Controlled release of hydrocortisone acetate from dermal bases.

The effect of the complexation with beta-cyclodextrin, hydroxypropyl beta-cyclodextrin and polyvinylpyrrolidone on the diffusion kinetics of hydrocortisone acetate through a non porous lipidic membrane was analyzed starting from different dermal bases: a Carbopol gel and lanovaseline. A constant diffusive gradient was achieved; this suggests that the complexation equilibrium controls the diffusable form, according to its stability constant. The following sequence was observed for the cumulative amount diffused: hydrocortisone acetate greater than hydrocortisone acetate/polyvinylpyrrolidone greater than hydrocortisone acetate/hydroxypropyl beta-cyclodextrin greater than hydrocortisone acetate/beta-cyclodextrin. Such behaviour was analyzed in terms of the main physical chemical parameters of the systems examined.