Comparison of three subcutaneous modes of prostaglandin F2 alpha administration for pregnancy termination in the hamster.

Dose response relationships for pregnancy termination in hamsters following administration of prostaglandin F2 alpha (PGF2 alpha) by three subcutaneous methods were determined in 526 hamsters. The median effective dose (ED50) for PGF2 alpha given as a single subcutaneous injection in 500 microliters of saline was 22.2 micrograms. Administration of the prostaglandin with an Alzet osmotic minipump (subcutaneous insertion for 24 hours) required 1.35 times more PGF2 alpha (ED50=30.0 micrograms). The least effective method of pregnancy termination in the hamster involved administration of PGF2 alpha by a single subcutaneous injection in 20.4 microliters of saline (the same volume delivered by the minipump in 24 hours); the ED50 for this method of administration was 41.3 micrograms of PGF2 alpha.