Isolation and measurement of colloids in human plasma by membrane-selective flow field-flow fractionation: lipoproteins and pharmaceutical colloids.

Using a modified flow field-flow fractionation (flow FFF) technique termed membrane-selective flow FFF, a capability is developed to isolate various colloidal constituents that are naturally present in or may be introduced into blood plasma. Once isolated, the colloids may be subject to quantitative measurement to provide relative amounts of the different constituents and the size distribution curve of each. The potential of the technique has been demonstrated by isolating and measuring (a) the lipoprotein fractions found in human blood plasma, (b) liposyn II pharmaceutical emulsion added at 2 mg/mL of plasma, and (c) amphotericin B colloidal dispersion (a drug delivery agent) added to plasma at 0.5 mg/mL.