Stability of Mixtoxantrone Hydrochloride in Solution

A stability-indicating reversed-phase high performance liquid chromatographic method was developed for the detection of mitoxantrone HC1 and its degradation products under accelerated degradation conditions. The degradation kinetics of mitoxantrone HC1 in aqueous solution over a pH range of 1.18 to 7.20 and its stability in propylene glycol-or polyethylene glycol 400-based solutions were investigated. The observed rate constants were shown to follow apparent first-order kinetics in all cases. The pH-rate profile shows that maximum stability of mitoxantrone HC1 was obtained at pH 4.01. No general acid or base catalysis from acetate or phosphate buffer species was observed. The catalysis rate constants on the protonated mitoxantrone imposed by hydrogen ion water and hydroxy ion were determined to be 3.72 × 10 min^-1 5.64 × 10-min^-1 and 1.108 × 10^-2min^-1, respectively. The degradation rate constants of mitoxantrone affected by different ionic strength systems. Irradiation with 254 nm UV light at 25±0.5°C was found when canpared with the light-protected controls. Incorporation of nonaqueous propylene glycol or polyethylene glycol in the pH 4.01 mitoxantrone solution shows an increase in its stability at 502±0.5°C.     

Stability of HI-6 in Solution

Abstract

A stability-indicating reversed-phase high performance liquid chromatographic method was developed for the detection of HI-6 and its degradation products under accelerated degradation conditions. The degradation kinetics of HI-6 in aqueous solution over a pH range of 1.14 to 5.54 and its stability in propylene glycol or polyethylene glycol 400-based solutions were investigated. The observed rate constants were shown to follow apparent firstorder kinetics in all cases. The pH-rate profile shows that maximum stability of HI-6 was observed in the pH range 2.0 to 3.0 No effect of general acid/base catalysis of HI-6 was noted in the study. The degradation rate constants of HI-6 affected by different ionic strength systems. Irradiation with 254 nm UV light at 25 ±0.5°C was found when compared with the light-protected controls. Incorporation of nonaqueous propylene glycol or polyethylene glycol 400 in the pH 3.10 HI-6 solution show an increase in its stability at 70±0.5°C.     

Stability of HI-6 in Solution

A stability-indicating reversed-phase high performance liquid chromatographic method was developed for the detection of HI-6 and its degradation products under accelerated degradation conditions. The degradation kinetics of HI-6 in aqueous solution over a pH range of 1.14 to 5.54 and its stability in propylene glycol or polyethylene glycol 400-based solutions were investigated. The observed rate constants were shown to follow apparent firstorder kinetics in all cases. The pH-rate profile shows that maximum stability of HI-6 was observed in the pH range 2.0 to 3.0 No effect of general acid/base catalysis of HI-6 was noted in the study. The degradation rate constants of HI-6 affected by different ionic strength systems. Irradiation with 254 nm UV light at 25 ±0.5°C was found when compared with the light-protected controls. Incorporation of nonaqueous propylene glycol or polyethylene glycol 400 in the pH 3.10 HI-6 solution show an increase in its stability at 70±0.5°C.     

Stability of 4-DMAP in Solution

A stability-indicating reversed-phase performance liquid chromatographic method was developed for the detection of 4-(N, N-dimethylamino)phenol (4-DMAP) and its degradation products under accelerated degradation conditions. The degradation kinetics of 4-DMAP in aqueous solution over a pH range of 1.12–6.05 and its stability in solutions based on propylene glycol or polyethylene glycol 400 were investigated. The observed rate constants were shown to follow apparent first-order kinetics in all cases. The pH rate profile shows that maximum stability of 4-DMAP was observed in the pH range 2.0 to 3.0. Acid/base catalysis of 4-DMAP was not affected by systems of various ionic strengths. Incorporation of nonaqueous propylene glycol or polyethylene glycol 400 in the pH 3.05 solution of 4-DMAP showed an increase in the stability at 55°C ± 0.5°C,     

Stability of 4-DMAP in Solution

A stability-indicating reversed-phase performance liquid chromatographic method was developed for the detection of 4-(N, N-dimethylamino)phenol (4-DMAP) and its degradation products under accelerated degradation conditions. The degradation kinetics of 4-DMAP in aqueous solution over a pH range of 1.12-6.05 and its stability in solutions based on propylene glycol or polyethylene glycol 400 were investigated. The observed rate constants were shown to follow apparent first-order kinetics in all cases. The pH rate profile shows that maximum stability of 4-DMAP was observed in the pH range 2.0 to 3.0. Acid/base catalysis of 4-DMAP was not affected by systems of various ionic strengths. Incorporation of nonaqueous propylene glycol or polyethylene glycol 400 in the pH 3.05 solution of 4-DMAP showed an increase in the stability at 55°C ± 0.5°C.     

