Table II.
Diffusion Coefficients for Insulin Drug Products Obtained Using DLS
| Drug product | Lot no. | Normalized diffusion coefficienta,b (10−6 cm2/s) |
% Poly-dispersityc (%Pd) | Hydrodynamic radiusd (nm) |
|---|---|---|---|---|
| Apidra® | 1 | 0.90 ± 0.04 | 9.9 ± 0.3 | 2.7 ± 0.1 |
| 2 | 0.93 ± 0.06 | 9 ± 4 | 2.6 ± 0.1 | |
| 3 | 0.88 ± 0.05 | 11 ± 1 | 2.7 ± 0.1 | |
| Humalog® | 1 | 1.02 ± 0.01 | 10.6 ± 0.3 | 2.4 ± 0.0 |
| 2 | 0.92 ± 0.09 | 30 ± 10 | 2.7 ± 0.2 | |
| 3 | 0.93 ± 0.01 | 14 ± 7 | 2.6 ± 0.0 | |
| Humulin R® | 1 | 1.35 ± 0.01 | 15 ± 1 | 1.8 ± 0.0 |
| 2 | 1.34 ± 0.04 | 11 ± 2 | 1.8 ± 0.0 | |
| 3 | 1.26 ± 0.01 | 20 ± 1 | 1.9 ± 0.0 | |
| Novolin R® | 1 | 1.31 ± 0.02 | 11 ± 1 | 1.9 ± 0.1 |
| 2 | 1.40 ± 0.07 | 13.2 ± 0.4 | 1.8 ± 0.1 | |
| 3 | 1.32 ± 0.02 | 16 ± 6 | 1.8 ± 0.0 | |
| Novolog® | 1 | 1.07 ± 0.01 | 12 ± 0.1 | 2.3 ± 0.0 |
| 2 | 1.00 ± 0.01 | 15 ± 5 | 2.4 ± 0.1 | |
| 3 | 1.06 ± 0.03 | 13 ± 3 | 2.3 ± 0.1 |
a
The experimental variation was from two technical repeats
b
The averaged DOSY diffusion coefficient from all 15 lots of insulin was 1.11 × 10−6 cm2 /s and the RSD was 17%
c
Percent poly-dispersity (%Pd) of the major species is shown. The %Pd value for RNAse A solution was 14.0 ± 0.4%
d
Hydrodynamic radius of the major specie is shown