the Western drug. The dose of the last two batches of rifapentine was therefore increased from the planned 600 mg to 750 mg, or briefly to 900 mg; serum concentrations were then similar to those obtained with the Western drug. Bioavailability did not change during the use of each drug batch.

Conclusion: A comparison of the results obtained in the trial with the initial two batches and the final batches will estimate the effects of rifapentine dose size on its efficacy and toxicity.