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Development of functionally-graded reservoir of PCL/PG by selective laser sintering for drug delivery devices

Drug delivery devices are systems employed to conduct a drug to a specific site of the body, where it should be released and absorbed. Reservoir-type systems are devices in which the drug is contained within a nucleus isolated from the outside environment by a thin polymeric layer, which regulates a diffusion process driven by a functional concentration gradient. In this study two reservoir-type drug delivery devices based on polycaprolactone (PCL) were developed for the release of progesterone (PG) using the Selective Laser Sintering (SLS) technique, in order to investigate the influence of the concentration gradient promoted during manufacturing on the drug delivery profile. Two types of controlled-drug-release devices were fabricated; the first containing only the polycaprolactone polymer in the reservoir wall (system R) and the second containing PLC and 15% of progesterone in the wall (system R*). The cores of both reservoirs were filled with 40 mg of progesterone. A study on the degradation was conducted to assess the release process of the two systems. The drug delivery results showed that for both reservoirs the amount of drug released was linear over time, featuring zero-order release kinetics. The higher mass loss with the incorporation of the drug into the wall of the reservoir was associated with faster release of the drug to the medium. The feasibility of building three-dimensional parts using the SLS technique allowed the construction of reservoir-type devices based on a functional gradient for the controlled-release of the drug.