Action and use
Lincosamide antibacterial.
Definition
Lincomycin Capsules contain Lincomycin Hydrochloride.
The capsules comply with the requirements stated under Capsules and with the following requirements.
Content of lincomycin, C18H34N2O6S
90.0 to 105.0% of the stated amount.
Identification
A. Extract a quantity of the capsules contents containing the equivalent of 0.2 g of lincomycin with 5 mL of a mixture of 4 volumes of
chloroform and 1 volume of
methanol, filter and evaporate the filtrate. Dissolve the oily residue in 1 mL of
water, add
acetone until precipitation begins and add a further 20 mL of
acetone. Filter the precipitate, wash with two 10-mL quantities of
acetone, dissolve the residue in a little of the chloroform–methanol mixture, evaporate to dryness and dry at 60° at a pressure not exceeding 2 kPa for 4 hours. The
infrared absorption spectrum of the dried precipitate,
Appendix II A, is concordant with the
reference spectrum of lincomycin hydrochloride
(RS 203).
B. In the Assay, the chromatogram obtained with solution (2) shows a peak with the same retention time as the peak due to the trimethylsilyl derivative of lincomycin in the chromatogram obtained with solution (1).
Tests
Lincomycin B
Examine solution (3) as described under the Assay but increasing the sensitivity by 8 to 10 times while recording the peak derived from lincomycin B, which is eluted immediately before that derived from lincomycin.
limits
The area of the peak derived from lincomycin B, when corrected for the sensitivity factor, is not more than 5% of the area of the peak derived from lincomycin.
The contents of the capsules contain not more than 7.0% w/w of water, Appendix IX C. Use 0.3 g.
Assay
Carry out the method for gas chromatography, Appendix III B, using the following solutions.
(1) Add 10 mL of a 0.8% w/w solution of
dotriacontane (internal standard) in
chloroform to 0.1 g of
lincomycin hydrochloride BPCRS, dilute to 100 mL with a 2% w/v solution of
imidazole in
chloroform and shake to dissolve. Place 4 mL of the resulting solution in a 15-mL ground-glass-stoppered centrifuge tube, add 1 mL of a mixture of 99 volumes of N
,O
-bis(trimethylsilyl)acetamide and 1 volume of
trimethylchlorosilane and swirl gently. Loosen the glass stopper and heat at 65° for 30 minutes.
(2) Prepare in the same manner as solution (1) but omitting the internal standard and using a quantity of the mixed contents of 20 capsules containing the equivalent of 90 mg of lincomycin in place of the lincomycin hydrochloride BPCRS.
(3) Prepare in the same manner as solution (1) but using a quantity of the mixed contents of 20 capsules containing the equivalent of 90 mg of lincomycin in place of the lincomycin hydrochloride BPCRS.
chromatographic conditions
(a) Use a glass column (1.5 m × 3 mm) packed with
acid-washed silanised diatomaceous support impregnated with 3% w/w of phenyl methyl silicone fluid (50% phenyl) (OV-17 is suitable) and maintained at 260°.
(b) Use
helium as the carrier gas at a flow rate of about 45 mL per minute.
(c) Use an inlet temperature of 260° to 290°.
(d) Use a flame ionisation detector at a temperature of 260° to 290°.
(e) Inject 1 µL of each solution.
determination of content
Calculate the content of C18H34N2O6S in the capsules using the declared content of C18H34N2O6S in lincomycin hydrochloride BPCRS.
Labelling
The quantity of active ingredient is stated in terms of the equivalent amount of lincomycin.