Simple Oral Solution
DEFINITION
Simple Linctus is an oral solution containing 2.5% w/v of Citric Acid Monohydrate in a suitable vehicle with an anise flavour.
The linctus complies with the requirements stated under Oral Liquids and with the following requirements.
Content of free acid, calculated as citric acid monohydrate, C6H8O7, H2O
2.00 to 2.65% w/v.
IDENTIFICATION
Dilute 5 mL to 50 mL with water, add 2 g of activated charcoal, mix and filter. To 1 mL of the filtrate add 1 mL of pyridine, swirl to mix, add 5 mL of acetic anhydride and mix using, for example, a rotary vortex mixer. Immediately place in a water bath at about 30° for 5 minutes. A yellow colour is produced.
ASSAY
Dilute 15 g with 50 mL of water and titrate with 0.5M sodium hydroxide VS using 2 mL of thymol blue solution as indicator.
Each mL of 0.5M sodium hydroxide VS is equivalent to 35.02 mg of C6H8O7, H2O. Determine the weight per mL of the linctus, Appendix V G, and calculate the content of C6H8O7, H2O, weight in volume.
