The therapeutic effects of many modern drugs were limited owing to their physical properties and half-life in the blood stream. The purpose of this research is to study the relationship between drug delivery performances and chemical properties of the polymer micelle drug carriers.

Polyethylene glycol (PEG) based alternating copolymer poly[(polyoxyethylene)-oxy-5-hydroxyisophthalic] (Ppeg) with PEG molecular weights of 600 and 1000 were synthesized and modified with different alkanes to study the effects of altering the hydrophobic and hydrophilic chain lengths. The nuclear magnetic resonance (NMR) spectrum, critical micelle concentration (CMC), micelle size, and micelle zeta potential of the synthesized polymers were measured. The resulting polymer particles were able to form micelles in aqueous solution with CMCs lower than 0.04 wt%. Drug delivery studies were performed with a model hydrophobic drug, pyrene. Drug loading data showed the polymer particles were able to encapsulate pyrene and has a loading capacity up to 8 wt%. The sustain release ability was measured and the pyrene release was extended over 5 days. Both loading capacity and sustain release ability were found to be highly dependent on CMC.

Cell culture study was implemented with RAW 264.7 cells in order to determine the polymer micelle’s cytocompatibility, Most Ppeg polymer micelles showed more than 85% cell viability with and without pyrene loading. Cell internalization of the micelles encapsulated drug was measured both quantitatively and qualitatively and was enhanced comparing to unencapsulated drug. The results indicated that the internalization enhancement effect of polymer micelle was mainly affected by hydrophilic chain length; neither hydrophobic chain length nor loading capacity has significant influence on internalization.