Phosphate solution: Dissolve 4.1 g of
monobasic potassium phosphate in about 900 mL of water in a 1000-mL volumetric
flask, and adjust with phosphoric acid to a pH of 2.0. Dilute with water to
volume, and mix.
Mobile phase: Dissolve 1.0 g of
sodium 1-hexanesulfonate in 800 mL of Phosphate solution. Add 200 mL of
acetonitrile, mix, filter, and degas.
Diluent: Prepare a mixture of
water and methanol (4:1).
Standard preparation: Dissolve an
accurately weighed quantity of Lisinopril ws in Diluent to obtain a solution
having a known concentration of about 0.2 mg per mL.
(Weigh
accurately about 22 mg of Lisinopril Dihydrate equ. To 20 mg of Lisinopril and
transfer it into 100 ml volumetric flask add 60 ml diluents to dissolve.
And make up volume to 100 ml with diluent.)
Assay preparation: Transfer to a
suitable size volumetric flask 10 Tablets, which when diluted with Diluent will
yield a solution having a concentration of about 0.2 mg per mL. Add Diluent,
and sonicate for 5 minutes. Shake the flask by mechanical means for 20 minutes,
dilute with Diluent to volume, mix, and filter.
(
Weigh and powderd tablets Weigh accurately powder containing of 20
mg Lisinopril and transfer it into 100 ml volumetric flask .Fill the flask to
50 ml with diluent sonicate for 5 min, and shake by mechanical means for 20
min. Dilute with Diluent to volume, mix, and filter. To obtain a solution
containing 0.2 mg of lisinopril/mL).
Chromatographic
system
Mode: LC
Detector: UV 215 nm
Column: 4.6-mm ×
20-cm; packing L7
Temperature : 40°C
Flow rate: 1 mL/min
Injection size: 20 µL
System
suitability
Sample: Standard solution
Suitability
requirements
Column efficiency: NLT 700
theoretical plates, Standard solution
Tailing factor: NMT 2.0,
Standard solution
Relative standard
deviation:
NMT 2.0%, Standard solution
Capacity factor, k’: The analyte peak
is greater than 1.5, Standard solution.
Procedure: [NOTE—Use peak areas
where peak responses are indicated.] Separately inject equal volumes (about 20
µL) of the Standard preparation and the Assay preparation into the
chromatograph, record the chromatograms, and measure the responses for the
major peaks.
Calculate the quantity, in mg, of C21H31N3O5
in each Tablet taken by the formula:
