Centrifugal Field Flow Fractionation Improves Characterisation of Drug Delivery Systems

Postnova Analytics reports that its CF2000 Centrifugal Field Flow Fractionation system is delivering exciting new data to scientists developing drug delivery systems.

Soheyl Tadjiki, Managing Director of Postnova Analytics Inc. commented "One of the grand challenges of characterisation of any drug delivery system is the determination of cargo mass per delivery vesicle. Size characterisation techniques are inherently inadequate to provide such information. By comparison we have found that our CF2000 Centrifugal Field-Flow Fractionation (CF3) system, a mass-based, high resolution separation instrument, is capable of measuring the cargo mass per vesicle to a limit of quantification of 12 attogram (12 x 10-18 g)".

In Centrifugal Field-Flow Fractionation (CF3) the separation force is established by a centrifugal field, which is generated by spinning the complete circular channel at a high rate. The bigger and denser particles are forced more in the direction of the outer wall than the smaller particles. As a consequence, bigger particles are eluted later from the CF3 channel as they are located in slower streamlines in the channel than the smaller particles which are located in faster stream lines. 

Based on the CF3 principle, the Postnova CF2000 employs a centrifugal field as the driving force for separations. Particles affected by this field are separated by dynamic diffusion on the basis of both particle size and density. This unique feature of the CF2000 allows the separation of different particulate materials having the same particle size. Separations on the CF2000 can be further optimised by using different eluents and temperature programs. As a consequence, the CF2000 system is proving an ideal tool for the separation and characterisation of complex particulate samples in areas including agriculture, cosmetics, nanomaterials and pharmaceutical drug delivery systems.

In contrast to traditional particle sizing techniques which work in the batch mode, the CF3 technique physically separates each particle fraction prior to sizing. This avoids numerous disadvantages of these batch techniques such as, low size resolution, discrimination and under estimation of smaller compared to larger particles. Using Postnova CF3 technology no special sample preparation is necessary as they can be injected directly without filtration, allowing the characterisation of even complex particulate materials without alteration and damage.