Integration of metformin-loaded mesoporous bioactive glass nanoparticles and free metformin into polymer microneedles for transdermal delivery on diabetic rats.

[Display omitted] • Polymer microneedles (MNs) have been prepared for transdermal delivery of drugs. • Free Met and Met-loaded BGNs were encapsulated into MNs for a sustained drug release. • MNs with integration of free and loaded Met exhibit a significant hypoglycemic effect. Transdermal delivery provides a suitable and painless self-administration for diabetic patients. In this work, the polymer microneedles (MNs) integrated with mesoporous bioactive glass nanoparticles (BGNs) for transdermal delivery of metformin (Met) have been developed for regulation of blood glucose levels (BGLs) on diabetic rats. The obtained MNs system contains free Met and Met-loaded BGNs (Met/BGNs) for independently controlling the kinetics of anti-diabetic drug during the treatment. Once these MNs are penetrated into the skin, the free Met is firstly released due to the swelling and degradation of matrix material of MNs. And then the loaded Met is slowly seep through the microchannels of BGNs to form a sustained drug release behaviors and a better hypoglycemic effect, suggesting the potential of this new transdermal delivery system as substitutes for multiple daily injections. [ABSTRACT FROM AUTHOR]