A pharmacokinetic comparison of the corn oil versus microemulsion gelcap formulation of cyclosporin used de novo after renal transplantation

The initial poor absorption of the corn oil-based, gel capsule oral formulation of cyclosporin (CyA) greatly limits its use for inception of immunosuppressive therapy. Insufficient drug concentrations during the early post-transplant period predispose to renal allograft rejection. The present study served to compare the time required to achieve therapeutic CyA concentrations after de novo administration of the corn oil-based gel capsule (CyA-GC; n = 11) versus the microemulsion (CyA-ME; n = 11) formulation of CyA. During the 1st month after renal transplantation, patients underwent serial pharmacokinetic profiling from which we obtained observed and dose-corrected values of several parameters. Although patients in neither the CyA-GC nor the CyA-ME group adequately absorbed the drug during days 0–2, from day 3 to 4 patients in the CyA-ME group showed significantly greater absorption than those in the CyA-GC group (P = 0.041). Patients in the CyA-ME group reached the 1st month target average concentration (C_av) values ( ≥ 550 ng/ml) earlier than those in the CyA-GC group and required significantly lower daily CyA doses (P = 0.018). We conclude that therapeutic CyA levels can be achieved more rapidly and with lower doses of the drug after de novo administration of CyA-ME than with CyA-GC. Received: 13 September 1996 Accepted: 7 January 1997     

微乳对难溶性药物增溶机理的研究

目的:初步探讨微乳对难溶性药物的增溶机理.方法:经处方筛选及相图研究确定(BL-9/正丁醇3∶1)/油/水比例为9∶1∶40的微乳处方;以二氢吡啶类药物为模型药物,测定其在微乳、胶束和油相中的溶解度及油/水分配系数;根据化学结构,采用计算机软件计算药物的特性参数,并结合模型药物的特性分析微乳增溶难溶性药物的机理.结果:微乳对药物的增溶效果远大于油相和胶束,并随药物的脂溶性和空间结构的改变而变化.结论:微乳可用于增溶难溶性药物,且脂溶性越大,空间位阻越小,增溶效果越明显.     

卡介苗多糖核酸微乳的研究

目的制备卡介苗多糖核酸(BCG-PSN)微乳。方法采用磷脂为乳化剂,乙醇为助乳化剂,油酸乙酯为油相,用改良三角相图法确定微乳区域,优化BCG-PSN微乳处方组成。结果与结论所制得BCG-PSN微乳澄清透明,性质稳定。     

十二烷基硫酸钠微乳体系的相行为及电导行为研究

目的 对十二烷基硫酸钠(SDS)/正庚烷/正丁醇/水体系微乳液的相行为和电导行为进行了研究.方法 用电化学方法测定了微乳体系的电导率.结果 体系在水滴定过程中均出现渗滤电导现象,温度升高,体系的电导率增大,表观活化能也增大,SDS微乳体系在pH2.5～11范围内具有良好的抗酸、碱性能.结论 通过电导率的测定可研究微乳体系的结构及结构转变.     

草乌甲素微乳的制备及其理化性质的考察

目的 选择适宜比例的油相、表面活性剂、助表面活性剂和水相,制备草乌甲素微乳制剂,以增加药物的溶解度,优化处方,并研究其理化性质.方法 绘制伪三元相图,确定各相的比例,以微乳区域大小为指标,考察优化微乳的处方.测定草乌甲素微乳的粒度及其分布.结果 草乌甲素微乳制剂中药物的溶解度极大提高,乳液滴的平均粒径为53.6 nm.结论 制备了O/W型草乌甲素微乳,为开发草乌甲素透皮制剂提供了依据.     

Using microemulsion formulations for oral drug delivery of therapeutic peptides

Peptide drugs are increasingly becoming a very important class of therapeutic agents with the rapid advances in the field of biotechnology engineering. However, these drugs are generally not suitable for oral administration. In this review, the main physico-chemical and biopharmaceutical characteristics of peptides are summarized. The obstacles to peptide drug absorption and the different possibilities for solving these difficulties are listed. Results using this formulation approach for oral drug delivery of peptides are apparently promising with some specific peptides such as cyclosporin. Various mechanisms are only beginning to be understood and further investigations need to be performed in this area to explain the results obtained with some peptides.     

In vivo evaluation of the safety of triptolide-loaded hydrogel-thickened microemulsion

Triptolide (TP) is a major active component of Tripterygium wilfordii Hook F (TWHF), which is used to treat rheumatoid arthritis (RA). TP has a narrow therapeutic window. To increase the therapeutic index of TP, a novel TP-loaded transdermal delivery system, named TP-loaded hydrogel-thickened microemulsion (TP-MTH), has been developed to treat RA. Our previous studies have demonstrated the good efficacy of TP-MTH in animals. This paper evaluated the safety of TP-MTH with several animals. Results demonstrated no obvious toxicities in a series of toxicity tests: acute toxicity study of TP-MTH (1.2 mg/kg) in rabbits, 6-month long-term toxicity study of TP-MTH (0.06, 0.18, 0.54 mg/kg) in rabbits, safety pharmacology study of TP-MTH (0.03, 0.09, 0.27 mg/kg, for 5 d) in mice and beagle dogs, skin irritation study in rabbits, and skin allergic reaction test in guinea pigs. Only mild reversible skin irritation signs were observed on the skin of animals. These studies suggest that topical TP-MTH is a promising drug formulation for the treatment of RA.     

Preparation and evaluation of aceclofenac microemulsion for transdermal delivery system

To develop novel transdermal formulation for aceclofenac, microemulsion was prepared for increasing its skin permeability. Based on solubility and phase studies, oil and surfactant was selected and composition was determined. Microemulsion was spontaneously prepared by mixing ingredients and the physicochemical properties such was investigated. The mean diameters of microemulsion were approximately 90 nm and the system was physically stable at room temperature at least for 3 months. In addition, the in vitro and in vivo performance of microemulsion formulation was evaluated. Aceclofenac was released from microemulsion in acidic aqueous medium, and dissolved amounts of aceclofenac was approximately 30% after 240 min. Skin permeation of aceclofenac from microemulsion formulation was higher than that of cream. Following transdermal application of aceclofenac preparation to delayed onset muscle soreness, serum creatine phosphokinase and lactate dehydrogenase activity was significantly reduced by aceclofenac. Aceclofenac in microemulsion was more potent than cream in the alleviation of muscle pain. Therefore, the microemulsion formulation of aceclofenac appear to be a reasonable transdermal delivery system of the drug with enhanced skin permeability and efficacy for the treatment of muscle damage.