[Relation between drug release and the drug status within curcumin-loaded microsphere]

Area of Science:

• Materials Science
• Pharmaceutical Sciences
• Biomedical Engineering

Background:

• Microspheres are crucial for controlled drug delivery.
• Understanding drug status within microspheres impacts release kinetics.
• Curcumin, a natural compound, has therapeutic potential but requires effective delivery systems.

Purpose of the Study:

• To investigate the relationship between drug loading, drug status, and in vitro release of curcumin from polylactic-co-glycolic acid (PLGA) microspheres.
• To characterize the physical state of curcumin within PLGA microspheres at varying drug loadings.

Main Methods:

• Curcumin-PLGA microspheres were prepared using Shirasu Porous Glass (SPG) membrane emulsification at three drug loading levels.
• In vitro drug release was quantified using high-performance liquid chromatography (HPLC).
• Microsphere morphology was analyzed via scanning electron microscopy (SEM), and drug status was assessed using X-ray diffraction (XRD), differential scanning calorimetry (DSC), and infrared analysis (IR).

Main Results:

• Drug loading achieved were approximately 5.85%, 11.71%, and 15.41%.
• No chemical interaction was observed between curcumin and PLGA.
• Curcumin existed in an amorphous state at the lowest loading, while crystalline forms were detected at higher loadings (2.12% and 5.66%).
• PLGA demonstrated a limited solubility for curcumin, leading to independent crystal formation above this limit.

Conclusions:

• The solubility limit of curcumin in PLGA influences its physical state within microspheres.
• The presence of crystalline curcumin, rather than amorphous, significantly affects drug release profiles.
• This study highlights the importance of considering drug solubility and solid-state properties for designing effective curcumin-loaded PLGA microspheres.