“…In vitro–in vivo correlations (IVIVCs) are correlations between in vitro dissolution data and in vivo release kinetics, estimated by the deconvolution of pharmacokinetic IVIVCs were constantly recommended by regulatory authorities in the last decades when developing extended-release formulations ( US Food and Drug Administration, 1997a ; US Food and Drug Administration, 1997b ; European Medicines Agency, 2014a ; European Medicines Agency, 2014b ). The correlation can be good and even linear ( Humbert et al, 1994 ; Eddington et al, 1998 ; Emami 2006 ) or nonlinear [ Lake et al, 1999 ; Varshosaz et al, 2000 ; Rao et al, 2001 ; Al-Behaisi et al, 2002 ], or even obscure ( Eddington et al, 1998 ; Mircioiu et al, 2005 ; Meyer et al, 1998 ; Mircioiu et al, 2018 ). Complex models were proposed in cases of nonlinearity ( Polli et al, 1996 ; Dunne et al, 1997 ; Dunne et al, 1999 ), but the number of parameters of models is higher, and the fitting algorithms are more unstable ( Sandulovici et al, 2009 ; Tvrdonova et al, 2009 ).…”