ADMINISTRATION OF UNMODIFIED PROGESTERONE BY NASAL SPRAY IN FERTILE WOMEN

A 11.20-mg dose of progesterone was administered by nasal spray to fiv e healthy fertile women in the follicular phase of the menstrual cycle . Serial blood samples were collected and C-max (the maximum progester one concentration reached), T-max (the time at which C-max was reached ) and the area under the curve (AUC), with the time limits of 0 and 72 0 min, were calculated. Serum progesterone levels were assayed by mean s of a non-extraction [I-125]radioimmunoassay. The mean C-max was 4.50 +/- 2.31 ng/ml at a T-max of 30 min; levels returned to baseline afte r 720 min. The mean AUC value was 1180.50 +/- 613.90 ng . h/ml. The pr ogesterone administered by nasal spray infertile women war effective i n reaching physiological progesterone levels. Even if a nasal first-pa ss metabolic effect is taken into account, this route allows progester one to avoid liver first-pass metabolism and its metabolic consequence s.