caa a22 4500 477126219 CHVBK 20180405111650.0 cr unu---uuuuu 170330e19970901xx s 000 0 eng 10.1023/A:1012182102257 doi (NATIONALLICENCE)springer-10.1023/A:1012182102257 A Population Growth Model of Dissolution [Elektronische Daten] [Aristides Dokoumetzidis, Panos Macheras] Purpose. To develop a new approach for describing drug dissolution which does not require the presuppositions of time continuity and Fick's law of diffusion and which can be applied to both homogeneous and heterogeneous media. Methods. The mass dissolved is considered to be a function of a discrete time index specifying successive 'generations' (n). The recurrence equation: Φ n+1 = Φ n + r(l − Φn)(1 − Φn X 0/θ) was derived for the fractions of dose dissolved Φ n and Φn +1, between generations n and n + 1, where r is a dimensionless proportionality constant, X 0 is the dose and θ is the amount of drug corresponding to the drug's solubility in the dissolution medium. Results. The equation has two steady state solutions, Φ ss = 1 when (X 0/θ) ≤ 1 and Φ ss = θ/X 0 when (X 0/θ) > 1 and the usual behavior encountered in dissolution studies, i.e, a monotonic exponential increase of Φ n reaching asymptotically the steady state when either r < θ/X 0 < 1 or r < 1 < θ/X 0. Good fits were obtained when the model equation was applied to danazol data after appropriate transformation of the time scale to 'generations'. The dissolution process is controlled by the two dimensionless parameters θ/X 0 and r, which were found to be analogous to the fundamental parameters dose anddissolution number, respectively. The model was also used for the prediction of fraction of dose absorbed for highly permeable drugs. Conclusions. The model does not rely on diffusion principles and therefore it can be applied under both homogeneous and non-homogeneous conditions. This feature will facilitate the correlation of in vitro dissolution data obtained under homogeneous conditions and in vivo observations adhering to the heterogeneous milieu of the GI tract. Plenum Publishing Corporation, 1997 dissolution nationallicence model nationallicence growth nationallicence fraction absorbed nationallicence in vitro-in vivo correlations nationallicence Dokoumetzidis Aristides Department of Physics, University of Athens, Athens, Greece aut Macheras Panos Department of Pharmacy, University of Athens, Panepistimiopolis, 15771, Athens, Greece aut Pharmaceutical Research Kluwer Academic Publishers-Plenum Publishers 14/9(1997-09-01), 1122-1126 0724-8741 14:9<1122 1997 14 11095 https://doi.org/10.1023/A:1012182102257 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1012182102257 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Dokoumetzidis Aristides Department of Physics, University of Athens, Athens, Greece aut NATIONALLICENCE 700 1- Macheras Panos Department of Pharmacy, University of Athens, Panepistimiopolis, 15771, Athens, Greece aut NATIONALLICENCE 773 0- Pharmaceutical Research Kluwer Academic Publishers-Plenum Publishers 14/9(1997-09-01), 1122-1126 0724-8741 14:9<1122 1997 14 11095 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer