Edition: BP 2025 (Ph. Eur. 11.6 update)
DEFINITION
| Soft Soap | 650 g |
| Ethanol (90 per cent) | Sufficient to produce 1000 mL |
In making Soap Spirit, the Ethanol (90 per cent) may be replaced by Industrial Methylated Spirit1 diluted so as to be of equivalent ethanolic strength.
Extemporaneous preparation
The following directions apply.
Dissolve the Soft Soap in 300 mL of Ethanol (90 per cent), add sufficient Ethanol (90 per cent) to produce 1000 mL, mix, allow to stand and decant.
The spirit complies with the requirements stated under Spirits and with the following requirements.
TESTS
Acidity or alkalinity
10 mL requires for neutralisation not more than 1.0 mL of 0.1M sodium hydroxide VS or 0.2 mL of 0.1M hydrochloric acid VS using phenolphthalein solution R1 as indicator.
Weight per mL
0.945 to 0.970 g, Appendix V G.
Ethanol content
28 to 32% v/v, Appendix VIII F.
Content of fatty acids
Not less than 27.0% w/v when determined by the following method. To 10 mL add 20 mL of water and 20 mL of 1M hydrochloric acid, extract with two 20 mL quantities of petroleum spirit (boiling range, 40° to 60°), wash the combined extracts with two 10 mL quantities of water, evaporate the petroleum spirit, add 5 mL of acetone, again evaporate and dry the residue at 80° for 2 hours.
1 The law and the statutory regulations governing the use of Industrial Methylated Spirit must be observed.
