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Development and chemical characterization of biodegradable polymeric implants containing sirolimus for the treatment
Abstract:
The use of sirolimus and its analogs has been evaluated in studies aimed at combating several types of cancer; however, because of the limited bioavailability of the drug, the search for new forms of administration is required. Biodegradable polymeric implants containing sirolimus were developed and assessed as an alternative method of drug administration. Implants containing 25 % (w/w) sirolimus were prepared employing the polymer matrices chitosan, polycaprolactone and poly(lactic-co-glycolic acid) (PLGA) in two proportions: PLGA 50:50 and PLGA 75:25. Thermal analysis techniques such as thermogravimetry and differential scanning calorimetry, combined with x-ray diffraction were used to characterize and evaluate the compatibility of the constituents of the formulation. No incompatibilities were found between the components, but drug amorphization was observed in all samples. Implants made from the polymers chitosan and PCL may accelerate the degradation of SRL when these polymers are dissolved in methanol at 50 °C. HPLC analysis showed that the implant prepared with PLGA 75:25 did not present degradation products and maintained its appropriate drug content, even when dissolved in methanol and heated to 50 °C. Therefore, it represents the most suitable biodegradable polymer for use in implants developed for the treatment of malignant solid tumors. However, it is still necessary to further study the drug effects after amorphization of the crystal and also to perform stability and solubility analysis.
Insights
Biodegradable polymeric implants containing sirolimus (SRL) were developed to improve cancer treatment. Implants using poly(lactic-co-glycolic acid) (PLGA) 75:25 demonstrated optimal drug content and stability, making them suitable for solid tumor therapy.
Area of Science:
- Biomaterials Science
- Drug Delivery Systems
- Oncology
Background:
- Sirolimus (SRL) analogs show promise in cancer therapy but suffer from limited bioavailability.
- Novel drug delivery systems are crucial for enhancing SRL efficacy.
- Biodegradable polymeric implants offer a potential solution for controlled SRL administration.
Purpose of the Study:
- To develop and evaluate biodegradable polymeric implants containing sirolimus for cancer treatment.
- To assess the compatibility and stability of sirolimus within different polymer matrices.
- To identify the most suitable polymer for sirolimus-loaded implants targeting solid tumors.
Main Methods:
- Preparation of sirolimus implants using chitosan, polycaprolactone (PCL), and poly(lactic-co-glycolic acid) (PLGA) in 50:50 and 75:25 ratios.
- Characterization using thermogravimetry, differential scanning calorimetry, and X-ray diffraction.
- High-performance liquid chromatography (HPLC) analysis to assess drug content and degradation under stress conditions (methanol, 50 °C).
Main Results:
- No incompatibilities were observed between sirolimus and the polymer matrices.
- Drug amorphization occurred in all tested implant formulations.
- Chitosan and PCL matrices showed potential for accelerated sirolimus degradation.
- PLGA 75:25 implants maintained drug content and showed no degradation products under stress conditions.
Conclusions:
- Biodegradable implants using PLGA 75:25 are a promising strategy for sirolimus delivery in malignant solid tumors.
- Further studies are needed to investigate the effects of drug amorphization and assess long-term stability and solubility.
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