Edition: BP 2025 (Ph. Eur. 11.6 update)
DEFINITION
Heavy Kaolin, finely sifted 527 g
Boric Acid, finely sifted 45 g
Methyl Salicylate 2 mL
Thymol 500 mg
Peppermint Oil 0.5 mL
Glycerol 425 g
Extemporaneous preparation
The following directions apply.
Mix the Heavy Kaolin, previously dried at 100°, and the Boric Acid with the Glycerol, heat at 120° for 1 hour, stirring occasionally, and allow to cool. Separately, dissolve the Thymol in the Methyl Salicylate, add to the cooled mixture, add the Peppermint Oil and mix thoroughly.
The heating step may be omitted if some other satisfactory means of mixing the solid ingredients with the Glycerol is used but in this case Heavy Kaolin that has been sterilised is used.
The poultice complies with the requirements stated under Topical Semi-solid Preparations and with the following requirements.
Content of boric acid, H3BO3
4.25 to 4.75% w/w.
ASSAY
Mix 20 g with a solution containing 10 g of D-mannitol in 40 mL of water, warm and stir until completely dispersed and titrate with 1M sodium hydroxide VS using phenolphthalein solution R1 as indicator. Each mL of 1M sodium hydroxide VS is equivalent to 61.83 mg of H3BO3.
STORAGE
Kaolin Poultice should be kept in suitable containers that minimise absorption, diffusion or evaporation of the ingredients.
If an appropriate heating step, such as that described under Extemporaneous preparation, is not included in the manufacturing process, Heavy Kaolin that has been sterilised is used.
