Controlled Delivery of Gentamicin Using Poly(3-hydroxybutyrate) Microspheres

Abstract

Poly(3-hydroxybutyrate), P(3HB), produced from Bacillus cereus SPV using a simple glucose feeding strategy was used to fabricate P(3HB) microspheres using a solid-in-oil-water (s/o/w) technique. For this study, several parameters such as polymer concentration, surfactant and stirring rates were varied in order to determine their effect on microsphere characteristics. The average size of the microspheres was in the range of 2 μm to 1.54 μm with specific surface areas varying between 9.60 m2/g and 6.05 m2/g. Low stirring speed of 300 rpm produced slightly larger microspheres when compared to the smaller microspheres produced when the stirring velocity was increased to 800 rpm. The surface morphology of the microspheres after solvent evaporation appeared smooth when observed under SEM. Gentamicin was encapsulated within these P(3HB) microspheres and the release kinetics from the microspheres exhibiting the highest encapsulation efficiency, which was 48%, was investigated. The in vitro release of gentamicin was bimodal, an initial burst release was observed followed by a diffusion mediated sustained release. Biodegradable P(3HB) microspheres developed in this research has shown high potential to be used in various biomedical applications.

Controlled Release of Drugs for Management of Pulpitis

“…In one study, gentamycin (GEN) was not only encapsulated into the microspheres, but also superficially absorbed on the external surface of microspheres. The mentioned study showed the initial release, including 60% of the entire encapsulated drug (16). In this study, slow and controlled release of drug occurred following the initial burst.…”

“…Slower release of the drug by larger microspheres is due to the decreased path of drug diffusion inside the microspheres and decreased specific superficial areas in larger microspheres compared to smaller ones. In one previous study, drug release during 24 hours was related to the small size of microspheres (1.54 μm) (16). Drug release under in vitro condition also depends on drug diffusion within the microspheres.…”

“…Drug release did not appear to be due to the surface erosion or slow degradation of polymer. Drug release in the final phase most probably occurs through the aqueous canals via the penetration mechanism (16). It has been demonstrated that water sorption into the polymer is accelerated in the presence of hydrophilic drugs and polyvinyl alcohol (PVA).…”

“…Several pharmacological and orthopedic studies have investigated the production of PLGA microspheres and have assessed the release of loaded antibiotics (16)(17)(18)(19)(20). In restorative dentistry, pulp-capping agents are used with the aim of eliminating microorganisms from the pulp chamber.…”

Passive targeting and lung tolerability of enoxaparin microspheres for a sustained antithrombotic activity in rats

“…Impediment of the emulsification efficiency at a given stirring rate may occur due to insufficient amount of surfactant as in case of low lecithin concentration or due to viscosity increase by higher span 80 concentration delivering larger MS (Francis et al, 2011). The larger particles, obtained with both surfactants, have a smaller surface area to volume ratio and thus a lower potential for drug escape to the external phase (Li et al, 1999).…”