PROCEDURE
Apparatus 1 and Apparatus 2
IMMEDIATE-RELEASE DOSAGE FORMS
Place the stated volume of the Dissolution Medium (±1%) in the vessel of the specified apparatus given in the individual monograph, assemble the apparatus, equilibrate the Dissolution Medium to 37 ± 0.5, and remove the thermometer. Place 1 dosage unit in the apparatus, taking care to exclude air bubbles from the surface of the dosage unit, and immediately operate the apparatus at the specified rate given in the individual monograph. Within the time interval specified, or at each of the times stated, withdraw a specimen from a zone midway between the surface of the Dissolution Medium and the top of the rotating basket or blade, not less than 1 cm from the vessel wall. [NOTE—Where multiple sampling times are specified, replace the aliquots withdrawn for analysis with equal volumes of fresh Dissolution Medium at 37 or, where it can be shown that replacement of the medium is not necessary, correct for the volume change in the calculation. Keep the vessel covered for the duration of the test, and verify the temperature of the mixture under test at suitable times.] Perform the analysis as directed in the individual monograph using a suitable assay method.3 Repeat the test with additional dosage form units.
If automated equipment is used for sampling or the apparatus is otherwise modified, verification that the modified apparatus will produce results equivalent to those obtained with the standard apparatus described in this general chapter is necessary.
Dissolution Medium— A suitable dissolution medium is used. Use the solvent specified in the individual monograph. The volume specified refers to measurements made between 20 and 25. If the Dissolution Medium is a buffered solution, adjust the solution so that its pH is within 0.05 unit of the specified pH given in the individual monograph. [NOTE—Dissolved gases can cause bubbles to form, which may change the results of the test. If dissolved gases influence the dissolution results, dissolved gases should be removed prior to testing.4 ]
Time— Where a single time specification is given, the test may be concluded in a shorter period if the requirement for minimum amount dissolved is met. Specimens are to be withdrawn only at the stated times within a tolerance of ±2%.
EXTENDED-RELEASE DOSAGE FORMS
Proceed as directed for Immediate-Release Dosage Forms.
Dissolution Medium— Proceed as directed for Immediate-Release Dosage Forms.
Time— The test-time points, generally three, are expressed in hours.
DELAYED-RELEASE DOSAGE FORMS
NOT ACCEPTED BY THE JAPANESE PHARMACOPOEIA
Use Method A or Method B and the apparatus specified in the individual monograph. All test times stated are to be observed within a tolerance of ±2%, unless otherwise specified.
Method A—
Procedure (unless otherwise directed in the individual monograph)—
ACID STAGE— Place 750 mL of 0.1 N hydrochloric acid in the vessel, and assemble the apparatus. Allow the medium to equilibrate to a temperature of 37 ± 0.5. Place 1 dosage unit in the apparatus, cover the vessel, and operate the apparatus at the specified rate given in the monograph.
After 2 hours of operation in 0.1 N hydrochloric acid, withdraw an aliquot of the fluid, and proceed immediately as directed under Buffer Stage.
Perform an analysis of the aliquot using a suitable assay method. The procedure is specified in the individual monograph.
BUFFER STAGE— [NOTE—Complete the operations of adding the buffer and adjusting the pH within 5 minutes.]
With the apparatus operating at the rate specified in the monograph, add to the fluid in the vessel 250 mL of 0.20 M tribasic sodium phosphate that has been equilibrated to 37 ± 0.5. Adjust, if necessary, with 2 N hydrochloric acid or 2 N sodium hydroxide to a pH of 6.8 ± 0.05. Continue to operate the apparatus for 45 minutes, or for the specified time given in the individual monograph. At the end of the time period, withdraw an aliquot of the fluid, and perform the analysis using a suitable assay method. The procedure is specified in the individual monograph. The test may be concluded in a shorter time period than that specified for the Buffer Stage if the requirement for the minimum amount dissolved is met at an earlier time.
Method B—
Procedure (unless otherwise directed in the individual monograph)—
ACID STAGE— Place 1000 mL of 0.1 N hydrochloric acid in the vessel, and assemble the apparatus. Allow the medium to equilibrate to a temperature of 37 ± 0.5. Place 1 dosage unit in the apparatus, cover the vessel, and operate the apparatus at the rate specified in the monograph. After 2 hours of operation in 0.1 N hydrochloric acid, withdraw an aliquot of the fluid, and proceed immediately as directed under Buffer Stage.
Perform an analysis of the aliquot using a suitable assay method. The procedure is specified in the individual monograph.
BUFFER STAGE— [NOTE—For this stage of the procedure, use buffer that previously has been equilibrated to a temperature of 37 ± 0.5.] Drain the acid from the vessel, and add to the vessel 1000 mL of pH 6.8 phosphate buffer, prepared by mixing 0.1 N hydrochloric acid with 0.20 M tribasic sodium phosphate (3:1) and adjusting, if necessary, with 2 N hydrochloric acid or 2 N sodium hydroxide to a pH of 6.8 ± 0.05. [NOTE—This may also be accomplished by removing from the apparatus the vessel containing the acid and replacing it with another vessel containing the buffer and transferring the dosage unit to the vessel containing the buffer.]