Collip’s purification process was much simpler than Banting’s. For Collip’s process a whole pancreas was placed into a blender with a 80% alcohol/20% water mixture. The pancreas tissue was homogenized (blended). After thoroughly blending, one would wait overnight for anything that failed to dissolve in the alcohol mixture to fall to the bottom of the container. The liquid solution was carefully drawn from the container, leaving the solid particles at the bottom. Then more alcohol was added to the solution to bring the alcohol concentration to 90% and reduce the water concentration to 10%. Again, one would wait overnight and a precipitate would form at the bottom of the container. This precipitate was the purest form of insulin ever obtained at the time.
Collip’s work was summarized by a Professor O. Leyton writing in the Dec 9, 1922 British Medical Journal by saying, “a dose [of insulin] needs half a pancreas of an ox and about three quarts of alcohol”. His point was that it was too expensive. His idea of minimizing costs was to produce insulin where both ox pancreases and alcohol were cheap. Apparently after asking around, he decided that Durban in Africa was the ideal location. Professor Leyton even provided a cost estimate. He wrote that in Durban, “alcohol is ninepence a gallon and the pancreas of an ox costs less than a shilling”, while also noting that much of the alcohol could be recovered after the procedure, purified, and reused.
Leonard Thompson, the boy close to death in the Toronto General Hospital, got his second dose of insulin on January 23, 1922. This second dose was from a batch prepared using Collip’s new method. Thompson received almost daily doses of insulin for the next two weeks.
This time, the results were stunning. His blood sugar dropped, glycosuria stopped, and a general overall improvement in his health occurred. He was saved from death, but reliant upon insulin. The Toronto team treated six other patients and saw similar improvements.
The clinical trials had been a quick success. Banting, Best, Collip and two of the doctors from the Toronto General Hospital quickly wrote up the results and published them in the March 12, 1922 issue of the Canadian Medical Association Journal. They were ready to make insulin widely available.
The only step required to make insulin widely available was to scale up Collip’s method of alcohol purification of insulin. The University of Toronto had the perfect place to scale up the production of insulin, Connaught Laboratories. Connaught Laboratories (now known as Sanofi Pasteur) was established in 1914. Its mission was to improve public health. It initially focused on the production of diphtheria and tetanus vaccines.
However, disaster struck. Collip could not reproduce his purification method on a large scale at Connaught Laboratories. With a dozen patients relying on insulin to stay alive and many more lining up for it, there was no insulin.