Study on release of naproxen and metformin encapsulated in biopolymer-inorganic mesoporous matrices as controlled drug-delivery systems

Abstract

In this study, a new methodology was applied for controlling the release of different drugs by encapsulating them in organic-inorganic hybrids via sol-gel technique. The assembled organic-inorganic hybrids had diverse BET surface area, porosity, and high heat resistance. The synthesized organic-inorganic hybrids were based on zirconium(IV) propoxide, and tetraethyl orthosilicate as precursor of inorganic network, and chitosan or N-triethylchitosan as organic or biopolymer components. In these hybrid composites, drug and biopolymer were coated with a mesoporous inorganic material. FT-IR, FE-SEM, DSC, BET, XRD techniques, and Zeta potential analysis used for investigating the formation of metformin/chitosan@ZrO2 and sodium naproxen/N-triethylchitosan@SiO2 hybrid composites. Then for investigating the role of sol-gel process, the release of metformin and sodium naproxen in the prepared hybrid composites was investigated as model drugs. Compare to drug/biopolymer composite, incorporation of ZrO2 or SiO2 coating enhanced the drug entrapment appreciably, and naturally reduced the rate of drug release. For example, the metformin/chitosan composite without ZrO2 coating released the whole drug in less than10 h in pH 7.4 when the composite coated with ZrO2 released the entrapped drug after 25 h.