LANOLIN DERIVATIVES IN PRESSURIZED FORMULATIONS II 33 Dispensers stored at OøC (1) Visible assessment of solubility at 0øC, and after being allowed to stand for 24 hours at 20øC. (2) Assessment of sprayability, and observation of possible valve block- age, at 0øC, and after being allowed to stand for 24 hours at 20øC. (3) Spray characteristics, if considered significant. (4) Ease of re-dispersion, by shaking, of any separated matter, partic- ularly in systems O, P and Q. Containers and valves Plastic coated glass containers were utilised for all tests, fitted with Precision valves of British origin, ref. 1792. Specification of valves (international part nos.): 14/23/12/3/standard buna/6/19]2. There was no definite preference for Precision valves, but other valves suitable for glass containers were not in stock when these experiments were commenced. RESULTS Table I Solubility of 10 lanolin products after 1 hour at 20øC. Lanolin products i ii iii iv v vi vii viii ix x Propellant systems K L M • 0 P 9 2 2 1 1 4 5 4 3 2 1 1 5m 6 4 1 1 1 1 4 4 4 4 5 2 1 5 5 4 1 1 1 1 5 5 5 1 1 1 1 5 5 6 1 3 1 1 5 5 6 1 1 2 1 5 5 4 4 4• 4• 3 2 2 2 4m 4m 4m 1 2 2 2 Total 22 24 18 12 42 44 41 Total 19 22 16 26 19 20 22 19 21 19 Key 1---- 2= 3---- 4= 5---- 6---- •= to Tables I, II and V. Soluble, no prdcipitate. Soluble with negligible precipitate (visible only on close scrutiny). Soluble with slight precipitate (readily seen on inverting bottle). Partially soluble, with either a dense precipitate or an insoluble liquid layer floating on the surface. Partially soluble, with either a dense precipitate or an insoluble liquid layer at the bottom of the container. Totally insoluble. Agglomeration of precipitate. Crystal formation.

34 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS