Biodegradable alginate microparticles developed by electrohydrodynamic spraying techniques for oral delivery of protein.

In this study, alginate microparticles were prepared by cross-linking alginate with calcium chloride solution using an electrohydrodynamic spraying technique. The effects of alginate and calcium chloride concentration as well as electrical potential on particle size and shape were investigated. The results showed that 1 mg ml(-1) alginate medium viscosity (AMV), 2.5 mg ml(-1) CaCl(2), electrical potential 18 kV (F1) and 0.5 mg ml(-1) alginate low viscosity (ALV), 2.5 mg ml(-1) CaCl(2), electrical potential 20 kV (F2) yielded the spherical shape and small particles of 937 +/- 158 nm and 1556 +/- 51 nm, respectively. In bovine serum albumin (BSA) entrapment efficiency study, initial BSA of 5, 10, 20, 40 and 60% w/w to polymer was incorporated into these alginate microparticles. The results revealed that F2 with initial BSA 10% w/w showed the highest entrapment efficiency of 49.70 +/- 0.01%. The result of BSA content revealed that F2' with the initial BSA of 20% w/w showed the highest amount of BSA content of 3.92 +/- 0.02 mg g(-1) of particles. F1 and F2 with the initial BSA of 5%, 20% and 40% w/w were chosen to evaluate for the release in PBS pH 7.4. It was found that F1 with the initial BSA of 40% w/w showed the slowest release rate and sustained release. The release of F1 in 0.1 N HCl solution (pH 1.2) was slower than that in pH 7.4. This electrohydrodynamic spray technique (EHDA) can be applied to prepare alginate in micro size and can encapsulate BSA. Alginate microparticles can further be optimized for oral delivery of several pharmaceutical peptides and proteins.