Ethylcellulose Microparticles Containing Photo Cross-Linked Poly(vinyl alcohol)-Coumarin Conjugate

Abstract

Microparticles containing either photo cross-linked poly(vinyl alcohol)-epoxypropoxy coumarin conjugate (PVA-EPC conjugate) or PVA were prepared by spray-drying W/O emulsions. Each polymer was dissolved in distilled water and was used as a water phase. Ethylcellulose (matrix material of microparticle) and span 80 (an emulsifier) were dissolved in dichloromethane. The two-phase system was emulsified in a homogenizer to obtain W/O emulsion and the emulsions were subjected to the UV irradiation. The size of the water droplets of the photo-treated emulsions was determined on optical microscopic photos using an image analyzer, and the mean droplet diameters containing PVA and PVA-EPC were 3 µm and 3.5 µm, respectively. The photo-treated emulsions were stable in terms of the size of water droplets for 12 h. The microparticles were prepared by spray-drying the photo-treated emulsions, and the sizes were several to tens of micrometers in diameter. The release degree of bovine serum albumin bovine from microparticles containing PVA-EPC was lower than that of microparticles containing PVA, possibly because of a lower diffusivity of the diffusate through the cross-linked PVA-EPC domains.