Solubility drug absorption

He X, Kadomura S, Takekuma Y, Sugawara M, Miyazaki K (2004) A new system for the prediction of drug absorption using a pH-controlled Caco-2 model Evaluation of pH-dependent soluble drug absorption and pH-related changes in absorption. J Pharm Sci 93 71-77. 

Only a small amount of drug can be absorbed in any one administration For a fat-soluble drug, absorption is rapid and effective Can cause damage when the drug is irritating or disrupts blood flow May be used for many drugs in pill form... 

The concept of maximum absorbable dose (MAD) relates drug absorption to solubility via [27, 28] ... 

An analysis of the solubility and absorption rates for the 254 drugs considered here shows that the 25 compounds fulfilling the condition of 0.25a - XQ > 5.0 and HQi > 20.0 have solubility of only a few micrograms per milHHter, and are absorbed at the level of only a few percents. Such properties are too poor for drug development, so these parameters can be useful as an alert in computer-aided compound selection. 

In Drug EioavailabiliPy, Estimation of Solubility, Permeability, Absorption and Bioavailability (Methods and Principles in Medicinal Chemistry), Van der Waterbeemd, H., Lennernas, H., Artursson, P. (eds.), Wiley-VCH, Weinheim, 2003, pp. 358-405. 

Fig. 12 Illustration of the Biopharmaceutical Classification System (BCS), which classifies drug absorption potential on the basis of aqueous solubility or membrane permeability. (Copyright 2000 Saguaro Technical Press, Inc., used with permission.)...

These mixing motions will tend to improve drug absorption for two reasons. Any factor that increases rate of dissolution will increase the rate (and possibly the extent) of absorption, especially for poorly water-soluble drugs (BCS Classes II and IV). Since rate of dissolution depends on agitation intensity, mixing movements will tend to increase dissolution rate and thereby influence absorption. As rate of absorption depends directly on membrane surface area, and since mixing increases the contact area between drug and... 

The subject of this book is to examine the components of the multimechanistic processes related to solubility, permeability, and charge state, with the aim of advancing improved strategies for in vitro assays related to drug absorption. 

Figure 7.15 Kinetics of transport across a filter-immobilized artificial membrane (a) desipramine and (b) dihydromethysticin concentrations in acceptor well. [Reprinted from Avdeef, A., in van de Waterbeemd, H. Lennemas, H. Artursson, R (Eds.). Drug Bioavailability. Estimation of Solubility, Permeability, Absorption and Bioavailability. Wiley-VCH Weinheim, 2003 (in press), with permission from Wiley-VCH Verlag GmbH.]...

---