Blanching activities of betamethasone formulations. The effect of dosage form on topical drug availability.

The blanching activities of Betnovate cream, lotion, ointment and scalp application (each containing 0.1% betamethasone (as the 17-valerate] were determined using healthy human subjects over a 32 h period in both the occluded and unoccluded modes. Considering that all four formulation types contained the same label concentration of corticosteroid, it may be presumed that the formulations would show similar topical drug availability: this was, however, not found to be the case. The scalp application demonstrated the highest topical availability in both the occluded and unoccluded modes. The lotion formulation showed the greatest increase in topical availability on occlusion and the ointment formulation was the least sensitive to the effects of occlusion. These differences, due solely to the effects of the vehicle, may have important clinical implications.