General Notices
Barium Sulphate for Suspension
Action and use
Radio-opaque preparation used in the investigation of the gastro-intestinal tract.
Preparation
Barium Sulfate Oral Suspension
DEFINITION
Barium Sulfate for Suspension is a dry mixture of Barium Sulfate with a suitable dispersing agent and may contain suitable flavours and suitable antimicrobial preservatives.
Content of barium sulfate, BaSO4
90.0 to 110.0% of the stated amount.
CHARACTERISTICS
A fine, white or creamy white powder.
IDENTIFICATION
A. Ignite 1 g to constant weight. To 0.2 g of the residue add 5 mL of a 50% w/v solution of sodium carbonate and boil for 5 minutes. Add 10 mL of water and filter. Reserve the residue for test B. Acidify a portion of the filtrate with 2M hydrochloric acid. The solution yields the reactions characteristic of sulfates, Appendix VI.
B. Wash the residue reserved in test A with water, add 5 mL of 2M hydrochloric acid, mix well and filter. Add 0.3 mL of 1M sulfuric acid to the filtrate. A white precipitate is produced which is insoluble in 2M hydrochloric acid.
TESTS
Acidity or alkalinity
pH of an aqueous suspension containing the equivalent of 60% w/w of Barium Sulfate or, for lower strengths, the aqueous suspension at the strength of intended use, 3.5 to 8.5, Appendix V L.
Loss on drying
When dried at 105° for 4 hours, loses not more than 1.0% of its weight. Use 1 g.
Barium Sulfate for Suspension
ASSAY
To a quantity containing 0.6 g of Barium Sulfate in a platinum dish add 5 g of sodium carbonate and 5 g of potassium carbonate sesquihydrate and mix. Heat to 1000° and maintain at this temperature for 15 minutes. Allow to cool and suspend the residue in 150 mL of water. Wash the dish with 2 mL of 6M acetic acid and add the washings to the suspension. Cool in ice and decant the supernatant liquid, transferring as little of the solid matter as possible to the filter.Wash the residue with successive quantities of a 2% w/v solution of sodium carbonate until the washings are free from sulfate and discard the washings. Add 5 mL of 2M hydrochloric acid to the filter, wash through into the vessel containing the bulk of the solid matter with water, add 5 mL of hydrochloric acid and dilute to 100 mL with water. Add 10 mL of a 40% w/v
solution of ammonium acetate, 25 mL of a 10% w/v solution of potassium dichromate and 10 g of urea. Cover and digest in a hot-air oven at 80° to 85° for 16 hours. Filter whilst still hot through a sintered-glass filter (ISO 4793, porosity grade 4, is suitable), washing the precipitate initially with a 0.5% w/v solution of potassium dichromate and finally with 2 mL of water. Dry to constant weight at 105°. Each g of the residue is equivalent to 0.9213 g of barium sulfate, BaSO4
