Initially used for its anti-haemorrhagic activity, tranexamic acid has in recent years been employed in the formulation of skincare products. But how is it obtained?
Tranexamic acid, what is it?
Discovered in the 1950s, tranexamic acid is a structurally similar derivative of the amino acid lysine. It was initially used in the medical field for its ability to inhibit fibrinolysis. Taken orally, it can manage excessive bleeding induced by events such as severe trauma, surgical procedures, postpartum haemorrhages, and heavy menstruation. This use is based on its coagulating abilities, which help to reduce blood loss.
It is noteworthy that tranexamic acid is listed on the World Health Organisation's (WHO) list of essential medicines. However, it was only recently, in 2009, that it was authorised and incorporated into cosmetic product formulations by the Cosmetology Commission. Thanks to its depigmenting action, this acid has the notable ability to reduce the appearance of various forms of skin hyperpigmentation, such as melasma, post-inflammatory hyperpigmented marks and sun spots.
By acting in this way, it promotes a clearer complexion by limiting the production of melanin. Studies have even suggested that the effectiveness of tranexamic acid could be comparable to that of thehydroquinone, an active ingredient widely used in this context. Furthermore, this acid is also sought after for its anti-inflammatory properties.
When applied topically in skincare products, tranexamic acid is generally well tolerated and does not cause major side effects However, in rare cases, it could cause temporary reactions, such as redness or itching. For this reason, it is recommended to perform a patch test by applying the product to a small area of the body during the first use.
How is tranexamic acid produced?
Tranexamic acid is a synthetic compound produced in a laboratory, derived from the amino acid lysine. However, the specific details of its chemical synthesis are typically protected and not disclosed. Nonetheless, there are studies that provide some insight into its production.
The synthesis begins with dimethyl terephthalate (C10H10O4), a diester formed from terephthalic acid and methanol, where potassium hydroxide (KOH) and methanol (CH4O) are added to the solution.
After the reaction mixture has been heated to reflux, methyl 4-(chlorocarbonyl)benzoate is formed through the use of bis(trichloromethyl) carbonate (BTC).
As the chemical reaction progresses, the reaction mixture transforms into a solid that reacts with an aqueous solution of ammonia (NH3).
Acetic anhydride (C4H6O3) is then added and heated.
Subsequently, a hydrogenation process takes place, which is a chemical reaction involving the addition of a dihydrogen molecule to another compound, resulting in the formation of potassium 4-(methoxycarbonyl)benzoate (C6H7KO4).
The obtained molecule is then hydrolysed and isomerised.
In conclusion, barium hydroxide (BaH2O2) is added to the solution along with water and ethanol (C2H6O) as solvents to produce tranexamic acid.
Note : The steps outlined above are merely the key stages in the synthesis process of tranexamic acid. The manufacturing process may vary from one laboratory to another.
LI Z. & al. An improved and practical synthesis of tranexamic acid. Organic Process Research & Development (2015).