Original research article Contraceptive efficacy and safety of HerbOshield™ vaginal gel in rats Kamalinder K. Singh ⁎ , Shruti Parmar, Pratima A. Tatke C.U. Shah College of Pharmacy, Shreemati Nathibai Damodar Thakersey Women's University, Santacruz (West), Mumbai-400049, India Received 3 August 2010; revised 12 April 2011; accepted 23 April 2011 Abstract Background: Spermicides represent one of the methods of contraception. The synthetic agents available as spermicides produce severe side effects. Hence, there is a need to replace these agents with safe and effective agents such as plant-based contraceptive agents. Study Design: The objective of the present study was to develop and evaluate a stable, safe, effective and easily acceptable contraceptive delivery system containing herbal drug. Efforts were made to evaluate the contraceptive potential of the hydroalcoholic extract from the seeds of Annona squamosa Linn. and the vaginal gel HerbOshield™ containing the extract. Results: Spermicidal effect was evaluated in vitro using healthy human spermatozoa and in vivo in rats. The in vitro results demonstrated that HerbOshield™ vaginal gel is an effective spermicide. At a 100-mg/mL dose, complete immobilization of human spermatozoa was observed within 20 s. None of the treated animals conceived, indicating 100% contraceptive effect as compared to Gynol II, a nonoxynol-9- containing marketed formulation, which showed only 67% contraceptive effect in vivo. HerbOshield™ vaginal gel was found to be safe in animals during a 14-day toxicity study. Conclusions: HerbOshield™ vaginal gel was found to be safe and effective in rats and could be developed as a potential vaginal contraceptive for future use in humans. © 2012 Elsevier Inc. All rights reserved. Keywords: Annona squamosa Linn.; Seed extract; Vaginal gel; HerbOshield™; Spermicidal; Rats 1. Introduction The world population is expanding at an alarming rate of 146 people per minute, 8760 per hour and 210,959 per day, leading to total annual increase of world population by 77 million. According to the medium-fertility scenario, the world population will grow to 9.4 billion in 2050, 10.4 billion in 2100 and 10.8 billion by 2150. The population of India accounts for approximately 17% of the world population. It is considered as the second most populous country in the world. In today's context, the problem of overpopulation and the resulting need for birth control are becoming even more important [1]. Contraceptives have proven their worth to some extent to control this menace. However, the synthetic oral contracep- tives available today for fertility control produce severe side effects such as hormonal imbalance, hypertension, increased risk of cancer, weight gain, etc. Therefore, many more efforts are still needed in this field. Spermicides represent an accepted method of vaginal contraception. Many compounds with diverse pharmacological activity have been evaluated in vitro and in vivo for their spermicidal activity; however, there is a paucity of data regarding the safety profile of most of these agents. Today, only nonoxynol-9 is marketed as a spermicide, and that too suffers from side effects of vaginal irritation on prolonged use. Combination formulations of two or more contact spermicides are being evaluated in order to minimize their adverse effects. There is still a need to develop more safe contact spermicides [2]. This has acce- lerated interest in identifying new compounds as alternatives to nonoxynol-9 that could prevent unintended pregnancies. Plant origin products are without any side effects as opposed to synthetic drugs. Therefore, plant-based products need more attention. There are many plants with reported antifertility activity. Some of these plants/plant extracts have been used as antifertility agents in folklore [3]. India, the center of mega-biodiversity with varied climatic, altitudinal and soil conditions, possesses 3500 medicinal plants [4]. Some of these plants/plant extracts such as Azadirachta indica [5,6], Chenopodium album [7] and Mallotus philippinensis [8] have Contraception 85 (2012) 122 – 127 ⁎ Corresponding author. Tel.: +91 22 26609577, +91 9821358880. E-mail address: kksingh35@hotmail.com (K.K. Singh). 0010-7824/$ – see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.contraception.2011.04.013