629. Pepsinum.—Pepsin.
Other tomes: Potter
A mixture containing a proteolytic ferment or enzyme obtained from the glandular layer of fresh stomachs of healthy pigs, and capable of digesting not less than 3000 times its own weight of freshly coagulated and disintegrated egg albumen. See details of test U.S.P. IX.
SOURCE.—Pepsin is prepared from the stomach of the ox (Bos taurus), the sheep (Ovis aries), or the hog (Sus scrofa), the mucous membrane being the part used. Several methods have been employed for its extraction. The ordinary methods of manufacture may be briefly stated as follows:
(1) The extraneous matter is first removed from the inner surface of the stomach by washing, and the mucous membrane scraped off with a blunt instrument; the pulp thus obtained is placed on glass or porcelain and dried and finally reduced to a powder. This forms a rather poor quality, owing to the presence of mucus and inert matter.
(2) The finely chopped mucous coat is macerated in dilute hydrochloric acid (about 2 per cent.), and to the filtered solution common salt is added; the floating precipitate which results is carefully washed, then dried, and the dried residue mixed with sugar of milk until the strength of the article is such that 1 grain will dissolve 3000 grains of coagulated albumen, the strength directed by the United States Pharmacopoeia.
(3) A scale pepsin is made by digesting the mucous lining at the temperature of about 100°C. with about 0.2 per cent. of HCl (or water acidulated with other acids to the same degree of acidity) until the membrane is completely or nearly all dissolved. The solution is neutralized by a suitable alkali and the filtered product, after reduction by evaporation at a low temperature (sometimes in vacuo) to a syrupy consistence, is spread on plates of glass and dried in a current of warm air, care being taken not to allow the temperature to exceed 40°C. (104°F.). The dried, transparent film is then scraped from the plates and broken into more or less fine lamellae.
DESCRIPTION.—A yellowish-white amorphous powder or thin, pale yellowish, somewhat transparent scales, with faint odor and slight saline or acidulous taste, but no indication of decomposition; should not be hygroscopic. It invariably contains some rennin; its solutions, therefore, will coagulate milk. Incompatible with alkalies, alcohol, and heat renders it inert.
ACTION AND USES.—Pepsin has a digestive action upon the food taken into the stomach, and is employed as an artificial agent to assist digestion when there is functional derangement of the stomach. Dose: 10 gr. (0.6 Gm.).
