Polymer coated polymeric microneedles for intravitreal delivery of dexamethasone.

The polymer coated polymeric (PCP) microneedles (MNs) is a novel approach for controlled delivery of drugs (without allowing release of the excipients) to the target site. PCP MNs was explored as an approach to deliver the drug intravitreally to minimize the risks associated with conventional intravitreal injections. The core MNs was fabricated with polyvinyl pyrrolidone K30 (PVP K30) and coating was with Eudragit E100. Preformulation studies revealed that the films prepared using Eudragit E 100 exhibited excellent integrity in the physiological medium after prolonged exposure. FTIR studies were performed to investigate the possible interaction between the API and the polymer. The PCP MNs fabricated with different drug loads (dexamethasone sodium phosphate) were subjected to in vitro drug release studies. The drug release from uncoated MNs was instantaneous and complete. On the other hand, a controlled release profile was observed in case of PCP MNs. Likewise, even in the ex vivo porcine eye model, the drug release was gradual into the vitreous humor in case of PCP MNs. The uncoated microneedles released all the drug instantaneously where the PCP MNs retarded the release up to 3 h.