Dextropropoxyphene Capsules
Action and use
Opioid receptor agonist; analgesic.
Definition
Dextropropoxyphene Capsules contain Dextropropoxyphene Napsilate.
Content of dextropropoxyphene, C22H29NO2
92.5 to 107.5% of the stated amount.
Identification
Shake a quantity of the contents of the capsules containing the equivalent of 0.15 g of dextropropoxyphene with 5 mL of chloroform and filter. The filtrate complies with the following tests.
Assay
Stir a quantity of the mixed contents of 20 capsules containing the equivalent of 0.5 g of dextropropoxyphene with 25 mL of chloroform and filter through absorbent cotton, washing the flask and filter with small quantities of chloroform. Add to the combined filtrates a mixture of 50 mL of water and 5 mL of 5m sodium hydroxide, shake, allow the layers to separate and wash the chloroform extract with 25 mL of water. Extract the aqueous layer with five 25 mL quantities of chloroform, washing each extract with the 25 mL of water and adding it to the original extract. Dry the combined extracts with anhydrous sodium sulfate, evaporate to about 3 mL on a water bath in a current of air, remove from the water bath and allow to evaporate to dryness at room temperature. Carry out Method I for non-aqueous titration, Appendix VIII A, on the residue using crystal violet solution as indicator. Each mL of 0.1m perchloric acid VS is equivalent to 33.95 mg of C22H29NO2.
Labelling
The quantity of active ingredient is stated in terms of the equivalent amount of dextropropoxyphene.