Lambert Joshua D, Kim Dou Hwan, Zheng Ruijin, Yang Chung S
Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
J Pharm Pharmacol. 2006 May;58(5):599-604. doi: 10.1211/jpp.58.5.0004.
Epigallocatechin-3-gallate (EGCG) is the most studied catechin in green tea (Camellia sinensis). EGCG and green tea are cancer preventive in many animal models, and numerous mechanisms have been proposed in cell lines. EGCG is poorly bioavailable in man and rodents. We hypothesized that transdermal delivery of EGCG could result in improved bioavailability. Following application of EGCG transdermal gel (50 mg kg(-1), t.d.) to SKH-1 mice, EGCG was observed in the epidermis (1365.7-121.0 ng g(-1)) and dermis (411.2-42.6 ng g(-1)). The maximum plasma concentration (Cmax) of EGCG was 44.5 ng mL(-1). The t(1/2) (94.4 h) and AUC(0-->24 h) (881.5 ng mL(-1) h) of EGCG were greater than values previously reported for oral EGCG. The t(1/2) and area under the concentration-time curve up to 24 h (AUC(0-->24 h)) in the liver, small intestine and colon were 21.3-74.6 h and 715-2802 ng g(-1)h, respectively. Stability studies showed that the transdermal formulation was stable at 4 degrees C and had a half-life (t(1/2)) of 47.1 and 20.2 h at 25 degrees C and 37 degrees C, respectively. These data indicate that transdermal EGCG is useful for delivering prolonged levels of EGCG to plasma and tissues, and may provide an alternative to tea consumption as a dosage form of EGCG.
表没食子儿茶素-3-没食子酸酯（EGCG）是绿茶（茶树）中研究最多的儿茶素。在许多动物模型中，EGCG和绿茶都具有防癌作用，并且在细胞系中已提出了多种机制。EGCG在人和啮齿动物中的生物利用度较差。我们推测EGCG的透皮给药可能会提高其生物利用度。将EGCG透皮凝胶（50 mg kg(-1)，每日一次）应用于SKH-1小鼠后，在表皮（1365.7 - 121.0 ng g(-1)）和真皮（411.2 - 42.6 ng g(-1)）中观察到了EGCG。EGCG的最大血浆浓度（Cmax）为44.5 ng mL(-1)。EGCG的t(1/2)（94.4小时）和AUC(0→24 h)（881.5 ng mL(-1)·h）大于先前报道的口服EGCG的值。在肝脏、小肠和结肠中，t(1/2)和浓度-时间曲线下面积直至24小时（AUC(0→24 h)）分别为21.3 - 74.6小时和715 - 2802 ng g(-1)·h。稳定性研究表明，透皮制剂在4℃下稳定，在25℃和37℃下的半衰期（t(1/2)）分别为47.1小时和20.2小时。这些数据表明，透皮EGCG可用于向血浆和组织中递送延长水平的EGCG，并且可能作为EGCG的剂型提供一种替代饮茶的方式。
