Penetration enhancement of ibuprofen from supersaturated solutions throughhuman skin

Systematic investigations on the diffusion of ibuprofen (IBU) from supersat urated solutions through human epidermis are reported. Significant flux enh ancement was obtained from supersaturated solutions compared to the saturat ed solution. Hydroxypropyl methylcellulose (HPMC), when used as an additive was found to be effective in maintaining the high activity state at high d egrees of saturation (DS). The increase in the flux was proportional to the DS. In the presence of 2-hydroxypropyl-beta -cyclodextrin (CD) at DS 2 and 3 a lower flux was observed compared to HPMC. At DS 5 a higher flux enhanc ement was found suggesting that CD might act as a penetration enhancer at c ertain CD/drug ratios. Studies on the mechanism of stabilisation of HPMC an d CD on IBU crystallisation from supersaturated systems showed that HPMC ac ts as a growth inhibitor and habit modifier whereas CD does not influence t he crystallisation process. (C) 2001 Elsevier Science B.V. All rights reser ved.