Gel permeation chromatography as a stability-indicating assay for human serum albumin

It has been known for a considerable period of time that preparations of normal human serum albumin contain a amount of polymers and their formation appears to be related to the stability of human albumin solutions. This report describes a gel permeation chromatography technique using Sephadex G-150 to separate albumin molecules into monomers, imers, and polymers. In order to determine if this system could detect small changes in albumin solutions, 5% solutions of albumin were heat denatured and assayed. The changes which resulted from the heat denaturation were easily measurable. Additional experiments using 5% and 25% albumin solutions showed that this system could also detect changes in the amount of aggregation which occurred in these solutions with time. It therefore appears that this technique may be of value in assessing the stability of albumin solutions as measured by the formation of protein aggregates.