Fig. 5

Experiments using side-by-side diffusion cells for Humulin®R. Saline #I (a), PBS (pH 7.4) #II (b), Saline + m-cresol #III (c), PBS (pH 5.5) #IV (d), and PBS (pH 6.5) #V (e) were applied to the other cell. Turbidity (), fluorescence intensity (), and pH (▲) were evaluated. The isoelectric point of human insulin in Humulin®R and the pH range of the original formulation of Humulin®R are expressed as a dotted line and filled area in grey. Each value is expressed as the mean ± S.D. (n = 3–6). Significantly lower pH value (*) than the lower standard pH value of Humulin®R (P < 0.05)