Patent GB-489623-A (GB)
Title: Improvements in high vacuum distillation of materials containing sterols and related compounds
IPC: A61K31/16
Filed: 1937-01-29
Abstract: Raw material containing a compound having a cholane nucleus such as sterols, saponins and bile acids, is subjected to short-path high-vacuum distillation to separate the substance therefrom, the compound then being purified.  The raw materials specified comprise animal oils and waxes, such as whale oil, faecal fats and oils and chinese wax; vegetable oils, such as soya bean oil, cotton-seed oil, wheat germ oil and calabar bean oil; and fungoid growths, such as ergot of rye, each of which groups are sources of zoösterols, phytosterols and mycosterols respectively.  Particular sterols which may thus be isolated comprise cholesterols, cinchol, coprosterol, stigmasterol, sitosterol, and ergosterol.  Other sterols such as cinchocerotin, quebrachol and rhamnol, saponins, such as digitonin, and bile acids, such as cholanic acid may also be separated from the raw materials containing them.  In a preferred apparatus the distilling surface comprises an internally-heated hollow vertical dome with a spirally - corrugated surface.  The distance between distilling and condensing surfaces may vary between ,25 inch and 10 feet and the degree of vacuum correspondingly between 8 microns and ,01 micron of mercury.  Temperatures may range between 70 and 325 DEG C.  In an example, clarified whale oil was distilled at temperatures of 90 to 220 DEG  C. and pressures of ,001 to ,003 mm. of mercury.  A first fraction containing free acids, squalene and other volatiles was withdrawn, and at 120-160 DEG  C. a mixture of cholesterol and cholesteryl esters distilled over.  The cholesterol was extracted with acetoacetic ester and recrystallized.  Purification may comprise saponification of the fraction followed by solvent extraction and distillation of the latter.  Specification 487,697 is referred to.ALSO:Raw material containing a compound having a cholane nucleus such as sterols, saponins, and bile acids is subjected to short path high vacuum distillation to separate the substance therefrom, the compound then being purified.  The raw materials specified comprise animal oils and waxes such as whale oil, faecal fats and oils and chinese wax; vegetable oils, such as soya bean oil, cotton-seed oil, wheat germ oil and calabar bean oil; and fungoid growths, such as ergot of rye, each of which groups are sources of zoösterols, phytosterols and mycosterols respectively. Particular sterols which may thus be isolated comprise cholesterol, cinchol, coprosterol, stigmasterol, sitosterol and ergosterol.  Other sterols such as cinchocerotin, quebrachol and rhamnol, saponins, such as digitonin, and bile acids such as chelanic acid may also be separated from the raw materials containing them.  The distance between distilling and condensing surfaces may vary between ,25 inches and 10 feet and the degree of vacuum correspondingly between 8 microns and ,01 microns of mercury.  Temperatures may range between 70 and 325 DEG  C.  In an example, clarified whale oil was distilled at temperatures of 90 to 220 DEG  C. and pressures of ,001 to ,003 millimetres of mercury.  A first fraction containing free acids, squalene and other volatiles was withdrawn, and at 120-160 DEG  C. a mixture of cholesterol and cholesteryl esters distilled over.  The cholesterol was extracted with acetoacetic ester and recrystallized.  Purification may comprise saponification of the fraction followed by solvent extraction and distillation of the latter.  Specification 487,697 is referred to.