Surface characterization by atomic force microscopy of sterilized PLGA microspheres

Area of Science:

• Materials Science
• Pharmaceutical Technology
• Surface Science

Background:

• Atomic force microscopy (AFM) is a powerful tool for surface analysis.
• Its application in the pharmaceutical field for microsphere/nanosphere characterization is emerging.
• Gamma irradiation is used for sterilization but can alter material properties.

Purpose of the Study:

• To investigate morphologic modifications in poly(lactide-co-glycolide) (PLGA) microspheres loaded with ovalbumin after gamma irradiation.
• To compare the efficacy of AFM with scanning electron microscopy (SEM) for surface characterization.
• To assess the protective effect of polyethylene glycol (PEG) against gamma irradiation damage.

Main Methods:

• Surface characterization of sterilized PLGA microspheres using Atomic Force Microscopy (AFM).
• Comparison of AFM results with Scanning Electron Microscopy (SEM) data.
• Analysis of surface roughness changes as an indicator of irradiation effects.

Main Results:

• AFM provided additional insights into surface morphology changes compared to SEM.
• Significant increases in surface roughness indicated damage to microspheres from gamma irradiation.
• Microspheres containing PEG showed unchanged surface roughness, suggesting a protective effect.

Conclusions:

• AFM is a valuable technique for detailed surface characterization of pharmaceutical microspheres.
• Gamma irradiation induces surface damage in PLGA microspheres, evidenced by increased roughness.
• PEG incorporation offers a protective strategy against gamma irradiation-induced morphologic alterations in microspheres.