The methanol disolvate and the dihydrate of fexofenadine,an anti­histamine drug

Fexofenadine [systematic name: (±)‐(4‐{1‐hydroxy‐4‐[4‐(hydroxydiphenyl­methyl)­piperidinium‐1‐yl]‐butyl}phenyl)‐2‐methyl­propionate], crystallizes in two forms, viz. as the methanol disolvate, C₃₂H₃₉NO₄·2CH₄O, and as the dihydrate, C₃₂H₃₉NO₄·2H₂O. It exists in the two structures as a zwitterion, which self‐assembles as dimers sustained by a pair of charged‐assisted N—H⋯OOC hydrogen bonds. In the methanol disolvate, the supramolecular organization consists of discrete fexofenadine dimers solvated by four mol­ecules of methanol. The dihydrate structure is sustained by a more extended hydrogen‐bonding scheme, wherein the hydrated dimeric entities are inter­linked by additional hydrogen bonds. The fexofenadine mol­ecule adopts different and differently disordered conformations of the 1‐hydroxy­butyl residue in the two structures.