Development of thalidomide-loaded biodegradable devices and evaluation of the effect on inhibition of inflammation and angiogenesis after subcutaneous application.

PURPOSE: To develop thalidomide-loaded poly-lactide-co-glycolide implants and evaluate its in vivo release and biological activity against inflammation and angiogenesis after subcutaneous administration. METHODS: Implants were prepared by the hot molding technique and characterized using stereomicroscopy, thermal analysis and X-ray diffraction. Swiss mice, divided in groups 1-3, received a subcutaneous implant containing 25% (w/w), 50% (w/w) or 75% (w/w) of thalidomide, respectively (n=6). The drug levels were determined during a 28-day study period. The toxicity associated with the implants was evaluated by light microscopy. The potential of the developed implant in the inhibition of inflammation and angiogenesis was evaluated in vivo using the sponge model. RESULTS: Thalidomide implant was developed and its characterization proved the stability of the drug and the polymer during preparation. Release profiles in vivo demonstrated an extended release of thalidomide from the implants during the 28 days. Histological evaluation did not show any sign of intense local inflammatory response to the presence of the implants in the subcutaneous pouch. The thalidomide implant reduced the number of vessels and N-acetyl-b-glucosaminidase (NAG) in vivo. CONCLUSION: The biodegradable implants delivered safe doses of thalidomide that were also effective to induce angiogenesis and inflammation regression.

Efficacy of methotrexate-loaded poly(ε-caprolactone) implants in Ehrlich solid tumor-bearing mice.

CONTEXT: Methotrexate (MTX) is used in the treatment of malignancies; however, its clinical application is limited by its toxic dose-related side effects. An alternative to overcome the toxicity of the MTX in healthy tissues is the design of an implantable device capable of controlling the delivery of this drug for an extended period within the tumor site. OBJECTIVE: To develop methotrexate-loaded poly(ε-caprolactone) implants (MTX PCL implants) and to demonstrate their efficacy as local drug delivery systems capable of inhibiting Ehrlich solid tumor bearing mice. MATERIALS AND METHODS: MTX PCL implants were produced by the melt-molding technique and were characterized by FTIR, WAXS, DSC and SEM. The in vitro and in vivo release of MTX from the PCL implants was also evaluated. The efficacy of implants in inhibiting tumor cells in culture and the solid tumor in a murine model was revealed. RESULTS AND DISCUSSION: The chemical and morphological integrity of the drug was preserved into the polymeric matrix. The in vitro and in vivo release processes of the MTX from the PCL implants were modulated by diffusion. MTX diffused from the implants revealed an antiproliferative effect on tumor cells. Finally, MTX controlled and sustained released from the polymeric implants efficiently reduced 42.7% of the solid tumor in mice paw. CONCLUSION: These implantable devices represented a contribution to improve the efficacy and safety of chemotherapy treatments, promoting long-term local drug accumulation in the targeted site.

Evaluation of the effects of thalidomide-loaded biodegradable devices in solid Ehrlich tumor.

Regarding thalidomide's effects in cancer and the problems related to its physicochemical characteristics and toxic effects, we proposed a new biodegradable polymeric implant to this drug. In this paper, we evaluate the antiangiogenic activity and antitumor effect of thalidomide when incorporated in poly-lactide-co-glycolide (PLGA) implants in an animal model for Ehrlich tumor. This dosage form permits the prolonged drug release. The biodegradable implants could reduce the blood vessel in a chorioallantoic membrane (CAM) model. When applied to the Ehrlich tumor model, implant also showed to reduce the number of vessels. It was also observed to reduce areas of inflammation and increases the area of necrosis in the group of thalidomide implant. A 47% reduction in tumor volume was observed in the thalidomide implant group, which is discussed in relation to literature reported results of thalidomide conventional administration ways.

Poly-ε -caprolactone microspheres containing interferon alpha as alternative formulations for the treatment of chronic hepatitis C

Interferon-alpha (IFN-alpha) is one of the main drugs used in the treatment of hepatitis C. Use of IFN-alpha has some limitations that result in poor treatment efficacy and low patient compliance. Therefore, the aim of this study was to develop poly-ε-caprolactone (PCL) microspheres containing IFN-alpha as an alternative for the treatment of chronic hepatitis C. Microspheres were prepared using the multiple emulsion followed by solvent evaporation technique. Particle size, surface morphology, drug content and encapsulation efficiency of the microspheres produced were evaluated. The stability of the formulation was assessed after 90 days at -20ºC. An in vitro release study was performed in PBS. In vitro cytotoxicity of the formulation was studied using hepatic cell line. The freeze-dried microspheres had mean particle size, IFN-alpha content, and encapsulation efficiency of 38.52 ± 4.64 µm, 15.52 ± 3.28% and 83.93 ± 5.76%, respectively. There were no significant changes during storage and the structural integrity of the protein was not compromised by the preparation technique. A total of 82% of the IFN-alpha was released after 28 days and the developed microspheres did not present cytotoxicity to the hepatic cell line. In vivo studies are currently underway to evaluate the biological activity of IFN-alpha encapsulated into microspheres.

O interferon alfa (IFN-alfa) é um dos principais fármacos utilizados no tratamento de hepatite C, mas o seu uso apresenta limitações que resultam em baixa eficácia do tratamento e não adesão do paciente. Diante disso, este estudo objetiva o desenvolvimento de microesferas de poli-ε-caprolactona (PCL) contendo IFN-alfa como alternativa ao tratamento de hepatite C crônica. As microesferas foram preparadas pelo método de emulsão múltipla seguido de evaporação do solvente e caracterizadas quanto ao diâmetro médio das partículas, morfologia da superfície, taxa e eficiência de encapsulamento. A estabilidade da formulação foi acompanhada durante 90 dias a -20 ºC. O estudo de liberação in vitro foi realizado em PBS. A citotoxicidade da formulação foi avaliada utilizando linhagem de células hepáticas. As microesferas liofilizadas apresentaram diâmetro médio, taxa de encapsulamento e eficiência de encapsulamento de 38,52 ± 4,64 µm, 15,52 ± 3,28% e 83,93 ± 5,76%, respectivamente. Não foram observadas alterações significativas durante o armazenamento e a integridade estrutural da proteína foi mantida após o preparo. Oitenta e dois por cento de IFN-alfa foram liberados em 28 dias e a formulação desenvolvida não apresentou toxicidade para as células testadas. Estudos in vivo estão em andamento para avaliar a atividade biológica do IFN-alfa encapsulado nas microesferas.