Rate and extent of absorption of clonidine from a transdermal therapeutic system.

The in-vivo performance of a clonidine transdermal therapeutic system (TTS 3.5 cm2, 2.5 mg) was assessed in 12 healthy normal volunteers. Particular attention was paid to the rate and extent of absorption of clonidine from the TTS dosage form by reference to a 2 h i.v. infusion of clonidine. The absolute bioavailability of clonidine from the TTS dosage form was found to be approximately 60% with clonidine being released from the TTS at a relatively reproducible and consistent rate of 4.32 micrograms h-1 over a 7-day period.