Table 4. Effect of excipients on rAvPAL-PEG activity rate of decay.
| Formulation | -kdecay (40°C) | -kdecay (37°C) | -kdecay (25°C) | -kdecay (4°C) | Ea(decay) (kJ/mol) | T90 4°C (weeks) |
|---|---|---|---|---|---|---|
| TBS | 0.1258, n = 1 | 0.1148±0.0082 n = 5 | 0.0457±0.0023 n = 4 | 0.0107±0.0018 (measured, n = 5) 0.0093 (calculated) | 51.89 ± 2.84 | 11.3 |
| TBS + Phe (0.4–2.5mM) | 0.0592±0.0098n = 6 | 0.0438±0.0023 n = 9 | 0.0146±0.0013 n = 12 | 0.0019±0.0008 (measured, n = 6) 0.0014 (calculated) | 75.64 ± 5.03 | 75.3 |
| TBS + t-CA (0.4-1mM) | ND | 0.0466±0.0029 n = 3 | 0.0151±0.0032 n = 3 | 0.0015 (calculated) | 75.03 ± 16.47 | 70.2 |
rAvPAL-PEG at 9-20mg/mL was formulated in the presence or absence of the indicated excipients. Rates of decay (kdecay ± SEM) were calculated for each condition tested from up to 7 independent experiments (n represents number of independent samples). Combined data were used to calculate the energy of decay, Ea(decay), and predict the T90 at 4°C using kdecay at 25°C. Average Ea(decay) ± SEM was determined by the best-fit slope of all data plotted on an Arrhenius plot (Fig 3) as determined by a non-linear regression algorithm using Graphpad Prism software. All data used to generate average kdecay and Ea(decay) values are shown in S1–S3 Tables. SEM = Standard Error of Mean.