Considering the advantageous for the rectal administration of non-steroidal anti-inflammatory drugs, the objective of this study was to formulate and evaluate rectal mucoadhesive hydrogels loaded with diclofenac-sodium chitosan (DFS-CS) microspheres. Hydroxypropyl methylcellulose (HPMC; 5%, 6%, and 7% w/w) and Carbopol 934 (1% w/w) hydrogels containing DFS-CS microspheres equivalent to 1% w/w active drug were prepared. The physicochemical characterization revealed that all hydrogels had a suitable pH for rectal application (6.5-7.4). The consistency of HPMC hydrogels showed direct proportionality to the concentration of the gelling agent, while carbopol 934 gel showed its difficulty for rectal administration. Farrow's constant for all hydrogels were greater than one indicating pseudoplastic flow. In vitro drug release from the mucoadhesive hydrogel formulations showed a controlled drug release pattern, reaching 34.6-39.7% after 6 h. The kinetic analysis of the release data revealed that zero-order was the prominent release mechanism. The mucoadhesion time of 7% w/w HPMC hydrogel was 330 min, allowing the loaded microspheres to be attached to the surface of rectal mucosa. Histopathological examination demonstrated the lowest irritant response to the hydrogel loaded with DFS-CS microspheres in response to other forms of the drug.

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Objective: Intraocular pressure has always been a great challenge for topical ophthalmic drugs. The study aimed to develop ocular surfactant based nanovesicles (NVs) carried in mucoadhesive nanogel providing efficient topical delivery of acetazolamide (ACZ). Methods: For the sake of optimizing formulation parameters, the effect of the type of edge activator and its ratio to sorbitan monostearate (Span 60) on the mean particle size, entrapment efficiency (%EE), and zeta potential (ZP) of produced NVs was investigated. Results: The selected formulation composed of Span 60:sodium deoxycholate with ratio 80:20 showed an average diameter of 202.90 nm, %EE of 90.2%, and ZP of −38.1 mV with a spherical and smooth surface. The ACZ loaded nanovesicles (ACZ-NVs) were embedded in different concentrations of Chitosan–sodium tripolyphosphate (CS-TPP) nanogels. The nanogel prepared using 1.5% CS showed the most promising viscosity, adhesion time, and rheological behavior (118,246 cP, 290 min, and thixotropic behavior, respectively). The in vitro release of ACZ showed a controlled release profile after incorporation in nanogels. The in vivo irritation test showed minimal irritation for the nanogel formulation compared to ACZ topical suspension. The effect of intraocular pressure lowering was significantly prolonged using ACZ-NV nanogels compared to ACZ oral tablets. Histopathological examination emphasized the healing power of CS on retinal atrophy. Conclusion: The research work indicated a promising potential for successful topical delivery of ACZ.

Nanocapsules can be equated to other nanovesicular systems in which a drug is entrapped in a void containing liquid core surrounded by a coat. The objective of the present study was to investigate the potential of polymeric and lipid nanocapsules (LNCs) as innovative carrier systems for miconazole nitrate (MN) topical delivery. Polymeric nanocapsules and LNCs were prepared using emulsification/nanoprecipitation technique where the effect of poly(ε-caprolactone (PCL) and lipid matrix concentrations with respect to MN were assessed. The resulted nanocapsules were examined for their average particle size, zeta potential, %EE, and in vitro drug release. Optimum formulation in both polymeric and lipidic nanocapsules was further subjected to anti-fungal activity and ex vivo permeation tests. Based on the previous results, nanoencapsulation strategy into polymeric and LNCs created formulations of MN with slow biphasic release, high %EE, and improved stability, representing a good approach for the delivery of MN. PNCs were best fitted to Higuchi’s diffusion while LNCs followed Baker and Lonsdale model in release kinetics. The encapsulated MN either in PNCs or LNCs showed higher cell viability in WISH amniotic cells in comparison with free MN. PNCs showed less ex vivo permeation. PNCs were accompanied by high stability and more amount drug deposition (32.2 ± 3.52 µg/cm 2 ) than LNCs (12.7 ± 1.52 µg/cm 2 ). The antifungal activity of the PNCs was high 19.07 mm compared to 11.4 mm for LNCs. In conclusion, PNCs may have an advantage over LNCs by offering dual action for both superficial and deep fungal infections.

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