OIL OF CAMPHOR.?Under the title Oleum Camphora

Currently camphor that is used in pharmacies is synthetic

OIL OF CAMPHOR.?Under the title Oleum Camphora

This information has been taken from the United Stated Dispensatory Wood-Osol 23rd Edition 1943. The information contained is for historical purposes only.

OIL OF CAMPHOR.—Under the title Oleum CamphorcB the U. S. V recognized a volatile oil obtained from the camphor tree. This is a color-less fluid or of a light yellowish-brown color, having a strong odor like that of camphor, a bitterish camphorous taste and a specific gravity, at 20° C., of 0.875 to 0.900. It acts strongly on polarized light, and is dextrogyrate. In addi-tion to camphor, the following substances have been reported in this oil: Terpineol, phellandrene, dipentene, cadinene, eugenol, cineol, d-pinene, safrol and acetaldehyde. The oil is said to be used in Japan for the preparation of Chinese ink and varnishes, and for burning. As a diluent for artists' colors it is useful because its capacity for dissolving resins is greater than that of oil of turpentine and similar liquids.

The oil of camphor is no longer employed as an internal remedy but is still used as a rubefa-cient and anodyne liniment, diluted with soap liniment or olive oil, in local rheumatism and neuralgic pains, bruises, sprains, etc.

The Dryobalanops oil of camphor is said to be found in trees too young to produce cam-phor, and is supposed to constitute the first stage in the development of this substance, as it occupies the cavities in the trunk which are after-wards filled with the camphor. The chief con-stituent of it is a peculiar volatile oil, which is termed borneene; it is isomeric with oil of tur-pentine, CioHis, and holds in solution borneol and resin. By fractional distillation this oil may be separated into two portions, the one more volatile than the other.

Uses.—Locally camphor is irritant, with prob-ably a benumbing influence upon the peripheral sensory nerves, and somewhat antiseptic. It is absorbed through mucous membranes not very readily, but easily from subcutaneous tissue. It combines in the body with glycuronic acid and is eliminated in this combination by the kidneys. The systemic action of camphor is not well un-derstood. In frogs it is depressant to the spinal cord and causes increasing paralysis of the central nervous system. In the higher mam-mals, however, it produces active convulsions which are apparently due to an effect upon the brain stem although it is not clear whether this is on the cerebral cortex or lower. With small doses there is more or less stimulation of respir-ation apparently most marked when that function is depressed by ether, morphine or similar drugs (see Hauzlik, J. P. Ex. T, 1923, 20, 463). After toxic doses there is secondary depTessiotv and death is usually due to respiratory failure.

The experiments with camphor on the circu-lation have been quite voluminous with extraor-dinary divergence of results. Although Christen-sen and Lynch (/. A. Ph. A., 1937, 26, 786) have reported that it consistently causes a rise in the blood pressure in all doses from 5 to 20 rng. per kilo, the bulk of evidence is that unless convul-sive doses are employed the blood pressure is lowered from the beginning, the degree of fall being proportional to the dose. Studies on the isolated animal heart are practically unanimous in the conclusion that there is no stimulating effect on the heart muscle. A number of investi-gators, however, hold that when the heart is weakened by poisons such as chloral hydrate or phosphorus it has a marked power of strengthen-ing its contractions (see Levy and Beaune, B. Sci. Pharm., 1932, 39, 217), but a number of competent investigators have failed to find any evidence of such effect. Froehlich and Gross-man (A. E. P. P., 1921, 89, 1) and others have reported that it will restore normal rhythm in fibrillating hearts but other competent investi-gators deny any such action.

While it is difficult to arrive at any positive conclusions from the contradictory results which have been reported we confess that we are in-clined to agree with the conclusions of Heath-cote (/. P. Ex. T., 1923, 21, 177) that there is "no convincing pharmacological evidence that camphor possesses any value as a cardiac or circulatory stimulant." Its value, if any, in clin-ical medicine as a circulatory stimulant, can only be established by more exact clinical studies than are at present available (see Marvin and Soifer, /. A. M. A., 1925, 83, 94). In Europe the drug is highly esteemed as an analeptic in various cardiac depressions, especially those of infectious fevers like typhoid or pneumonia, and has also been used in the treatment of myo-carditis. But in this country when it is em-ployed, it is rather with the hope than with the expectation of benefit.

In pneumonia camphor has been used not only as a cardiac stimulant but with the idea that it inhibits the growth of the pneumococci. While the evidence for this view is strongly suggestive it cannot be considered in any way conclusive. (For review of the literature on this subject see /. A. M. A., 1920, 74, 46.)

Aside from its action as a circulatory stimu-lant, camphor is used internally for its calmative influence in hysteria, general nervousness and neuralgia. Whether the effects in these condi-tions are due to any action other than a psychic influence from the strong taste of the drug, is open to question. It is also employed in the treatment of serous diarrheas, its effects being probably due to a local irritant action upon the mucous membrane of the intestines.

When a profound influence is desired, as in heart failure, it is necessary to give the drug hypodermically.