Table 1.

Mathematical model of mean cumulative release rate versus time

Release medium	pH 7.4 PBS	0.1 mol/L HCl	pH 6.8 PBS	0.1 mol/L HCL (2 hours) pH 6.8 PBS (70 hours)
Zero-order kinetic model	Q = 0.0422t + 51.752 r = 0.8992	Q = 0.0539t + 49.479 r = 0.8109	Q = 0.0517t + 49.781 r = 0.8320	Q = 0.0939t + 493495 r = 0.7541
First-order kinetic model	ln(1 − Q) = −0.0009t + 3.8764 r = 0.9032	ln(1 − Q) = −0.0011t + 3.9222 r = 0.8193	ln(1 − Q) = −0.0011t + 3.9164 r = 0.8401	ln(1 − Q) = −0.0019t + 3.9212 r = 0.7666
Higuchi model	Q = 0.4087t1/2 + 51.078 r = 0.9618	Q = 0.5466t1/2 + 48.529 r = 0.9067	Q = 0.4946t1/2 + 48.978 r = 0.8785	Q = 0.9863t1/2 + 47.716 r = 0.8740
Hixcon-Crowell model	(100 − Q)1/3 = −0.0011t + 3.6405 r = 0.9019	(100 − Q)1/3 = −0.0013t + 3.6967 r = 0.8166	(100 − Q)1/3 = −0.0013t + 3.6894 r = 0.8374	(100 − Q)1/3 = −0.0023t + 3.6956 r = 0.7625
Ritger-Peppas model	ln Q = 0.0126 Int + 3.936 r = 0.9763	(100 − Q)1/3 = 0.0188t + 3.8833 r = 0.9786	(100 − Q)1/3 = 0.0161t + 3.894 r = 0.9086	(100 − Q)1/3 = 0.0347t + 3.865 r = 0.9679
Weibull model	lnln[1/(1 − Q)] = 0.0187t − 0.331 r = 0.9722	lnln[1/(1 − Q)] = 0.0272t − 0.4077 r = 0.9795	lnln[1/(1 − Q)] = 0.0234t − 0.3925 r = 0.9081	lnln[1/(1 − Q)] = 0.0504t − 0.4334 r = 0.9702

Note:Q means cumulative pyridostigmine release at time t.

Abbreviation: PBS, phosphate-buffered solution.