Identification—
A: Ultraviolet Absorption 
197U
—
Medium:
methanol.
Procedure—
Powder a portion of Capsule contents equivalent to 5 mg of lansoprazole. Add 5 mL of methanol, shake well, and centrifuge. To 0.1 mL of the supernatant, add 10 mL of methanol.
B:
The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
Drug release, Method A 724—
ACID STAGE—
Acid stage medium:
0.1 N hydrochloric acid; 500 mL.
Apparatus 2:
75 rpm.
Time:
60 minutes.
Procedure—
Withdraw a 25-mL aliquot and then proceed immediately as directed for
Test solution in the
Buffer stage leaving the remaining 475 mL in the vessel for use in the
Buffer stage. Using a filtered portion of the aliquot, determine the amount of C
16H
14F
3 N
3O
2S dissolved by employing UV absorption at the wavelength of maximum absorbance at about 306 nm, using
Acid stage medium as the blank. Concomitantly determine the absorbance of the
Acid stage test solution in comparison with a Standard solution of
USP Lansoprazole RS having a known concentration equivalent to about 8% of the labeled amount of lansoprazole dissolved per 500 mL of
Acid stage medium. A volume of methanol not to exceed 0.5% of the total volume of the Standard solution may be used to dissolve
USP Lansoprazole RS prior to dilution with
Acid stage medium.
Tolerances—
Not more than 10% of the labeled amount of C16H14F3N3O2S is dissolved in 60 minutes.
BUFFER STAGE—
Buffer concentrate—
Transfer 65.4 g of monobasic sodium phosphate, 28.2 g of sodium hydroxide, and 12 g of sodium dodecyl sulfate to a suitable container, and add enough water to dissolve. Dilute with water to 4 L, and mix well.
Blank solution—
Prepare a mixture of Acid stage medium and Buffer concentrate (19:17). Adjust, if necessary, with either phosphoric acid or sodium hydroxide to a pH of 6.8.
Test solution—
Add 425 mL of Buffer concentrate to the remaining 475 mL of solution in each vessel from the Acid stage. Adjust, if necessary, with either phosphoric acid or sodium hydroxide to a pH of 6.8.
Apparatus 2:
75 rpm.
Time:
60 minutes.
Procedure—
Determine the amount of C
16H
14F
3N
3O
2S dissolved in filtered portions of the
Test solution, using the difference between the absorbances at the wavelengths of about 286 nm and 650 nm, with
Blank solution as the blank. Concomitantly determine the absorbances of the
Test solution in comparison with a Standard solution of
USP Lansoprazole RS having a known concentration equivalent to about 70% of the labeled amount of lansoprazole dissolved in 900 mL of
Blank solution. An amount of methanol not to exceed 2% of the total volume of the Standard solution may be used to dissolve
USP Lansoprazole RS prior to dilution with
Blank solution.
Tolerances—
Not less than 80% (Q) of the labeled amount of C16H14F3N3O2S is dissolved in 60 minutes.
Dissolution 711—
Proceed as directed for
Procedure for
Method A under
Apparatus 1 and Apparatus 2, Delayed-Release Dosage Forms.
ACID STAGE—
Acid stage medium:
0.1 N hydrochloric acid; 500 mL.
Apparatus 2:
75 rpm.
Time:
60 minutes.
Procedure—
Withdraw a 25-mL aliquot and then proceed immediately as directed for
Test solution in the
Buffer stage, leaving the remaining 475 mL in the vessel for use in the
Buffer stage. Using a filtered portion of the aliquot, determine the amount of C
16H
14F
3 N
3O
2S dissolved by employing UV absorption at the wavelength of maximum absorbance at about 306 nm, using
Acid stage medium as the blank. Concomitantly determine the absorbance of the
Acid stage test solution in comparison with a Standard solution of
USP Lansoprazole RS having a known concentration equivalent to about 8% of the labeled amount of lansoprazole dissolved per 500 mL of
Acid stage medium. [Note—A volume of methanol not to exceed 0.5% of the total volume of the Standard solution may be used to dissolve
USP Lansoprazole RS prior to dilution with
Acid stage medium.]
