Influence of Uric Acid on Photostability of Sulfathiazole Sodium Solutions

The effect of uric acid as a photoprotective agent for buffered and unbuffered solutions of sulfathiazole sodium was investigated. Uric acid solution in glycerin was found to enhance the photostability of sulfathiazole sodium solutions. The higher the concentration of uric acid used, the greater was its photoprotective action within the concentration range studied. Uric acid was also found to demonstrate its photoprotective effect in the presence of either sodium sulfite or EDTA. Sodium sulfite alone in a concentration of 0.1% produced a detrimental effect on the photostability of sulfathiazole sodium in either borate or phosphate buffer of pH 9 ± 0.2. From the standpoint of the overall chemical stability of sodium sulfathiazole, uric acid appeared to be most effective when used alone in the borate buffer. However, the incorporation of 0.1% sodium sulfite in addition to uric acid contributed to the prevention of discoloration in either the borate or the phosphate buffer.     

Influence of DL-Methionine on the Photostability of Ascorbic Acid Solutions

Abstract

The photostablizing effect of DL-methionine for various buffered solutions of ascrobic acid was investigated. DL-methionine in a concentration of 10 mg% was found to enhance the photostability of 40 mg% ascorbic acid in acetate and phosphate buffers, but not in citrate buffer of pH 4.5. The photoprotective action of DL-methionine appeared to be influenced by its concentration, the pH of the medium and its buffer species. DL-methionine was also found to demonstrate its photoprotective action in presence of glycerin, EDTA and Tween 80. PEG 300, however, appeared to have a detrimental effect on the photostabilizing action of DL-methionine for ascorbic acid in acetate buffer of pH 4.5     

Influence of Uric Acid on Photostability of Fd& C Blue no. 2

The effect of uric acid as a photoprotective agent for various solutions of FD&C Blue No. 2 was investivated. Due to the poor aqueous solubility of uric acid, solutions were made in glycerin, triethanolamine and N/5 NaOH. Uric acid in glycerin or triethanolamine was found to enhance the photostability of the dye solutions. The higher the concentration of uric acid in triethanolamine, the greater was the photoprotective action of uric acid. Increasing the amount of glycerin in solution resulted in acceleration of the rate of fading of the color presumably due to dielectric constant effect. The photoprotective action of uric acid was found to be influenced by the pH of the medium and its buffer species.     

Influence of Certain Additives on the Photostability of Colch Icine Solutions

Abstract

The photostability of colchicine solutions in the presence of selected additives under shortwave ultraviolet light was investigated P-aminobenzoic acid (PABA) and uric acid solubilized by lithium carbonate enhanced the photostability of colchicine. Glycerin on the other hand demonstrated a detrimental effect. Buffer species and pH of the vehicle were found to influence the apparent zero-order rate of degradation of colchicine solutions.     

Influence of Certain Additives on the Photostability of Colch Icine Solutions

The photostability of colchicine solutions in the presence of selected additives under shortwave ultraviolet light was investigated P-aminobenzoic acid (PABA) and uric acid solubilized by lithium carbonate enhanced the photostability of colchicine . Glycerin on the other hand demonstrated a detrimental effect . Buffer species and pH of the vehicle were found to influence the apparent zero-order rate of degradation of colchicine solutions.     

Influence of Certain Additives on the Photostabilizing Effect of Uric Acid for Solutions of Fd&c Blue No. 2

The influence of certain pharmaceutical materials on the photostabilizing effect of uric acid for solutions of FD&C Blue No.2 was investigated. Uric acid in a concentration of 2.5 mg % was found to excercise its effect as a photoprotective agent in presence of DL-methionine, DL-leucine, Tween 80, lactose, sodium benzoate and methyl-paraben. These materials were noted to accelerate the rate of fading of the dye solutions. On the other hand, uric acid appeared to be practically ineffective in presence of sodium edetate and tartaric acid, Uric acid demonstrated the greatest photoprotective action in presence of sodium benzoate or methylparaben.     

Influence of Thiourea on the Photostability of FD & C Red No. 3 Solutions

Abstract

The effect of thiourea as a photostabillzlng agent for FD & C Red No. 3 solutions was investigated. Thiourea was found to enhance the stability of the dye solutions prepared in phosphate buffers of pH values of 7 and 7.9 and exposed to long-wave or short-wave ultraviolet light sources. Thiourea also demonstrated a photoprotective action for the dye solution in phosphate buffer of pH 7 on exposure to fluorescent light. However, thiourea was detrimental to the photostability of the dye solutions prepared in distilled water, acetate, phophate or citrate buffer of pH A.5 and exposed to long-wave or short-wave ultraviolet light sources. The pH of the solution, its buffer species and the concentration of thiourea appeared to influence the photo-stability of FD & C Red No. 3.     

