[A Study on the Feasibility to Assay Minipig Insulin Through Human Insulin Radioimmunoassay Kit].

OBJECTIVES: To investigate the feasibility of using human-specific insulin radioimmunoassay (Ins-RIA) kit to measure the concentrations of serum insulin in minipigs. METHODS: The Serum samples (219) of Bama minipigs were collected. The concentrations of serum insulin in Bama minipigs were measured by Ins-RIA kit and porcine-specific insulin enzyme linked immunosorbent assay (Ins-ELISA) kit, respectively. The linear regression analysis was undertaken in a randomly selected 175 samples (80% of total samples) to establish predictive equations between the concentrations of serum insulin measured by Ins-ELISA and the concentrations of serum insulin measured by Ins-RIA. The equations were then cross-validated in the remaining 44 samples (20% of total samples) that had not been included in the regression analysis. RESULTS: Measured insulin concentration was lower with the Ins-ELISA than that with the Ins-RIA [(15.32±15.50) µIU/mL vs. (32.31±21.74) µIU/mL, respectively, P<0.000 1]; The final predictive equation for the Ins-ELISA (µIU/mL) was equal to -7.29+0.70 × Ins-RIA(µIU/mL) ( R2=0.94). The differences between the predicted values and the actual measured values were 17.18%. CONCLUSIONS: Insulin values in Bama minipigs obtained from the Ins-ELISA and Ins-RIA are not equivalent and differ significantly. However, the insulin concentration by Ins-ELISA can be well estimated by Ins-RIA.

Efficacy of transdermal magnesium ascorbyl phosphate delivery after ultrasound treatment with microbubbles in gel-type surrounding medium in mice.

Liquid microemulsions appropriate for topical application were obtained by increasing their viscosity through the addition of thickening agents. The present study first assessed the usefulness of ultrasound (US) plus US contrast agent, microbubbles (MBs), in agarose gel for enhancing transdermal drug delivery. The effect of US plus MBs in agarose gel on the penetration of the skin by magnesium ascorbyl phosphate (MAP) was explored both in vitro and in vivo. In the in vitro experiments, the stability of MBs was investigated by examining the penetration of MAP by the model drug, Evans blue, in two media: an agarose phantom and pig skin. The penetration depth in the agarose phantom and pig skin increased by 40% and 195%, respectively, when treated with US plus MBs in 0.1% agarose solution combined with MAP (UMB1), and by 48% and 206%, respectively, when treated with US plus MBs in 0.15% agarose solution and MAP (UMB2). The skin-whitening effects in C57BL/6J mice in the UMB1 and UMB2 groups over a 4-week experimental period were significantly increased by 63% and 70%, respectively, in the fourth week. The findings of this study suggest that the survival of MBs with US is affected by the viscosity of the surrounding medium, and that in mice, treatment with US plus MBs in a suitable agarose gel can increase skin permeability and enhance transdermal MAP delivery.