E325 (Sodium lactate) is a natural salt obtained from the fermentation of lactic acid. Sodium lactate is the sodium salt of lactic acid produced by fermenting corn or beets, and then neutralising the resulting lactic acid to create sodium lactate.

It occurs as a clear, colourless or light yellow, slightly viscous liquid. Or as a fine white powder. Slightly salty taste. Miscible with water and ethanol in any ratio, nearly neutral in its aqueous solution and insoluble in diethyl ether and trichloromethane.

What it is used for and where it is used 

Human body

Sodium lactate plays a key role in metabolic regulation and in several biological processes.

Medical

Here are some extracts from the best studies published on sodium lactate:

Traumatic brain injury (TBI) following increased intracranial pressure (ICP) is a neuroemergency case which should be managed promptly to prevent secondary brain injury. This will lead to a condition called cerebral energy dysfunction which is an important determinant factor toward worse outcome. Lactate, which was historically known as an end waste product, now is considered as an alternative cerebral energetic fuel. Hypertonic sodium lactate (HSL) is a promising hyperosmolar fluid which serves not only to decrease ICP but also to readily supply exogenous lactate to fulfill increased cerebral energy demand. Pioneer studies have shown the harmlessness and usefulness of HSL in treating pathological condition including TBI (1).

This study aimed to investigate the metabolic and cardiac effects of intravenous administration of two hypertonic solutions - 3% saline (SAL) and 0.5M sodium lactate (LAC). he administration of SAL or LAC has opposing effects on acid base variables such as simplified strong ion difference . Hypertonic fluid infusion lead to increased cardiac preload and performance with Sm, suggesting better left ventricular systolic function during LAC as compared with SAL. Lactated hypertonic solutions should be evaluated as resuscitation fluids (2).

Sodium lactate seemed to improve fluid balance and avoid fluid overload. The objective of this study was to determine if these beneficial effects can be at least partly explained by an improvement in disseminated intravascular coagulation (DIC)-associated renal microvascular thrombosis. In this study, we report that sodium lactate improves DIC-associated renal microvascular thrombosis and preserves GFR. These findings could at least partly explain the better fluid balance observed with sodium lactate infusion (3).

Hyperosmolar solutions have been used in neurosurgery to modify brain bulk. The aim of this animal study was to compare the short-term effects of equivolemic, equiosmolar solutions of hypertonic saline (HTS) and sodium lactate (HTL) on cerebral cortical microcirculation and brain tissue oxygenation in a rabbit craniotomy model. Findings suggest that equivolemic, equiosmolar HTS and HTL solutions equally preserve perfusion of cortical brain microcirculation in a rabbit craniotomy model. The use of HTS was better in preventing the worsening of brain tissue oxygen tension (4).

Hypertonic sodium lactate (HTL) expands intravascular volume and may provide an alternative substrate for cellular metabolism in sepsis. We compared the effects of HTL, hypertonic saline (HTS), 0.9% ("normal") saline (NS) and Ringer's lactate (RL) on hemodynamics, sublingual and renal microcirculation, renal, mesenteric and brain perfusion, renal and cerebral metabolism, and survival in anesthetized, mechanically ventilated, adult female sheep.... In conclusion, in an ovine model of septic shock, administration of HTL was associated with earlier onset impaired tissue perfusion and shorter survival time. These observations raise concerns about use of HTL in septic shock (5).

Fluid resuscitation in the critically ill is a hot topic. The current strategy of rapid and adequate resuscitation in shock followed by conservative fluid administration is often difficult to achieve with standard crystalloid solutions. Research into alternative intravenous fluids tailored to individual patient needs is required. In the previous issue of Critical Care, Somasetia and colleagues compare the effects of hypertonic sodium lactate with the World Health Organization-recommended strategy of Ringer’s lactate resuscitation in children with severe Dengue, a viral infection for which causal treatment and vaccination are not available. The results not only suggest unimpaired lactate metabolism during shock in children but document improvement in endothelial barrier function, limited coagulopathy, and avoidance of fluid overload with hypertonic sodium lactate. Their study invites several important questions to be answered. Is hypertonicity or lactate per se important for the beneficial effects? Are the metabolic or anti-inflammatory effects responsible? Is the raised lactate in shock an adaptive response? Should reduction in lactate levels be the goal of resuscitation? These questions may trigger further research into the role of lactate and lactate-based intravenous fluids in resuscitation of the critically ill (6).

Food

It is used in foodstuffs as an antioxidant additive in the European additives list under E325, but also as a flavour enhancer in bakery products, an antioxidant synergist and an emulsifier. In some cases moisturising and flavouring.

Widely used in the production of processed meats.

