Table I.

Models Available in DDSolver for Fitting Drug Release Data^a

Module	Model	Equation	Parameter(s)	Reference(s)
# 301b	Zero-order		k 0	(15)
# 302b, c	Zero-order with Tlag		k 0, T lag	(16)
# 303b, d	Zero-order with F0		k 0, F 0	(13)
# 304e	First-order		k 1	(8)
# 305c, e	First-order with T lag		k 1, T lag	(17)
# 306e, f	First-order with F max		k 1, F max	(18)
# 307c, e, f	First-order with T lag and F max		k 1, T lag, F max	(19)
# 308g	Higuchi		k H	(12)
# 309c, g	Higuchi with T lag		k H, T lag	(20)
# 310d, g	Higuchi with F 0		k H, F 0	(21)
# 311h	Korsmeyer–Peppas		k KP, n	(22,23)
# 312c, h	Korsmeyer–Peppas with T lag		k KP, n, T lag	(20)
# 313d, h	Korsmeyer–Peppas with F 0		k KP, n, F 0	(13)
# 314i	Hixson–Crowell		k HC	(24)
# 315c, i	Hixson–Crowell with T lag		k HC, T lag	(25)
# 316j	Hopfenberg		k HB, n	(26)
# 317c, j	Hopfenberg with T lag		k HB, n, T lag	(27)
# 318k	Baker–Lonsdale		k BL	(28)
# 319c, k	Baker–Lonsdale with T lag		k BL, T lag	(28)
# 320l	Makoid–Banakar		k MB, n, k	(29)
# 321c, l	Makoid–Banakar with T lag		k MB, n, k, T lag	(29)
# 322m	Peppas–Sahlin_1		k 1, k 2, m	(30)
# 323c, m	Peppas–Sahlin_1 with T lag		k 1, k 2, m, T lag	(21)
# 324n	Peppas–Sahlin_2		k 1, k 2	(30)
# 325c, n	Peppas–Sahlin_2 with T lag		k 1, k 2, T lag	(30)
# 326o	Quadratic		k 1, k 2	(8,13)
# 327c, o	Quadratic with T lag		k 1, k 2, T lag	(8)
# 328p, q	Weibull_1		α, β, Ti	(31)
# 329p	Weibull_2		α, β	(11)
# 330f, p	Weibull_3		α, β, F max	(18)
# 331f, p, q	Weibull_4		α, β, Ti, F max	(32)
# 332r	Logistic_1		α, β	(11)
# 333f, r	Logistic_2		α, β, F max	(18,33)
# 334f, s	Logistic_3		k, γ, F max	(8,32)
# 335t	Gompertz_1		α, β	(18)
# 336f, t	Gompertz_2		α, β, F max	(18,19)
# 337f, u	Gompertz_3		k, γ, F max	(8,32)
# 338f, v	Gompertz_4		k, β, F max	(34)
# 339w	Probit_1		α, β	(11,18)
# 340f, w	Probit_2		α, β, F max	(18)

^aIn all models, F is the fraction(%) of drug released in time t

^b k ₀ is the zero-order release constant

^c T _lag is the lag time prior to drug release

^d F ₀ is the initial fraction of the drug in the solution resulting from a burst release

^e k ₁ is the first-order release constant

^f F _max is the maximum fraction of the drug released at infinite time

^g k _H is the Higuchi release constant

^h k _KP is the release constant incorporating structural and geometric characteristics of the drug-dosage form; n is the diffusional exponent indicating the drug-release mechanism

ⁱ k _HC is the release constant in Hixson–Crowell model

^j k _HB is the combined constant in Hopfenberg model, k _HB = k ₀/(C ₀ × a ₀), where k ₀ is the erosion rate constant, C ₀ is the initial concentration of drug in the matrix, and a ₀ is the initial radius for a sphere or cylinder or the half thickness for a slab; n is 1, 2, and 3 for a slab, cylinder, and sphere, respectively

^k k _BL is the combined constant in Baker–Lonsdale model, k _BL = [3 × D × Cs/(r ²₀ × C ₀)], where D is the diffusion coefficient, Cs is the saturation solubility, r ₀ is the initial radius for a sphere or cylinder or the half-thickness for a slab, and C ₀ is the initial drug loading in the matrix

^l k _MB, n, and k are empirical parameters in Makoid–Banakar model (k _MB, n, k > 0)

^m k ₁ is the constant related to the Fickian kinetics; k ₂ is the constant related to Case-II relaxation kinetics; m is the diffusional exponent for a device of any geometric shape which inhibits controlled release

ⁿ k ₁ is the constant denoting the relative contribution of t ^0.5-dependent drug diffusion to drug release; k ₂ is the constant denoting the relative contribution of t-dependent polymer relaxation to drug release

^o k ₁ is the constant in Quadratic model denoting the relative contribution of t ²-dependent drug release; k ₂ is the constant in Quadratic model denoting the relative contribution of t-dependent drug release

^p α is the scale parameter which defines the time scale of the process; β is the shape parameter which characterizes the curve as either exponential (β = 1; case 1), sigmoid, S-shaped, with upward curvature followed by a turning point (β > 1; case 2), or parabolic, with a higher initial slope and after that consistent with the exponential (β < 1; case 3)

^q Ti is the location parameter which represents the lag time before the onset of the dissolution or release process and in most cases will be near zero

^r α is the scale factor in Logistic 1 and 2 models; β is the shape factor in Logistic 1 and 2 models

^s k is the shape factor in Logistic 3 model; γ is the time at which F = F _max/2

^t α is the scale factor in Gompertz 1 and 2 models; β is the shape factor in Gompertz 1 and 2 models

^u k is the shape factor in Gompertz 3 model; γ is the time at which F = F _max/exp(1) ≈ 0.368 × F _max

^v β is the scale factor in Gompertz 4 model; k is the shape factor in Gompertz 4 model

^wФ is the standard normal distribution; α is the scale factor in Probit model; β is the shape factor in Probit model