How should a Hypurin Porcine Isophane (porcine insulin) cartridge be mixed before insertion into a pen?

Before pen insertion, shake the Hypurin Porcine Isophane (porcine insulin) cartridge vigorously up and down in a “bell ringing” action at least ten times; invert the pen at least ten times immediately before each injection, and do not use cartridges previously frozen or containing lumps that do not disperse on mixing.