Apparatus:
Paddle
Use as the medium 900 mL of a 2.722% w/v solution of
sodium acetate, the pH of which has been adjusted to 5.0 with glacial acetic
acid and rotate the paddle at 50 revolutions per minute.
Sample:
Transfer 5 mL of a filtered sample to a graduated flask, add 40 mL of glacial
acetic acid and 10 mL of a 0.5% w/v solution of 4- dimethylaminobenzaldehyde in
glacial acetic acid and dilute to 100 mL with a mixture of 35 volumes of
glacial acetic acid and 70 volumes of hydrochloric acid. Allow to stand
for 15 minutes and measure the absorbance of the resulting solution at the
maximum at 485 nm, using in the reference cell dissolution medium that has been
subjected to the conditions of the test.
Prepare a suitable solution of erythromycin stearate ws in the
dissolution medium and filter. Take 50 mg quantity of the erythromycin stearate
ws with 70 mL of the dissolution medium for 10 minutes, dilute to 100 mL with
the same solvent, Transfer 5 mL of the filtered solution to a graduated flask,
add 40 mL of glacial acetic acid and 10 mL of a 0.5% w/v solution of
4-dimethylaminobenzaldehyde in glacial acetic acid and dilute to 100 mL with a
mixture of 35 volumes of glacial acetic acid and 70 volumes of hydrochloric
acid. Allow to stand for 15 minutes and measure the absorbance of the resulting
solution at the maximum at 485 nm, using in the reference cell dissolution
medium that has been subjected to the conditions of the test.
Calculate the total content of C37H67NO13 in the medium from the
absorbances obtained using the declared content of C37H67NO13 in erythromycin
stearate ws.
Dissolution (%) =
Spl reading x wt of std. x 5 x 900 x 100 x std potency x 100
Std
reading x 100 x 100 x 500 x 5 x 100
