Design of Mucoadhesive Strips for Buccal Fast Release of Tramadol

Tramadol hydrochloride is a synthetic analogue of codeine and shows activity on the central nervous system as an opioid agonist and inhibitor of serotonin and norepinephrine reuptake. It has been used for controlling moderate to severe pain. Mucoadhesive fast-dissolving films can present greater drug availability and patient acceptance when compared to the systems of peroral administration. The films were prepared using the solvent casting method with ethylcellulose, polyvinylpyrrolidone and poly(vinyl alcohol). The effect of each polymer concentration was investigated using a 2³ factorial design with repetition at the central point. The formulations were subjected to physicochemical, mechanical, ex vivo mucoadhesive and in vitro drug release profile analysis. These properties were dependent on the polymeric composition (independent factors) of each system. The optimized formulations showed good macroscopic characteristics, improved resistance to bending, rigidity, rapid swelling up to 60 s, improved mechanical and mucoadhesive characteristics, and also fast dissolving and tramadol release. The optimized formulations constitute platforms and strategies to improve the therapy of tramadol with regard to availability at the site of application, considering the necessity of rapid pain relief, and show potential for in vivo evaluation

Boosting the photodynamic activity of erythrosine B by using thermoresponsive and adhesive systems containing cellulose derivatives for topical delivery

Erythrosine displays potential photodynamic activity against microorganisms and unhealthy cells. However, erythrosine has high hydrophilicity, negatively impacting on permeation through biological membranes. Combining biological macromolecules and thermoresponsive polymers may overcome these erythrosine-related issues, enhancing retention of topically applied drugs. The aim of this work was to investigate the performance of adhesive and thermoresponsive micellar polymeric systems, containing erythrosine in neutral (ERI) or disodium salt (ERIs) states. Optimized combinations of poloxamer 407 (polox407) and sodium carboxymethylcellulose (NaCMC) or hydroxypropyl methylcellulose (HPMC) were used as platforms for ERI/ERIs delivery. The rheological and mechanical properties of the systems was explored. Most of the formulations were plastic, thixotropic and viscoelastic at 37 °C, with suitable gelation temperature for in situ gelation. Mechanical parameters were reduced in the presence of the photosensitizer, improving the softness index. Bioadhesion was efficient for all hydrogels, with improved parameters for mucosa in contrast to skin. Formulations composed of 17.5 % polox407 and 3 % HPMC or 1 % NaCMC with 1 % (w/w) ERI/ERIs could release the photosensitizer, reaching different layers of the skin/mucosa, ensuring enough production of cytotoxic species for photodynamic therapy. Functional micelles could boost the photodynamic activity of ERI and ERIs, improving their delivery and contact time with the cells