Preparation and in vitro study of lipid nanoparticles encapsulating drug loaded montmorillonite for ocular delivery

Solid lipid nanoparticles (SLNs) are effective for drug delivery as they can improve the drug release and its bioavailability while reducing its side effects. An acid-treated montmorillonite (acid-Mt) was first intercalated with Betaxolol Hydrochloride (BH) in the interlayers and this nanocomposite was encapsulated by SLNs (Mt-BH-SLNs) using an emulsion evaporation-low temperature solidification method. The successful intercalation of BH in montmorillonite was verified by showing an increase in d₀₀₁ value from 1.54 to 1.93nm using X-ray diffraction (XRD). The successful encapsulation of BH intercalated Mt (Mt-BH) and formation of a new nanocomposite of Mt-BH-SLNs was indicated by the disappearance of the characteristic band at 1512cm^-1 representing C-H aromatic ring of BH in infrared spectrum (IR). The mean particle size of Mt-BH-SLNs was ca. 150nm, which is favorable for cornea permeation. The experimental results of in vitro release, ocular irritation and in vitro corneal penetration indicated that the Mt-BH-SLNs possessed a controlled release of BH for a period of 12h and led to a lower stimulation than that of BH solution.