Lee Philp J, Langer Robert, Shastri V Prasad
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
Pharm Res. 2003 Feb;20(2):264-9. doi: 10.1023/a:1022283423116.
Microemulsion (ME) systems allow for the microscopic co-incorporation of aqueous and organic phase liquids. In this study, the phase diagrams of four novel ME systems were characterized.
Water and IPM composed the aqueous and organic phases respectively, whereas Tween 80 served as a nonionic surfactant. Transdermal enhancers such as n-methyl pyrrolidone (NMP) and oleyl alcohol were incorporated into all systems without disruption of the stable emulsion.
A comparison of a W/O ME with an O/W ME of the same system for lidocaine delivery indicated that the O/W ME provides significantly greater flux (p < 0.025). The water phase was found to be a crucial component for flux of hydrophobic drugs (lidocaine free base, estradiol) as well as hydrophilic drugs (lidocaine HCl, diltiazem HCl). Furthermore, the simultaneous delivery of both a hydrophilic drug and a hydrophobic drug from the ME system is indistinguishable from either drug alone. Enhancement of drug permeability from the O/W ME system was 17-fold for lidocaine free base, 30-fold for lidocaine HCl, 58-fold for estradiol, and 520-fold for diltiazem HCl.
The novel microemulsion systems in this study potentially offers many beneficial characteristics for transdermal drug delivery.
微乳（ME）系统可使水相和有机相液体在微观层面上共同掺入。在本研究中，对四种新型ME系统的相图进行了表征。
水和IPM分别构成水相和有机相，而吐温80用作非离子表面活性剂。将诸如N-甲基吡咯烷酮（NMP）和油醇等透皮促进剂掺入所有系统中，而不破坏稳定的乳液。
对同一系统用于利多卡因递送的油包水型微乳和水包油型微乳进行比较表明，水包油型微乳的通量显著更高（p < 0.025）。发现水相对于疏水性药物（利多卡因游离碱、雌二醇）以及亲水性药物（盐酸利多卡因、盐酸地尔硫䓬）的通量而言是关键成分。此外，从微乳系统同时递送亲水性药物和疏水性药物与单独递送任何一种药物没有区别。从水包油型微乳系统中药物渗透性的增强倍数，对于利多卡因游离碱为17倍，对于盐酸利多卡因是30倍，对于雌二醇是58倍，对于盐酸地尔硫䓬是520倍。
本研究中的新型微乳系统可能为透皮给药提供许多有益特性。
