Prodigiosin release from an implantable biomedical device: kinetics of localized cancer drug release

• Fabricated thermo-sensitive hydrogels for localized drug release from an implantable biomedical device.
• Determined the cancer drug diffusion mechanisms of PNIPA-co-AM copolymer hydrogel.
• Encapsulated PNIPA-based hydrogels in PDMS capsules for controlled drug delivery.
• Established the kinetics of drug release from gels and channels in an implantable biomedical device.
• Demonstrated the potential for the controlled release of prodigiosin (PG) as an anticancer drug.

This paper presents an implantable encapsulated structure that can deliver localized heating (hyperthermia) and controlled concentrations of prodigiosin (a cancer drug) synthesized by bacteria (Serratia marcesce (subsp. marcescens)). Prototypical Poly-di-methyl-siloxane (PDMS) packages, containing well-controlled micro-channels and drug storage compartments, were fabricated along with a drug-storing polymer produced by free radical polymerization of Poly(N-isopropylacrylamide)(PNIPA) co-monomers of Acrylamide (AM) and Butyl-methacrylate (BMA). The mechanisms of drug diffusion of PNIPA-base gels were elucidated. Scanning Electron Microscopy (SEM) was also used to study the heterogeneous porous structure of the PNIPA-based gels. The release exponents, n, of the gels were found to between 0.5 and 0.7. This is in the range expected for Fickian (n = 0.5). Deviation from Fickian diffusion was also observed (n > 0.5) diffusion. The gel diffusion coefficients were shown to vary between 2.1 × 10− 12 m2/s and 4.8 × 10− 6 m2/s. The implications of the results are then discussed for the localized treatment of cancer via hyperthermia and the controlled delivery of prodigiosin from encapsulated PNIPA-based devices.