DESCRIPTION
TWINRIX® [Hepatitis A Inactivated & Hepatitis B (Recombinant) Vaccine] is a sterile bivalent vaccine containing the antigenic components used in producing HAVRIX® (Hepatitis A Vaccine, Inactivated) and ENGERIX-B® [Hepatitis B Vaccine (Recombinant)]. TWINRIX is a sterile suspension of inactivated hepatitis A virus (strain HM175) propagated in MRC5 cells, and combined with purified surface antigen of the hepatitis B virus. The purified hepatitis B surface antigen (HBsAg) is obtained by culturing genetically engineered Saccharomyces cerevisiae cells, which carry the surface antigen gene of the hepatitis B virus, in synthetic media containing inorganic salts, amino acids, dextrose, and vitamins. Bulk preparations of each antigen are adsorbed separately onto aluminum salts and then pooled during formulation.
A 1.0-mL dose of vaccine contains not less than 720 ELISA Units of inactivated hepatitis A virus and 20 mcg of recombinant HBsAg protein. One dose of vaccine also contains 0.45 mg of aluminum in the form of aluminum phosphate and aluminum hydroxide as adjuvants, amino acids, 5.0 mg 2-phenoxyethanol as a preservative, sodium chloride, phosphate buffer, polysorbate 20, Water for Injection, traces of formalin (not more than 0.1 mg), a trace amount of thimerosal (<1 mcg mercury) from the manufacturing process, and residual MRC5 cellular proteins (not more than 2.5 mcg). Neomycin sulfate, an aminoglycoside antibiotic, is included in the cell growth media; only trace amounts (not more than 20 ng) remain following purification. The manufacturing procedures used to manufacture TWINRIX result in a product that contains no more than 5% yeast protein.
TWINRIX is supplied as a sterile suspension for intramuscular administration. The vaccine is ready for use without reconstitution; it must be shaken before administration since a fine white deposit with a clear colorless supernatant may form on storage. After shaking, the vaccine is a slightly turbid white suspension.
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