Carbolic acid—Phenol

Other tomes: Petersen

Source and Composition. Carbolic Acid, C6H5HO, or C6H6O,—also known by the names Phenyl Alcohol, Phenic Acid and Phenol,—is a constituent of coal tar, obtained by fractional distillation and subsequently purified. Its claims to be considered an acid are very feeble, as, though it has a faint acid reaction and combines with salifiable bases, it is incapable of neutralizing alkalies, and its combinations are decomposed by the feeblest acids, sometimes even by water. Considered as the hydroxyl derivative of Benzene, it might be classed with the alcohols, but as it does not yield the same products on oxidation (yielding finally oxalic instead of acetic acid), it is taken as the type of a class called Phenols, which are simple hydroxyl (HO) derivatives of the aromatic hydrocarbons.

Official Forms are two, viz.:—

Acidum Carbolicum, Carbolic Acid, (Phenol),—colorless, interlaced crystals, sometimes acquiring a reddish tint, of characteristic odor, deliquescent in damp air; soluble in about 15 of water, very soluble in alcohol, ether, chloroform, oils, etc., almost insoluble in benzin. Dose, gr. ¼-ij, well diluted.
Acidum Carbolicum Crudum, Crude Carbolic Acid,—consists of various constituents of coal tar, chiefly Cresol and Phenol, obtained by fractional distillation. Is used only as a disinfectant.

Characteristics. Peculiarities about Carbolic Acid are that the addition of about 8 per cent. of water liquefies it, a further addition of water produces a turbid mixture, until about 15 of water are added, when a stable and clear solution is formed. One volume of the liquefied acid, containing 8 per cent. of water, forms with one volume of Glycerin a clear mixture, which is not rendered turbid by the addition of three volumes of water (absence of Creosote and Cresol). Carbolic acid coagulates albumen or collodion (Creosote does not), and by the addition of nitric acid it is converted into Picric Acid, etc., (Creosote into Oxalic Acid).

Preparations. Only two are official, viz.:—

Unguentum Acidi Carbolici, Carbolic Acid Ointment,—10 per cent.
Glyceritum Acidi Carbolici, Glycerite of Carbolic Acid,—1 to 4 of Glycerin.
*Liquor Acidi Carbolici, Solution of Carbolic Acid,—for local use in antiseptic surgery, of various proportions in water, 2 ½ per cent. for sponges, hands, etc., 5 per cent. as spray, etc.

Derivatives. Two are official, viz.:—

Sodii Sulpho-carbolas, Sodium Sulpho-carbolate,—prepared by dissolving carbolic in an equal part of sulphuric, to form sulpho-carbolic acid, and neutralizing this with barium and sodium carbonates. Occurs in rhombic prisms, soluble in 5 of water. Dose, gr. x-xxx.
Salol, Phenyl Salicylate,—the salicylic ether of phenol, (see under Salicin, next title)
*Phenol Iodatum, Iodized Phenol,—a mixture of Iodine and Carbolic Acid, in various proportions, for local use in gynecology. Also called Carbolated Iodine.

Analogues of Carbolic Acid.

Creosotum, Creosote,—is a mixture of phenols, chiefly Guaiacol and Creosol, obtained during the distillation of wood-tar, preferably of that derived from the beech. Dose, ♏︎j-iij.

A colorless or yellowish, oily liquid, of strongly empyreumatic odor, burning and caustic taste, and neutral reaction; freely soluble in alcohol, ether, acetic acid, etc., sparingly in water (1 in 150), more readily in boiling water. It does not coagulate albumen or collodion (difference from Carbolic acid, which does). By the action of nitric acid it is converted into Oxalic Acid chiefly, (Carbolic into Picric Acid, etc.).

