Tetanus toxoid: 1. purification in 50 kD molecular weight cut-off membrane

The tetanus anatoxin (M.W.=150,000 dALTONS) is the fundamental component for Tetanus Toxoid (TT) combined vaccines production and must follow the parameters established by World Health Organization (WHO). Among other qualifications the purity degree must be equal or greater than 1,000 Lf/mg PN and the residual formaldehyde must be at maximum level of 0,02 per cent. The Tangential Flow Filtration technique with 50,000 Nominal Molecular Weight Limit (NMWL) membranes and gel filtration in Sephadex G-50 were associated to purify 18 consecutive lots of tetanus anatoxin