Formulation and characterization of curcumin loaded polymeric micelles produced via continuous processing

A continuous processing platform was developed to produce polymeric micelles. A block copolymer of mPEG (5kD)-PCL (2kD) was used as the model drug carrier. The polymeric micelles were produced using an innovative co-axial turbulent jet with co-flow continuous technology to precisely control the physicochemical properties of the micelles. A 3 x 3 x 4 full factorial design of experiment (DoE) study was conducted to optimize the polymeric micelle processing to achieve the desired critical quality attributes such as particle size and polydispersity index (PDI). Curcumin was used as a hydrophobic model drug as polymeric micelles are traditionally used to improve solubility and chemical stability of hydrophobic drug molecules. A second DoE study was conducted to achieve maximal drug loading. The average size of the optimized curcumin-loaded polymeric micelles was 29.1 +/- 0.51 d.nm with a PDI value in the range of 0.05 +/- 0.02 and a maximum drug loading of 11.1 +/- 0.81% (w/w). When compared to polymeric micelles prepared using a manual ethanol injection method the particle size, PDI and drug loading for curcumin-loaded polymeric micelles was 74.8 +/- 8.68 d.nm, and 0.46 +/- 0.12 and 8.12 +/- 1.23%, respectively. These data show that the continuous processing method provided significant improvement in controlling the key quality attributes. The curcumin-loaded polymeric micelles exhibited a sustained release profile during dissolution of about 50% drug released in 12 h compared to the free drug, which was completely released within 10 h. The curcumin-loaded polymeric micelles were characterized for other key quality attributes such as critical micelle concentration (CMC), and morphology by transmission electron microscopy, X-ray powder crystallography, polarized light microscopy, and differential scanning calorimetry. A novel method for determining the CMC of the polymer was developed using dynamic light scattering (DLS). Curcumin-loaded polymeric micelles were further processed by lyophilization to prevent hydrolytic cleavage of the polymers and maintain long term stability. The current study highlighted the potential advantages of transitioning from manual batch processing to continuous processing and serves as an example of improving processing efficiency as well as product quality through utilization of advanced processing technologies.