Acidum Hypophosphorosum Dilutum. Diluted Hypophosphorous Acid. A liquid composed of about 10 per cent., by weight, of absolute Hypophosphorous Acid (Hph2o2=65.88) and about 90 per cent. of water.


Decompose Potassium Hypophosphite by Sulphuric Acid, filter and evaporate to a syrupy consistence. 2Kph2o2+H2So4=K2So4+2H Ph2o2.


A colorless liquid, without odor, and having an acid taste. Sp. gr., about 1.046. Solubility. - Miscible in all proportions, with water.

Diluted Hypophosphorus Acid is used in Syrupus Hypophosphitum.

Therapeutics of Ferric, Calcium, Sodium, and Potassium Hypophosphites

These drugs have been recommended for phthisis. Although in many cases there is no satisfactory evidence of their value yet they are extensively used and are the basis of a large number of proprietary preparations.

Following Churchill they should be of chemical purity, neutral in reaction; the presence of free alkali or alkaline carbonates quickly giving rise to an atonic dyspepsia. The preparation, the syrup of the hypophosphites, is faulty in that each salt has a peculiar property, yet the final result being due to the hypophosphite, and its beneficial effect upon nutrition. In the early stages of phthisis (infiltration) the sodium salt should be administered and the sodium salt alone; if excavation is present the calcium salt is indicated, and that alone, provided that it does not too suddenly check expectoration, when the sodium salt should be resumed.

The potassium salt is a valuable expectorant in chronic bronchitis; but it has a very limited usefulness in phthisis. The hypo-phosphites, when administered intelligently, will improve nutrition and relieve some of the symptoms of phthisis. If administered in too large doses, or simultaneously with other remedies, as arsenic, stimulants, strychnine, or cod-liver oil, they are likely to produce headaches and dyspepsia, and fail to cause improvement. The objection to the syrup, U. S. P., namely, the use of the salts in combination, applies to nearly all of the proprietary preparations, most of which contain impure drugs, contain a low percentage of hypophosphites, and are not scientific combinations. The syrup of the hypophosphites with iron is valuable as a reconstructive. Zinc phosphide is believed to have the same physiological and therapeutical effects as phosphorus.