Comparison of Shell-Cross-Linked Micelles with Soft and Glassy Cores as a Drug Delivery Vehicle for Albendazole: Is There a Difference in Performance?

The understanding of glass transition temperatures T-g in drug and polymer systems is indispensable for drug encapsulation and delivery. Amphiphilic block copolymers consisting a various ratios of poly(methyl methacrylate) (T-g = 100 degrees C) and poly(ethyl acrylate) (T-g = 22 degrees C) as the hydrophobic block have been synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization as drug delivery carrier for albendazole (ABZ). Self-assembled micelles with diameters of similar to 25 nm with glassy (PMMA) and soft (PEA) core have been synthesized. Differential scanning calorimetry (DSC) has been used to evaluate crystallinity and miscibility of ABZ with the core-forming polymer. All drug-polymer systems are compatible, but they become less miscible with increasing amount of PMMA. The most noticeable difference was the suppression of the crystallinity of the drug with increasing PEA content, a prerequisite for of the drug carrier. Since the different micelles are subject to different thermodynamic stability, shell-cross-linking was carried out. Cell experiments against OVCAR-3 cell lines show a fast and efficient uptake of these nanoparticles. Shell-cross-linked micelles were found to be 2-4 times more efficient against OVCAR-3 cells at low concentrations. In contrast, there was no significant difference in the IC50 value of drug carriers with glassy and soft cores.