1974

• Contract pharmaceutical manufacturing business established as Custom Pharmaceuticals Ltd. in Fort Erie, Canada. Facility later renamed Niagara Region Operations.

1982

• Expanded operations to Burlington, Canada by forming Promix Laboratories Inc. Facility later renamed Burlington Gateway Operations.

1990

• Began providing pharmaceutical manufacturing services to the U.S. market, capitalizing on opportunities created as a result of the North American Free Trade Agreement (NAFTA).

1993

• January - Became a publicly traded company on the Toronto Stock Exchange
• May – Changed Company name to Patheon Inc. (Stock symbol: PTI)

1994

• Added another facility in Burlington, Canada. Facility later renamed Burlington Century Operations.

1995

• May – Entered prescription (R_x) product and clinical trial materials manufacturing by acquiring 48% ownership of Global Pharm Inc. The facility had U.S. FDA-approved manufacturing capabilities and was formerly owned by Upjohn of Canada. Facility later renamed Toronto York Mills Operations.

1996

• November - Completed a fully marketed public offering, raising gross proceeds of C$14.4 million by issuing 11.5 million common shares for C$1.25 per share.

1997

• January - Patheon acquired the Toronto Region Operations facility in Mississauga, Canada from Hoffman-La Roche Limited (former Syntex facility). The 184,000 ft² (17,100 m²) facility included high-potency capacity for prescription products and modern laboratory facilities in which to expand the Pharmaceutical Development Services (PDS) business. The facility also offered U.S. FDA approved manufacturing capabilities.

1998 

• November – Established a European presence with the acquisition of a facility in Monza, Italy. The 300,000 ft² (27,900 m²) former Boehringer Mannheim facility was acquired from the Roche Group and represented Patheon’s first facility offering sterile injectable and lyophilized product services.

1999

• December – Strengthened European presence with the acquisition of two European facilities from Hoechst Marion Roussell group. The addition of Swindon Operations, UK and Bourgoin-Jallieu Operations, France added significant prescription manufacturing capacity as well as sterile injectable and cephalosporin capabilities.

2000

• September – Acquired the remaining 52% of the shares of Global Pharm Inc. which it did not previously own. The facility was later renamed Toronto York Mills Operations.

2001

• March – Opened newly constructed 8,500 ft² (800 m²) formulation development facility at Toronto Region Operations, expanding PDS capacity and expanded high-potency development capabilities.
• May – Acquired Whitby Operations from Novartis Pharmaceuticals Canada Inc. The 193,000 ft² (17,900 m²) facility increased Patheon’s capacity to manufacture high-volume prescription and OTC products.
• June – Opened a PDS facility in Swindon, UK enabling Patheon to offer integrated development services in both Europe and North America and adding capabilities to develop sterile injectable products.

2002

• February – Acquired Ferentino Operations located outside of Rome, Italy expanding Patheon’s lyophilization capacity and adding Large Volume Parenteral (LVP) manufacturing capabilities. Both Ferentino and Monza Operations significantly upgraded and expanded their lyophilization capacity to meet increasing client demand for these services.
• December – Acquired Cincinnati Operations from Aventis (now Sanofi-Aventis) representing Patheon’s first facility in the United States. The site included a 372,000 ft² (34,500 m²) manufacturing facility and an 85,000 ft² (7,900 m²) dedicated development facility to further expand Patheon's PDS capacity.

2004

• December – Completed acquisition of MOVA Pharmaceutical Corporation (MOVA), a leading U.S. prescription pharmaceutical contract manufacturer located in Puerto Rico, U.S.A. MOVA comprised three U.S. FDA-approved facilities, with over 900,000 ft² (83,600 m²)  of solid, liquid, sterile liquid and solid oral cephalosporin manufacturing capacity.

2006

• January - Merck & Co., Inc. selected Patheon as one of Merck’s strategic partners for commercial manufacturing and pharmaceutical development services. Patheon entered into a five-year master supply agreement to provide commercial manufacturing and pharmaceutical development services to Merck.

2007

• April - JLL Partners, through its investment vehicle, JLL Patheon Holdings, LLC completed the purchase of US$150 million of convertible preferred shares of Patheon through a private placement.
• November – Appointment of  Wesley P. Wheeler as Chief Executive Officer of Patheon Inc.