Optimizing Formulation and Geometry of Agar–Tapioca-Based Biodegradable Retentive Intravaginal Modules

Abstract

The development of biodegradable retentive intravaginal modules requires a balance between material characteristics and design to ensure product integrity within the reproductive tract. This study is a preliminary investigation aimed at examining the effects of variations in material formulation and design geometry on the physical stability of agar- and tapioca starch-based retentive intravaginal modules. A total of 36 module variations were fabricated through a series of experimental steps involving variations in agar concentration, tapioca starch concentration, the addition of plasticizers such as glycerin and polyethylene glycol, and modifications to the synthetic polymer polycaprolactone. Evaluation was conducted through qualitative physical observation of moldability, density, and manual flexibility across design evolutions ranging from Y-shaped, rod-shaped, to circular forms. The observation results indicated that the Y-shaped design faced challenges during module removal from the mold and fracture susceptibility at the junction of the arms, whereas the rod-shaped design tended to be rigid. The circular design ensures a more even pressure distribution, thereby minimizing the risk of breakage when subjected to mechanical stress. Based on descriptive assessment, module no. 36, which combines agar, tapioca starch, and glycerin through heating and steaming techniques, yielded the most stable consistency with uniform density and good manual flexibility, showing no signs of damage when bent. This study provides a foundation that the synergy between the agar-tapioca hydrocolloid base and circular geometry holds potential for the further development of intravaginal implant prototypes.