The Ontario College of Pharmacists is taking action to try to prevent future problems in preparing chemotherapy.

The move comes after patients in the Ontario communities of Oshawa, Peterborough, London and Windsor, as well as in Saint John, N.B., were given lower than intended doses of the chemotherapy drugs cyclophosphamide and gemcitabine.

Too much saline was in the IV chemotherapy bags, overdiluting them by between three and 20 per cent, according to Cancer Care Ontario.

The college, Health Canada, Ontario and New Brunswick's health ministries, and an independent investigator are all checking into how patients received overdiluted chemotherapy.

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Chemotherapy preparation is sometimes done in hospitals, and sometimes it's outsourced. (CBC)

The Hamilton, Ont.-based owner of Marchese Hospital Solutions, which provided the drugs, has said the problem occurred in how the intravenous bags of chemotherapy were administered at the five hospitals, not in how they were prepared at the company's Mississauga facility.

So far, health officials have found an oversight gap when chemotherapy is prepared outside of a hospital or an accredited pharmacy.

On Monday, Ontario College of Pharmacists spokeswoman Lori DeCou said the college is drafting regulations to help close that gap in regulatory oversight.

"We are in the final stages of developing a draft regulation for provincial government consideration," DeCou said. 

"That would provide the college, ourselves, with the authority to inspect premises where pharmacists and pharmacy technicians practice, including where drugs are prepared. So this would include facilities such as Marchese Hospital Solutions."

If the Ontario government accepts the college's proposed regulation, then the college would gain the authority to inspect Marchese's facility. Currently, the college conducts routine inspections of community pharmacies and investigates pharmacists or pharmacy technicians if it receives a complaint.

The college plans to sign off on the draft regulations at a meeting in early May and will ask the Ontario government to fast-track approval.

On Friday, the Ontario government announced a plan to limit hospital drug suppliers to provincially accredited pharmacies, hospitals and federally licensed suppliers who manufacture drugs. The province's health ministry is also asking hospitals to confirm quality assurance levels for drugs mixed on site or bought from companies.

Dr. Supriya Sharma, senior medical adviser at Health Canada, also outlined three conditions for drug suppliers to continue to provide mixing (also known as compounding) services while a long-term plan is worked out by Ottawa and the provinces and territories.

Together the changes proposed by the Ontario government, the college and Health Canada safeguard the drug supply, DeCou said.

With files from CBC's Amina Zafar