US4247298A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drug dissolution with a cascade barrier bed
Assignee: University of Minnesota System
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Filing: 1979-03-29
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Granted: 1981-01-27
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Expires: 1999-03-29
Abstract
Abstract A pore-size graded, packed cascade barrier bed, flow-through cell for the measurement of dissolution behavior. The cell containing a porous packing of insoluble multi-particulate solids is designed to retain, in a flow of solvent, particulate solids such as contained in suspensions and slurries or as a result from the disintegration of tablets, capsules, or the like. The vertical bed is packed in discrete layers with uniform sized, inert particles, progressing from layers of small particles at the bottom to layers of large particles at the top. The solid material to be dissolved, when introduced at the top, is carried down into the bed by gravity and the downward flow of the solvent, separated into particle size fractions by the bed, and held in contact with the flowing solvent. The cell is used in conjunction with suitable means for pumping and controlling solvent flow, for controlling ambient and solvent temperature, and for measuring the concentration of the dissolved solid in the effluent solvent.
Inventors
- 👤 Edward G. Rippie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:54
CPC Classifications
B; B01; B01F; B01F21/00; B01F21/20; B01F21/15; B01F2101/00; B01F2101/23
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
115 words
A solids dissolution measurement cell comprising: (A) a vertical tubular cell housing, (B) porous retention means adjacent to the bottom end of said housing, (C) a cascade barrier bed composed of a plurality of discrete layers of uniformly sized insoluble and inert particles packed within said housing supported on said retention means, the size of particles in each layer increasing successively from bottom to top, (D) a non-pervious barrier wall disposed within the housing atop the uppermost particle layer, said barrier wall having a central solids-receiving aperture therein, (E) a solvent receiving chamber at the top of the housing above said barrier wall, and (F) a solvent discharge opening at the bottom of the housing.
Claim 2
Dependent Claim
115 words
A solids dissolution measurement cell comprising: (A) a vertical tubular cell housing, (B) porous retention means adjacent to the bottom end of said housing, (C) a cascade barrier bed composed of a plurality of discrete layers of uniformly sized insoluble and inert particles packed within said housing supported on said retention means, the size of particles in each layer increasing successively from bottom to top, (D) a non-pervious barrier wall disposed within the housing atop the uppermost particle layer, said barrier wall having a central solids-receiving aperture therein, (E) a solvent receiving chamber at the top of the housing above said barrier wall, and (F) a solvent discharge opening at the bottom of the housing.
Claim 3
Dependent Claim
18 words
A cell according to claim 1 wherein said layers of inert particles are at least two in number.
Claim 4
Dependent Claim
19 words
A cell according to claim 1 wherein said inert particles range in size from about 0.05 to 5 mm.
Claim 5
Dependent Claim
35 words
A cell according to claim 1 wherein the cell housing is between about 2 to 20 cm inside diameter and said layers are of substantially uniform depth and from about 1 to 10 cm deep.
Claim 6
Dependent Claim
17 words
A cell according to claim 1 wherein said cell housing is enclosed with a temperature control means.
Claim 7
Dependent Claim
64 words
A solids dissolution measurement apparatus comprising: (A) a cascade barrier bed cell according to claim 1, (B) a solvent reservoir, (C) means for conducting solvent at a controlled and measured rate from said reservoir to the top of said cell, (D) concentration detecting means, and (E) means for conducting solvent containing dissolved solids from the bottom of said cell to said concentration detecting means.
Claim 8
Independent Claim
164 words
A method for the measurement of the dissolution behavior of solid soluble materials in particular solvents, which method comprises: (A) introducing a solid soluble material on the top surface of a cascade barrier bed composed of a plurality of discrete layers of uniformly sized insoluble and inert particles whose size increases successively in each layer from bottom to top, (B) introducing a solvent for said solid material above the bed for partial dissolution of the material and distribution through the bed, with material particles of larger size being distributed in the voids among the larger bed particles and material particles of smaller size being distributed in the voids among the smaller bed particles, (C) continuing introduction of solvent above the bed for flow through the bed at shear rates relative to the material particles inversely proportional to bed particle size at equivalent locations within the voids of various bed layers, (D) collecting the solvent effluent passed through the bed, and (E) analyzing said effluent.
Claim 9
Independent Claim
164 words
A method for the measurement of the dissolution behavior of solid soluble materials in particular solvents, which method comprises: (A) introducing a solid soluble material on the top surface of a cascade barrier bed composed of a plurality of discrete layers of uniformly sized insoluble and inert particles whose size increases successively in each layer from bottom to top, (B) introducing a solvent for said solid material above the bed for partial dissolution of the material and distribution through the bed, with material particles of larger size being distributed in the voids among the larger bed particles and material particles of smaller size being distributed in the voids among the smaller bed particles, (C) continuing introduction of solvent above the bed for flow through the bed at shear rates relative to the material particles inversely proportional to bed particle size at equivalent locations within the voids of various bed layers, (D) collecting the solvent effluent passed through the bed, and (E) analyzing said effluent.
Claim 10
Dependent Claim
32 words
The method according to claim 7 wherein said solvent is introduced to the top of the topmost bed layer at a higher relative velocity by restricting the effective cross-sectional solvent flow area.
Claim 11
Dependent Claim
28 words
The method of claim 8 wherein the solid soluble material is introduced to the top of the topmost bed layer at the point of higher relative solvent velocity.
Claim 12
Dependent Claim
15 words
The method of claim 7 wherein the solvent effluent is analyzed by determining its concentration.
Claim 13
Dependent Claim
17 words
The method of claim 7 wherein the solvent effluent is recycled for successive passes through the bed.
Claim 14
Dependent Claim
20 words
The method of claim 7 wherein the bed is maintained at a temperature between about 15° C. to 45° C.
Claim 15
Dependent Claim
29 words
The method of claim 7 wherein said bed layers are at least two in number and said inert bed particles range in size from about 0.05 to 5 mm.
Claim 16
Dependent Claim
24 words
The method of claim 7 wherein the solvent flux is between about 3 to 300 ml/cm 2 /min in terms of bed cross-sectional area.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-27 | 1984-07-28 | 1985-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-27 | 1988-07-28 | 1989-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-27 | 1992-07-28 | 1993-01-27 | $7700.00 | Window Closed / Lapsed |