In certain embodiments, a vial adaptor comprises a housing member, a connector configured to couple the adaptor with a vial, and an extractor channel formed in the housing member. The extractor channel is configured to facilitate withdrawal of fluid from the vial when the adaptor is coupled to the vial. In some embodiments, an anti-reflux valve is positioned within the extractor channel. The anti-reflux valve can be configured to impede or obstruct fluid returning to a fluid source after withdrawal of the fluid from the fluid source.
