pirenoxine pirenoxine pirenoxine (abbreviated prx, trade name catalin) is a medication used in the possible treatment and prevention of cataracts. pirenoxineclinical datatrade namescatalinatcvet codeqs01xa91 (who) identifiers iupac name 1,5-dioxo-4h-pyridophenoxazine-3-carboxylic acid cas number1043-21-6pubchem cid4846chemspider4846unii27l0ep6izkcomptox dashboard (epa)dtxsid6048335 echa infocard100.012.612 chemical and physical dataformulac16h8n2o5molar mass308.249 g·mol−13d model (jsmol)interactive image smiles c1=cc=c2c(=c1)n=c3c(=cc(=o)c4=c3c(=o)c=c(n4)c(=o)o)o2 inchi inchi=1s/c16h8n2o5/c19-9-5-8(16(21)22)18-14-10(20)6-12-15(13(9)14)17-7-3-1-2-4-11(7)23-12/h1-6h,(h,18,19)(h,21,22)key:okpnygawtyobfz-uhfffaoysa-n a report in the journal inorganic chemistry showed that in liquid solutions pirenoxine could cause decreased cloudiness of a crystallin solution produced to mimic the environment of the eye. pirenoxine interacts with selenite or calcium ions that have been proven as factors leading to the formation of lens cataract. pirenoxine reduces the cloudiness of the lens solution containing calcium by 38% and reduced the cloudiness of the selenite solution by 11%. “...there are not any proctored studies that prove the utility of these drops. in canada and in the u.s. they are considered homeopathic—probably do no harm but doubtful that they will have any protective value."