Carbenoxolone

Preparation

Take 140g of glycyrrhizic acid powder (glycyrrhizic acid content approximately 25% HPLC), add 1120ml of 95% edible ethanol, extract at 40℃ for 3 hours, filter to remove insoluble impurities, distill the filtrate to recover ethanol to obtain the extract, dry the extract at 100℃ in a water bath to obtain 118g of dry extract with a water content of no more than 20%; pulverize the dry extract and take 100g, add 300ml of 70% glacial acetic acid and 7ml of concentrated sulfuric acid, hydrolyze and acetylate under normal pressure, heat to 98-103℃, react for 2 hours, after hydrolysis and acetylation are completed, cool to room temperature, filter the precipitated solid, wash the filter cake with 250ml of 65% acetic acid, then wash with 200ml of ethanol, and finally wash with 300ml of water, dry at 100℃ to obtain 20.21g of crude acetylglycine with a purity of 88.2% (HPLC).

Take 20g of acetylglycyrrhetinic acid, add 300ml of water, add 5g of sodium hydroxide to adjust the pH to 13, hydrolyze under reflux at normal pressure for 4 hours, cool to room temperature, acidify the pH to 5.2 with hydrochloric acid, filter, wash the filter cake with pure water to remove inorganic salts, and dry at 100℃ to obtain 17.8g of crude glycyrrhetinic acid with a purity of 92.9% (HPLC). Dissolve the crude glycyrrhetinic acid in 214ml of 95% ethanol (v/v), add 25% (4.45g) of activated carbon for reflux decolorization, filter after reflux decolorization, recover the ethanol from the filtrate, precipitate the solid, and filter to obtain 16.4g of glycyrrhetinic acid with a purity of 98.2% (neutralization method). For further purification, recrystallize three times with 95% ethanol to obtain glycyrrhetinic acid product with a purity of 98% (HPLC), with total impurity peaks not exceeding 2% and single impurity peaks not exceeding 0.7%, fully complying with the European Pharmacopoeia standards.

Originator

Biogastrone,Winthrop,UK,1963

Uses

Glucocorticoid.

Manufacturing Process

23.5 g of glycyrrhetinic acid were dissolved in 50 cc of dry pyridine. A solution of 6.0 g of succinic anhydride in 30 cc of dry pyridine was added, followed by 30 cc of dry triethylamine and then, for washing purposes, 5 cc of dry pyridine. The solution was heated on a boiling water bath for ten hours and then poured into excess of dilute hydrochloric acid and ice. The fine gray precipitate formed was filtered off, washed with water, dissolved in chloroform, and the solution repeatedly extracted with dilute hydrochloric acid and later with water. It was dried over sodium sulfate and evaporated to dryness. Crystallization from methanol, using charcoal to effect decolorization, gave the hydrogen succinate as cream-colored crystals, MP 291° to 294°C, with previous softening.
One molecular proportion of glycyrrhetinic acid hydrogen succinate was ground with a dilute (5%) aqueous solution containing two molecular proportions of sodium hydroxide. The solution was filtered and evaporated in vacuum over concentrated sulfuric acid. The sodium salt is then obtained as a creamy white water-soluble solid. Glycyrrhetinic acid is obtainable from licorice root.

Therapeutic Function

Antiinflammatory (gastric)

Safety Profile

Poison by intravenous andintraperitoneal routes. Moderately toxic by ingestion andsubcutaneous routes. Human systemic effects byingestion: muscle weakness and flaccid paralysis. Whenheated to decomposition it emits acrid smoke and fumes.