OBJECTIVETo investigate the feasibility of swelling hydrogel instead of polyethylene oxide as swelling polymer in push-layer of push-pull osmotically controlled-release tablets.

METHODThe swelling patterns of tablets made of pure polymers were studied by immerging the tablets into purified water and testing their size at different time points. The push-pull osmotic-pump tablets were prepared and their release patterns in vitro were studied and compared by their similar factor (f2).

RESULTTablets with different swelling materials all showed satisfying release pattern in vitro and their release ratio at 12 h were all above 80%.

CONCLUSIONWith its release rate and cumulative release percentage at 12 h, the mixture of HPMC K15M and CMCNa in ratio of 1:1 is the best choice instead of polyethylene oxide as swelling polymer in push-layer.

Chemistry, Pharmaceutical ; Drug Carriers ; chemistry ; Osmosis ; Polymers ; chemistry ; Tablets ; Water ; chemistry

To seek the optimum experiment methods of animal immunization with HCV gene and to explore the effect on antibody responses in mice immunized by pCD-HCV1 recombinant in different administration, recombinant pCD-HCV1 was constructed by technique of molecular biology and was injected into muscles of Balb/c of mice with different times, routes and dosage of inoculations as well as different treatment. The results showed that the serum antibody level reached 0.183±0.06,0.428±0.05,0.707±0.08 and 0.773±0.07(OD410 value) respectively after recombinant pCD-HCV1(100μg/mouse) were injected into mice once, twice, three times and four times. The antibody level of mice (n＝12) with four times inoculation was the highest; pCD-HCV1 was perfused into stomach orally in mice or were into mice by i.p, s.c and i.m(100μg/mouse, three times) in different routes (n＝6), and the antibody levels were 0.138±0.05, 0.178±0.07, 0.233±0.08 and 0.691±0.05 respectively; after the mice (n＝8) were inoculated with the pCD-HCV1 of different dosage(10μg, 50μg and 100μg) the antibody levels of three groups were 0.11±0.09, 0.33±0.04, and 0.700±0.07, and the results showed a significant difference (P＜0.01); Mice was injected with procaine (100μl, 0.4mg) by i.m or s.c. Then pCD-HCV1 was injected into mice and antibody levels were higher than that of mice immunized directly with recombinant pCD-HCV1 of same dosage. The results may provide a reference data deserved for screening the optimum immunization method of development HCV-DNA-based vaccine in mice model.