Lactic Acid

Synonyms:  Acidum lacticum; E270; Eco-Lac; 2-hydroxypropanoic acid; ahydroxypropionic acid; DL-lactic acid; Lexalt L; milk acid; Patlac LA; Purac 88 PH; racemic lactic acid.

Description:  Lactic acid consists of a mixture of 2-hydroxypropionic acid, its condensation products, such as lactoyllactic acid and other polylactic acids, and water. It is usually in the form of the racemate, (RS)-lactic acid, but in some cases the (S)-(þ)-isomer is predominant. Lactic acid is a practically odorless, colorless or slightly yellowcolored, viscous, hygroscopic, nonvolatile liquid.

Chemical Name:  2-Hydroxypropionic acid 

(R)-(–)-2-Hydroxypropionic acid 

(S)-(þ)-2-Hydroxypropionic acid

(RS)-( )-2-Hydroxypropionic acid

Adsorbent; suspending agent; tablet and capsule diluent.

• Lactic acid is used in beverages, foods, cosmetics, and pharmaceuticals as an acidifying agent and acidulant.

• In topical formulations, particularly cosmetics, it is used for its softening and conditioning effect on the skin.

• Lactic acid may also be used in the production of biodegradable polymers and microspheres, such as poly(D-lactic acid), used in drug delivery systems.

• Lactic acid is also used as a food preservative.

• Therapeutically, lactic acid is used in injections, in the form of lactate, as a source of bicarbonate for the treatment of metabolic acidosis; as a spermicidal agent; in pessaries for the treatment of leukorrhea; in infant feeds; and in topical formulations for the treatment of warts

Incompatible with oxidizing agents, iodides, and albumin. Reacts violently with hydrofluoric acid and nitric acid.

Lactic acid occurs in appreciable quantities in the body as an end product of the anaerobic metabolism of carbohydrates and, while harmful in the concentrated form, can be considered nontoxic at the levels at which it is used as an excipient. A 1% v/v solution, for example, is harmless when applied to the skin. There is evidence that neonates have difficulty in metabolizing (R)-lactic acid, and this isomer and the racemate should therefore not be used in foods intended for infants aged less than 3 months old

Lactic acid is caustic in concentrated form and can cause burns on contact with the skin and eyes. It is harmful if swallowed, inhaled, or absorbed through the skin. Observe precautions appropriate to the circumstances and quantity of material handled. Eye protection, rubber gloves, and respirator are recommended. It is advisable to handle the compound in a chemical fume hood and to avoid repeated or prolonged exposure. Spillages should be diluted with copious quantities of water. In case of excessive inhalation, remove the patient to a well-ventilated environment and seek medical attention. Lactic acid presents no fire or explosion hazard but emits acrid smoke and fumes when heated to decomposition.

Aliphatic polyesters; sodium lactate.