Development of oral suspensions of microparticles of ethylcellulose with tramadol

Free-standing three-dimensional hollow bacterial cellulose structures with controlled geometry via patterned superhydrophobic-hydrophilic surfaces

Bacteria can produce cellulose, one of the most abundant biopolymer on earth, and emerge as an interesting candidate to fabricate advanced materials. Cellulose produced by Komagataeibacter Xylinus, a bacterial strain, is a pure water insoluble biopolymer, without hemicellulose or lignin. Bacterial cellulose (BC) exhibits a nanofibrous porous network microstructure with high strength, low density and high biocompatibility and it has been proposed as cell scaffold and wound healing material. The formation of three dimensional (3D) cellulose self-standing structures is not simple. It either involves complex multi-step synthetic procedures or uses chemical methods to dissolve cellulose and remold it. Here we present an in situ single-step method to produce self-standing 3D-BC structures with controllable wall thickness, size and geometry in a reproducible manner. Parameters such as hydrophobicity of the surfaces, volume of the inoculum and time of culture define the resulting 3D-BC structures. Hollow spheres and convex domes can be easily obtained by changing the surface wettability. The potential of these structures as a 3D cell scaffold is exemplified supporting the growth of mouse embryonic stem cells within a hollow spherical BC structure, indicating its biocompatibility and future prospective.

Poloxamer-based binary hydrogels for delivering tramadol hydrochloride: sol-gel transition studies, dissolution-release kinetics, in vitro toxicity, and pharmacological evaluation

In this work, poloxamer (PL)-based binary hydrogels, composed of PL 407 and PL 188, were studied with regard to the physicochemical aspects of sol-gel transition and pharmaceutical formulation issues such as dissolution-release profiles. In particular, we evaluated the cytotoxicity, genotoxicity, and in vivo pharmacological performance of PL 407 and PL 407-PL 188 hydrogels containing tramadol (TR) to analyze its potential treatment of acute pain. Drug-micelle interaction studies showed the formation of PL 407-PL 188 binary systems and the drug partitioning into the micelles. Characterization of the sol-gel transition phase showed an increase on enthalpy variation values that were induced by the presence of TR hydrochloride within the PL 407 or PL 407-PL 188 systems. Hydrogel dissolution occurred rapidly, with approximately 30%-45% of the gel dissolved, reaching ~80%-90% up to 24 hours. For in vitro release assays, formulations followed the diffusion Higuchi model and lower K(rel) values were observed for PL 407 (20%, K(rel) = 112.9 ± 10.6 μg · h(-1/2)) and its binary systems PL 407-PL 188 (25%-5% and 25%-10%, K(rel) =80.8 ± 6.1 and 103.4 ± 8.3 μg · h(-1/2), respectively) in relation to TR solution (K(rel) =417.9 ± 47.5 μg · h(-1/2), P<0.001). In addition, the reduced cytotoxicity (V79 fibroblasts and hepatocytes) and genotoxicity (V79 fibroblasts), as well as the prolonged analgesic effects (>72 hours) pointed to PL-based hydrogels as a potential treatment, by subcutaneous injection, for acute pain.

Pseudolatex from STR 5L Block Rubber for Drug Delivery

Pseudolatex is colloidal dispersion containing spherical solid or semisolid particles and can be prepared from any existing thermoplastic water-insoluble polymers. It is useful for drug encapsulation and controlled drug release. In this study, pseudolatex base was prepared from STR 5L block rubber. The various parameters such as speed and time of homogenization, type and concentration of surfactants, amount of mineral oil, and type of drug loading were studied to prepare the stable pseudolatex. These preparations were evaluated in particle size, pH, viscosity, emulsion stability, drug encapsulation, and in vitro drug release. It was found that the most stable formulation contained 3.5% block rubber, 0.2% methyl cellulose, 6% mineral oil, 4% dibutyl phthalate, 2% sodium lauryl sulfate, and 2% Uniphen P-23 using the speed and time of homogenizer as 20000 rpm and 20 minutes, respectively. Furthermore, the pseudolatex bases reduced the protein impurity form 0.5516% to 0.2108% in formulation with mineral oil and to 0.1781% in formulation without mineral oil, that could decrease contact allergy caused by the protein allergens. Dichloromethane residues in pseudolatex bases were 22.05 mg/L and 7.85 mg/L in formulations with and without mineral oil, respectively, that were satisfied from USP recommendation value of lower than 600 mg/L. Propranolol HCl, lidocaine HCl, and indomethacin could be loaded into pseudolatex only in the concentration of 1%. However, lidocaine base in the concentration of 1-5% could be loaded into pseudolatex which had the similar physical properties and stability to pseudolatex base. The in vitro drug release from pseudolatexs provided the controlled drug release for more than 24 hr.