title: Azoospermia in rabbits following an intravas injection of Vasalgel ™.
abstract: BACKGROUND
  Vasectomy is currently the only long-acting contraceptive option available for men, despite increasing demand and potentially significant positive impacts on human health of additional male contraceptive options. Vasalgel ™ is a high molecular weight hydrogel polymer being developed as a non-hormonal long-acting reversible male contraceptive. Vasalgel consists of styrene-alt-maleic acid dissolved in dimethyl sulfoxide, which is distinct from styrene-alt-maleic anhydride materials previously studied.
  
  
  METHODS
  The goal of the study was to determine the contraceptive efficacy of two test articles with different levels of styrene maleic acid (100 %, and 80 % acid/20 % anhydride). The test articles were injected bilaterally in the vasa deferentia of mature male rabbits. Post-implantation analyses of semen parameters were completed over a 12 month period and compared to baseline measures of sperm concentration, motility and forward progression.
  
  
  RESULTS
  Both test articles were effective in blocking the passage of spermatozoa through the vasa deferentia in the 12 subjects completing the study. A significant decrease in sperm concentration occurred following implantation of the test material, with no measurable sperm concentration except for a few samples in one animal that were markedly oligospermic. Vasalgel produced a rapid onset of azoospermia, with no sperm in semen samples collected as early as 29-36 days post-implantation, and was durable over a 12 month period.
  
  
  CONCLUSIONS
  This study indicated that Vasalgel is an effective non-hormonal long-acting male contraceptive in a rabbit model.
authors.affiliation: Prelabs, LLC Inc., 33 W Chicago Ave., Oak Park, IL 60302 USA.
authors.forename: Donald
authors.identifier: 0000-0002-6856-5003
authors.initials: D
authors.lastname: Waller
authors.affiliation: Seraphim Life Sciences Consulting, LLC, 2158 Bonaventure Drive, Suite 101, Vienna, VA 22181 USA.
authors.forename: David
authors.initials: D
authors.lastname: Bolick
authors.affiliation: Parsemus Foundation, PO Box 2246, Berkeley, CA 94702 USA.
authors.forename: Elaine
authors.initials: E
authors.lastname: Lissner
authors.affiliation: Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, 1925 Coffey Road, Columbus, OH 43215 USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Premanandan
authors.affiliation: Seraphim Life Sciences Consulting, LLC, 2158 Bonaventure Drive, Suite 101, Vienna, VA 22181 USA.
authors.forename: Gary
authors.initials: G
authors.lastname: Gamerman
keywords: Hydrogel; Male contraception; Polymer; Styrene maleic acid; Vas deferens; Vasectomy