Evaluation of the Influence of Hyoscine Butylbromide on the Oral Bioavailability of Lansoprazole in Healthy Adult Volunteers

Abstract

The gastroesophageal reflux and/or peptic ulcer diseases are clinical conditions that occur usually accompanied of symptomatic pain. Lansoprazole, a proton pump inhibitor class drug is widely used in clinical practice for treatment of these diseases. However, its efficacy can be improved by combining with spasmolytic and/or visceral analgesic such as hyoscine butylbromide. Since hyoscine butylbromide is barely absorbed and exerts some local effects at gastrointestinal tract which may modify the absorption of lansoprazole, it is important to establish if there is a pharmacokinetic interaction after the oral concomitant administration of both drugs. For this objective, twenty-five subjects received under a crossover design an oral administration of lansoprazole (15 mg) plus placebo or a fixed-dose combination with hyoscine butiylbromide (15 mg + 10 mg, respectively). Plasma samples were obtained at different times during 10 hours. Lansoprazole plasma concentrations were determined by a high performance liquid chromatography method coupled to tandem mass spectrometry. Fixed-dose combination was well tolerated. Lansoprazole pharmacokinetic parameters were: Cmax 621.81 ± 212.79 and 450.38 ± 192.14 ng/mL; AUC 0 - t 1941.36 ± 845.57 and 1454.66 ± 757.28 ng·h/mL; tmax 2.83 ± 0.99 and 3.40 ± 1.82h; t1/2 1.35 ± 0.39 and 1.45 ± 0.51 h, for alone and combined fixed-dose formulation, respectively. Pharmacokinetic parameters were compared by analysis of variance and ratios of AUC 0 - t , Cmax and 90% confidence intervals obtained. Since confidence intervals exceed the 80% - 125% limits for these parameters, we conclude that there is a significantly pharmacokinetic interaction of lansoprazole when it is administered concomitantly with hyoscine butylbromide.