Intestinal absorption and bioavailability of traditional Chinese medicines: a review of recent experimental progress and implication for quality control.

OBJECTIVES: Experimental studies on the pharmacokinetics of traditional Chinese medicines (TCMs) have achieved great progress in recent years. This review aims to summarize the progress made on intestinal absorption and bioavailability of TCMs, and proposes the application of intestinal absorption assays as new tools for the quality and safety control of these medicines. KEY FINDINGS: Since only the absorbed constituents may produce possible therapeutic effect (except those that directly target the digestive tract), intestinal absorption is of utmost importance for the drug action of TCMs, which are usually taken orally. Meanwhile, complicated drug interactions may occur among the multiple ingredients in a herbal mixture. In this regard, the intestinal permeability assays not only provide useful pharmacokinetic data of TCMs, but have potential applications for quality and safety control. Moreover, knockout animals, 2/4/A1 in-vitro cell model and physiologically-based in-silico models based on the online TCM database can be quite useful for the prediction of absorption and bioavailability of TCMs. SUMMARY: A variety of in-vivo, in-vitro, in-situ and in-silico models for predicting the intestinal absorption and bioavailability can be applied to study the herbal interactions and screen appropriate biomarkers for the quality and safety control of TCMs.

A randomized, crossover comparison of herbal medicine and bromocriptine against risperidone-induced hyperprolactinemia in patients with schizophrenia.

Hyperprolactinemia is a common adverse effect that occurs as a result of antipsychotic therapies, which often results in discontinuation. Empirical evidence has shown that some herbal medicines have suppressive effects on prolactin (PRL) hyperactivities. This study was designed to compare the herbal preparation called Peony-Glycyrrhiza Decoction (PGD) with bromocriptine (BMT), a dopamine agonist widely used for PRL-secreting disorders, in the treatment of risperidone-induced hyperprolactinemia. Twenty schizophrenic women who were under risperidone maintenance treatment, diagnosed with hyperprolactinemia (serum PRL levels >50 mug/L), and currently experiencing oligomenorrhea or amenorrhea were selected for the study. Subjects were randomized to additional treatment with PGD (45 g/d) followed by BMT (5 mg/d) or BMT followed by PGD at the same doses for 4 weeks each, with an interval of 4-week washout period between 2 treatment sessions. The severity of psychotic symptoms, adverse events, serum PRL, estradiol, testosterone, and progesterone levels were examined at baseline and end point. Peony-Glycyrrhiza Decoction treatment produced a significant baseline-end point decrease in serum PRL levels, without exacerbating psychosis and changing other hormones, and the decreased amplitudes were similar to those of BMT (24% vs 21%-38%). Moreover, there was a significantly greater proportion of patients during PGD treatment than BMT treatment showing improvements on adverse effects associated with hyperprolactinemia (56% vs 17%, P = 0.037). These results suggest that the herbal therapy can yield additional benefits while having comparable efficacy in treating antipsychotic-induced hyperprolactinemia in individuals with schizophrenia.