Source of haze to some lyophilized parenterals when rubber stoppers were not applied in the lyophilization process were studied in this report. First, it was confirmed that phthalates contaminated in PL-385 raw material, a kind of antibiotics, are a large source of haze. Then, PL-385 solution after extracting the phthalates by chloroform was used in this study. As the result, it was found that n-butyl phthalate, di (2-ethylhexyl) phthalate, C20H42, C22H46, di (2-ethylhexyl) adipate, sulfur, etc., which are volatiled from the rubber bags used for pressing rubber stoppers, silicone packing, and covered rubber for the thermocouples, etc. are a source of haze. It was specifically confirmed from the relationship between turbidity and adsorbed amount of C20H42, that C20H42 volatiled from rubber bags is a main source of haze, when a M-1700 Freeze Dryer is used. In addition, 9 kinds of drugs containing PL-385 were lyophilized at the same time and under the same conditions, and it was proved that lyophilized PL-385 adsorbs most of phthalates and saturated hydrocarbons because of large specific surface area (1.3 m2/g) and therefore, PL-385 makes haze most strongly.
