Table II.
Model Coefficients for the Release of THC-HG from PEO Matrices as a Function of Polymer Molecular Weight in 1% SLS at 37°C and a Paddle Rotation Speed of 100 rpm
| Formulation | Kopcha model 
|
Peppas model 
|
|||
|---|---|---|---|---|---|
| A (mgh−1/2) | B (mgh−1) | C (mg) | A/B | n (release exponent) | |
| PEO N-10 | 8.89 | 130.73 | −0.20 | 0.06 | 0.98 |
| PEO N-80 | 7.41 | 94.39 | −0.08 | 0.08 | 0.95 |
| PEO N-750 | 4.05 | 42.16 | −0.01 | 0.11 | 1.00 |
| PEO WSR 1105 | 3.24 | 21.34 | 0.30 | 0.15 | 1.02 |
A/B < 1; erosion predominates over diffusion [Kopcha Model (17)]. For swellable matrices, n = 1; case II transport mechanism (erosion) with zero-order kinetics [Peppas Model (18)]
A Diffusion term, B erosion term, C related to physical parameters, M t/M ∞ fraction of drug released, t release time, k kinetic constant, n release exponent indicative of the release mechanism of the drug