Oral pharmacokinetics of omeprazole and lansoprazole after single and repeated doses as intact capsules or as suspensions in sodium bicarbonate

Abstract

Background: Omeprazole and lansoprazole can be given in sodium bicarbonate as, respectively, simplified omeprazole suspension and simplified lansoprazole suspension. We previously found the antisecretory effect of omeprazole 20 mg given as simplified omeprazole suspension to be lower than with intact capsules. However, lansoprazole 30 mg as simplified lansoprazole suspension produced an effect similar to that seen with intact capsules. Aim: To evaluate the absorption of both drugs when given orally as capsules or as suspensions in sodium bicarbonate. Methods: In random order, we gave 5-day courses of omeprazole 20 mg and lansoprazole 30 mg as capsules and as suspensions in sodium bicarbonate to 12 healthy women. Serial blood samples were taken on days 1 and 5 of each course for pharmacokinetic measurements. Results: There was impairment of omeprazole absorption when given as simplified omeprazole suspension. Maximum plasma concentration and area under the concentration/time curve were lower with simplified omeprazole suspension than with omeprazole capsules (P = 0.034 and 0.013, respectively, on day 5). No differences were found in lansoprazole absorption when simplified lansoprazole suspension was compared with its standard capsule formulation. Relative bioavailability of omeprazole from simplified omeprazole suspension compared to the capsule was 58.4% on day 5. The corresponding value for lansoprazole was 84.7%. Conclusions: Simplified omeprazole suspension 20 mg does not supply adequate omeprazole for systemic absorption. Lansoprazole absorption from simplified lansoprazole suspension is maintained.