Isopropyl myristate permeability coefficient

Percutaneous penetration of 7V-nitrosodiethanolamine was measured using cryo-preserved human trunk skin and three vehicle formulations (isopropyl myristate, sunscreen cream or a 10% shampoo) containing 7V-nitroso[ C]diethanolamine. The absorption rate of a low dermal dose (10 ixg/cm ) of 7V-nitrosodiethanolamine was a linear function of the concentration (0.06, 0.2 or 0.6 Xg/ xL) applied to the skin. The peak rates for the isopropyl m uistate and shampoo vehicles were seen within five hours and for the sunscreen somewhat later. Total 48-h absorption ranged from 35 to 65% of the dose and was formulation-dependent (isopropyl m uistate > shampoo > sunscreen). A total absorption of 4-6 x JcaE was estimated to equate to an applied N-nitrosodiethanolamine dose of 10 x%lcaE. When applied as a large infinite dose (0.5 mg/cm ), total 7V-nitrosodiethanolamine absorption (4-35% of the applied dose) followed a different rank order (shampoo > isopropyl m uistate > sunscreen), probably due to the barrier-damaging properties of the vehicles. The permeability coefficient for isopropyl myristate was 3.5 X 10 cm/h (Franz etal., 1993). 

Note ER, a ratio of the skin permeability coefficient or the flux for skin exposed to azone vs. a oontrol value for skin not exposed to azone PG, propylene glycol ET, ethanol IPA, isopropanol IPM, isopropyl myristate. 

Figure 2 ( ) Isopropyl myristate/buffer partition coefficient and (O) permeability coefficient Kof propranolol over a hydrophilic membrane from Tween 60-isopropyl myristate-butanol-water microemulsions with varying octanoic acid/propranolol ratios. (Data from Ref. 18.)...

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