The production of a novel poly(vinyl alcohol) hydrogel cryogenic spheres for immediate release using a droplet system

Although freeze-thaw mechanism for producing crosslinked hydrogels is relatively easy and simple, it lacks sufficient integrity and support leading to modifications on its three-dimensional polymeric network arrangement during water removal—drying. Therefore, a strengthening method for obtaining cryogenic spheres of polyvinyl alcohol hydrogels is purposed by dispensing it as liquid droplets into a low temperature solution followed by a modification on its freeze-thaw cycles to confer a good geometry without aggregation. Various materials were incorporated into this hydrogel structure, including poly(acrylic acid) to impart pH sensitivity; hydroxyapatite to improve biocompatibility; and ciprofloxacin as an antimicrobial agent relevant for the treatment of osteomyelitis. The overall network presented a porous structure with a fibrous-like pattern which varied in size and volume, with presence of Ca and P when hydroxyapatite is incorporated. These materials varied the crystalline melting point of the poly(vinyl alcohol) and a linear pH sensitivity function was obtained by the addition of the materials. These hydrogels were found to release ciprofloxacin within 60 min and were able to dissolve at the same time intervals. Therefore, the hydrogel synthesised in this work can be used as an immediate release drug delivery mechanism for the in situ delivery of active pharmaceutical such as ciprofloxacin for a treatment of osteomyelitis.