A note on the solubility of griseofulvin

The solubility of griseofulvin in heptane, water and benzene over the temperature range 15–45° is reported together with the thermodynamic properties for solution of the antibiotic in these solvents.     

The effect of urea on the solubility of methyl p-hydroxybenzoate in aqueous sodium chloride solutions

The effects of sodium chloride and urea, separately and together, on the solubility of methyl p-hydroxybenzoate in water have been studied. Sodium chloride decreases and urea increases the solubility. Observed and calculated “salting-out” parameters have been obtained for addition of sodium chloride to the benzoate-urea-water systems. Good agreement was observed between calculated and observed values, and the change in the “salting-out” parameters as the concentration of urea altered may indicate dipole-ion interaction between urea and sodium chloride.     

Short-term toxicity study on sodium bromide in rats

Five groups, each of 4 female rats, received for 4 weeks either a standard diet or diets containing 300, 1200, 4800 or 19 200 ppm sodium bromide. The rats receiving 19 200 ppm sodium bromide did not clean themselves sufficiently and showed signs of motor incoordination in their hind legs. There was no clear influence on growth, food or water intake. During the first week of the experiment the plasma concentration of bromide increased rapidly, but by the third week a plateau level was reached. Only at the beginning of the experiment did the total halide concentration in the blood show a tendency to increase. In the highest dosage group about 50% of the chloride in the plasma, brain, kidneys and liver had been replaced by bromide. In the other treatment groups there was also a dose-related replacement of chloride by bromide. The relative weight of the kidneys of the animals in the 19 200 ppm group was increased significantly. There were no histological changes which could be attributed to the feeding of a diet containing sodium bromide.     

Study on the toxicity of sodium bromide to different freshwater organisms

The toxicity of sodium bromide for freshwater organisms was tested using algae (Scenedesmus pannonicus), crustaceans (Daphnia magna) and fish (Poecilia reticulata and Oryzias latipes). Depending on the species tested, the acute toxicity varied from 44 to 5800 mg Br-/litre (EC50 values) and the No Observed Effect Concentrations (NOEC values) in the long-term tests varied from 7.8 to 250 mg Br-/litre. Bromide ion markedly impaired reproduction in both crustaceans and fish. Histologically no effects were observed in the long-term test with Oryzias, but in the reproduction test with Poecilia, hyperplasia of the thyroid, atrophy and degeneration of the musculature and regressive changes in the female reproductive tract were observed. As a criterion of water quality, 1 mg Br-/litre has been proposed, on the basis of reproductive performance in the Poecilia test. The concentrations found in surface water frequently exceed this value and sometimes reach levels at which acute effects on water organisms can be expected.     

红霉素在几种缓冲液中的溶解度

红霉素在水中溶解度同其解离度有一定关系，当ｐＨ＜６．０时红霉素以盐的形式存在，其溶解度随ｐＨ值降低而迅速增大。在酸性范围内，红霉素的溶解度随温度升高而增大，这与游离碱的反温度溶解特性不同，不同温度下的溶解度随ｐＨ变化曲线相交于ｐＫａ为８．６附近。     

Semichronic toxicity study of sodium bromide in rats

A 90-day toxicity study was carried out in rats on diets containing 0, 75, 300, 1200, 4800 and 19200 ppm sodium bromide. The animals on the highest level did not groom themselves sufficiently and exhibited signs of motor incoordination. The male animals in this group showed significant growth retardation. Plasma bromide levels increased within 3 weeks to a plateau. In all groups, except in the highest dosage group, these plateaus were directly proportional to the bromide concentrations in the diets, as were the bromide concentrations in brain and kidneys after 13 weeks. Total molar halogen concentration in plasma, however, remained constant throughout the investigation. No striking effects on hematological and biochemical parameters were seen except for a doubling of the percentage of neutrophil granulocytes in the highest dosage group. In female animals on 1200, 4800 and 19200 ppm and in male animals on 19200 ppm bromide an increase of relative thyroid weight was found. In male rats an increase of the relative weight of the adrenals was found in the 19200 ppm group and a decrease of relative prostate weight was seen in the two highest dosage groups. Histopathologically a dose-related disturbance of the endocrine system and some of its target organs was found.     

色甘酸钠滴眼液中苯扎溴铵抑菌剂量筛选研究#br#

目的 检测色甘酸钠滴眼液中苯扎溴铵抑菌效力,筛选合理添加剂量。方法 采用《中国药典》2015年版四部抑菌效力检查法,检测色甘酸钠滴眼液制剂中不同剂量苯扎溴铵的抑菌效力,筛选出适宜的苯扎溴铵添加量。结果 所选色甘酸钠滴眼液在加入各试验菌后24h及14d的菌落对数下降值均未达到《中国药典》2015年版中眼用制剂的相应要求;苯扎溴铵在体外实验中对各试验菌有明显的抑菌作用,最低抑菌浓度(minimal inhibitory concentration, MIC)值为0.01%,最低杀菌浓度(minimal bactericidal concentration, MBC)为0.02%;在色甘酸钠滴眼液中最低抑菌剂量为0.003%。结论 0.003%~0.004%的苯扎溴铵可作为色甘酸钠滴眼液的抑菌剂添加量。     

Estimation of the effect of NaCl on the solubility of organic compounds in aqueous solutions

The Setschenow constant, K(salt), of a nonelectrolyte in a NaCl solution is shown to be related to the logarithm of its octanol-water partition coefficient, log K(ow), determined by K(salt) = A log K(ow) + B, where K(ow) is the octanol-water partition coefficient of the solute and the coefficients A and B are constants. The values of A and B were empirically determined from literature data for 62 organic compounds and validated for a test set of 15 compounds including several drugs.     

On the size and shape dependence of the solubility of nano-particles in solutions

The general equation is derived for the equilibrium of a small solid particle and a large solution, being consistent with the thermodynamics of Gibbs. This equation can be solved in a closed form for solubility if an ideal (or an infinitely diluted) solution is considered, if the interfacial energy is independent of the composition of the solution and if all physical parameters (other than the solubility itself) are taken size independent. The solubility of the particles is found to increase with increasing its specific surface area, i.e. if non-spherical particles are applied. This simplified solution further simplifies if the shape of the solid is supposed to be spherical. This latter equation, however, is found to be in contradiction with the Ostwald-Freundlich equation, widely used in chemistry, biology and materials science to describe the size dependence of solubility of a spherical crystal. The reason for its incorrectness is shown to be due to the incorrect application of the Laplace equation. It is found that the solubility increases with decreasing the size of the dissolving phase not due to the increased curvature of the phase (Kelvin and Freundlich), but rather due to the increased specific surface area of the phase (Gibss, Ostwald). Equations are also derived for the case, when the size effect of the interfacial energy is taken into account, and when the crystal is surrounded by several planes of different interfacial energies. The role of wettability is discussed on the size dependence of solubility.