Lactate buffers

An oral suspension of chlorpromazine has the following composition and must be extracted so that excipients are removed prior to analysis by UV spectrophotometry Chlorpromazine 0.025% w/v, parahydroxybenzoic acid methyl ester 0.1 % w/v, neutral water soluble dye, lipophilic flavouring agent, sodium lactate buffer. 

Fluoride release is enhanced in acidic conditions [277,278], and in lactate buffer has been shown to be diffusion based [277]. A plot of cumulative fluoride release against square root of time was found to remain linear for up to 169 h, and to follow the equation ... 

D. Sales, D. Sae-Lee, S. Matsuya, I.D. Ana, Short-term fluoride and cations release from polyacid-modified composites in distilled water and an acidic lactate buffer. Biomaterials 21 (2003) 1687-1696. 

Figure 1. Liquid chromatograms of a mixture of cysteine.HCL and xylose after different periods of heating at 90 °C and pH 5.0 (lactate buffer). Moisture content 20%. a solvent + xylose + cysteine unknown b chloride c lactate d 2-xylulosylthiazolidine -4- Carboxylic acid (compound 7 in Figure 2 2...

PROBLEM 3.5 Calculate the ratio of lactic acid and lactate required in a buffer system of pH 5.00. The p fa of lactic acid is 3.86. Solution The equation, . .T,, [lactate] P P a °g [lactic acid] can be rearranged to, [lactate] TT ° [lactic acid] a = 5.00 - 3.86 = 1.14 Therefore the required ratio is [lactic acid] - mtllo6 L14 = 13.8 For a lactate buffer to have a pH of 5, the lactate and lactic acid components must be present in a ratio of 13.8 to 1. Because a good buffer contains a mixture of a weak acid and its conjugate base present in near equal concentrations and when the buffered pH is within 1 pH unit of the pK lactate buffer is a poor choice in this situation. A better choice would be the acetate buffer. 

Schober, T.J., Dockery, P., and Arendt, E.K. 2003. Model studies for wheat sourdough systems using gluten, lactate buffer and sodium chloride. Eur. Food Res. Technol. 217, 235-243. 

Jenei S.R., Bajpai P.K., and Salsbury R.L. ResorbabiHty of commercial hydroxyapatite in lactate buffer. Proceedings of the Second Annual Scientific Session of the Academy of Surgical Research. S.C. Clemson and D.N. Powers (Ed.), pp. 13-16. Clemson University Press, Clemson, SC. 

A diffusion-based mechanism has been found when polyacid-modified composite specimens were stored in a lactate buffer [36], and to apply for up to 169 h. Scanning electron microscopy examination of the specimens at the end of the fluoride release... 

A. Pasinli, M. Yuksel, E. Celik, S. Sener, and A. C. Tas, A New Approach in Biomimetic Synthesis of Calcium Phosphate Coatings using Lactic acid-Na Lactate buffered Body Fiuid Soiution, Acta Biomater., 6, 2282-8 (2010). 

First, let us consider the effect of actual salt and acid concentration on the buffer capacity. Let us add 1 ml of 0.1 N HCl to a lactate buffer solution containing 10 ml of 0.1 M lactate and 10 ml of 0.1 N lactic acid (pH of this buffer will be equal to the pK of lactic acid, 3.86, since the ratio of salt to acid is unity). What will be the change in pH of the uffer solution The HCl will convert 1 ml of the salt to 1 ml of acid. The pH of the solution will therefore be... 

Let us now consider the effect of salt to acid concentration ratio upon the buffer capacity. To understand this, let us consider a lactate buffer composed of 15 ml of 0.1M lactate and 5 ml of 0.1 N lactic acid. The pH of this buffer would be... 

Literature data showed that the emulsions obtained with 1.25 mM monocaprin acid in citrate-lactate buffer at low pH values (4.0-5.0) caused a greater reduction in the number of viable cells (> 6 to 7Togio CFU) of Salmonella spp., Escherichia coli and Clostridium jejuni (Thormar et al., 2006). 

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