| Objective:sSAN-VD3 is the special alginate nanoparticles embedding vitamin D3 and forming by means of self-assembling, while special alginate is modified by oleic acid. To observe the preventive effect of sSAN-VD3 to rats rickets and the feature of pharmacokinetics in mice.Methods:Part one. Study of prevention effect of sSAN-VD3 on rats rickets.1.The form of rats rickets model:Rats were bred 35 days with Vitamin D3 deficiency diet and in the room kept from sunlight.2. At the same time of forming rats rickets model, rats were taken drugs with high dose sSAN-VD3 (4.2mg·kg-1·d-1 included VD337.5μg),low dose sSAN-VD3 (1.70 mg·kg-1·d-1 included VD315.0μg),high dose VD3 (37.5μg·kg-1·d-1),low dose VD3 (15.0μg·kg-1·d-1)by intragastric administration for 35 days.3.Examining: General situation (the weights, hair, actions, appetite) were observed; The content of Ca, P and AKP of blood serum in rats were determined by omni-automatic movement biochemistry analysator; The content of 25-(OH)VD3 and the activity of Bone Alkaline Phosphatase were determined by solid phase sandwich method enzyme-linked immunosorbent assay; The Bone Mineral Density of femoral bone were detected by the dual energy X-ray absorptiometry; The content of bone mine were detected by the inductively coupled plasma optical emission spectrograph; The X ray picture were photographed by molybdenum target soft X tank unit.Part two. The feature of sSAN-VD3's pharmacokinetics in mice.1.The KM mice were bred for 15 days with Vitamin D3 deficiency diet and in the room kept from sunlight, and then were were taken drugs with sSAN-VD3(222mg·kg-1 include VD32mg)and VD3 (2mg·kg-1)by intragastric administration. The mices were taken blood through culling the eye globe at 2,4,8,16,24,48h after taken drugs. 2. The concentration of VD3 in serum and pharmacokinetics parameter determined:The protein in the serum was precipitated by alcohol, and VD3 in serum was extracted by Tetrachloride Hexane. VD3 was detected by HPLC and carried out precision test, recovery test. The pharmacokinetics parameters were given by DAS software dealing with the experimental results.Results:1.The weights of rickets rats in model group were lower than normal control group obviously after five weeks'feeding, the activities of AKP and BAP in serum increased obviously, and the contents of P,25-(OH)VD3 in the serum and BMD of femoral bone decreased obviously (P<0.05). Bone X ray picture showed that the skeleton of shin bone of model group rats were small and tiny, bone density degraded, and epiphyseal disk widen. 2. Compared with rats in model groups, the weights, content of P in serum and BMD of rats in preventive medication administration groups increased obviously(P<0.05), the activities of BAP in serum of rats decreased and the content of P of thighbone and 25-(OH) VD3 increased in high dose sSAN-VD3, low dose sSAN-VD3 and high dose VD3 groups, the difference is significant (P<0.05), and the picture of bone X ray was similar as normal group; Compared with rats in low dose VD3 group, the results of BAP, 25-(OH) VD3 in serum and BMD of thighbone showed sSAN-VD3 had visible anti-rachitic effect (P<0.05).3. Concentration of VD3 was detecting by HPLC, the results showed that the peak shape of VD3 was well, and had fine separation with other metabolines. The impurity had no influence and the basal line was stable. The retention time in serum was 10.393 min. The lowest detectable limit was 0.025ug/ml, and it assumed a fine line relationship between 0.025-0.8ug/ml. The average recovery was more than 90%, and the RSD of precision and stability was less than 15%.4. The reaching hump time of VD3 and sSAN-VD3 were 9.6±3.578h and 12.800±4.382h, the distribution half life were 3.740±1.620h and 6.095±1.697h, the absorption half life were 5.874±2.564 and 7.583±3.00,the elimination half life were 13.657±3.070 and 15.320±5.825.The AUC were 9.018±0.784 and 14.035±0.764.Conclusion:1.Both sSAN-VD3 and VD3 taken by mouth have preventive effect to rats rickets, and sSAN-VD3 has more obvious effect than VD3 in the low dose(VD315.0μg·kg-1·d-1)(P<0.05).2. Contrast with VD3, the half life of sSAN-VD3 was longer and the AUC increased obviously. It demonstrates that, as a carrier of VD3, self-assembly sodium polymannuronate nanoparticle can elevate the bioavailability, and enhance the preventive effect to rats rickets. |
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