bucillamine bucillamine bucillamine is an antirheumatic agent developed from tiopronin. activity is mediated by the two thiol groups that the molecule contains. research done in usa showed positive transplant preservation properties. bucillamine is currently being investigated for covid-19 drug repurposing. bucillamine names iupac name 2--3-sulfanylpropanoic acid identifiers cas number 65002-17-7 r y 3d model (jsmol) interactive image chembl chembl80830 y chemspider 2365 y kegg d01809 y mesh bucillamine pubchem cid 2459656604 r636373 s unii r80lra5wtf y comptox dashboard (epa) dtxsid2048587 inchi inchi=1s/c7h13no3s2/c1-7(2,13)6(11)8-4(3-12)5(9)10/h4,12-13h,3h2,1-2h3,(h,8,11)(h,9,10) ykey: vuafhzcukuddbc-uhfffaoysa-n y smiles cc(c)(s)c(=o)nc(cs)c(=o)o properties chemical formula c7h13no3s2 molar mass 223.31 g·mol−1 log p 1.032 acidity (pka) 3.012 basicity (pkb) 10.985 pharmacology atc code m01cc02 (who) related compounds related alkanoic acids acetylcysteineglycylglycineiminodiacetic acidnitrilotriacetic acidn-oxalylglycinetioproninoxalyldiaminopropionic acidgamma-glutamylcysteine related compounds n-acetylglycinamide except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). infobox references bucillamine has a well-known safety profile and is prescribed in the treatment of rheumatoid arthritis in japan and south korea for over 30 years. it is a cysteine derivative with 2 thiol groups that is 16-fold more potent than acetylcysteine (nac) as a thiol donor in vivo, giving it vastly superior function in restoring glutathione and therefore greater potential to prevent acute lung injury during influenza infection. bucillamine has also been shown to prevent oxidative and reperfusion injury in heart and liver tissues. bucillamine has both proven safety and proven mechanism of action similar to that of nac, but with much higher potency, mitigating the previous obstacles to using thiols therapeutically. it is hypothesized that similar processes related to reactive oxygen species (ros) are involved in acute lung injury during ncov-19 infection, possibly justifying the investigation of bucillamine as an intervention for covid-19. on july 31st, 2020, the u.s. food & drug administration (fda) has approved revive therapeutics ltd. to proceed with a randomized, double-blind, placebo-controlled confirmatory phase 3 clinical trial protocol to evaluate the safety and efficacy of bucillamine in patients with mild-moderate covid-19.