"doesn't work" covers a lot of ground. Can you be more specific about the method (we do not all have access to USP), what you have tried, and what the problem was?
Dear Sir,
Thank you for the reply and following is the test method.
Problem: no peak observed. Used with some adjustments, but we couldn't obtain a peak for high concentraions of standard solutions too.
Kindly advise me to solve the problem
Thank you
Clarithromycin - Related Substances
Chromatographic System:
Detector: 205nm, and a 4.6mm x 10cm column that contains packing L1 at 40 C. flow rate is ~ 1.1mL per minute.
Chromatograph program is as follows;
Time -- Solution A --------Solution B --- --------Elution
(Minutes) -----(%) --------- (%)
0 to 32 --- 75 to 40 ------------25 to 60 -------- Linear gradient
32 to 34 ------40 -----------------60 -------------Isocratic
34 to 36 ---40 to 75 ----------60 to 25 ------------- Linear gradient
36 to 42 ----- 75 ----------------25 -----------Isocratic
Relative retention time with reference to clarithromycin (retention time = ~ 11 minutes) include the following : impurity I = ~0.38; impurity C = ~0.89; impurity F = ~1.33; impurity A = ~ 0.42; impurity D = ~0.96; impurity P = ~ 1.35; impurity J = ~ 0.63; impurity N = ~1.15; impurity K = ~ 1.59; impurity L = ~0.74; impurity E = ~1.27, impurity G = ~1.72; impurity B = ~0.79; impurity O = ~ 1.38; impurity H = ~ 1.82; and impurity M = ~ 0.81.
Solution A:
4.76 g of monobasic potasium phosphate per L. Adjust pH to 4.4 with dilute phosphoric acid and pass it through C 18 filtration kit.
Solution B: acetonitril
Mobile Phase:
Use variable mixture of solution A and B as directed above.
Diluting Solution:
50:50 mixture of acetonitril and water
Standard solution A:
transfer 75mg of USP Clarithromycin RS to 50mL volumetric flask and dissolve in 25mL of acetonitril and dilute water to volume, and mix.
Standard solution B:
transfer 5.0 mL of std. solution A to 100 mL volumetric flask, dilute with Diluting solution to volume and mix.
Standard solution C:
transfer 1.0 mL of STD. solution B to a 10 mL volumetric flask, diute with diluting solution to volume and mix. it contains about 0.0075mg of USP clarithromycin RS per mL.
Standard solution D:
transfer about 15mg of USp clarithromycin identity RS, to 10mL volumetric flask and dossolve in 5.0 mL of acetonitril, dilute with water to volume and mix.
Test solution: Trasfer about 75mg of clarithromycin to a 50 mL volumetric flask and dissolve in 25 mL of acetonitril, dilute with water to volume and mix.
System suitability:
Chromatograph std. solution B and record the responses. tailing factor for the main clarithromycin peak is not more than 1.7.
Chromatograph std. solution D and record the responses. The peak to valley ratio of impurity D and clarithromycin is not less than 3.0
Procedure:
seperatly inject equal volumes of diluting solution, std. solution B, D & C and test solution.
Thank you
