Lipid microparticles as a parenteral controlled release device for peptides

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Nanotechnology

Background:

• Synthetic polymers like poly(lactide-co-glycolide) are commonly used in drug delivery but have limitations.
• Physiological lipids present a potential biocompatible alternative for microparticle formulation.
• Investigating lipid-based systems is crucial for developing advanced, safe drug delivery platforms.

Purpose of the Study:

• To evaluate glyceryl tripalmitate microparticles as a physiological lipid alternative to synthetic polymers.
• To assess the feasibility of preparing peptide-loaded microparticles using solvent evaporation and melt dispersion techniques.
• To characterize the microparticles' properties, including size, morphology, biocompatibility, encapsulation efficiency, and in vitro release.

Main Methods:

• Preparation of peptide-containing glyceryl tripalmitate microparticles using modified solvent evaporation and melt dispersion.
• Incorporation of model peptides (Thymocartin and insulin) as solid or aqueous solutions.
• Characterization via particle size analysis, electron spectroscopy for chemical analysis, biocompatibility testing (in vivo implantation), and in vitro release studies.

Main Results:

• Both preparation methods yielded microparticles in the 20-150 micrometer range with acceptable efficiency.
• Glyceryl tripalmitate microparticles demonstrated biocompatibility comparable to poly(lactide-co-glycolide) microparticles.
• High encapsulation efficiency (>80%) was achieved, particularly with the melt dispersion technique using peptide solutions.
• In vitro peptide release profiles were significantly influenced by the peptides' physicochemical properties.

Conclusions:

• Physiological lipids, specifically glyceryl tripalmitate, are suitable for creating microparticle drug delivery systems.
• The melt dispersion technique offers an efficient, solvent-free method for high-efficiency peptide encapsulation.
• These lipid-based microparticles represent a promising alternative to synthetic polymers for peptide delivery applications.