Tolerances—
Not more than 10% of the labeled amount of C16H14F3N3O2S is dissolved in 60 minutes.
BUFFER STAGE—
Buffer concentrate—
Transfer 65.4 g of monobasic sodium phosphate, 28.2 g of sodium hydroxide, and 12 g of sodium dodecyl sulfate to a suitable container, and add enough water to dissolve. Dilute with water to 4 L, and mix well.
Blank solution—
Prepare a mixture of Acid stage medium and Buffer concentrate (19:17). Adjust, if necessary, with either phosphoric acid or sodium hydroxide to a pH of 6.8.
Test solution—
Add 425 mL of Buffer concentrate to the remaining 475 mL of solution in each vessel from the Acid stage. Adjust, if necessary, with either phosphoric acid or sodium hydroxide to a pH of 6.8.
Apparatus 2:
75 rpm.
Time:
60 minutes.
Procedure—
Determine the amount of C
16H
14F
3N
3O
2S dissolved in filtered portions of the
Test solution, using the difference between the absorbances at the wavelengths of about 286 nm and 650 nm, with
Blank solution as the blank. Concomitantly determine the absorbances of the
Test solution in comparison with a Standard solution of
USP Lansoprazole RS having a known concentration equivalent to about 70% of the labeled amount of lansoprazole dissolved in 900 mL of
Blank solution. [Note—An amount of methanol not to exceed 2% of the total volume of the Standard solution may be used to dissolve
USP Lansoprazole RS prior to dilution with
Blank solution.]
Tolerances—
Not less than 80% (Q) of the labeled amount of C16H14F3N3O2S is dissolved in 60 minutes.
(Official April 1, 2006)
Assay—
Diluent, Mobile phase, and Resolution solution—
Prepare as directed in the
Assay under
Lansoprazole.
Internal standard solution—
Dissolve an accurately weighed quantity of 4¢-ethoxyacetophenone in acetonitrile to obtain a solution having a known concentration of about 7.5 mg per mL.
Standard preparation—
Dissolve an accurately weighed quantity of
USP Lansoprazole RS in a mixture of 0.1 M sodium hydroxide and acetonitrile (3:2) to obtain a solution having a known concentration of 3.0 mg per mL. Transfer 25.0 mL of this solution and 5.0 mL of
Internal standard solution to a 50-mL volumetric flask, dilute with
Diluent to volume, and mix. Quantitatively dilute with
Diluent to obtain a solution having a known concentration of about 0.1 mg of
USP Lansoprazole RS per mL.
Assay preparation—
Transfer the contents of not fewer than 10 Capsules, equivalent to about 300 mg of lansoprazole, to a 300-mL conical flask containing 60.0 mL of 0.1 M sodium hydroxide, and sonicate until completely disintegrated. Add 20.0 mL of acetonitrile and 20.0 mL of Internal standard solution, shake well, and centrifuge a portion of the suspension. Quantitatively dilute a volume of the supernatant with Diluent to obtain a solution containing about 0.1 mg of lansoprazole per mL, and pass through a membrane filter having a 0.5-µm or finer porosity.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 285-nm detector and a 4.6-mm × 25-cm column that contains 5-µm packing L1. The flow rate is about 1 mL per minute. Chromatograph the
Resolution solution, and record the peak responses as directed for
Procedure: the resolution,
R, between the two major peaks is not less than 5. Chromatograph the
Standard preparation, and record the peak responses as directed for
Procedure: the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 10 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the peak responses. Calculate the quantity, in mg, of lansoprazole (C
16H
14F
3N
3O
2S) in each Capsule taken by the formula:
(LC/D)(RU / RS),
in which
L is the labeled quantity, in mg, of lansoprazole in each Capsule taken;
C is the concentration, in mg per mL, of
USP Lansoprazole RS in the
Standard preparation; D is the concentration, in mg per mL, of lansoprazole in the
Assay preparation, based on the labeled quantity of lansoprazole in the Capsules taken and the extent of dilution; and
RU and
RS are the peak response ratios obtained from the
Assay preparation and the
Standard preparation, respectively.
for 5 hours: it loses not more than 5.0% of its weight.