Influence of Thiourea on the Photostability of FD & C Red No. 3 Solutions

The effect of thiourea as a photostabillzlng agent for FD & C Red No. 3 solutions was investigated. Thiourea was found to enhance the stability of the dye solutions prepared in phosphate buffers of pH values of 7 and 7.9 and exposed to long-wave or short-wave ultraviolet light sources. Thiourea also demonstrated a photoprotective action for the dye solution in phosphate buffer of pH 7 on exposure to fluorescent light. However, thiourea was detrimental to the photostability of the dye solutions prepared in distilled water, acetate, phophate or citrate buffer of pH A.5 and exposed to long-wave or short-wave ultraviolet light sources. The pH of the solution, its buffer species and the concentration of thiourea appeared to influence the photo-stability of FD & C Red No. 3.     

Influence of Certain Additives on the Photostabilizing Effect of Uric Acid for Solutions of Fd&c Blue No. 2

The influence of certain pharmaceutical materials on the photostabilizing effect of uric acid for solutions of FD&C Blue No.2 was investigated. Uric acid in a concentration of 2.5 mg % was found to excercise its effect as a photoprotective agent in presence of DL-methionine, DL-leucine, Tween 80, lactose, sodium benzoate and methyl-paraben. These materials were noted to accelerate the rate of fading of the dye solutions. On the other hand, uric acid appeared to be practically ineffective in presence of sodium edetate and tartaric acid, Uric acid demonstrated the greatest photoprotective action in presence of sodium benzoate or methylparaben.     

Optimization of a Slow-Release Tablet Formulation Containing Sodium Sulfathiazole and a Montmorillonite Clay

Abstract

A slow-release tablet formulation containing high levels of a montomorillonite clay, Veegum F®, was initially developed by trial and error. The present study was undertaken to utilize an approach involving statistics with the aid of computer science to develop a formula with desired characteristics. An experimental design for five factors was employed. The five factors consisted of levels of various components and the amount of compressional force applied while tableting. The response or dependent variables included tablet weight uniformity, hardness and friability; and percent drug in solution after 3 hours of dissolution testing. The response variables were fitted to a second-order polynomial with the five formulation factors as the independent variables. The resulting equations were used to optimize the formulation with respect to the response variables. The results indicated that a formulation with the desired characteristics could be predicted by the technique.     

Optimization of a Slow-Release Tablet Formulation Containing Sodium Sulfathiazole and a Montmorillonite Clay

A slow-release tablet formulation containing high levels of a montomorillonite clay, Veegum F®, was initially developed by trial and error. The present study was undertaken to utilize an approach involving statistics with the aid of computer science to develop a formula with desired characteristics. An experimental design for five factors was employed. The five factors consisted of levels of various components and the amount of compressional force applied while tableting. The response or dependent variables included tablet weight uniformity, hardness and friability; and percent drug in solution after 3 hours of dissolution testing. The response variables were fitted to a second-order polynomial with the five formulation factors as the independent variables. The resulting equations were used to optimize the formulation with respect to the response variables. The results indicated that a formulation with the desired characteristics could be predicted by the technique.     

Influence of Certain Additives on the Photostabilizing Effect of Dimethyl Sulfoxide for Sodium Nitroprusside Solutions

Abstract

The influence of certain pharmaceutical adjuvants on the photostabilizing effect of dimethyl sulfoxide for a buffered solution of sodium nitroprusside was investigated. Dimethyl sulfoxide in a concentration of 10% v/v was found to exercise its effect as a photoprotective agent in the presence of methylparaben, sodium sulfite, sodium chloride, destrose, PEG 300, Tween 80, citric acid and sodium edetate. In the absence of dimethyl sulfoxide, sodium sulfite produced the most deleterious effect on the photostability of sodium nitroprusside solution. The photoprotective action of dimethyl sulfoxide appeared to be slightly enhanced by the presence of sodium edetate, methylparaben, sodium chloride or citric acid.     

