Comparison of mucoadhesive and cohesive features of poly(acrylic acid)-conjugates respective their molecular mass

Nanoparticles Loaded Thermoresponsive In Situ Gel for Ocular Antibiotic Delivery against Bacterial Keratitis

Antibiotics delivered through conventional dosage against ophthalmic infections show lower therapeutic efficacy due to their low residence time. Therefore, there is a great need to design and develop novel dosage forms that would increase the ocular residence time of antibiotics at the site of infection. This study describes the development of nanoparticles laden in situ gelling solution, intended to sustain antibiotic release for improved therapeutic efficiency. Oxytetracycline-loaded gelatin-polyacrylic acid nanoparticles were prepared and incorporated in poloxamer-N407 solution. The rheological properties of the system were studied concerning time and temperature. Moreover, in vivo biocompatibility of the system was ascertained using the Draize test and histological studies. Finally, the optimized formulation was evaluated for in vitro antibacterial activity against one of the most common keratitis causing bacteria, Pseudomonas aeruginosa. Additionally, the in vivo efficacy was evaluated on the rabbit's eye conjunctivitis model. The formulation showed a sustained effect against keratitis; furthermore, the antibacterial activity was comparable with the commercial product.

Rheological analysis and mucoadhesion: A 30 year-old and still active combination

At the end of 80s and in the early 90s, an increasing interest in the development of mucoadhesive formulations occurred in the pharmaceutical field. Such formulations, prolonging the drug permanence on the mucosa of action/absorption, improve drug availability/bioavailability and therefore its therapeutic effectiveness. Among the various methods reported in the literature for the evaluation of the mucoadhesive properties of polymers, in the early 1990s, the study of the rheological variation of the polymer solutions after mixing with a mucin solution/dispersion has been proposed as an approach to measure the strength of the mucoadhesive joint. Even today, both viscosity and viscoelastic measurements are used to evaluate the ability of polymers and formulations to adhere to the mucosa of application/action. This review aims at providing an overview of the rheological approaches employed in the development and characterization of mucoadhesive formulation, highlighting their advantages and disadvantages. To do this the scientific path that, since the beginning of the 90s, has led to the affirmation of the rheological analysis as a useful tool for the evaluation of the strength of the mucoadhesive bond is retraced.

Synthesis of thiomers: screening and optimization using chemometrics

A chemometric study of the processing variables involved in the synthesis of thiomers based on poly(acrylic acid) functionalized with l-cysteine (PAA-cys) mediated by carbodiimide was successfully carried out.