Amphiphilic sodium alginate-vinyl acetate microparticles for drug delivery

To overcome the fast or burst release of hydrophilic drugs from hydrophilic alginate-based carriers, hydrophobic molecule (vinyl acetate, VAc) was grafted on alginate (Alg), which was further used to prepare drug carriers. Amphiphilic Alg-g-PVAc hydrogel beads were firstly prepared by emulsification/internal gelation technique for the loading of bovine serum albumin (BSA). Then, chitosan was coated on the surface of beads to form novel amphiphilic Alg-g-PVAc/chitosan (Alg-g-PVAc/CS) microcapsules. The BSA-loading amphiphilic Alg-g-PVAc/chitosan (Alg-g-PVAc/CS) microcapsules display similar morphology and size to the hydrophilic alginate/chitosan (AC) microcapsules. However, the drug loading and loading efficiency of BSA in Alg-g-PVAc/CS microcapsules are higher, and the release rate of BSA from Alg-g-PVAc/CS microcapsules is slower. The results demonstrate that the introduction of hydrophobic PVAc on alginate can effectively help retard the release of BSA, and the higher degree of substitution is, the slower the release rate is. In addition, the complex membrane can also be adjusted to delay the release of BSA. As a whole, amphiphilic sodium alginate-vinyl acetate/CS microparticles could be developed for macromolecular drug delivery