Efficacy of nonhormonal vaginal contraceptives from a hydrogel delivery system.
This investigation describes the synthesis of a biodegradable hydrogel composed of a core surrounded by four concentric sheaths containing dextran, copolymers of polylactide and epsilon-caprolactone. The hydrogel was impregnated with iron (II) d-gluconate dihydrate, which causes complete spermiostasis due to lipid peroxidation, ascorbic acid to increase the viscosity of the cervical mucus and mixtures of polyamino and polycarboxylic acids to sustain vaginal pH close to 4.5. The combined effects of the agents in the daily eluates of the hydrogel were efficacious up to 16 days, within 30 s, as shown by sperm penetration tests. For in vivo studies, rabbits were chosen as the experimental model because they are easy to handle and the female is always in estrus. The anterior vagina of estrous female rabbits was instilled with the hydrogel, and then inseminated with the semen from a fertile male. Postinsemination flush from the female rabbits showed that all of the sperm were dead. These observations demonstrate the potential for the development of a biocompatible, nonhormonal, intravaginal contraceptive device.
Division of Reproductive Endocrinology, Weill Medical College, Cornell University, 515 East 71st Street, S-412, New York, NY 10021, USA. brs2003@med.cornell.edu
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Saxena
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Singh
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Chu
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Ledger
D000282:Administration, Intravaginal; D000665:Ampholyte Mixtures / Q000737:chemistry; D000818:Animals; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D002582:Cervix Mucus / Q000187:drug effects*; D003271:Contraceptive Agents, Female / Q000008:administration & dosage / Q000494:pharmacology*; D003911:Dextrans / Q000737:chemistry; D005260:Female; D005296:Ferrous Compounds / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008297:Male; D011091:Polyesters / Q000737:chemistry; D011817:Rabbits; D013081:Sperm Motility / Q000187:drug effects*; D013084:Sperm-Ovum Interactions / Q000187:drug effects
D000665:Ampholyte Mixtures; D003271:Contraceptive Agents, Female; D003911:Dextrans; D005296:Ferrous Compounds; D020100:Hydrogels; D011091:Polyesters; C033616:poly(lactide); D001205:Ascorbic Acid; C011819:ferrous gluconate