
Attention, c'est pour un public TRES averti, mais c'est une source inépuisable du point de vue scientifique.
The original medication was manufactured in the form of semisolid gel capsules, based on the only known crystal form of the drug ("Form I"). In 1998, however, a second crystal form ("Form II") was unexpectedly discovered, which had significantly lower solubility, and which was not medically effective.[14]
Form II was of sufficiently lower energy that it became impossible to produce Form I in any laboratory where Form II was introduced, even indirectly. Scientists who had been exposed to Form II in the past seemingly contaminated entire manufacturing plants by their presence, probably because they carried over microscopic seed crystals of the new polymorph.[3] The drug was temporarily recalled from the market, and tens of thousands of AIDS patients went without medication for their condition, until ritonavir was reformulated, approved, and re-released to the market in 1999.
Altay a écrit : ↑dim. juin 30, 2024 3:52 pm Vous connaissez les « polymorphes disparus » ? C'est un phénomène qui se produit quand une molécule avec une structure cristalline est remplacée par la même molécule, mais sous une autre forme cristalline, dans une réaction en chaîne inarrêtable.
Je connaissais avec la Glace-9 de Cat's Cradle de Kurt Vonnegut, mais apparemment ça s'est déjà produit à plusieurs reprises dans la réalité dans le milieu pharmaceutique. Par exemple, le ritonavir, un médicament pour le traitement du SIDA, a failli disparaître à cause de ça :
The original medication was manufactured in the form of semisolid gel capsules, based on the only known crystal form of the drug ("Form I"). In 1998, however, a second crystal form ("Form II") was unexpectedly discovered, which had significantly lower solubility, and which was not medically effective.[14]
Form II was of sufficiently lower energy that it became impossible to produce Form I in any laboratory where Form II was introduced, even indirectly. Scientists who had been exposed to Form II in the past seemingly contaminated entire manufacturing plants by their presence, probably because they carried over microscopic seed crystals of the new polymorph.[3] The drug was temporarily recalled from the market, and tens of thousands of AIDS patients went without medication for their condition, until ritonavir was reformulated, approved, and re-released to the market in 1999.
https://en.wikipedia.org/wiki/Disappearing_polymorphs
Terrifiant.
Chestel a écrit : ↑lun. mars 11, 2024 5:30 pm https://www.marius-fabre.com/fr/blog/le ... pes-n-n263
Prouvé par de nombreux autres fabricants de savon...