Model Higuchi

Special cases of such bilinear models are the McFarland model [McFarland, 1970], where b2 = 2b and p = 1 and the Higuchi-Davis model [Higuchi and Davis, 1970], where 2 = 1 and P = Vup / Vaq, which is the ratio between the volume of the lipid phase Viip and the volume of the aqueous phase Vaq. 

Drug release data have been analyzed according to different kinetic models Higuchi, Korsmeyer and Peppas Sahlin [6,113,114]. Table 4.3 shows the results obtained for these models. 

In vitro dissolution was virtually complete after 6-8 hr. Since the plot of cumulative drug release versus time is hyperbolic, the authors attempted to fit the data to the Higuchi matrix dissolution model (116,117), which predicts a linear correlation between cumulative drug release and the square root of time. Linearity occurred only between 20 and 70% release. 

Higuchi and Lachman [122] pioneered the approach of improving drug stability by complexation. They showed that aromatic esters can be stabilized in aqueous solutions in the presence of xanthines such as caffeine. Thus, the half-lives of benzocaine, procaine hydrochloride, and tetracaine are increased by approximately two- to fivefold in the presence of 2.5% caffeine. This increase in stability is attributed to the formation of a less reactive complex between caffeine and the aromatic ester. Professor K. A. Connors has written a comprehensive textbook that describes methods for the measurement of binding constants for complex formation in solution—along with discussions of pertinent thermodynamics, modeling statistics,... 

Higuchi applied this method to 2-naphthol as molecule A and used the resulting ratio for several compounds and complexes to treat mass transport data for com-plexation using a particular model. In general, ad hoc methods may be useful, particularly when dealing with a homologous series or a series of related compounds. 

The Higuchi-Hiestand model [43] permits the a priori estimation of the mass transport coefficient for the dissolution of finely divided drug particles. The model relates the particle radius, a(t), with time according to... 

T Higuchi, S Dayal, I Pitman. Effects of solute-solvent complexation reactions on dissolution kinetics Testing of a model by using a concentration jump technique. J Pharm Sci 61 695, 1972. 

Ho NFH, JY Park, PF Ni, WI Higuchi. (1983). Advancing quantitative and mechanistic approaches in interfacing gastrointestinal drug absorption studies in animals and man. In WG Crouthamel, A Sarapu, eds. Animal Models for Oral Drug Delivery in Man In Situ and In Vivo Approaches. Washington, DC APh/APS, pp 27-106. 

Komiya I, JY Park, NFH Ho, WI Higuchi. (1980). Quantitative mechanistic studies in simultaneous fluid flow and intestinal absorption using steroids as model solutes. Int J Pharm 4 249-262. 

S Suzuki, WI Higuchi, NFH Ho. Theoretical model studies of drug absorption and transport in the gastrointestinal tract. I. J Pharm Sci 59 644-651, 1970. 

PF Ni, NFH Ho, JF Fox, H Leuenberger, WI Higuchi. Theoretical model studies of intestinal drug absorption. V. Nonsteady-state fluid flow and absorption. Int J Pharm 5 33-47, 1980. 

Ho, N. F., Higuchi, W. I., Quantitative interpretation of in vivo buccal absorption of n-alkanoic acids by the physical model approach, /. Pharm. Sci. 1971, 60, 537-541. 

Suzuki A, Higuchi WI and Ho NF (1970a) Theoretical Model Studies of Drug Absorption and Transport in the Gastrointestinal Tract. I. J Pharm Sc. 59 pp 644-651. 

Ni PF, Ho NF, Fox JL, Leuenberger H and Higuchi WI (1980) Theoretical Model Studies of Intestinal Drug Absorption 5. Non-Steady-State Fluid Flow and Absorption. Int J Pharm 5 pp 33-48. 

Komiya I, Park JY, Kamani A, Ho NF and Higuchi WI (1980) Quantitative Mechanistic Studies in Simultaneous Fluid Flow and Intestinal Absorption Using Steroids As Model Solutes. Int J Pharm 4 pp 249-262. 

Tsutsumi K, Li SK, Ghanem AH, Ho NFH, Higuchi WI (2003) A systematic examination of the in vitro Ussing chamber and the in situ single-pass perfusion model systems in rat ileum permeation of model solutes. J Pharm Sci 92 344-359. 

Higuchi, M., O Brien, D., Kumaravelu, P., Lenny, N., Yeoh, E.-J. and Downing, J. (2002) Expression of a conditional AMLl-ETO oncogene bypasses embryonic lethality and establishes a murine model of human t(8 21) acute myeloid leukemia. Cancer Cell 1, 63-74. 

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