<p>Chitosan-Coated PLGA Nanoparticles for Enhanced Ocular Anti-Inflammatory Efficacy of Atorvastatin Calcium</p>

Abstract

Background: Atorvastatin calcium (AT) is an ocular anti-inflammatory with limited bioavailability when taken orally due to its low solubility in low pH and extensive first-pass effect. To overcome these problems, AT was entrapped in polymeric nanoparticles (NPs) to improve surface properties and sustained release, in addition to achieving site-specific action. Methods: AT was entrapped in chitosan (CS)-coated polylactic-co-glycolic acid (PLGA) NPs to form AT-PLGA-CS-NPs (F1). F1 and free AT were embedded in thermosensitive Pluronic ® 127-hydroxypropyl methylcellulose (HPMC) to form thermosensitive gels (F2) and (F3) while F4 is AT suspension in water. F1 was assessed for size, surface charge, polydispersity index (PDI), and morphology. F2 and F3 were examined for gelation temperature, gel strength, pH, and viscosity. In vitro release of the four formulations was also investigated. The ocular irritancy and anti-inflammatory efficacy of formulations against prostaglandin E 1-(PGE 1) induced ocular inflammation in rabbits were investigated by counting the polymorphonuclear leukocytes (PMNs) and protein migrated in tears. Results: Oval F1 of 80.0-190.0±21.6 nm exhibited a PDI of 0.331 and zeta potential of 17.4 ±5.62 mV with a positive surface charge. F2 and F3 gelation temperatures were 35.17±0.22°C and 36.93±0.31°C, viscosity 12,243±0.64 and 9759±0.22 cP, gel strength 15.56±0.6 and 12.45 ±0.1 s, and pHs of 7.4±0.02 and 7.4±0.1, respectively. In vitro release of F1, F2, F3, and F4 were 48.21±0.31, 26.48±0.5, 84.76±0.11, and 100% after 24 hrs, respectively. All formulations were non-irritant. F2 significantly inhibited lid closure up to 3 h, PMN counts and proteins in tear fluids up to 5 h compared to other formulations. Conclusion: AT-PLGA-CS-NP thermosensitive gels proved to be successful ocular antiinflammatory drug delivery systems.

<p>Clarithromycin-Loaded Ocular Chitosan Nanoparticle: Formulation, Optimization, Characterization, Ocular Irritation, and Antimicrobial Activity</p>

“…It accelerates the mixing of STPP dispersion into the CH solution, leading to an increase in the shear force and thereby breakdown of NPs takes place. 32 On other hand, the combined effect of CH and STPP (A and B) showed a more prominent negative effect on particle size than CH and stirring speed (AC) as well as STPP and stirring speed (BC). As the concentration of CH and STPP simultaneously increases the particle size decreases.…”

Nanosystems for the Encapsulation of Natural Products: The Case of Chitosan Biopolymer as a Matrix

“…This double diffusional barrier release is desirable for specific applications and depending on the release conditions could lead to tailormade release profiles. Arafa et al [ 198 ] support that chitosan physical barrier limits the diffusion and surface erosion of the encapsulated compound from the PLGA nanoparticles, which in addition to the limited tendency of chitosan to hydrate when it is in high pH dissolution media, leads to the elimination of burst release effectand drug release retardancy [ 74 ]. On the other hand, chitosan coating in acidic conditions seems to increase the release of several drugs such as diclofenac.…”

Dual-Target Peptide-Modified Erythrocyte Membrane-Enveloped PLGA Nanoparticles for the Treatment of Glioma

“…However, the clinical application of EFL1 is limited by its poor water solubility and low bioavailability. The solubility of EFL1 can be increased by encapsulation in PLGA nanoparticles (32,33).…”