Chemical penetration enhancers azone

On the other hand, SEPA (2-n-nonyl-l,3-dioxolane) has been shown to be a more versatile penetration enhancer in terms of its ease of formulation, chemical stability and its ability to enhance the skin penetration of a wide variety of compounds of varying physicochemical characteristics. Permeants that have been evaluated include indomethacin, ibuprofen, minoxidil, acyclovir, caffeine, econazole, papaverine, progesterone and estradiol. The degree of skin penetration enhancement using SEPA is dependent on the physicochemical characteristics of the permeant. For example, following application of indomethacin in a simple ethanol-propylene glycol vehicle to human skin in vitro, cumulative absorption over 24 h amounted to 0.7 percent of the applied dose. The addition of 2 percent SEPA to the vehicle increased the 24 h absorption value to 23 percent of the applied dose (Marty et al. 1989). Furthermore, in comparative studies between SEPA and Azone, SEPA was shown to be a more effective human skin permeation enhancer for indomethacin (Figure 14.6, Marty et al. 1989). 

Azone (l-dodecylazacycloheptan-2-one, laurocapram), along with its derivatives are probably the most widely investigated penetration enhancers and are effective at low concentrations for both lipophilic and hydrophilic drugs but suffer from toxicity problems. Azone is a hybrid of a cychc amide with an alkyl sulfoxide, and its chemical structure has a long alkyl chain and a lactam group (Wilhams and Barry,... 

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