Pentazocine Capsules
Action and use
Opioid receptor agonist; analgesic.
Definition
Pentazocine Capsules contain Pentazocine Hydrochloride.
Content of pentazocine hydrochloride, C19H27NO,HCl
95.0 to 105.0% of the stated amount.
Identification
Tests
Dissolution
Comply with the requirements for Monographs of the British Pharmacopoeia in the dissolution test for tablets and capsules, Appendix XII B1,
After 45 minutes withdraw a 10 mL sample of the medium and measure the absorbance of the filtered sample, suitably diluted with the dissolution medium if necessary, at the maximum at 278 nm, Appendix II B, using water in the reference cell.
Calculate the total content of pentazocine hydrochloride, C19H27NO,HCl, in the medium taking 61.2 as the value of A(1%, 1 cm) at the maximum at 278 nm.
Related substances
Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions.
3 volumes of isopropylamine, 3 volumes of methanol and 94 volumes of chloroform.
By each method of visualisation, in the chromatogram obtained with solution (1):
any secondary spot is not more intense than the spot in the chromatogram obtained with solution (2)(1%);
not more than one such spot is more intense than the spot in the chromatogram obtained with solution (3)(0.5%);
and not more than four such spots are more intense than the spot in the chromatogram obtained with solution (4)(0.25%).
Disregard any spot remaining on the line of application.
Assay
Shake a quantity of the mixed contents of 20 capsules containing 50 mg of Pentazocine Hydrochloride with 200 mL of water for 15 minutes, add 5 mL of 1m hydrochloric acid and sufficient water to produce 500 mL, mix and filter. Measure the absorbance of the filtrate at the maximum at 278 nm, Appendix II B. Calculate the content of C19H27NO,HCl taking 61.2 as the value of A(1%, 1 cm) at the maximum at 278 nm.