Preclinical development of a novel injectable hydrogel for vas-occlusion

Abstract

Objectives

The objective of this work is to outline the preclinical development of ADAM, an injectable, two-component polyethylene glycol hydrogel designed for long-lasting and nonpermanent vas-occlusive contraception.

Study design

A newly developed hydrogel was comprehensively characterized to evaluate its potential as a male contraceptive device. The material was optimized for porosity to ensure sperm occlusion, rheological properties, injectability, and mechanical durability within the dynamic vessel. Biocompatibility of the hydrogel was assessed using a suite of ISO 10993 tests, which are critical for clinical translation and supporting a future regulatory submission. The canine model was utilized to assess the chronic tissue response of the vas deferens post implantation, providing insights into long-term safety and functionality.

Results

The vas-occlusive hydrogel demonstrates selective permeability with a pore size of 10 to 20 nm, effectively preventing sperm passage while allowing diffusion of small molecules. Its mechanical properties facilitated injection into the vas deferens with minimal force (3.1 N), forming a viscoelastic material within 30 seconds, with the ability to resist ejaculatory pressures. The implant and its degradation products were found to be noncytotoxic, nonirritating, nonsensitizing, and nongenotoxic. Moreover, a 2-year in vivo study in a canine model showed minimal tissue reaction following implantation, with no adverse effects reported.

Conclusions

These findings indicate that the hydrogel’s chemical and mechanical properties align with the requirements for a safe, effective, and nonpermanent vas-occlusive contraceptive.

Implications

Currently, men lack options for effective, long-lasting, and reversible contraception. The development and evaluation of the study hydrogel described here suggest it would make a safe and effective vas-occlusive contraceptive and should be researched further in a clinical setting.