title: Study of the micro-structural properties of RISUG--a newly developed male contraceptive.
abstract: A new male contraceptive given the name RISUG (an acronym for reversible inhibition of sperm under guidance) and presently undergoing advanced clinical trials has been developed. When injected into the lumen of the vas deferens, its polyelectrolytic nature induces a surface charge imbalance on sperm membrane system leading to the leakage of enzymes essential for fertilization. Contact mode atomic force microscopy (AFM) has been used to analyze quantitatively the micro-structural properties of RISUG and its precipitate in various systems. Hydrolysis of the contraceptive gel resulted in the formation of pores of varying dimensions. RISUG being a highly charged molecule, as evident from zeta potential measurements, has a tendency to form a complex with ionic biomolecules present in the seminal plasma. This is supported by the experimental observations using AFM. This RISUG-biomolecule complex possibly acts as an ionic trap for spermatozoa passing through the vas deferens. Micro-structural properties of RISUG including amplitude (root mean square, peak-to-valley distance, skewness and kurtosis) and spatial roughness have been studied to understand its response to various physiological conditions. Significant alterations in the surface charge distribution of the sperm cell is observed on exposure to RISUG.
authors.affiliation: School of Medical Science and Technology, Indian Institute of Technology, Kharagpur 721302, India.
authors.forename: Sunil
authors.initials: S
authors.lastname: Kumar
authors.forename: Sohini
authors.initials: S
authors.lastname: Roy
authors.forename: Koel
authors.initials: K
authors.lastname: Chaudhury
authors.forename: Prasenjit
authors.initials: P
authors.lastname: Sen
authors.forename: Sujoy K
authors.initials: SK
authors.lastname: Guha
mesh_terms: D000327:Adsorption; D001672:Biocompatible Materials / Q000737:chemistry*; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism; D003272:Contraceptive Agents, Male / Q000737:chemistry / Q000494:pharmacology*; D004121:Dimethyl Sulfoxide / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D007477:Ions; D008297:Male; D008298:Maleates / Q000737:chemistry / Q000494:pharmacology*; D018625:Microscopy, Atomic Force / Q000379:methods; D011091:Polyesters; D011137:Polystyrenes; D025341:Principal Component Analysis; D012661:Semen / Q000187:drug effects* / Q000378:metabolism; D013094:Spermatozoa / Q000187:drug effects* / Q000378:metabolism; D055672:Static Electricity; D013343:Styrenes / Q000737:chemistry / Q000494:pharmacology*; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D003272:Contraceptive Agents, Male; D007477:Ions; D008298:Maleates; D011091:Polyesters; D011137:Polystyrenes; D013343:Styrenes; C440495:contraceptive agent, RISUG; D004121:Dimethyl Sulfoxide