Aqua Creosoti, Creosote water,—strength 1 per cent., is the only official preparation. Dose,ʒj-ʒiv.
*Guaiacolum, Guaiacol, (Methyl Pyrocatechin),—is the most active ingredient of Creosote, of which it constitutes from 60 to 90 per cent. Occurs as a colorless, inflammable liquid, soluble in alcohol. Dose, ♏︎j-xv.
*Benzosolum, Benzosol,—is prepared by heating Guaiacol with Benzoic Acid, and occurs in small, tasteless crystals, insoluble in water, containing 54 per cent. of Guaiacol. Dose, gr. v-xv.

Resorcinum, Resorcin, (Meta-dioxy-benzol), C6H4(OH)2—is a diatomic phenol, and one of the three isomeric substances formed by substituting two atoms of hydroxyl for two of hydrogen in Benzene (Benzol), as the substitution of one produces Carbolic Acid. The relative positions of the hydroxyl atoms in the ring are for Resorcin 1 and 3, for Pyrocatechin 1 and 2, and for Hydroquinone 1 and 4, the two latter having the respective prefixes "Ortho," and "Para," with the composition name "Dioxy-benzol," and the same formula as the first. Resorcin occurs in colorless, rhombic Prisms or plates of neutral reaction, soluble in water, also in alcohol, ether, etc. Dose, gr. v-xv; as an antipyretic ʒss-j not repeated for several hours, or gr. v every 2 hours.

*Hydroquinone occurs in plates of sweetish taste, and is about four times stronger than Resorcin, having the same action and uses.

*Pyrocatechin also occurs in plates or crystals, is three times stronger than Resorcin, but otherwise the same; is readily soluble in water, alcohol and ether.

Pyrogallol, Pyrogallic Acid, C6H3(OH)3—is a triatomic phenol obtained chiefly by the dry distillation of gallic acid. It has the same form of composition as the preceding substances, except in it 3 atoms of Hydroxyl are substituted for 3 of Hydrogen in the Benzene-ring, instead of 1 as in Carbolic Acid, and 2 as in Resorcin. It occurs in light, glistening crystals, which are readily soluble in water and in alcohol, and combine rapidly with oxygen, becoming of a dark color. Dose, gr. ss to gr. jss.

Physiological Action. Carbolic Acid is a powerful antiseptic and antiferment, deodorizer and disinfectant, being very destructive to low forms of life when used in sufficient strength. It prevents the decomposition of albuminous fluids by bacteria, the fermentation of sugar by yeast, the conversion of starch into sugar, of albumen into peptones, and the decomposition of amygdalin with formation of hydrocyanic acid (Brunton). As ordinarily used in solutions its action upon low organisms is inhibitive rather than destructive, its safe solutions being only sufficient to prevent their development. Locally it is styptic, anaesthetic and superficially escharotic, coagulating the albumen of the part, and the blood also when outside the body. It is powerfully poisonous to the tissues, and when applied directly to muscle or nerve, it paralyzes them at once without previous stimulation.

When swallowed undiluted, Carbolic Acid produces violent gastro-enteritis, with vomiting and purging, followed by collapse, delirium, and often by convulsions and death. After absorption it acts by selection upon the medulla, especially on the respiratory and vaso-motor centres therein, which it first briefly stimulates and then completely paralyzes. It stimulates the cardiac inhibition., first slowing the heart, then depressing and finally paralyzing it. Respiration, at first increased, is soon depressed, the pupils are contracted, and the brain and spinal cord are directly affected,—stupor, coma, suspended reflexes, impaired motility and sensibility being produced. It is rapidly absorbed and diffused, many fatal cases having occurred from its local use in full strength. It is partly oxidized in the body, and partly eliminated by the lungs and kidneys, imparting to the urine a smoky appearance. ♏︎vj of the pure acid have produced dangerous symptoms. Death from a medium dose occurs by paralysis of respiration, from a large dose by paralysis of the heart. The blood, after death, is very dark in color, and is almost non-coagulable.