Investigation of the Stability of Doxorubicin Hydrochloride Using Factorial Design

Abstract

Using drug concentration remaining at a given time as the criterion, a 2⁴x3 factorial design has been employed to investigate the effects of temperature, light, media (aqueous or organic/aqueous), ionic strength and pH on the stability of doxorubicin hydrochloride. Following the application of first order kinetics, and assuming an additive model, the statistical significance of the factors and their interactions have been determined using analysis of variance (ANOVA) on the dependent variable ln(lnC_o-InC). The results indicate that temperature, pH and media are the major factors responsible for the stability of drug. The two-way interaction between temperature and pH, and the three-way interaction between temperature, light and ionic strength are also significant. It is found that doxorubicin is more stable in non-aqueous media at low temperature and low pH values. A combination of darkness and low ionic strength is also conducive to its stability.     

氢化丁腈橡胶在高温盐酸中的老化过程

研究了氢化丁腈橡胶(HNBR)在不同温度下和10%的盐酸中,老化前后的化学组成、微观结构和力学性能变化。通过固态碳核磁、X射线光电子能谱、扫描电镜、红外光谱和拉伸测试表征分析了经盐酸浸泡和未经浸泡的HNBR试样。由这些结果可知,在110℃和130℃的条件下,HNBR发生的老化反应主要是腈基水解为酰胺基,并有少量羧酸基产生。当温度升高到150℃时,会有一部分碳酰胺基转变为羧酸基,并且伴有少量氨气生成。在170℃时,随着温度的进一步升高,氨气的产生速度加快;生成大量的羧酸基团和氨气,导致HNBR基体内部形成大量孔洞;与此同时,碳酰胺基团之间会发生缩合反应,产生交联,导致HNBR的硬度提高。这些反应很好地解释了氢化丁腈橡胶材料老化前后的力学性能变化。     

Quantitation and Stability of Verapamil Hydrochloride using High-Performance Liquid Chromatography

Abstract

A high-performance liquid chromatography method for the quantitation of verapamil hydrochloride in pharmaceutical dosage forms has been developed. The method is precise and accurate with a relative standard deviation of 0.63% based on six injections. No preliminary extraction procedure is required to assay injections and a very simple extraction procedure is needed for tablets. There is no interference from the excipients and the method appears to be stability-indicating. The optimum pH range of stability is about 3.2 to 5.6 and the phosphate buffer and ionic strength have very little effect on the stability. Verapamil hydrochloride appears to be a very stable compound since in 105 days at 50°, the aqueous solutions (0.5 mg/ml) did not decompose.     

Quantitation and Stability of Verapamil Hydrochloride using High-Performance Liquid Chromatography

A high-performance liquid chromatography method for the quantitation of verapamil hydrochloride in pharmaceutical dosage forms has been developed. The method is precise and accurate with a relative standard deviation of 0.63% based on six injections. No preliminary extraction procedure is required to assay injections and a very simple extraction procedure is needed for tablets. There is no interference from the excipients and the method appears to be stability-indicating. The optimum pH range of stability is about 3.2 to 5.6 and the phosphate buffer and ionic strength have very little effect on the stability. Verapamil hydrochloride appears to be a very stable compound since in 105 days at 50°, the aqueous solutions (0.5 mg/ml) did not decompose.     

A Stability Study of Clindamycin Hydrochloride and Phosphate Salts in Topical Formulations

Abstract

The stability of clindamycin hydrochloride and clindamycin phosphate was studied in topical liquid formulations prepared with the following solvents: solvent A (70% isopropanol, 10% propylene plycol and 20% water), solvent B (48% isopropanol, polyoxyethelene ethers, acetone, salicylic acid and allantoin), solvent C (40% alcohol, acetone, polysorbate 20, fragrance and water) and “standard” (50% isopropyl alcohol, propylene glycol and water) in glass and plastic containers at 25°, 40°, and 50°C.

