Plasma levels of 15(S)15-methyl PGF2alpha following administration via various routes for induction of abortion.
Plasma levels of 15(S)15-methyl PGF2alpha were measured by gas chromatography - mass spectrometry following intravenous, intramuscular and subcutaneous administration. During intravenous infusion of 1.0 and 2.5 microgram/min of the drug for six hours the plasma levels were relatively constant around 600 and 1200 picog/ml, respectively. At an infusion rate of 5 microgram/min the plasma level continuously increased during the administration. Intramuscular injections of 100-400 microgram of 15(S)15-methyl PGF2alpha gave maximum levels in plasma (700-1700 picog/ml) after 15-20 minutes followed by a gradual decrease during more than three hours. This rapid resorption of drug into plasma could be delayed by addition of 5 microgram epinephrine to the injected solution. Analyses during a series of intramuscular injections demonstrated that a therapeutical plasma level could be maintained by injections at two to three hour intervals.