Food and Drug Regulations

C.04.569 The insulin preparation “Insulin Zinc Suspension — Prolonged” shall be a sterile suspension in a buffered aqueous medium of insulin modified by the addition of zinc in such a way that the suspended precipitate consists of crystals with not more than a trace of amorphous material, shall have a pH of not less than 7.0 and not more than 7.8 and shall contain

• (a) weight by volume,

  • (i) not less than 0.15 per cent and not more than 0.17 per cent of sodium acetate (NaC₂H₃O₂.3H₂O),

  • (ii) not less than 0.65 per cent and not more than 0.75 per cent of sodium chloride, and

  • (iii) not less than 0.09 per cent and not more than 0.11 per cent of methyl-p-hydroxybenzoate; and

• (b) as determined by an acceptable method, for each 1,000 International Units of insulin,

  • (i) not more than 7.0 milligrams of nitrogen, of which not less than 90 per cent shall be in the crystalline component, and

  • (ii) not less than 1.2 milligrams and not more than 2.5 milligrams of zinc, of which not less than 20 per cent and not more than 65 per cent shall be in the supernatant liquid.