RESUMO
A degradable ultraphosphate (55 mol % P2O5) quinternary phosphate glass composition has been characterised in terms of its chemical, mechanical and degradation properties both as a bulk material and after drawing into fibres. This glass formulation displayed a large processing window simplifying fibre drawing. The fibres displayed stiffness and strength of 65.5 ± 20.8 GPa and 426±143 MPa. While amorphous discs of the glass displayed a linear dissolution rate of 0.004 mg cm(-2) h(-1) at 37 °C, in a static solution with a reduction in media pH. Once drawn into fibres, the dissolution process dropped the pH to <2 in distilled water, phosphate buffer saline and corrected-simulated body fluid, displaying an autocatalytic effect with >90 % mass loss in 4 days, about seven times faster than anticipated for this solution rate. Only cell culture media was able to buffer the pH taking over a week for full fibre dissolution, however, still four times faster dissolution rate than as a bulk material. However, at early times the development of a HCA layer was seen indicating potential bioactivity. Thus, although initial analysis indicated potential orthopaedic implant applications, autocatalysis leads to accelerating degradation in vitro.
Assuntos
Materiais Biocompatíveis/química , Vidro/química , Teste de Materiais/métodos , Fosfatos/química , Polímeros/química , Substitutos Ósseos , Catálise , Meios de Cultura/química , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Peso Molecular , Ortopedia , Poliésteres/química , Pressão , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Estresse Mecânico , Temperatura , Resistência à Tração , Engenharia TecidualRESUMO
The usefulness of oral naltrexone has been limited by compliance. Sub-cutaneous implants would seem to offer a solution to this problem and improve long-term outcomes. The aim of the present study was to compare levels of blood serum naltrexone of patients who had received a naltrexone implant after detoxification to a number of dependent variables of interest. These dependent variables included drug use including urine screens of each patient, any adverse response to the implant, subjective evaluation of self-esteem, quality of relationships, and changes in social functioning. Sixty six patients received an implant and were surveyed; urine and blood samples were taken at about 1, 3, and 6 months after implantation. Naltrexone levels were on average above 1 ng/mL at 6 months after insertion and patients showed significant improvements on all dependent variables. The preliminary evidence indicates that implants can improve compliance rates and outcomes.
RESUMO
Naltrexone's current use has been limited by compliance. Subcutaneous implants would seem to offer a solution to this problem and improve long-term outcomes. The aim of the present study was to compare groups of patients who had received oral naltrexone or a naltrexone implant after detoxification and to follow their progress. Forty-one patients received an implant, and 42 patients received oral naltrexone. They were surveyed at one, three, six, and 12 months after detoxification. Their designated support person was also contacted to confirm the self-reports of the participants. Patients were compared on gender, age, and length of time since detoxification. Implant patients showed much higher abstinence rates, while those in both groups who were abstinent showed greater compliance to naltrexone (time spent in treatment) and attended more counseling sessions. Although the participants were not randomly allocated to each treatment condition, the preliminary evidence indicates that implants can improve compliance rates and outcomes.