1999 年 47 巻 4 号 p. 492-497
To prevent temperature-dependent gel-sol transformation of an o/w emulsion type new vehicle system for a soft gelatin capsule, which may be available for both preclinical and clinical trials, the basic new vehicle formulation (PEG 400 : purified water : medium chain triglyceride : polyoxyethylene (20) cetylether=77 : 10 : 10 : 3) was modified by partially (1, 2 or 3%) replacing PEG 400 with PEG 6000 or PVP K30.When 2 or 3% of PEG 400 was replaced with PEG 6000, temperature-dependent gel-sol transformation was prevented at temperatures below 40 °C, and the vehicle appeared to be stable during 8 weeks of storage at 4 to 40 °C; the particle size distribution remained unchanged. When 1% of PEG 400 was replaced with PEG 6000, gel-sol transformation was not prevented, though phase separation was not observed at sol state, and the particle size distribution was shifted to be in a larger particle size range after 2 weeks of storage.When PEG 400 was partially (1, 2 or 3%) replaced with PVP K30, temperature-dependent gel-sol transformation was not prevented and, after 2 weeks of storage at 40 °C, the particle size distributions of the vehicles were shifted to be in a larger particle size range and the vehicles were separated into two layers.These results suggested that a small amount of PEG 6000 plays an important role in preventing temperature-dependent gel-sol transformation of our developed vehicle system.
