Background: Blepharitis is considered one of the most common ocular
surface conditions in optometry and ophthalmology practice. While azithromycin
and dexamethasone have been used successfully to treat blepharitis, they are
generally formulated as eye drops requiring frequent administration. Ocular inserts
based on biodegradable polymers may overcome some of the problems associated
with conventional eye drops such as the fast nasolacrimal drainage.
Methods: Inserts with different β-glucan and hydroxypropyl methycellulose
(HPMC) compositions were prepared using the solvent-casting method and
evaluated in terms of their appearance, thickness, weight, pH, mechanical strength,
bioadhesive properties and drug-polymer interactions. The ability of the ocular
inserts to provide controlled release of the drugs was assessed through an in vitro release study of
dexamethasone and an antibacterial assay for azithromycin.
Results: All parameters were found acceptable for ocular use, with the film laminate exhibiting the
highest tensile strength and mucoadhesion. Differential Scanning Calorimetry (DSC) and Fourier
Transform Infrared Spectroscopy (FTIR) revealed that the drugs were molecularly dispersed within the
polymer films with no obvious interactions. Dexamethasone release was fast with 100% released within
1 hr. Azithromycin also showed a high burst release achieving the minimum inhibitory concentration
after only 5 min; however, antibacterial activity was maintained for 24 hrs.
Conclusion: Ocular inserts were successfully prepared and delivered both drugs over prolonged periods
compared to conventional eye drops. However, additional coating may be required to further control the