Biodegradable poly(DL-lactic acid) formulations in a calcitonin delivery system.

A synthetic analogue of eel calcitonin, [Asu1, 7]-ECT, was incorporated into biodegradable poly(DL-lactic acids) with number-average molecular weights (Mn) of 1400-4400 by the melt-pressing technique. The in vitro release of drug from a parabolically degradable poly(DL-lactic acid) with Mn = 1400 showed an initial burst release and completed the release in 3 d from the start of the test. The drug release from a Mn = 4400 polymer with an S-type degradation pattern was kept at 14 +/- 5 units/d for an experimental period of 24 d.