Pharmacokinetic bioequivalence, safety and acceptability of Ornibel®, a new polymer composition contraceptive vaginal ring (etonogestrel/ethinylestradiol 11.00/3.474 mg) compared with Nuvaring® (etonogestrel/ethinylestradiol 11.7/2.7 mg)

To show the clinical development of Ornibel® (ExeltisHealthcare, Spain) a contraceptive vaginal ring manufactured with a new polymer composition and containing etonogestrel/ethinylestradiol, compared to Nuvaring® (MSD, Spain).Randomised, single dose, 2-period, 2-sequence, 2-stage crossover, comparative bioavailability study conducted in 40 healthy female subjects. All subjects received both treatments for 28 days in each of two periods, separated by a 28 days washout. Ornibel® contains etonogestrel/ethinylestradiol 11.00/3.47 mg and Nuvaring® contains etonogestrel/ethinylestradiol 11.7/2.7 mg, both rings delivering 120/15 µg/day. For the calculation of pharmacokinetic parameters, 37 blood samples were collected up to 840 h after each ring insertion to quantify plasma concentrations of etonogestrel and ethinylestradiol using a validated MS/MS-HPLC. Safety was assessed by adverse events recording, clinical laboratory and vital signs and tolerability by vaginal examination. Acceptability was investigated by a 5-point scale questionnaire.Bioequivalence was demonstrated in the first stage as the 94.12% Confidence Intervals of the primary parameters laid within the 80-125% acceptance range for both etonogestrel (Cmax: 96.81-112.20%; AUC0-504h: 98.71-108.61%; AUC0-t: 100.14-109.10%) and ethinylestradiol. (Cmax: 105.91-120.62%; AUC0-504h: 105.47-114.59%; AUC0-t: 108.31-117.61%). During the first day of use a burst effect was observed with Nuvaring®, with significantly higher level of ethinylestradiol (Cmax0-24h ratio: 78.34%, 94.12CI: 73.55-83.45%). Both products were well tolerated and accepted, without significant differences between them.Ornibel® is bioequivalent to Nuvaring® in terms of efficacy, safety, tolerability and acceptability. The new polymer composition provides Ornibel® with more stability and gradual hormonal release during the first day of use, particularly for ethinylestradiol.