Dihydrocodeine Tablets

General Notices

Action and use

Opioid receptor agonist; analgesic.

Definition

Dihydrocodeine Tablets contain Dihydrocodeine Tartrate.

The tablets comply with the requirements stated under Tablets and with the following requirements.

Content of dihydrocodeine tartrate, C18H23NO3,C4H6O6

92.5 to 107.5% of the stated amount.

Identification

Shake a quantity of the powdered tablets containing 0.15 g of Dihydrocodeine Tartrate with 50 mL of water, filter and evaporate the filtrate to dryness on a water bath. The residue complies with the following tests.

A. Add 10 mg, in powder, to 1 mL of a mixture of sulfuric acid and 0.05 mL of formaldehyde solution. A purple colour is produced (distinction from pholcodine).
B. Dissolve 10 mg in 0.05 mL of nitric acid. A yellow but no red colour is produced (distinction from morphine).
C. Dissolve 0.1 g in 1 mL of sulfuric acid, add 0.05 mL of iron(iii) chloride solution R1 and warm gently. A brownish yellow colour is produced which does not become red on the addition of 0.05 mL of 2m nitric acid (distinction from codeine and morphine).

Assay

Weigh and powder 20 tablets. Dissolve a quantity of the powder containing 0.15 g of Dihydrocodeine Tartrate as completely as possible in 30 mL of water, make alkaline with 5m ammonia and extract with five 20 mL quantities of chloroform, washing each extract with the same 10 mL of water. Filter the combined extracts through absorbent cotton moistened with chloroform and wash the filter with a small quantity of chloroform. Evaporate on a water bath until the volume is reduced to about 50 mL and titrate with 0.02m perchloric acid VS using crystal violet solution as indicator. Each mL of 0.02m perchloric acid VS is equivalent to 9.030 mg of C18H23NO3,C4H6O6.

Storage

Dihydrocodeine Tablets should be protected from light.