A crystalline form of 6-{2-[1-(6-methyl-3-pyridazinyl)-4-piperidinyl]ethoxy}-3-ethoxy-1,2-benzoxazole is provided which is useful in the treatment of infections caused by Picornaviridae such as human rhinovirus (HRV), and in particular the crystal form is an anhydrous crystalline free base form of 6-{2-[1-(6-methyl-3-pyridazinyl)-4-piperidinyl]ethoxy}-3-ethoxy-1,2-benzoxazole. In addition, a method of manufacturing the free base crystalline form is also provided, including a step of micronizing the compound particles, optionally using a wetting agent, as well as pharmaceutical compositions incorporating the free base crystalline form such as tablets or suspensions, and methods of therapeutic treatments using this form and pharmaceutical compositions thereof.
