| Purpose: In this study, we aimed to prepare an extended drug delivery formulation of
clarithromycin (CAM) based on a semi-interpenetrating polymer network (semi-IPN) hydrogel.
Methods: Synthesis of semi-IPN hydrogel nanocomposite made of chitosan (CS), acrylic
acid (AA), acrylamide (AAm), polyvinylpyrrolidone (PVP), and montmorillonite (MMT) was
performed by free radical graft copolymerization method. Swelling kinetic studies were done in
acidic buffer solutions of hydrochloric acid (pH = 1.2), acetate (pH = 4), and also distilled water.
Also, the effects of MMT on the swelling kinetic, thermal stability, and mechanical strength
of the hydrogels were evaluated. Moreover, in vitro release behavior of CAM and its release
kinetics from hydrogels were studied in a hydrochloric acid buffer solution.
Results: Fourier transform infrared spectroscopy (FTIR) results revealed that synthesis of semi-
IPN superabsorbent nanocomposite and CAM incorporation into hydrogel was performed,
successfully. Introducing MMT into hydrogel network not only improved its thermal stability
but also increased mechanical strength of the final hydrogel product. Also, in comparison
with neat hydrogel (1270 g/g), hydrogel nanocomposite containing 13 wt% MMT exhibited
greater equilibrium swelling capacity (1568 g/g) with lower swelling rate. In vitro drug release
experiments showed that CS-g-poly(AA-co-AAm)/PVP/MMT/CAM formulation possesses a
sustained release character over extended period of time compared with CS-g-poly(AA-co-
AAm)/PVP/CAM formulation.
Conclusion: In the presence of MMT, the effective life time of drug is prolonged, demonstrating a
sustained release property. The reason is that interlinked porous channels within superabsorbent
nanocomposite network hinder penetration of aqueous solutions into hydrogel and subsequently
cause a slower drug release. |