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The results obtained pointed out that liposome coating process resulted in entrapment efficiency reduction and higher chitosan concentration, and molecular weight showed a more pronounced effect. No morphological differences between coated and uncoated liposomes were observed. Diffusion was the drug release mechanism from chitosomes. Concerning rheological behavior, pseudoplastic flow was characteristic to the prepared chitosomal dispersions. In addition, chitosan coating improved the ocular permeation of ciprofloxacin HCl. Microbiologically; this formulated system enhanced antimicrobial activity of ciprofloxacin HCl against both Gram-positive and Gram-negative bacteria. Moreover, this mucoadhesive system was able to inhibit the growth of Pseudomonas aeruginosa in rabbits' eyes for 24 hours when compared to the marketed preparation. In vivo bacterial conjunctivitis model elucidated that symptoms were controlled by the prolonged release formulation such as that done by the marketed product.

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Introduction: Triple negative breast cancer is an aggressive disorder which accounts for at least 15% of breast cancer diagnosis and a high percentage of breast cancer morbidity, hence intensive research efforts are focused on the development of effective therapies to overcome the disease. Thymoquinone (TQ), the bioactive constituent of Nigella sativa, exhibits anticancer activity, yet its translation to the clinic is hindered by its poor bioavailability and lack of quantification method in blood and tissues. To overcome these limitations, cubosomes were utilized for the encapsulation and delivery of this anticancer molecule. Methods: Thymoquinone loaded cubosomes were prepared through the emulsification homogenization method. The physicochemical characteristics, including particle size, zeta potential, morphology and entrapment efficiency, were studied. Moreover, the in vitro antitumor activity was tested on breast cancer cell lines (MCF-7 and MDA-MB-231) and compared to non-tumorigenic cell line (MCF-10A). Subcellular localization, cellular uptake and apoptotic effects of the formulations were assessed. Results: The results revealed that the TQ loaded cubosomal formulation exhibited a mean particle size of 98.0 ± 4.10 nm with narrow unimodal distribution. The high entrapment efficiency (96.60 ± 3.58%) and zeta potential (31.50 ±4.20 mV) conceived the effectiveness of this nanosystem for TQ encapsulation. Cell viability in both breast cancer cell lines demonstrated a dose-dependent decrease in response to treatment with free TQ or TQ-loaded cubosomes, with enhanced antitumor activity upon treating with the latter formulation. A significant increase in apoptotic bodies and cleaved caspase 3 was observed upon treatment of MDA-MB-231 cells with either TQ or TQ-loaded cubosomes. Localization and trafficking studies unveiled that cubosomes accumulate in the cytoplasm of the studied breast cancer cell lines. Discussion: Our results show that thymoquinone encapsulation in cubosomal nanoparticles provides a promising anticancer drug delivery system with the ability to label, detect and subsequently trace it within the human cells.

Management of extraocular diseases is mainly limited by the inability to provide long-term drug delivery without avoiding the systemic drug exposure and/or affecting the intraocular structures and poor availability of drugs, which may be overcome by prolonging the contact time with the ocular system, for instance with liposomes. Development and optimization of reverse phase evaporation ciprofloxacin (CPF) HCl liposomes for ocular drug delivery was carried out using a 2(5) full factorial design based on five independent variables. The effects of the studied parameters on drug entrapment efficiency (EE), particle size, and percentage of drug released after 1 and 10 h were investigated. The results obtained pointed out that the molar concentration of cholesterol was the predominant factor that increased the EE% of the drug and the particle size responses. The percentage of drug released after 1 h was significantly controlled by the initial CPF concentration while that after 10 h was controlled by molar cholesterol concentration. The designed liposomes had average particle sizes that ranged from 2.5 to 7.23 microm. In addition, liposomes revealed a fast release during the first hour followed by a more gradual drug release during the 24-h period according to Higuchi diffusion model.

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