Influence of Certain Additives on the Photostabilizing Effect of Dimethyl Sulfoxide for Sodium Nitroprusside Solutions

The influence of certain pharmaceutical adjuvants on the photostabilizing effect of dimethyl sulfoxide for a buffered solution of sodium nitroprusside was investigated. Dimethyl sulfoxide in a concentration of 10% v/v was found to exercise its effect as a photoprotective agent in the presence of methylparaben, sodium sulfite, sodium chloride, destrose, PEG 300, Tween 80, citric acid and sodium edetate. In the absence of dimethyl sulfoxide, sodium sulfite produced the most deleterious effect on the photostability of sodium nitroprusside solution. The photoprotective action of dimethyl sulfoxide appeared to be slightly enhanced by the presence of sodium edetate, methylparaben, sodium chloride or citric acid.     

猫须草纳米分散液的制备及其降尿酸活性研究

纳米中药是近年来迅速发展起来的前沿科技领域.纳米技术和传统中药制剂的有机结合,有力地推动了医药科技的发展.以猫须草为研究对象,采用剪切、 研磨和高压均质等方法制备了猫须草纳米分散液,获得了平均粒径约为100 nm的均匀、 稳定的分散体系,研究了纳米分散液降尿酸(UA)的作用.结果表明:相对于高尿酸模型组,纳米分散液对U...     

硝酸钠及亚硝酸钠对乳化炸药生产安全性的影响

应用加速量热仪对乳化炸药生产中的硝酸钠及亚硝酸钠对硝酸铵热稳定性的影响进行测试及分析,研究结果表明硝酸钠对硝酸铵的热稳定性没有影响,少量的亚硝酸钠杂质对于硝酸铵的热稳定性有显著的改变。结合生产实际,对乳化炸药生产过程中水相配料泡沫量大及发生的严重＂溢料＂问题进行了分析,提出了预防同类问题再次发生的措施。     

冰冻人血清尿酸标准物质的研制

介绍了冰冻人血清尿酸标准物质的研制方法.采用液相色谱/同位素稀释质谱法(LC/ID-MS)对该标准物质进行了定值研究、均匀性检验和稳定性检验.研究结果表明,冰冻人血清尿酸标准物质定值结果为55.88 mg/kg,扩展不确定度为0.74 mg/kg,其均匀性和稳定性检验结果均符合国家一级标准物质的技术要求.     

聚乙烯亚胺/纤维素的合成及对脲酸的吸附性能

以聚乙烯亚胺(PEI)为功能基团、以微晶纤维素(MCC)为载体通过环氧氯丙烷将PEI接枝到MCC上,制得功能高分子吸附材料聚乙烯亚胺/纤维素(PEI/MCC)。通过红外光谱、元素分析、X射线衍射对PEI/MCC进行结构表征;测定其对脲酸的吸附性能。PEI/MCC的合成条件:在N2保护下,环氧化纤维素(EC)与PEI的质量比为1∶6,碳酸钠0.047mol,1,4-二氧六环20 mL,反应温度为60℃,反应时间为6 h。静态吸附实验结果表明,PEI/MCC对脲酸有较强的吸附能力,含氮量与吸附容量成正比,对脲酸的最大吸附容量为9.53 mg/g。     

Oxidation of Urea with Nitrous Acid in Nitric Acid Solutions

The kinetics of the reaction between urea and HNO₂ in nitric acid solution was studied spectrophotometrically. It was found that, at a constant ionic strength of the solution μ = 2, in the range of the initial concentrations of urea from 0.01 to 0.1 M, HNO₂, from 0.003 to 0.012 M, and hydrogen ions, from 0.1 to 1.5 M, the rate constant of the reaction is described by the equation -d[HNO₂]/dt = k[HNO₂][CO(NH₂)₂][H⁺] · K([H⁺]K +1)⁻¹, where the rate constant k = 15.6±0.3 l mol⁻¹ min⁻¹ and the protonation constant of urea K = 1.38 l mol⁻¹ at 15°C. From the temperature dependence of the reaction rate in the range of 15–35°C, the activation energy was determined to be 61±5 kJ mol⁻¹. The reaction mechanism involving the reaction of nondissociated HNO₂ molecules and protonated urea species NH₂CONH ₃ ⁺ was suggested.__________Translated from Radiokhimiya, Vol. 47, No. 1, 2005, pp. 57–60.Original Russian Text Copyright © 2005 by Dvoeglazov, Marchenko.     

Critical Locus of Aqueous Solutions of Sodium Chloride Revisited

There exists a formulation for the critical locus of aqueous solution of NaCl recommended by the International Association for the Properties of Water and Steam. In this article, we present slightly modified equations for the critical parameters of H₂O + NaCl that incorporate a non-analytic concentration dependence predicted by theory.