Determination of polyvinyl alcohol in a poly(DL-lactide-co-glycolide) matrix by size exclusion chromatography using evaporative light scattering detection.

Polyvinyl alcohol (PVA) is used in the manufacture of poly(DL-lactide-co-glycolide) (PLGA) microparticles for the delivery of drugs in an injectable implant form. The levels of residual PVA may affect the release or injectability of the microparticles, and thus must be controlled. Previous work had shown the use of visible detection of iodine-borate complexes of PVA, but this was found to be insensitive and prone to interferences from other formulation components and the sample solvents required. Refractive index detection did not appear to be sensitive enough to detect low levels of PVA. Evaporative light scattering detection was found to be more sensitive and less prone to interferences from the sample matrix than refractive index, and gave reproducible results with acceptable recoveries.