What makes a requirement binding here
The Food and Drugs Act, and the Food and Drug Regulations (C.R.C., c. 870) made under it. Within Part C of those Regulations the licensing regime and the manufacturing standard sit in separate divisions: Division 1A carries drug establishment licences, and Divisions 2 to 4 carry good manufacturing practices. An establishment licence application must be supported by evidence — a certificate from a Canadian inspector, or other documentation — that the buildings, equipment, practices and procedures of the fabricator, packager/labeller and tester meet the applicable requirements of Divisions 2 to 4.
Through a licence, and inspection against it. Health Canada issues a Drug Establishment Licence naming each regulated activity — fabricating, packaging/labelling, testing, importing, distributing, wholesaling — and each site, so adding an activity or a site is an amendment rather than a notification. The agency publishes GUI-0001, its good manufacturing practices guide for drug products, which interprets the Division 2 requirements. GUI-0001 is an administrative document and does not itself have the force of law: the Regulations create the obligation, and the guide explains how Health Canada expects it to be met.