principle

(prin’sip-l) [L. princip’tum]. 1. A chemic component. 2. A substance on which certain of the properties of a drug depend. active p., any constituent of a drug which helps to confer upon it a medicinal property. immediate p., organic p., proximate p., any onc of the more or le complex substances of definite chemic constitution into which a heterogeneous substance can be readily resolved. ultimate p., a chemic element.