Drug absorption, and

Chan LM, Lowes S, Hirst BH (2004) The ABCs of drug transport in intestine and liver efflux proteins limiting drug absorption and bioavailability. Eur J Pharm Sci 21 25—51... 

Van de Waterbeemd, H., Smith, D. A., Beaumont, K., Walker, D. K. Property-based design optimization of drug absorption and pharmacokinetics. 

Dietary modification can improve constipation, nausea, erratic drug absorption, and minimize the risk of aspiration... 

Opioids maybe administered in a variety of routes including oral (tablet and liquid), sublingual, rectal, transdermal, transmucosal, intravenous, subcutaneous, and intraspinal. While the oral and transdermal routes are most common, the method of administration is based on patient needs (severity of pain) and characteristics (swallowing difficulty and preference). Oral opioids have an onset of effect of 45 minutes, so intravenous or subcutaneous administration maybe preferred if more rapid relief is desired. Intramuscular injections are not recommended because of pain at the injection site and wide fluctuations in drug absorption and peak plasma concentrations achieved. More invasive routes of administration such as PCA and intraspinal (epidural and intrathecal) are primarily used postoperatively, but may also be used in refractory chronic pain situations. PCA delivers a self-administered dose via an infusion pump with a preprogrammed dose, minimum dosing interval, and maximum hourly dose. Morphine, fentanyl, and hydromorphone are commonly administered via PCA pumps by the intravenous route, but less frequently by the subcutaneous or epidural route. 

Factors Influencing Drug Absorption and Drug Availability... 

VI. PHYSICOCHEMICAL VERSUS BIOCHEMICAL FACTORS INFLUENCING DRUG ABSORPTION AND DRUG AVAILABILITY... 

Gel-Forming Solutions. One disadvantage of solutions is their relatively short residence time in the eye. This has been overcome to some degree by the development of solutions that are liquid in the container and thus can be instilled as eyedrops but gel on contact with the tear fluid and provide increased contact time with the possibility of improved drug absorption and increased duration of therapeutic effect. 

B. Hoener and L. Z. Benet, Factors influencing drug absorption and drug availability, in Modern Pharmaceutics (G. S. Banker and C. T. Rhodes, eds.), Marcel Dekker, New York, 1979, pp. 143-182. 

Borchardt, R. T. Smith, P. L. Wilson, G., Models for Assessing Drug Absorption and Metabolism, Plenum Press, New York, 1996. 

Colonic Drug Absorption and Metabolism, edited by Peter R. Bieck... 

GL Flynn. Topical drug absorption and topical pharmaceutical systems. In GB Banker, CT Rhodes, eds. Modem Pharmaceutics. New York Marcel Dekker, 1990, pp 263-326. 

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. 

Artursson, P. and R. T. Borchardt. Intestinal drug absorption and metabolism in cell cultures Caco-2 and beyond, Pharm. Res. 1997, 34, 1655-1658... 

The most commonly used methods for studies of partitioning into a membrane, mechanisms of drug absorption, and interactions with epithelial proteins, such as transporters and enzymes, are the cell culture-based models. These are both sim-... 

Griffiths, R., Lewis, A., Jeffrey, P., Models for drug absorption in situ and in conscious animals, in Models for Assessing Drug Absorption and Metabolism. Borchard, R. T., Smith, P. L., Wilson, G. (eds), Plenum Press, New York, 1996, pp. 67-84. 

Fig. 7.5. The Biopharmaceutics Classification System (BCS) provides a scientific basis for predicting intestinal drug absorption and for identifying the rate-limiting step based on primary biopharmaceutical properties such as solubility and effective intestinal permeability (Pefr). BCS serves as a product control instrument. The BCS divides drugs into four different classes based on their solubility and...

K. M., Role of organic cation transporters in drug absorption and... 

Application of ultra-high-throughput in silico estimation of biopharmaceutical properties to the generation of rule-based computational alerts has the potential to improve compound selection to those drug candidates that are likely to prove less troublesome in their development. The extension of purely in silico methods to the realm of mechanistic simulation further enhances our ability to predict the impact of physiological and biochemical process on drug absorption and bioavailability. 

Oral bioavailability of a drug is primarily dependent upon its rate and extent of drug absorption and systemic clearance. Systemic clearance is primarily composed of hepatic, renal and biliary clearance. The PK properties are in turn directly impacted by the drug s physical properties, such as, log P, log D and pKa. The physical properties are in turn a function of the compound s structure, molecular weight, number of hydrogen bond donors and acceptors, and number of rotatable bonds. Oral bioavailability is the outcome from the dynamic interplay of these factors in the biological system. 

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