High-pressure treatments (400 and 600 MPa) combined with the addition of sodium lactate (1 and 3%) were tested to reduce Escherichia coli O157:H7 (STEC O157) and spoilage microbiota contamination in a manufactured cured beef carpaccio in fresh or frozen conditions....Lethality of high-pressure treatments on STEC O157 was enhanced in frozen carpaccio, while the addition of sodium lactate at 3% reduced the lethality on STEC O157 in frozen samples, and the degree of injury in fresh carpaccio (7).

Cosmetics

Buffering agent. It is an iingredient that can bring an alkaline or acid solution to a certain pH level and prevent it from changing, in practice a pH stabiliser that can effectively resist instability and pH change.

Humectant. Hygroscopic compound used to minimise water loss in the skin and to prevent it from drying out by facilitating faster and greater absorption of water into the stratum corneum of the epidermis. The epidermis is the most superficial of the three layers that make up human skin (epidermis, dermis and hypodermis) and is the layer that maintains hydration in all three layers. In turn, the epidermis is composed of five layers: horny, the most superficial, granular, spinous, shiny, and basal. Humectants have the ability to retain the water they attract from the air in the stratum corneum and have the function of moisturising the skin. They are best used before emollients, which are oil-based.

Keratolytic. It is a lysis agent, i.e. a process of physically removing corneocytes or surface cells on the stratum corneum. It basically removes dead cells.

Farmaceutical

Pharmaceutical raw material.

The most relevant studies on the subject have been selected with a summary of their contents:

Sodium lactate studies

Typical optimal commercial product characteristics Sodium Lactate

• Molecular Formula  C₃H₅NaO₃
• Molecular Weight  112.06 g/mol
• CAS   72-17-3   312-85-6   867-56-1
• UNII    
• EC Number   208-534-8
• DSSTox Substance ID    DTXSID6052829
• IUPAC  sodium;2-hydroxypropanoate
• InChI=1S/C3H6O3.Na/c1-2(4)3(5)6;/h2,4H,1H3,(H,5,6);/q;+1/p-1  
• InChl Key      NGSFWBMYFKHRBD-UHFFFAOYSA-M
• SMILES   CC(C(=O)[O-])O.[Na+]
• MDL number  MFCD00066576
• PubChem Substance ID    329751114
• ChEBI  75228
• NSC   760108
• Beilstein   4567087

Synonyms : 

• Lactic acid, monosodium salt
• Monosodium 2-hydroxypropanoate
• Lactic acid sodium salt
• Monosodium lactate
• Sodium DL-lactate

References______________________________________________________________________

(1) Arifianto MR, Ma'ruf AZ, Ibrahim A, Bajamal AH. Role of Hypertonic Sodium Lactate in Traumatic Brain Injury Management. Asian J Neurosurg. 2018 Oct-Dec;13(4):971-975. doi: 10.4103/ajns.AJNS_10_17.

(2) Nalos M, Kholodniak E, Smith L, Orde S, Ting I, Slama M, Seppelt I, McLean AS, Huang S. The comparative effects of 3% saline and 0.5M sodium lactate on cardiac function:a randomised, crossover study in volunteers. Crit Care Resusc. 2018 Jun;20(2):124-130.

(3) Duburcq T, Durand A, Tournoys A, Gnemmi V, Gmyr V, Pattou F, Jourdain M, Tamion F, Besnier E, Préau S, Parmentier-Decrucq E, Mathieu D, Poissy J, Favory R. Sodium lactate improves renal microvascular thrombosis compared to sodium bicarbonate and 0.9% NaCl in a porcine model of endotoxic shock: an experimental randomized open label controlled study. Ann Intensive Care. 2018 Feb 14;8(1):24. doi: 10.1186/s13613-018-0367-9. 

(4) Dostalova V, Schreiberova J, Dostalova V Jr, Paral J, Kraus J, Ticha A, Radochova V, Dostal P. Effects of Hypertonic Saline and Sodium Lactate on Cortical Cerebral Microcirculation and Brain Tissue Oxygenation. J Neurosurg Anesthesiol. 2018 Apr;30(2):163-170. doi: 10.1097/ANA.0000000000000427.

(5) Su F, Xie K, He X, Orbegozo D, Hosokawa K, Post EH, Donadello K, Taccone FS, Creteur J, Vincent JL. The Harmful Effects of Hypertonic Sodium Lactate Administration in Hyperdynamic Septic Shock. Shock. 2016 Dec;46(6):663-671. doi: 10.1097/SHK.0000000000000684. 

(6) Nalos M, Tang BM, Nanan R. Is lactate the new panacea for endothelial dysfunction? Crit Care. 2014 Dec 1;18(6):614. doi: 10.1186/s13054-014-0614-x.

(7) Masana MO, Barrio YX, Palladino PM, Sancho AM, Vaudagna SR. High pressure treatments combined with sodium lactate to inactivate Escherichia coli O157:H7 and spoilage microbiota in cured beef carpaccio. Food Microbiol. 2015 Apr;46:610-617. doi: 10.1016/j.fm.2014.10.007.