Studies on the fractionation of equine antivenom IgG by combinations of ammonium sulfate and caprylic acid

► Antivenom IgG was fractionated by a combination of ammonium sulfate and caprylic acid. ► Ammonium sulfate reduced turbidity and increased the yield but not the purity of IgG. ► Optimum fractionation condition was 3.5% caprylic acid. ► Better overall results were observed with one hour than with overnight precipitation.