Pharmacokinetics absorption

Inhaled tobramycin (TOBI ) is typically administered to patients 6 years of age and older in alternating 28-day cycles of 300 mg nebulized twice daily, followed by a 28-day washout or off period to minimize development of resistance. Longterm intermittent administration improves pulmonary function, decreases microbial burden, and reduces the need for hospitalization for IV therapy.24,25 Due to minimal systemic absorption, pharmacokinetic monitoring is not necessary with normal renal function. Lower doses of nebulized tobramycin solution for injection have been used in younger children, and studies are underway using 300 mg twice daily in children under age 6. 

Wright, J. D., Ma, T., Chu, C. K., Boudinot, F. D., Discontinuous oral absorption pharmacokinetic model and bioavailability of l-(2-fluoro-5-methyl-beta-L-arabinofuranosyl)uradl (L-FMAU) in rats, Biopharm. Drug Dispos. 1996, 17, 197-207. 

C(t) modeled according to two-compartment model with zero-order and first-order absorption Pharmacokinetic/pharmacodynamic relationship modeled using Hill model with first-order absorption. Modeled parameters matched experimental parameters when bicompartmental model with zero-order input was used. Linear PKs, anticlockwise hysteresis loop established for all doses studied. Apomorphine and growth hormone concentration predicted with good accuracy... 

Table 1 Nicotine absorption pharmacokinetics of different forms of nicotine administration in single doses (modified from Hukkanen et al. 2005c)...

Pharmacokinetics No studies have investigated the absorption/pharmacokinetics of chloroxine. 

Hellriegel et al. (1996) observed a signiLcant inverse linear relationship between the bioavailability of a drug and its coefLcient of variation. An insoluble drug with very low oral bioavailability usually has a very large intersubject variability in its absorption pharmacokinetic parameters, which may result in a worrisome safety proLle or unfavorable efLcacy. 

These linear kinetic models and diffusion models of skin absorption kinetics have a number of features in common they are subject to similar constraints and have a similar theoretical basis. The kinetic models, however, are more versatile and are potentially powerful predictive tools used to simulate various aspects of percutaneous absorption. Techniques for simulating multiple-dose behavior evaporation, cutaneous metabolism, microbial degradation, and other surface-loss processes dermal risk assessment transdermal drug delivery and vehicle effects have all been described. Recently, more sophisticated approaches involving physiologically relevant perfusion-limited models for simulating skin absorption pharmacokinetics have been described. These advanced models provide the conceptual framework from which experiments may be designed to simultaneously assess the role of the cutaneous vasculature and cutaneous metabolism in percutaneous absorption. 

A. Rousseau, F. Leger, Y. Le Meur, F. Saint-Marcoux, G. Paintaud, M. Buchler, and P. Marquet, Population pharmacokinetic modeling of oral cyclosporin using NONMEM comparison of absorption pharmacokinetic models and design of a Bayesian estimator. 

For all routes of administration, the absorption, distribution, and elimination kinetics are important for obtaining the desired therapeutic effect. For drugs expected to act in the eye after ocular absorption, pharmacokinetic parameters are difficult to obtain in both animals and humans. Accordingly, it has been proposed to rely essentially on pharmacodynamic measurements by use of a specific biological response after topical administration (258,259). For example, the apparent absorp-... 

Phelps, S.J. Alpert, B.S. Ward, J.L. Pieper, J.A. Lima, J.J. Absorption pharmacokinetics of atenolol in patients with the Marfan s3mdrome. J.Clin.PharmacoL, 1995, 35, 268-274... 

Carver, M.P., Williams, PL., and Riviere, J.E., 1989, The isolated perfused porcine skin flap (IPPSF). 111. Percutaneous absorption pharmacokinetics of organophosphates, steroids, benzoic add and caffeine, Toxicol Appl Pharmacol, 97 324—337. 

High absorption, pharmacokinetic profile comparable with intravenous injection - + (for lipophilic substances)... 

Konikoff MR, Denson LA (2006) Role of fecal calprotectin as a biomarker of intestinal inflammation in inflammatory bowel disease. Inflamm Bowel Dis 12 524-534 Kunta JR, Perry BA, Sutyak JP, Sinko PJ (2001) Development of a novel intestinal and vascular access port (IVAP) rabbit model to study regiospecific oral absorption pharmacokinetics. Comp Med 51(4) 349-356... 

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