Table 1.

Model parameters

Independent parameters	Value	Description
${\mathrm{D}}_1^{\mathrm{B}}$	2.2 × 10−9 (m2·s−1) (Caccavo et al., 2015)	Water diffusivity in the dissolved drug layer (ΩB)
${\mathrm{D}}_2^{\mathrm{B}}$	1.5 × 10−10 (m2·s−1) (Caccavo et al., 2015)	Drug diffusivity in the dissolved drug layer (ΩB)
${\mathrm{D}}_1^{\mathrm{C}}$	1.99 × 10−12 (m2·s−1) (from experiment)	Water diffusivity in the polymeric film (ΩC)
${\mathrm{D}}_2^{\mathrm{C}}$	3.1 × 10−13 (m2·s−1) (from experiment)	Drug diffusivity in the polymeric film (ΩC)
${\mathrm{D}}_1^{\mathrm{D}}$	3 × 10−9 (m2·s−1) (Holz et al., 2000)	Water diffusivity in the dissolution medium (ΩD)
${\mathrm{D}}_2^{\mathrm{D}}$	8.21 × 10−10 (m2·s−1) (Grassi et al., 2001)	Drug diffusivity in the dissolution medium (ΩD)
${\mathrm{\omega }}_{2,\mathrm{sat}}^{\mathrm{B}}$	0.0115 (−) (Serajuddin and Jarowski, 1985)	Theophylline saturation mass fraction in water
${\mathrm{m}}_1^{\mathrm{BC}}$	4.95 (−) (from experiment)	Water equilibrium constant: relates the water mass fraction in ΩC to its equilibrium counterpart in ΩB
${\mathrm{m}}_1^{\mathrm{CD}}$	0.2 (−) (from experiment)	Water equilibrium constant: relates the water mass fraction in ΩDto its equilibrium counterpart in ΩC
ρ10	1000 (kg·m−3) (Caccavo et al., 2015)	Pure water density
ρ20	1200 (kg·m−3) (Caccavo et al., 2015)	Pure theophylline density
ρ30	1200 (kg·m−3) (Caccavo et al., 2015)	Pure HPMC density
ρ40	1200 (kg·m−3)	Pure Surelease density

Dependent parameters	Expression	Description
kdiss	${\mathrm{D}}_2^{\mathrm{B}}/{\mathrm{R}}_{\mathrm{A}}$	Theophylline dissolution rate constant
${\mathrm{K}}_1^{\mathrm{BC}}$	${\left(1/{\mathrm{k}}_1^{\mathrm{B}}+{\mathrm{m}}_1^{\mathrm{BC}}/{\mathrm{k}}_1^{\mathrm{C}}\right)}^{-1}$	Overall water mass transport coefficient between ΩB and ΩC
${\mathrm{K}}_2^{\mathrm{BC}}$	${\left(1/{\mathrm{k}}_2^{\mathrm{B}}+1/{\mathrm{k}}_2^{\mathrm{C}}\right)}^{-1}$	Overall Theophylline mass transport coefficient between ΩB and ΩC
${\mathrm{k}}_1^{\mathrm{B}}$	${\mathrm{D}}_1^{\mathrm{B}}/\left({{\mathrm{R}}_{\mathrm{B}}-\mathrm{R}}_{\mathrm{A}}\right)$	Water mass transport coefficient between ΩB
${\mathrm{k}}_2^{\mathrm{B}}$	${\mathrm{D}}_2^{\mathrm{B}}/\left({{\mathrm{R}}_{\mathrm{B}}-\mathrm{R}}_{\mathrm{A}}\right)$	Theophylline mass transport coefficient between ΩB
${\mathrm{K}}_1^{\mathrm{CD}}$	${\left(1/{\mathrm{k}}_1^{\mathrm{C}}+{\mathrm{m}}_1^{\mathrm{CD}}/{\mathrm{k}}_1^{\mathrm{D}}\right)}^{-1}$	Overall water mass transport coefficient between ΩC and ΩD
${\mathrm{K}}_2^{\mathrm{CD}}$	${\left(1/{\mathrm{k}}_2^{\mathrm{C}}+1/{\mathrm{k}}_2^{\mathrm{D}}\right)}^{-1}$	Overall Theophylline mass transport coefficient between ΩC and ΩD
${\mathrm{k}}_1^{\mathrm{C}}$	${\mathrm{D}}_1^{\mathrm{C}}/\left({{\mathrm{R}}_{\mathrm{C}}-\mathrm{R}}_{\mathrm{B}}\right)$	Water mass transport coefficient between ΩC
${\mathrm{k}}_2^{\mathrm{C}}$	${\mathrm{D}}_2^{\mathrm{C}}/\left({{\mathrm{R}}_{\mathrm{C}}-\mathrm{R}}_{\mathrm{B}}\right)$	Theophylline mass transport coefficient between ΩC
${\mathrm{k}}_1^{\mathrm{D}}$	${\mathrm{D}}_1^{\mathrm{D}}/{\mathrm{R}}_{\mathrm{C}}$	Water mass transport coefficient between ΩD
${\mathrm{k}}_2^{\mathrm{D}}$	${\mathrm{D}}_2^{\mathrm{D}}/{\mathrm{R}}_{\mathrm{C}}$	Theophylline mass transport coefficient between ΩD