AUTOMATIC DISSOLUTION RATE DETERMINATOR

• US 3,802,272 A
• Filed: 01/24/1973
• Issued: 04/09/1974
• Est. Priority Date: 01/24/1973
• Status: Expired due to Term

• Current Assignee: David W. Skiles, Dennis E. Bischoff, Robert M. Brooker
• Original Assignee: David W. Skiles, Dennis E. Bischoff, Robert M. Brooker
• Inventors: Bischoff, Dennis E., Skiles, David W., Brooker, Robert M.
• Primary Examiner(s): Woodiel, Donald O.
• Application Number:
  US05/326,428
• Time in Patent Office: 440 Days
• Field of Search: 73/432R,86 259/90,8
• US Class Current: 73/866
• CPC Class Codes: G01N 13/00 Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects scanning-probe techniques or apparatus G01Q
• CPC Class Codes: G01N 2013/006 Dissolution of tablets or the like
• CPC Class Codes: G01N 2035/00198 Dissolution analysers
• CPC Class Codes: G01N 33/15 Medicinal preparations ; Physical properties thereof, e.g. dissolubility

Abstract

An automatic dissolution rate determinator for determining dissolution rates of pharmaceutical tablets, capsules or the like includes a plurality of dissolution test chambers connected by appropriate tubing and valves to an analyzer, with valving and control means for rapid sequential sampling of liquid dissolution test medium from each chamber.

Claims

1. In a dissolution rate testing apparatus comprising a plurality of dissolution test chambers for containing a liquid medium and a solid test material to be dissolved therein, an analyzer for analyzing the quantity of test material dissolved in the liquid medium, and sampling means including valves, tubes and a pump for sequentially transporting a liquid medium sample from each test chamber to the analyzer and returning said sample to its corresponding test chamber through a return tube, and control means for operating said sampling means to sample each test chamber in a predetermined, timed sequence;

the improvement wherein;

the sampling means includes a plurality of sample intake tubes, a sample intake tube being disposed in each test chamber in communication with the liquid medium therein;

screening means in each dissolution chamber for preventing undissolved solid test material from entering the intake tube associated therewith; and

back-flush means;

including a valve coupled to the sampling means, for selectively reversing the direction of fluid flow in each intake tube.

2. Apparatus of claim 1 wherein the pump is adapted to maintain continuous, unidirectional fluid flow in a unidirectional flow tube portion of the sampling means;

and wherein the back flush means includes valve means selectively communicating with said tube portion, with selected intake and return tubes, and with a source of a back-flush fluid, said valve means being operable between a forward mode in which the selected intake tube is communicably coupled upstream of the pump and through the unidirectional flow tube portion to the selected return tube, and a back-flush mode in which the source of back-flush fluid is communicably coupled upstream of the pump and through the unidirectional flow tube portion to the intake tube.

3. Apparatus of claim 2, further comprising an intake valve having an outlet port and a plurality of inlet ports, each inlet port communicatively coupled to corresponding intake tube, a first back-flush valve having a first port communicably coupled to the outlet port of the intake valve, a second port communicably coupled to an upstream portion of the unidirectional flow tube, a third port communicably coupled to a downstream portion of the unidirectional flow tube and a fourth port;

a second back flush valve having a first port communicatively coupled to the fourth port of the first back flush valve to selectively communicate with a second port vented to air and a third port communicatively coupled to a selected return tube; and

means for simultaneously operating both back flush valves between a forward mode in which the first and second ports, and the third and fourth ports of the first valve communicate and the first port of the second valve communicates with the third port thereof; and

a back flush mode wherein the first and third ports and the second and fourth ports of the first valve communicate and the first port of the second valve communicates with the second port thereof.

4. Apparatus of claim 3 wherein the analyzer comprises a spectrophotometer and a flow cell in the unidirectional flow tube, and wherein the control means comprises means for deactivating the spectropHotometer during the back-flush phase.

5. Apparatus of claim 4 wherein the control means comprises a timer having first output operatively connected to the intake valve to selectively, sequentially couple each intake tube to the first back flush valve for a predetermined sampling time interval, and a second output operatively connected to the back-flush valve operating means for operating the back-flush valves through both phases of operation during each sampling time interval.