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Okamoto, Hirokazu; Mori, Kiyoko; Ohtsuka, Kumiko; Ohuchi, Hiroyuki; Ishii, Hiroaki

doi:10.1023/a:1012037819211

Cited by 13 publications

(3 citation statements)

References 2 publications

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“…The amounts of NaCl to be added were calculated using the computer program reported elsewhere. 19) When the drugs were dissolved in propylene glycol, the concentration was fixed at 5%.…”

Section: Methodsmentioning

confidence: 99%

Effect of Sucrose Fatty Acid Esters on Transdermal Permeation of Lidocaine and Ketoprofen

Okamoto

Sakai

Danjo

2005

Biological & Pharmaceutical Bulletin

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Skin has many advantages as a site for local and systemic drug administration. However, the barrier properties of the outermost layer, the stratum corneum, have limited the number of successful transdermal dosage forms developed thus far. One of the strategies for overcoming this problem is temporary local reduction of the barrier function of the stratum corneum with the aid of a percutaneous absorption enhancer.Sucrose fatty acid esters (sugar esters) are nonionic surfactants with sucrose as the polar head group and one or several fatty acid chains as the lipophilic moiety. Some of them are legally approved as food additives due to their high safety 1) and are registered as pharmaceutical excipients in Japan, USA, Canada, Australia, and New Zeeland.2) Sugar esters have low irritancy to the skin and eyes. 1) There have been several reports or patents about utilizing sugar esters as additives for drug formulations. Some sugar esters enhance gastrointestinal absorption of elastase 3) and blactam antibiotics.4) The nasal mucosal absorption of peptides such as calcitonin, 5) interferon, 6) and a-human atrial natriuretic polypeptide 7) are increased by sucrose laurate or sucrose stearate. Sucrose palmitate enhances the absorption of calcitonin from the oral mucosa 8) and gingiva 9) in rats. Ganem-Quintanar et al. examined the effect of sucrose stearate, oleate, palmitate, and laurate on the permeation of lidocaine hydrochloride through excised pig palate and cheek and reported that only sucrose laurate acted as an absorption enhancer.10) Some sugar esters act as percutaneous absorption enhancers. It has been reported that sucrose stearate and sucrose laurate increase percutaneous absorption of bromhexine in rats 11) and oestradiol in rabbits, 12) respectively. The percutaneous absorption of diltiazem and hydromorphone are also aided by some sugar esters. 13,14) Nakada et al. examined the effect of more than 10 sugar esters with HLB ranging 2 to 16 on the absorption of calcitonin from oral mucosa in rats.8) An enhancing effect was found for sugar esters with HLB values ranging from 11 to 16. However, the effect of the length of the fatty acid chain and HLB of sugar esters on their activity as percutaneous absorption enhancers has not been reported.In the present study, we selected six sugar esters with HLB 5-16 and evaluated their effect on percutaneous drug permeation in in vitro experiments using excised hairless mouse skin. We employed lidocaine (LC, pK a ϭ7.9) 15) and ketoprofen (KP, pK a ϭ4.0) 16) as model basic and acidic drugs, respectively. The drugs were dissolved in buffer solutions with several pHs so that we could evaluate the effect of the sugar esters on the percutaneous permeation of ionized and unionized drug species.It has been reported that sugar esters form micelles in water and in an organic solvent.17) The micelles would affect the thermodynamic properties of a penetrant in a vehicle. To examine the effect of sugar esters on skin permeability and to minimize the effect on vehicle or interaction wi...

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“…The amounts of NaCl to be added were calculated using the computer program reported elsewhere. 19) When the drugs were dissolved in propylene glycol, the concentration was fixed at 5%.…”

Section: Methodsmentioning

confidence: 99%

Effect of Sucrose Fatty Acid Esters on Transdermal Permeation of Lidocaine and Ketoprofen

Okamoto

Sakai

Danjo

2005

Biological & Pharmaceutical Bulletin

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“…Most of these studies explored temperature effects on one of two types of electrolyte properties, but not on both. These two types are (1) weak electrolyte pK (e.g., Okamoto et al 25 ) and (2) the "actual" mobility of fully ionized electrolytes. (e.g., Anderko and Lencka 26 ) In Table 1, we indicate with a dash if temperature effects on an electrolyte property were not considered in (or if property was not relevant to) the study.…”

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confidence: 99%

Temperature Effects on Electrophoresis

Rogacs

Santiago

2013

Anal. Chem.

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We present a model capturing the important contributors to the effects of temperature on the observable electrophoretic mobilities of small ions, and on solution conductivity and pH. Our temperature model includes relations for temperature-dependent viscosity, ionic strength corrections, degree of ionization (pK), and ion solvation effects on mobility. We incorporate thermophysical data for water viscosity, temperature-dependence of the Onsager-Fuoss model for finite ionic strength effects on mobility, temperature-dependence of the extended Debye-Huckel theory for correction of ionic activity, the Clarke-Glew approach and tabulated thermodynamic quantities of ionization reaction for acid dissociation constants as a function of temperature, and species-specific, empirically evaluated correction terms for temperature-dependence of Stokes' radii. We incorporated our model into a MATLAB-based simulation tool we named Simulation of Temperature Effects on ElectroPhoresis (STEEP). We validated our model using conductivity and pH measurements across a temperature variation of 25-70 °C for a set of electrolytes routinely used in electrophoresis. The model accurately captures electrolyte solution pH and conductivity, including important effects not captured by simple Walden-type relations.

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“…Others have expanded Van Slyke's work, applying the concept of buffer capacity to various areas (27,29,(33)(34)(35)(36). Fortunately, the advent of spreadsheets has made short work of the lengthy, involved calculations required for effective use of buffer capacity (1,(37)(38)(39), and JCE Software itself has produced a software package that includes buffer capacity calculation (40).…”

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confidence: 99%

Understanding, Deriving, and Computing Buffer Capacity

Urbansky

Schock

2000

J. Chem. Educ.

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The concept of buffer capacity appears in varied disciplines, including bio-, geo-, analytical, and environmental chemistry, physiology, medicine, dentistry, and agriculture. Unfortunately, however, derivation and systematic calculation of buffer capacity is a topic that seems to be neglected in the undergraduate analytical chemistry curriculum. In this work, we give an account of the development of the buffer capacity concept and derive the buffer capacity contribution equations for buffer systems containing mono-, di-, and triprotic weak acids (and their conjugate bases) and aluminum(III), which undergoes hydrolysis. A brief review of pH is provided because pH is involved in applying buffer capacity to the real world. In addition, we discuss evaluation of the equations, numerical approximation of buffer capacity when an analytic solution is not derived, and the mathematical properties of the buffer capacity expressions.

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Abstract: These programs will be useful for identifying appropriate buffer solutions at various temperatures and/or ionic strengths.

Cited by 13 publications

References 2 publications

Effect of Sucrose Fatty Acid Esters on Transdermal Permeation of Lidocaine and Ketoprofen

Effect of Sucrose Fatty Acid Esters on Transdermal Permeation of Lidocaine and Ketoprofen

Temperature Effects on Electrophoresis

Understanding, Deriving, and Computing Buffer Capacity

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