Table 4.
Stability of free papain and optimised formulations of papain (HS4, LS4 and SS4) under room temperature storage (30°C ± 2°C/65% ± 5% RH)
| Formulation code | % Papain activity remaining | Kcalc (day)−1 | t90 (Days) | Intcalc for 2 years | ||||
|---|---|---|---|---|---|---|---|---|
| 0 M | 3 M | 6 M | 9 M | 12 M | ||||
| Papain | 100.00 ± 2.26 | 94.56 ± 2.32 | 87.42 ± 3.05 | 79.21 ± 2.87 | 72.55 ± 3.38 | 8.79 × 10−4 | 118.27 | 170.95 |
| HS4 | 100.00 ± 4.19 | 98.22 ± 2.86 | 96.19 ± 4.02 | 94.59 ± 3.28 | 92.09 ± 2.63 | 2.26 × 10−4 | 460.57 | 106.14 |
| LS4 | 100.00 ± 3.77 | 98.35 ± 3.50 | 96.52 ± 3.26 | 94.45 ± 4.09 | 92.62 ± 3.28 | 2.10 × 10−4 | 495.05 | 104.91 |
| SS4 | 100.00 ± 3.11 | 98.13 ± 3.49 | 96.44 ± 3.89 | 94.19 ± 3.68 | 92.31 ± 3.33 | 2.19 × 10−4 | 474.31 | 105.60 |
*
Note: Values are mean ± SE (n = 3).
Abbreviations: M, months; Kcalc, calculated first order degradation rate constant; t90, time to reach 90% of initial drug concentration; Intcalc, calculated initial drug concentration for shelf life (t90) of 2 years.