The use of long acting subcutaneous levonorgestrel (LNG) gel depot as an effective contraceptive option for cotton‐top tamarins (Saguinus oedipus)

Abstract

Cotton-top tamarins (Saguinus oedipus) are a critically endangered species that have been bred successfully in captivity for many years. For two decades, the Cotton-top Tamarin SSP(©) has been challenged with a high rate of reproduction combined with a history of contraceptive failures and nonrecommended births using the current Depo Provera(®) (medroxyprogesterone acetate) injection followed by MGA (melengestrol acetate) implant contraception combination. To address these issues we have developed and tested the use of levonorgestrel (LNG) as an effective contraception option for cotton-top tamarins. LNG was delivered in an injectable, gel matrix consisting of polylactic-co-glycolic acid, triethyl citrate and N-methylpyrrolidone. This gel matrix forms a biodegradable depot at the subcutaneous injection site providing slow release of the active ingredient. Gel matrix composition and LNG concentration were adjusted in four gel formulations to maximize the duration of contraceptive efficacy while minimizing immediate post-injection increases in fecal LNG concentration. LNG treatment (68.44 ± 8.61 mg/kg) successfully eliminated ovarian cycles (fecal pregnanediol-3-glucuronide (PdG) and estrone conjugates (E(1) C)) for 198.8 ± 70.3 days (formulation four; range 19-50 weeks). It was demonstrated that subcutaneous LNG depot injection was an effective, reversible contraceptive option for the management of cotton-top tamarins in captivity.

Fertility control to mitigate human–wildlife conflicts: a review

“…Because of side effects such as migraine and weight changes, the implant was withdrawn from the human-contraception market in some countries (Benfield and Darney 2011). A single administration of levonorgestrel implants inhibits reproduction in wildlife species for several years, without apparent adverse side effects (Nave et al 2002a;Middleton et al 2003;Coulson et al 2008;Wheaton et al 2011). In addition, levonorgestrel and quinestrol have been successfully used as contraceptives for rodents such as plateau pikas (Ochotona curzioniae) and Mongolian gerbils (Meriones unguiculatus) (e.g.…”

Nonsurgical fertility control for managing free-roaming dog populations: A review of products and criteria for field applications

“…For instance, levonorgestrel implants provided 3 to 4 years of contraception in tammar wallabies (Macropus eugenii) [35], gray kangaroos (Macropus giganteus) [36], and koala (Phascolarctos cinereus) females [37]. Levonorgestrel implants induced infertility in captive Cotton-top tamarins (Saguinus oedipus) for 19 to 50 weeks [38] and in domestic cats for at least 1 year [39]. Because the patent on levonorgestrel implants has recently expired, at least in Australia, it is now possible to obtain these products for US$ 10 per dose (G. Coulson, personal communication), although no trial has been published on effects and effectiveness in dogs.…”

Conserving Cotton‐top tamarins Saguinus oedipus through effective captive management, public engagement and in situ conservation efforts

“…This population is strictly managed to maintain high genetic diversity (97·8%) as well as to provide the necessary social skills for animals to breed and rear their offspring successfully. Cotton‐top tamarins continue to thrive in the SSP population with significant emphasis placed on regulating population size to a maximum of 300 individuals through the use of contraception and sterilization (Lee‐Parritz & Roberts, ; Porton & DeMatteo, ; Wheaton et al ., ). Developing effective methods of contraception for Cotton‐top tamarins is challenging, given they have an 18 day post‐partum ovulation, 80% of which result in a new pregnancy.…”