Estudo inicial da degradação in vivo de poli(L-co-D,L ácido lático), sintetizado em laboratório, aplicado como prótese tibial em coelhos

The copolymer poly (L-co-D,L lactic acid), PLDLA, has gained prominence in the field of temporary prostheses due to the fact that their time of degradation is quite compatible with the requirement in the case of osseous fracture. In this work the in vivo degradation of devices from copolymer, as a system of plates and screws, used in fixation of the tibia of rabbits was studied. The devices were implanted in 15 adult rabbits, albinos, New Zealand race, and they were used as control devices of alloys of titanium (Ti-6Al-4V/ V grade). The use of copolymers, synthesized in the laboratory, was tested in the repair of fracture in rabbits'tibias, being assessed in the following times: 2 weeks, 2 months and 3 months. Morphological analysis of tissue surrounding the plate and screw system, for 2 weeks of implantation, showed the presence of osteoblasts, indicating a pre bone formation. After 2 months there was new bone formation in the region in contact with the polymer. This bone growth occurred simultaneously with the process of PLDLA degradation, invading the region where there was polymer and after 3 months there was an intense degradation of the copolymer and hence greater tissue invasion compared to 2 months which characterized bone formation in a region where the polymer degraded. The in vivo degradation study of the devices for PLDLA by means of histological evaluations during the period of consolidation of the fracture showed the efficiency of plate and screw system, and it was possible to check formation of bone tissue at the implantation site, without the presence of inflammatory reaction

Desenvolvimento e caracterização de nanocápsulas de poli (L-lactídeo) contendo benzocaína

In this paper we describe the preparation poly (L-lactide) (PLA) nanocapsules as a drug delivery system for the local anesthetic benzocaine. The characterization and in vitro release properties of the system were investigated. The characterization results showed a polydispersity index of 0.14, an average diameter of 190.1± 3 nm, zeta potential of -38.5 mV and an entrapment efficiency of 73%. The release profile of Benzocaine loaded in PLA nanocapsules showed a significant different behavior than that of the pure anesthetic in solution. This study is important to characterize a drug release system using benzocaine for application in pain treatment.

Avaliação do amaciamento de carne bovina de dianteiro (Triceps brachii) pelos métodos de maturação, estimulação elétrica, injeção de ácidos e tenderização mecânica

Twenty-two Triceps brachii muscle obtained from 11 cows aged 3 and 4 years , killed in an experimental slaughter plant, were submitted to mechanical tenderization, injection with acetic acid 0,1M and lactic acid 0,2M, ageing for 9 and 14 days and electrical stimulation (250v - 60Hz - 90s), some of them were reserved as a control group, without treatment. The 14 days ageing time presented 21% of increase in subjective tenderness and 12% of reduction in shear force, these values were similar to the electrical stimulated meat. However the injection with acids and the ageing time 9 days did not present significant effect in the texture. Although the shear force values of mechanical tenderized meat was the shortest among all treatments, suspect of superestimation because of the fractures plan created by this process. Another analyses were carried out: pH reduction curve, R value; colour analysis; weight losses by cooking and by treatment; and microbiological analysis.