Author(s): Lee PJ, Langer R, Shastri VP
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Abstract PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: The novel microemulsion systems in this study potentially offers many beneficial characteristics for transdermal drug delivery.
This article was published in Pharm Res
and referenced in Journal of Proteomics & Bioinformatics