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Resorbable polymeric microspheres for drug delivery--production and simultaneous surface modification using PEO-PPO
A G Coombes1, P D Scholes, M C Davies
1Department of Pharmaceutical Sciences, University of Nottingham, University Park, UK.
Biomaterials
|July 1, 1994
Summary
This study shows how poly(oxyethylene)-poly(oxypropylene) (PEO-PPO) surfactants can create uniform, resorbable poly(DL-lactide co-glycolide) (PLG) microspheres. These modified microspheres offer new possibilities for drug delivery applications.
Area of Science:
- Biomaterials Science
- Polymer Chemistry
- Nanotechnology
Background:
- Resorbable microspheres are crucial for drug delivery systems.
- Controlling microsphere size and surface properties is essential for efficacy.
- Poly(oxyethylene)-poly(oxypropylene) (PEO-PPO) co-polymers are versatile surfactants.
Purpose of the Study:
- To investigate the use of PEO-PPO as a surfactant in producing poly(DL-lactide co-glycolide) (PLG) microspheres.
- To characterize the size, polydispersity, and surface composition of the resulting microspheres.
- To explore the potential for simultaneous manufacture and surface modification of PLG microspheres.
Main Methods:
- Emulsification/solvent evaporation technique using acetone-dichloromethane mixtures.
- Production of poly(DL-lactide co-glycolide) (PLG) microspheres with PEO-PPO.
- Surface analysis using static secondary ion mass spectroscopy (SSIMS).
- Microsphere cleaning via centrifuging, resuspension, and dialysis.
Main Results:
- PEO-PPO surfactants facilitated the production of resorbable PLG microspheres in the 500 nm-1 micron size range.
- High microsphere polydispersity was reduced by employing low PLG concentrations (1% w/v).
- SSIMS confirmed the presence of PEO-PPO at the microsphere surface after rigorous cleaning processes.
- Evidence suggests physical entrapment of PEO-PPO chains due to rapid PLG network collapse during solvent extraction.
Conclusions:
- PEO-PPO co-polymers are effective surfactants for producing uniform, resorbable PLG microspheres.
- The emulsification/solvent evaporation method, optimized with low PLG concentration, yields microspheres with reduced polydispersity.
- The presence of PEO-PPO on the microsphere surface indicates successful surface modification during fabrication.
- This technique offers a promising approach for the simultaneous manufacture and surface functionalization of microspheres for advanced applications.