Hanson Research Corporation

William A Hanson

Steven W Shaw

Graham S Barr

A diffusion cell to facilitate the automated removal of test aliquots of liquid from a receptor chamber of the diffusion cell so as to determine percutaneous absorption through a membrane of a donor media from a donor chamber into the receptor chamber of the diffusion cell. There is utilized a sampling port through which the test aliquot is to be removed, the removal being achieved by means of a sample tube. Within the receptor chamber is located a stirring device in the form of a helical coil which is to be rotated to achieve stirring and homogeneous mixing of the liquid within the receptor chamber. Mounted within the coil is a filter screen to prevent particulate matter over a certain size from entering the sample tube and clogging such.

Diffusion cell with filter screen

A diffusion cell to facilitate the automated removal of test aliquots of liquid from a receptor chamber of the diffusion cell so as to determine percutanous absorption through a membrane of a donor fluid from a donor chamber into the receptor chamber of the diffusion cell. There is utilized a sampling port through which the test aliquot is to be removed, the removal being achieved by means of a sample tube which is to be movable into and out of the receptor chamber. Within the receptor chamber is located a stirring device in the form of a helical coil which is to be rotated to achieve stirring and homogeneous mixing of the liquid within the receptor chamber. A refilling tube connects also with the receptor chamber to add liquid into the receptor chamber as the test aliquot has been removed. A leveling tube within the sampling port is to restore the initial preset receptor liquid volume between sampling intervals.

Diffusion cell

An automated sample changing chemical analysis system for sequentially analyzing a series of samples such as pharmaceutical chemical samples, the system being particularly useful for dissolution rate testing. A pressure/vacuum source provides motivation for withdrawing each sample from its respective source in sequence through a sample selector valve and transporting the sample to the flow cell of a chemical analyzer such as an U.V. Spectrophotometer, and then returning all or part of the sample to its source through the same selector valve and purging the flow cell and conduits back to the sample source. In one form each sample is simply drawn by vacuum from its source through the selector valve into the flow cell and then the entire sample is returned after analysis, by air pressure, back through the selector valve to the source, while in another form a diluent or reagent is mixed with the sample in an intermediate step to bring the sample within the testing range of the analyzer. Novel microporous filter stop means is employed to protect the pressure/vacuum source from system liquids, to accurately measure a quantity of diluent or reagent to be mixed with the sample, and to minimize bubbles in the system.

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Westlake Village, CA, United States of America

William A Hanson