Effects of storage and temperature upon soft jelly capsules containing nonoxynol as spermicide.

ABSTRACT

Recently, adverse effects of long periods of storage and high temperature on physical characteristics of the soft jelly capsule wall were observed. In the present study, the effects of both parameters upon the mean rupture time of the capsule, and the release of the active compound were evaluated in vivo in 40 women. The results disclosed that the storage for long time and the exposure of the capsules to high temperatures, delays significantly the mean rupture time and the release of the active compound. A rapid distribution, adequate storage, as well as a delay of intercourse after vaginal insertion of the device are suggested.

ABSTRACT

PIP In Coahuila, Mexico, 20 women vaginally inserted soft jelly capsules containing the spermicide nonoxynol-9 which had been stored for 90 days at 25-30 degrees Celsius (group I), and 20 more women inserted capsules of the same type which had been stored in an incubator for 90 days at 45 degrees Celsius (group II). All 40 women inserted the capsules during days 12-14 of the menstrual cycle to avoid physiological changes of vaginal humidity during the cycle. At the end of each study period (2-13 minutes), rupture/nonrupture and weight of the capsules were recorded. A loss of more than 15% of the capsule's weight constituted release of nonoxynol-9. The time for the capsule to rupture ranged from 4 to 12 minutes for group I and from 6 to 13 minutes for group II. The mean rupture time was greatest for those capsules stored at the higher temperature (i.e., group II) (10.2 vs. 5.6 minutes; p 0.001). The mean release time was also greatest for group II (12.1 vs. 6.7 minutes; p 0.02). Thus, long storage and high temperature delayed the minimum time for capsule rupture in the vagina by 4-6 minutes. Capsules stored for a long time and at a high temperature had a higher wall consistency than their counterparts. Capsules stored at a high temperature had a harder consistency than those stored at a lower temperature. These findings suggest the need to rapidly distribute capsules, to store them under controlled temperature, and to delay intercourse after insertion for more than 10 minutes.