Comparative pharmacokinetics and pharmacodynamics of lansoprazole oral capsules and suspension in healthy subjects

The pharmacokinetics and pharmacodynamics of lansoprazole suspension and lansoprazole capsules were studied. Thirty-six healthy males and females were randomized in a single-dose, open-label, two-period crossover study. Lansoprazole 30 mg was administered via a nasogastric tube as simplified lansoprazole suspension (in 8.4% sodium bicarbonate) or orally as the intact capsule after a minimum 12-hour fast and 5 hours before lunch. Ambulatory 24-hour intragastric pH was monitored at baseline and on day 1 of each treatment period to assess lansoprazole’s pharmacodynamics. Blood samples were collected before drug administration and at predetermined intervals up to 24 hours after each dose to assess lansoprazole’s pharmacokinetics. Both formulations effectively raised the mean 24-hour intragastric pH (mean 24-hour pH of 3.75 with suspension and 3.52 with intact capsule) and maintained it above threshold values of 3 and 4 for more than 40% of the 24-hour postdose period. The suspension was associated with a significantly shorter mean time to the maximum observed concentration (tmax) compared with the intact capsule. The mean maximum observed plasma concentration (Cmax) of the suspension was significantly higher and the mean area under the concentration-time curve from time zero to infinity (AUC_∞) was significantly lower than those of the intact capsule (879 versus 810 ng/mL and 1825 versus 2229 ng.hr/mL). The 90% confidence intervals obtained by two one-sided tests for both Cmax and AUC∞ were contained within the 0.80 to 1.25 range, confirming the bioequivalence of the two regimens. Simplified lansoprazole suspension effectively controls intragastric pH, is bioequivalent to the intact capsule, and represents an effective therapeutic option for patients who have difficulty swallowing or are unable to swallow lansoprazole capsules.