Studies on Corticosteroid Ointments. VII. Percutaneous Absorption of Hydrocortisone-4-¹⁴C (3) Accumulation into the Skin of Hydrocortisone Acetate

Abstract

Accumulation of hydrocortisone [4-¹⁴C] acetate into the epidermis and its release from the corium into saline were examined by the in vitro method described previously. The skin used was epidermis separated from a full-thickness of the skin excised from human or guinea pig abdomen. The results of examination showed that the rate of release of hydrocortisone [4-¹⁴C] acetate from the liquid vehicles to the epidermis was equal to the rate of its release to the full-thickness skin, and radioactivity was not detected in the saline, as reported ealier. However, when the corium, removed of epidermis, was used, release of labeled hydrocortisone acetate from liquid paraffin into saline through the corium was remarkably increased, and the amount of labeled hydrocortisone acetate in saline increased with lapse of time. When other vehicles were used, such as propylene glycol-water (30 : 70) or HS-12-P (Iauricdiethanolamide) -water (10 : 90), the release of labeled hydrocortisone acetate into saline was not detected. Therefore, release of hydrocortisone [4-¹⁴C] acetate from liquid vehicle into saline through the corium dose not always increased with removal of the epidermis.