Method for extraction and reaction using supercritical fluids
AssigneeBoehringer Ingelheim Pharmaceuticals, Inc.
InventorsStephen T. Horhota, Said Saim
Life of this patent
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Abstract
Methods for removing soluble material from confined spaces within substrates such as containers, capsules and porous powders comprising extraction with supercritical fluids, the pressure of which is preferably modulated between an upper level and a lower level within a relatively narrow range of fluid pressure and density. The method permits enhanced extraction efficiency, catalytic reaction rates and ability to maintain catalyst activity.
Claims26
A method for extracting supercritical fluid soluble material from one or more cavities or confined spaces in a substrate comprising the steps of:
- a) exposing the substrate to a supercritical fluid in which said material is substantially soluble but said substrate is not, wherein said supercritical fluid has a critical temperature less than about 200° C. and a critical pressure of less than about 10,000 psi and wherein said substrate is a container selected from the group consisting of vials, bottles, jars, flasks, cylinders, capsules, boxes, tubes, drums and bags;
- and
- b) repeatedly modulating the pressure of said supercritical fluid between two or more pressure levels such that the relative difference between the uppermost and lowermost levels of density of said supercritical fluid at such pressure levels is not more than about 30%.
A method for treating gelatin, cellulose, modified starch, or plastic capsules used for storing a dry, powdered formulation wherein the capsule has supercritical fluid-extractable material on its surfaces comprising the steps of:
- a) exposing the capsule to a supercritical fluid in which said supercritical fluid-extractable material is substantially extractable but in which said capsule is not, wherein said supercritical fluid has a critical temperature less than about 200° C. and a critical pressure of less than about 10,000 psi;
- and
- b) repeatedly modulating the pressure of said supercritical fluid between two or more pressure levels such that the relative difference between the uppermost and lowermost levels of density of said supercritical fluid at such pressure levels is not more than about 30%.
Dependencies are inferred from the claim text.