Controlled release of insulin from folic acid-insulin complex nanoparticles

[Display omitted] •Insulin encapsulation is more than 90% and insulin loss is less than 10% during the synthesis of insulin-loaded folic acid nanoparticles.•Release of insulin is controlled by changing crosslinking salt concentration and folic acid loading.•Insulin molecules were well distributed though out the particle rather than under the pocket of folic acid shell.•This formulation can provide controlled release of many protein having associative interactions with folic acid. Associative interactions between folic acid and proteins are well known. This work leverages these interactions to engineer folic acid nanoparticles for controlled release of insulin during diabetes therapy. The insulin-loaded folic acid nanoformulation is synthesized during this study to achieve better insulin loading and encapsulation than previous strategies. The maximum insulin loading in the FA particles was kept at 6mg with less than 10% insulin loss during the synthesis process which is significantly better compare to previous strategies. The folic acid nanoparticles of 50–150nm size are further characterized in the present study. The release behaviour of insulin from the nanoparticles has been studied to quantify released insulin and folic acid with time using high performance liquid chromatography. Insulin release results suggest that more than 90% of the insulin is encapsulated and released within 24h from folic acid nanoparticles. The analysis of folic acid release along with insulin release indicates that the particles are formed by folic acid-insulin complexation at the molecular level. The release of insulin from nanoparticles is controllable with the change in the crosslinking salt concentration as well as the amount of folic acid loaded during particle synthesis. These results prove that folic acid nanocarriers are capable to control the release of therapeutic proteins.