analysis of Atorvastatin Calcium

raw material testing of atorvastatin Calcium

Description : White to off white powder

Solubility :
1. 1gm in 10 ml Methanol (Freely Soluble) Should be soluble
2. 10 mg in 10 ml Water, Ethanol (Slightly soluble) Should be soluble
Complies / Does not comply
Identification :
A and B by outside laboratory.
C. In the assay the principal peak in the chromatogram obtained of test solution corresponds
to the peak in the chromatogram obtained with reference solution respectively
Complies / Does not comply

Specific Optical Rotation Limit -6.0 to -12.0°

Weigh accurately…………(250 mg) sample dissolve in 20 ml dimethylsulphoxide and dilute to 25 ml with dimethylsulphoxide.
Measure the rotation with polerimeter.

Calculation

Related Substances.

Determine by liquid chromatography

Solvent mixture. 40 volumes of Acetonitrile and 60 volumes of water.

Test solution.
Weight accurately ……………..(50 mg) of Aatorvastatin calcium dissolve in 10 ml methanol and 100 ml with the solvent mixture.

Reference solution
(a). Weigh accurately ……….…(125 mg) Atorvastatin calcium WS, dissolve in 25 ml of methanol and
dilute to 25 ml with methanol.
To 5 ml dilute to 50 ml with solvent mixture.
(b). Dilute 1 ml of reference solution (a) to 100 ml with the solvent mixture.

Chromatographic system

Column- a stainless steel column 25 cm x 4.6 mm, packed with octadecylsilane bonded to porous silica
(5 μm)

Buffer solution – Prepared by dissolving 5.75 g of ammonium dihydrogen orthophosphate in 1000 ml of
water

Mobile Phase A- a mixture of 92.5 volumes of Acetonitrile and 7.5 volumes Tetrahydrofuran,
Mobile Phase B- a mixture of 58 volumes Buffer and 42 volumes of mobile phase A,
Mobile Phase C- a mixture of 20 volumes of the buffer solution, 20 volumes of mobile phase A and 60
volumes of methanol,

Gradient program
– spectrophotometer set at 246 nm,
– injection volume: 20 μl,
– injection delay 10 minutes.

Time (Minutes)	Flow Rate (ml/min)	Mobile phase B %	Mobile phase C %
0.01	1.8	100	0
20.00	1.8	100	0
35.00	1.5	25	75
40.00	1.5	25	75
55.00	1.5	0	100
60.00	1.8	100	0
70.00 (10 min delay)	1.8	100	0

Colum efficiency

Theoretical plates ……………… Limit NLT 5000

Inject reference solution (a).
The test is not valid unless the column efficiency is not less than 5000 theoretical plates and the tailing factor is not more than 1.5.

Inject reference solution (b) and Test solution
In the chromatogram obtained with the test solution, the area of any secondary peak is not more than the area of the peak in the chromatogram obtained with reference solution (b) (0.5.0%) and the sum of the areas of all the secondary peaks is not more than 2 times the area of the peak in the chromatogram obtained with reference solution (b) (2.0 per cent).
Ignore any peak with an area less than 0.05 times the area of the peak
obtained with reference solution (b) (0.05 per cent).

Calculation

Heavy metals (Method B) — Limit NMT 20 ppm

Standard solution. Into a 50 ml Nessler cylinder pipette 1.0 ml of lead standard solution (20 ppm)

Lead standard solution(0.1%Pb)

Weigh accurately ………….(0.4g) of lead nitrate in water containing 2ml of nitric acid and add sufficient water to produce 250ml.dilute with water to 25ml.Adjust with dilute acetic acid or dilute ammonia solution to a pH between3.0 &4.0,dilute with water to about 35ml and mix.

lead standard solution (100 ppm)

Dilute 5 volume of lead standard solution(0.1%Pb) 10 ml to volumes with water.

lead standard solution (20 ppm)

To 2 ml of 100 ppm solution and dilute to 100 ml with water .

Test solution. Weigh accurately ……….(1.0 gm) sample in crucible , add sufficient sulphuric acid to wet the sample , ignite carefully at a low temperature until thoroughly charred. Add to the charred mass 2ml of nitric acid and 5 drops of sulphuric acid and heat cautiously until with fumes are no longer evolved. Ignite, preferably in muffle furnace , at 500° to 600° , until the carbon is completely burnt off. Cool , add 4 ml of hydrochloric acid , cover, digest on a water bath for 15 minutes uncover and slowly evaporate to dryness on a water bath moisten the residue with 1 drop of hydrochloric acid , add 10 ml of hot water and digest for 2 minutes. Add ammonia solution dropwise until the solution is just alkaline to litmus paper, dilute to 25 ml with water and adjust with dilute acetic acid to a ph 25 ml with water and adjust with dilute acetic acid to a ph between 3.0 and 4.0 filter , if necessary , rinse the crucible and the filter with 10ml of water , combine the filtrate and washings in a50 ml Nessler cylinder, dilute with water to about 35 ml and mix.

Procedure: Each cylinders containing Std & Test add 10 ml hydrogen sulphide solution, mix, dilute to50 ml with water, allow to stand for 5 min and the test is not more intense than that produced with the standard

solution.

Preparation of Hydrogen sulphide solution-

By action of 20 ml Hydrochloric acid+20 ml water add 5 gm Iron sulphide.

— Complies / Does not comply

Water — Limit 3.0% to 7.0%

Assay : Limit 98.0% to 102.0%

Solvent mixture. – 40 volume acetonitrile and 60 volume of water.

Test solution.
Weigh accurately………..(80 mg) substance under examination in 50 ml methanol heat to 40°C, sonicate for 1 minute and dilute to 100 ml with solvent mixture.
To 5 ml of this solution and dilute to 50 ml with the solvent mixture to produce a solution containing 0.008 per cent w/v of Atorvastatin

Standard solution.
Weigh accurately………..(80 mg) Atorvastatin calcium WS and dissolve in 50 ml methanol heat to 40°C, sonicate for 1 minute and dilute to 100 ml with solvent mixture.
To 5 ml of this solution and dilute to 50 ml with the solvent mixture to produce a solution containing 0.008 per cent w/v of Atorvastatin

Chromatographic system

Column- a stainless steel column 25cm x 4.6 mm, packed with octadecylsilane bonded to porous silica
(5 μm),

Buffer solution – Prepared by dissolving 5.75 g of ammonium dihydrogen orthophosphate in 1000 ml of water

Mixture- 92.5 Volumes of Acetonitrile and 7.5 volumes of Tetrahydrofuran

(Same as Mobile Phase B used in Related substances)
Mobile phase: a mixture of 58 volumes of a buffer solution and 42 volumes of mixture.

Injection Sequence