The word "correlation" is used for the relationship between two variables. The strength of the relationship (linear) between the variables is given by "r".
(D. Brockmeier et al.)Change in pH, formulation agitation, Motility and Absorption rate constant of gastrointestinal tract are helpful in determining the in vitro in vivo biphasic linear correlation.
(K. Ishii et al.)Novel approaches by the use of Mathematical deconvolution method (Deconvolution is an algorithm based process for the reversal of effects of convolution. It is used for the techniques of signal processing and image processing. It uses fourier transform mathematics to restore a blurred image to an unblurred state as much as possible. It is used in optimization techniques by the researchers.) have been used for the study of in vitro and in vivo correlation studies. It has been found that kappa d shows better correlation between in vitro and in vivo data for ibuprofen capsules as compared to dissolution time at 50 % (t50%).
Reza A. Fassihi et al. found that triple layer model shows good correlation between in vitro and in vivo results.
H. Lennernäs et al. in their studies found that passivley or rapidly transported drugs show comparable permeability co-efficients in vitro (in Caco-2 monolayers) and in vivo (in human jejunum) whereas actively transported drugs show slow carrier mediated transport rates in vitro than in vivo.
D. Brockmeier, H.J. Dengler, D. Voegele. In vitro--in vivo correlation of dissolution, a time scaling problem? Transformation of in vitro results to the in vivo situation, using theophylline as a practical example. European Journal of Clinical Pharmacology 1985;28(3), Pages 291-300.
H. Lennernäs, , K. Palm, U. Fagerholm and P. Artursson, Comparison between active and passive drug transport in human intestinal epithelial (caco-2) cells in vitro and human jejunum in vivo. International Journal of Pharmaceutics, Volume 127, Issue 1, 15 January 1996, Pages 103-107.
K. Ishii, Y. Saitou, R. Yamada, S. Itai, M. Nemoto. Novel approach for determination of correlation between in vivo and in vitro dissolution using the optimization technique. Chemical and Pharmaceutical bulletin (Tokyo). 1996 Aug;44(8):1550-5.
Reza A. Fassihi, Wolfgang A. Ritschel, Multiple-layer, direct-compression, controlled-release system: In vitro and in vivo evaluation.
Journal of Pharmaceutical Sciences, 2006, Volume 82 Issue 7, Pages 750 - 754.
Pharmaceutical Principles of Solid Dosage Forms by Jens T. Carstensen
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