Comparison of the pharmacokinetics of XXXX 8% administered vaginally versus Prometrium administered orally in postmenopausal @entity1 (3).

@entity1 @entity26602 @entity1420
OBJECTIVE: Compare the pharmacokinetics of vaginal @entity1420 gel ( @entity26602 8%, 90 mg) with that of oral @entity1420 (Prometrium, 100 mg). DESIGN: Open-label, randomized, parallel-group protocol. SETTING: Outpatient clinic. @entity1 (S): Twelve healthy postmenopausal @entity1 . INTERVENTION(S): Six subjects each were randomized to receive @entity1420 , which was administered either as 90 mg of @entity1420 gel ( @entity26602 8%) given vaginally or 100 mg @entity1420 in a capsule (Prometrium) given orally. MAIN OUTCOME MEASUREMENT(S): Serum @entity1420 levels were measured by both radioimmunoassay (RIA) and liquid chromatography-mass spectrometry (LC-MS). RESULT(S): @entity1420 given vaginally resulted in greater bioavailability with less relative variability in absorption than oral @entity1420 (mean AUC(0-24) = 1.48 +/- 0.16 ng. h/mL per milligram vs. 0.035 +/- 0.0052 ng. h/mL per milligram). Mean C(max) for oral @entity1420 was much lower than that of vaginal @entity1420 (i.e., 2.20 +/- 3. 06 ng/mL vs. 10.51 +/- 0.46 ng/mL). Mean T(max) occurred earlier for oral @entity1420 than for @entity26602 (1.00 +/- 0.41 hours vs. 7.67 +/- 3.67 hours). Radioimmunoassay is inappropriate for determining serum @entity1420 levels after oral administration, because it provided erroneously high values that were approximately eightfold higher than those obtained with LC-MS. CONCLUSION(S): @entity26602 ( @entity1420 gel) given vaginally results in greater bioavailability with less relative variability than oral @entity1420 , thus providing more reliable delivery of @entity1420 , compared with oral @entity1420 . Measuring circulating @entity1420 with use of direct RIA is not appropriate after oral @entity1420 administration.
