PLGA Nanoparticles as Subconjunctival Injection for Management of Glaucoma.

Nanoparticles fabricated from the biodegradable and biocompatible polymer, polylactic-co-glycolic acid (PLGA), could be a promising system for targeting ocular drug delivery. The objective of this work was to investigate the possibility of encapsulating brinzolamide in PLGA nanoparticles in order to be applied as a subconjunctival injection that could represent a starting point for developing new therapeutic strategies against increase in ocular pressure. The brinzolamide-loaded PLGA nanoparticles were fabricated using emulsion-diffusion-evaporation method with varying concentrations of Tween 80 or poloxamer 188 (Plx) in aqueous and organic phases. The nanoparticles were characterized in terms of particle size and size distribution, entrapment efficiency and in-vitro drug release pattern as well as DSC and X-ray analysis. Nanoparticles prepared using Tween 80 in the aqueous phase showed higher encapsulation efficiency and smaller particle size-values compared to those prepared using Plx. Furthermore, the addition of Plx 188 or Brij 97 to the organic phase in the formulation containing Tween 80 in the aqueous phase led to an increase in the particle diameter-values of the obtained nanoparticles. The nanoparticles had the capacity to release the brinzolamide in a biphasic release profile. The nanoparticles were spherical in shape and the drug was entraped in the nanoparticles in an amorphous form. Selected nanoparticles, injected subconjunctivally in normotensive Albino rabbits, were able to reduce the IOP for up to 10 days. Nanoparticles loaded with brinzolamide with lower particle size were able to reduce the IOP for longer period compared to those with higher particle size. Histopathological studies for the anterior cross sections of the rabbits' eyes revealed that the tested nanoparticles were compatible with the ocular tissue. The overall results support that PLGA nanoparticles, applied as subconjunctival injection, can be considered as a promising carrier for ocular brinzolamide delivery with targeting delivery of the drug to the eye tissues.

Brain delivery of olanzapine by intranasal administration of transfersomal vesicles.

The aim of this study was to investigate the presence of a possible direct correlation between vesicle elasticity and the amount of drug reaching the brain intranasally. Therefore, transfersomes were developed using phosphatidylcholine (PC) as the lipid matrix and sodium deoxycholate (SDC), Span® 60, Cremophor® EL, Brij® 58, and Brij® 72 as surfactants. The influence of the type of surfactant and PC-to-surfactant ratio on vesicle morphology, size, membrane elasticity, drug entrapment, and in vitro drug release was studied. The prepared transfersomes were mainly spherical in shape, with diameters ranging from 310 to 885 nm. Transfersomes containing SDC and Span 60 with optimum lipid-to-surfactant molar ratio showed suitable diameters (410 and 380 nm, respectively) and deformability indices (17.68 and 20.76 mL/sec, respectively). Values for absolute drug bioavailability in rat plasma for transfersomes containing SDC and those containing Span 60 were 24.75 and 51.35%, whereas AUC(0-360 min) values in rat brain were 22,334.6 and 36,486.3 ng/mL/min, respectively. The present study revealed that the deformability index is a parameter having a direct relation with the amount of the drug delivered to the brain by the nasal route.

Phospholipid based colloidal poloxamer-nanocubic vesicles for brain targeting via the nasal route.

In this study, new phospholipid based colloidal nanocubic vesicles encapsulating olanzapine for its brain targeting via the nasal route were developed. The nanocubic vesicles were prepared by incorporating non-ionic copolymers, poloxamer 188 or 407, in the lipid bilayer. The effect of phospholipid:poloxamer molar ratio on the physicochemical properties of the nanocubic vesicles was investigated. The in vivo behavior and brain targeting of these vesicles were evaluated in rats. TEM photographs showed that the vesicles looked spherical before adding poloxamer. However, after poloxamer incorporation, the vesicles showed a predominant cubic shape, except those containing phospholipid:poloxamer in the molar ratio 5:1 which were spherical. DSC study confirmed perturbation of the packing characteristics as well as fluidization of the lipid bilayer by the polymer with consequent formation of the nanocubic structure. The mean diameter of the vesicles was in the range of 363-645 nm. All vesicles were elastic and the elasticity was found to depend on both poloxamer type and concentration. The intranasal nanocubic vesicles were significantly more efficient in targeting olanzapine to the brain compared to the liposomal vesicles with drug targeting efficiency values of 100% and 80%, respectively, and absolute bioavailability of 37.9% and 14.9%, respectively.