A Westborough drug company with the same owners as the Framingham specialty pharmacy at the center of the national fungal meningitis outbreak will remain closed until at least Feb. 22, public health regulators said Thursday.

Ameridose LLC, which voluntarily ceased operations Oct. 10, will remain shuttered while a joint investigation by state and federal authorities continues into “unsanitary conditions and questionable sterility practices at the facility,” according to a statement by the Massachusetts Department of Public Health.