No abstract

The effect of piperine on the bioavailability and pharmacokinetics of propranolol and theophylline has been examined in a crossover study. Six subjects in each group received a single oral dose of propranolol 40 mg or theophylline (150 mg) alone or in combination with piperine 20 mg daily for 7 days. An earlier tmax and a higher Cmax and AUC were observed in the subjects who received piperine and propranolol. It produced a higher Cmax, longer elimination half-life and a higher AUC with theophylline. In clinical practice, the enhanced systemic availability of oral propranolol and theophylline could be exploited to achieve better therapeutic control and improved patient compliance.

Treatment cost is a major concern for modern medicine in developing countries like India and systematic innovative means to reduce these costs are needed. This article reviews the concept of bioenhancers to reduce treatment costs by increasing drug bioavailability. This concept, based on the Ayurvedic system of medicine, works for a wide range of ingested substances, and has been applied to modern drugs, particularly single chemicals. It offers a fine example of the benefit of integrating an ancient system with modern medicine in both theory and practice.

Peppers are common food ingredients used worldwide. They are also added in traditional antidiarrhoeal formulations of different herbs. Piperine (1) is an alkaloidal constituent of black and long peppers recently established as a bioavailability enhancer of drugs and other substances. As a part of efforts to study its effects on the gastrointestinal tract, the experiments were performed to determine the rationale, if any, for its use in traditional antidiarrhoeal formulations. Antidiarrhoeal activity of 1 against castor oil, MgSO4 and arachidonic acid was studied in mice. It significantly inhibited diarrhoea produced by these cathartics at 8 and 32 mg/kg p.o. dose. Inhibition of castor oil induced enteropooling by 1 suggests its inhibitory effect on prostaglandins. The results validate the rationale for its use in traditional antidiarrhoeal formulations.

Piperine (1), an alkaloid of black and long peppers, inhibited gastric emptying (GE) of solids/liquids in rats and gastrointestinal transit (GT) in mice in a dose and time dependent manner. Compound 1 significantly inhibited GE of solids and GT at the doses extrapolated from humans (1 mg/kg and 1.3 mg/kg p.o. in rats and mice, respectively). However, at the same dose the effect was insignificant for GE of liquids. One week oral treatment of 1 mg/kg and 1.3 mg/kg in rats and mice, respectively, did not produce a significant change in activity as compared to single dose administration. GE inhibitory activity of 1 is independent of gastric acid and pepsin secretion.