BackgroundTo date, the rapid clearance from ocular surface has been a huge obstacle for using eye drops to treat glaucoma, since it has led to the short preocular residence time and low bioavailability.MethodsThe novel nanoparticles (NPs) were designed for topical ophthalmic controlled drug delivery system through intercalating the BH into the interlayer gallery of Na-montmorillonite (Na+Mt) and then further enchasing chitosan nanoparticles. The resulting nanoparticles had a positive charge (+29±0.18 mV) with an average diameter of 460±0.6 nm.ResultsIn vitro study of drug release profiles suggested controlled release pattern. The irritation experiment analysis on both human immortalized cornea epithelial cell (iHCEC) and chorioallantoic membrane-trypan blue staining (CAM-TBS) showed good tolerance for ocular tissues. It was interestingly found that the nanoparticles could enter into iHCEC from the result of cellular uptake experiment measured by confocal layer scan microscopy (CLSM). Meanwhile, multilayered iHCEC was used to simulate the barrier of corneal epithelial cells for in vivo preocular retention capacity study, which suggested that BH-Mt/CS NPs could prolong the retention time in comparison with BH solution. The ocular pharmacokinetics studied by microdialysis sampling technique showed that AUC0−t and MRT0−t of BH-Mt/CS NPs were 1.99-fold and 1.75-fold higher than those of BH solution, indicating higher bioavailability. Moreover, the study of blood drug concentration, few researchers have reported, showed that low level drug could enter into blood, suggesting lower systematic side effect. Importantly, pharmacodynamics studies suggested that BH-Mt/CS NPs could make a significant decreased intraocular pressure on glaucomatous rabbits.ConclusionInspired by these advance of montmorillonite/chitosan nanoparticles, we envision that the BH-Mt/CS NPs will be a potential carrier for BH, opening up the possible applications in glaucoma therapy.

Aim The aim of this work was to develop a novel vesicular carrier, ultradeformable liposomes (UDLs), to expand the applications of the Chinese herbal medicine, imperatorin (IMP), and increase its transdermal delivery. Methods In this study, we prepared IMP-loaded UDLs using the thin-film hydration method and evaluated their encapsulation efficiency, vesicle deformability, skin permeation, and the amounts accumulated in different depths of the skin in vitro. The influence of different charged surfactants on the properties of the UDLs was also investigated. Results The results showed that the UDLs containing cationic surfactants had high entrapment efficiency (60.32%±2.82%), an acceptable particle size (82.4±0.65 nm), high elasticity, and prolonged drug release. The penetration rate of IMP in cationic-UDLs was 3.45-fold greater than that of IMP suspension, which was the highest value among the vesicular carriers. UDLs modified with cationic surfactant also showed higher fluorescence intensity in deeper regions of the epidermis. Conclusion The results of our study suggest that cationic surfactant-modified UDLs could increase the transdermal flux, prolong the release of the drug, and serve as an effective dermal delivery system for IMP.

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Drug delivery carriers can maintain effective therapeutic concentrations in the eye. To this end, we developed lipid nanoparticles (L/NPs) in which the surface was modified with positively charged chitosan, which engaged in hydrogen bonding with the phospholipid membrane. We evaluated in vitro corneal permeability and release characteristics, ocular irritation, and drug dynamics of modified and unmodified L/NPs in aqueous humor. The size of L/NPs was uniform and showed a narrow distribution. Corneal permeation was altered by the presence of chitosan and was dependent on particle size; the apparent permeability coefficient of dexamethasone increased by 2.7 and 1.8 times for chitosan-modified and unmodified L/NPs, respectively. In conclusion, a chitosan-modified system could be a promising method for increasing the ocular bioavailability of unmodified L/NPs by enhancing their retention time and permeation into the cornea. These findings provide a theoretical basis for the development of effective drug delivery systems in the treatment of ocular disease.

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