Levocarnitine Tablets          

Levocarnitine Tablets contain not less than 90.0 per cent and not more than 110.0 per cent of the stated amount of levocarnitine, C₇H₁₅NO₃.

Usual strengths. 330 mg; 500 mg.

Identification

1. In the Assay, the principal peak in the chromatogram obtained with the test solution corresponds to the peak in the chromatogram obtained with reference solution (a).
2. To a quantity of the powdered tablets containing 1 mg or 2 mg of levocarnitine add 5 ml ofwatermix and filter. Transfer 2 ml of the filtrate in a test tube, add 5 ml of 1 M hydrochloric acid and few drops of 2.5 per cent w/v solution of ammonium reineckate; a red-violet colour precipitate is produced.

Tests

Dissolution (2.5.2).

Apparatus No. 1,

Medium. 900 ml of water,

Speed and time. 75 rpm and 30 minutes.

Withdraw a suitable volume of the medium and filter.

Determine by liquid chromatography (2.4.14).

Buffer solution— Dissolve 6.8 g of monobasic potassium phosphate in 900 ml of water, adjust to pH 4.5 with orthophosphoric acid, and dilute with water to 1000 ml.

Test solution. Use the filtrate, dilute, if necessary, with water.

Reference solution. Dissolve a quantity of levocarnitine RS in water to obtain a solution having similar concentration as that of  the test solution.

Chromatographic system

     –   a stainless steel column 30 cm x 3.9 mm, packed with aminopropylsilane bonded to porous silica (10 µm) (Such as Bondapak –NH2),

     –   mobile phase: a mixture of 65 volumes of acetonitrile and 35 volume of buffer solution, adjust to pH 4.7 with orthophosphoric acid,

     –   flow rate: 1.0 ml per minute,

     –   spectrophotometer set at 205 nm,

     –   injection volume: 20 µl.

Inject the reference solution and the test solution.

3. Not less than 75 per cent of the stated amount ofC7H15NO₃.

Other tests. Comply with the tests stated under Tablets.

Assay. Determine by liquid chromatography (2.4.14), as described under Dissolution with the following modification.

Test solution. Weigh and powder 20 tablets. Dissolve a quantity of the powder containing 300 mg of Levocarnitine in 50 ml of water, mix with the aid of ultrasound until the powder have dissolve completely, dilute to 100.0 ml with water and filter.

Reference solution (a). A 0.3 per cent w/v solution of levocarnitine RS  in water.

Reference solution (b). A solution containing 0.15 per cent w/v of levocarnitine RS  and 0.0007 per cent w/v of levocarnitine impurity A (2-Propen-1-aminium, 3-carboxy-N,N,N-trimethyl-, chloride RS)  in water.xc

Inject reference solutions (a) and (b). The test is not valid unless the resolution between the levocarnitine impurity A and levocarnitine peaks is not less than 1.0 in the chromatogram obtained with reference solution (b) and the relative standard deviation for replicate injections is not more than 2.0 per cent in the chromatogram obtained with reference solution (a).

Inject  reference solution (a) and the test solution.

Calculate the content of C7H15NO₃ in the tablets.

Storage. Store in tight containers.