Absorption and Excretion of Drugs. XIX. Some Pharmacokinetic Aspects of Absorption and Excretion of Sulfonamides. (1). Absorption from Rat Stomach.

Koizumi, Tamotsu; Arita, Takaichi; Kakemi, Kiichiro

doi:10.1248/cpb.12.413

Cited by 79 publications

(15 citation statements)

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“…The pKa values for SP and AcSP were estimated from chloroform/aqueous buffer partition coefficient data at 37° C and were 8.2 and 7.7, respectively (Table VI). The former value is in good agreement with the literature value of 8.43 determined at 25° C. 19 As demonstrated for SP (Table VI) and for other sulfonamides by Despopoulos and Callahan , 9 N4-acetylation apparently increases the acidity of most sulfonamides. Equation 1 does not account for the degree of lipid solubility of the drug, which has been shown for several sulfonamides 16 , 18,23 and barbiturates 23 to strongly affect drug diffusion across the salivary epithelium.…”

Section: Resultssupporting

confidence: 91%

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Salivary excretion and pharmacokinetics of sulfapyridine after sulfasalazine

Bates

Blumenthal

Pieniaszek

1977

Clin Pharma and Therapeutics

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The concentrations of sulfapyridine (SP) and N4-acetylsulfapyridine (AcSP) in the plasma and saliva of 5 healthy male adults (3 slow and 2 rapid acetylators) were determined as a function of time after a single 2.0-gm oral dose of sulfasalazine (salicylazosulfapyridine). SP absorption commenced 3.5 to 6 hr after sulfasalazine administration and occurred slowly (apparent absorption t1/2s ranged from 1.6 to 5 hr) irrespective of acetylator phenotype. Appreciable differences existed between slow and rapid acetylators with respect to the biologic t1/2 and total body clearance of SP. SP concentrations in the saliva correlated well with those in the plasma. The saliva:plasma concentration ratio for SP was 0.559 +/- 0.027 (mean of 5 subjects +/- SE) and was dependent of plasma concentration and saliva pH. The mean saliva:plasma concentration ratio for AcSP was lower (0.246 +/- 0.056), consistent with the pH-partition hypothesis, and showed considerably more intrasubject and intersubject variation than the ratio for SP. These findings suggest that measurement of SP concentrations in the saliva may be a convenient, noninvasive method for monitoring indirectly the steady-state plasma (serum) concentrations of SP in patients with ulcerative colitis or Crohn's disease who are receiving sulfasalazine.

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Section: Resultssupporting

confidence: 91%

“…The average saliva: plasma concentration ratio for AcSP (0.246 ± 0.056) was approxi- tReported pKa value for SP at 25° is 8.43. 19 mately 44% of the average ratio for SP (0.559 ± 0.027) and showed considerably more intrasubject and intersubject variation (Table IV and V).…”

Section: Resultsmentioning

confidence: 97%

Salivary excretion and pharmacokinetics of sulfapyridine after sulfasalazine

Bates

Blumenthal

Pieniaszek

1977

Clin Pharma and Therapeutics

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“…The phosphate buffers of pH 5.5, 6.4 and 7.4 used by Koizumi et al (1964a) were diluted with saline (system-I) or isotomic mannitol solution (system-11) to minimize the difference of sodium ion concentration among the three buffers. The phosphate buffers of pH 5.5, 6.4 and 7.4 used by Koizumi et al (1964a) were diluted with saline (system-I) or isotomic mannitol solution (system-11) to minimize the difference of sodium ion concentration among the three buffers.…”

Section: Effect Of P H On Water Movement and On Mercury Absorption Anmentioning

confidence: 99%

Mechanisms of Absorption of Inorganic Mercury from Rat Small Intestine. I. Solvent Drag Effect on Absorption of Inorganic Mercury

Endo

Nakaya

Kimura

1988

Pharmacology & Toxicology

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A correlation of mercury absorption with water absorption was investigated by using the perfusion of rat small intestine with buffers containing 10(-4) M HgCl2. With a decrease in the osmolarity of the buffers or with increases in the sodium ion and urea concentrations in the buffers, absorption of water and mercury and accumulation of mercury in the intestinal tissue increased, and the increases in mercury absorption and accumulation were found to correlate with the increase in water absorption. Both the decrease in osmolarity and the increase in sodium ion concentration increased mercury accumulation in the epithelial cell after the perfusion. But these changes did not alter the mercury distribution in subcellular fractions. The results suggest that the increase in water absorption due to the hyptonicity or the increase in concentration of sodium ion or urea increases the mercury absorption and accumulation in the epithelial cell without change in the distributional pattern of mercury in the cell.

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“…The following equation has been proposed with respect to the drug absorption from the stomach and small intestine via passive diffusion [29,30] on the basis of the principle that the diffusibility of a substance in uniform solutions is approximately inversely proportional to the square root of the molecular weight of the drug…”

Section: Relationship Between Molecular Weights and Absorption Rate Omentioning

confidence: 99%

Absorption characteristics of compounds with different molecular weights after application to the unilateral kidney surface in rats

Nishida

Tomiyama

Mukai

et al. 2004

European Journal of Pharmaceutics and Biopharmaceutics

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The aim of the present study is to clarify the absorption mechanism of a drug from the kidney surface membrane in rats. We studied the absorption characteristics of phenolsulfonphthalein (PSP) and other compounds with different molecular weights after their application to the rat kidney surface in vivo, employing a cylindrical diffusion cell (i.d. 6 mm, area 0.28 cm 2 ). The time course of free PSP amounts remaining in the diffusion cell obeyed first-order kinetics at a dose of 1 mg, and its rate constant k a was calculated to be 0.0137 min -1 . Absorption ratios of PSP in 4 h were calculated from the amount recovered from the diffusion cell to be 91.4, 96.4 and 97.7 % at doses of 0.5, 1 and 1.5 mg, respectively.The area under the curve for the plasma concentration profile of free PSP was proportional to the application dose. It is thus suggested that the absorption process of PSP from the rat kidney surface does not approach saturation at a dose of 1.5 mg. Also, no significant difference was seen in the k a values within the dose range of 0.5 -1.5 mg, which were estimated by curve-fitting the plasma concentration profiles of free PSP in a two-compartment model with first-order absorption. Furthermore, we examined the importance of molecular weight on the absorption from the kidney surface using fluorescein isothiocyanate-dextrans (FDs) with molecular weights of 4,400 (FD-4), 11,000 (FD-10), 40,500 (FD-40) or 69,000(FD-70), including the organic anions bromphenol blue and bromosulfonphthalein. The absorption ratios of FDs from the rat kidney surface in 6 h decreased with an increase in the molecular weight (76.1 % for FD-4, 54.4 % for FD-10, 11.5 % for FD-40 and 3.9 % for FD-70). A linear relationship was observed between the k a and the reciprocal value with the square root of the molecular weight of these compounds. The limit of absorption from the rat kidney surface was extrapolated to be at a molecular weight of approximately 130,000.

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Absorption and Excretion of Drugs. XIX. Some Pharmacokinetic Aspects of Absorption and Excretion of Sulfonamides. (1). Absorption from Rat Stomach.

Cited by 79 publications

References 0 publications

Salivary excretion and pharmacokinetics of sulfapyridine after sulfasalazine

Salivary excretion and pharmacokinetics of sulfapyridine after sulfasalazine

Mechanisms of Absorption of Inorganic Mercury from Rat Small Intestine. I. Solvent Drag Effect on Absorption of Inorganic Mercury

Absorption characteristics of compounds with different molecular weights after application to the unilateral kidney surface in rats

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