Creosote has similar properties, but is not so actively toxic as Carbolic Acid; it causes increased coagulability of the blood, and does not produce convulsions. It is largely eliminated by the bronchial mucous membrane, which it stimulates, and is therefore a good expectorant. In small doses it seems to have a selective sedative influence on the terminal nerve-filaments in the gastric mucous membrane. It explodes when combined with Oxide of Silver in pill, unless previously diluted with an inert powder.

Resorcin is not irritant to the skin or the submucous tissue, and but slightly so to mucous membranes. It is equally powerful as an antiseptic and antiferment, arresting decomposition and destroying low organisms. ʒss to ʒj causes a sense of heat, discomfort and oppression, followed by profuse perspiration and languor; if fever has existed the temperature is lowered several degrees, but rises again, after a rigor, in from two to four hours.

Pyrogallic Acid is exceedingly poisonous, the symptoms coming on in rapid succession, with headache, vomiting and purging, collapse, etc. It decomposes the red blood-corpuscles, causing thrombi in the venous radicles, hemorrhagic infarcts in the kidneys, and hematuria, also melanaemic discoloration of the skin and mucous membranes. Its antiseptic action is doubtful.

Antidotes and Antagonists to Carbolic Acid. Any soluble sulphate is the chemical antidote, forming a sulpho-carbolate. Magnesium Sulphate used in one case, (nearly 3 ounces), where half-an ounce of 95 per cent. acid had been swallowed, with full recovery from an all but hopeless condition of collapse. Liquor Calcis Saccharatus or Syrupus Calcis, are also antidotal, but are less efficient than the sulphates. Cider Vinegar removes the local effects of the application of the strong acid, and may prove a good antidote. Atropine is said to be a very complete physiological antagonist, maintaining the heart and respiration until elimination occurs, which should be promoted by diluents, used freely. Vegetable Demulcents, (but no oils or glycerin), to protect the mucous surfaces.

Therapeutics. Carbolic Acid owes its past prominence to its having been the principal agent used in Lister's Antiseptic Method; but its use in that connection has become greatly restricted, many surgeons having abandoned it altogether in favor of other germicides. Locally, it has many uses, relieving pruritus of almost any form if applied in a 5 per cent. solution over the itching surface, and making an excellent gargle (1 per cent.) for the painful sore throat of diphtheria, tonsillitis, etc. Internally, in ¼-grain doses it is an excellent remedy for nausea and vomiting, and it may be advantageously administered in dilute solution (2 to 5 per cent.) by spray, in many chronic pulmonary affections; also locally and by injection in—

Catarrhs,—acute and chronic.
Parasitic Skin Diseases.
Uterine and other Ulcers.
Pulmonary Phthisis.
Exanthematous Fevers, and other Septic diseases,—Sodium Sulpho-carbolate internally in 5-grain doses every two or three hours, has been much praised by many practitioners.

Creosote is more suitable for internal administration, and is used with benefit for vomiting from many causes, that due to abnormal gastric fermentation, ulceration of the stomach, cancer, sea-sickness, Bright's disease, and even pregnancy. It is also useful in the irritative diarrhoea of children, and its vapor is well employed by inhalation in phthisis and bronchitis. Being a very complex substance of varying composition, Creosote is being supplanted by Guaiacol, its principal ingredient, for internal administration.

Resorcin has been used as a local antiseptic in diphtheria, cystitis, facial erysipelas and syphilitic sores; also in 5-grain doses internally to prevent gastric fermentation. As an antipyretic it has been employed in typhoid fever and in phthisis, but its short antipyretic power, and the profuse perspirations which it induces, are objections to its ever being a favorite remedy.

Pyrogallol is employed locally in skin diseases; a 20 per cent. ointment being used as a caustic in lupus, cancer and chancres. It is said to destroy the diseased tissue without affecting the healthy tissue in the vicinity (Brunton). A 10 per cent. ointment is applied in psoriasis, lupus erythematosus, etc., but the dangers of absorption must be borne in mind.

A Compend of Materia Medica, Therapeutics, and Prescription Writing, 1902, by Sam'l O. L. Potter, M.D., M.R.C.P.L.