It was found that, in general, better stability was obtained in glass containers than in plastic containers. At 25°C both the clindamycin hydrochloride and phosphate formulations in solvent B showed poorer stability than in the other solvents irrespective of the type of container, while formulations in solvent C showed the best stability. In addition, the effect of the pH on the stability of the formulations was determined, and it was clear that at pH values below 4 the stability of all formulations decreased.     

A Stability Study of Clindamycin Hydrochloride and Phosphate Salts in Topical Formulations

The stability of clindamycin hydrochloride and clindamycin phosphate was studied in topical liquid formulations prepared with the following solvents: solvent A (70% isopropanol, 10% propylene plycol and 20% water), solvent B (48% isopropanol, polyoxyethelene ethers, acetone, salicylic acid and allantoin), solvent C (40% alcohol, acetone, polysorbate 20, fragrance and water) and “standard” (50% isopropyl alcohol, propylene glycol and water) in glass and plastic containers at 25°, 40°, and 50°C.

It was found that, in general, better stability was obtained in glass containers than in plastic containers. At 25°C both the clindamycin hydrochloride and phosphate formulations in solvent B showed poorer stability than in the other solvents irrespective of the type of container, while formulations in solvent C showed the best stability. In addition, the effect of the pH on the stability of the formulations was determined, and it was clear that at pH values below 4 the stability of all formulations decreased.     

无氰镀镉钛镀液的稳定性分析

为了研究无氰镀镉钛镀液的稳定性情况,通过陈化试验和连续镀试验检测了无氰镀镉钛镀液的稳定性,并利用X射线衍射仪(XRD)分析了镀液的沉淀产物。结果表明:镀液pH值应严格控制在6.70左右,前期时应在低温或室温保存,否则产生白色沉淀,且沉淀物不可溶解,沉淀产物主要是Ti(OH)_4、TiO_2、H_2Ti_2O_(11)·3H_2O、NH_4Cl;连续镀28 d镀液良好,无白色沉淀,镀层钛含量在0.1%~0.7%之间。     

The Effect of Various Additives on the Stability of Isoproterenol Hydrochloride Solutions

The effect of various additives on the rate of degradation of eight isoproterenol hydrochloride aqueous formulations was studied. In addition, the reaction was studied at various pH values and temperatures. From the latter data, activation parameters were determined. Rate constants increased from 10 to 100 times over a 25 degree increase in temperature. The activation energy for the reaction averaged approximately 25 kcal/mole. Ascorbic acid and sodium bisulfite appear to be the most efficient antioxidants in the system. Sequestering agents such as EDTA and citric acid do not appear to reduce the rate and, in one instance, EDTA seemed to enhance the degradation process. The reaction appears to be an oxidation of the catechol ring system of isoproterenol similar to that observed with epinephrine.

Catecholamines such as isoproterenol and epinephrine are highly subject to degradative oxidation in solutions. A number of antioxidants and other substances are added to formulations containing these substances in an effort to retard this degradation. This study was undertaken to investigate the effect on the stability of the solutions. An attempt was also made to compare the interaction of isoproterenol with bisulfite and boric acid to the analogous interaction of the latter compounds with epinephrine.     

The Effect of Various Additives on the Stability of Isoproterenol Hydrochloride Solutions

Abstract

The effect of various additives on the rate of degradation of eight isoproterenol hydrochloride aqueous formulations was studied. In addition, the reaction was studied at various pH values and temperatures. From the latter data, activation parameters were determined. Rate constants increased from 10 to 100 times over a 25 degree increase in temperature. The activation energy for the reaction averaged approximately 25 kcal/mole. Ascorbic acid and sodium bisulfite appear to be the most efficient antioxidants in the system. Sequestering agents such as EDTA and citric acid do not appear to reduce the rate and, in one instance, EDTA seemed to enhance the degradation process. The reaction appears to be an oxidation of the catechol ring system of isoproterenol similar to that observed with epinephrine.

Catecholamines such as isoproterenol and epinephrine are highly subject to degradative oxidation in solutions. A number of antioxidants and other substances are added to formulations containing these substances in an effort to retard this degradation. This study was undertaken to investigate the effect on the stability of the solutions. An attempt was also made to compare the interaction of isoproterenol with bisulfite and boric acid to the analogous interaction of the latter compounds with epinephrine.     

Urokinase: Stability Studies in Solution and Lyophilized Formulations

Urokinase - a serine protease - is used clinically as a thrombolytic agent to dissolve blood clots. Low molecular weight Urokinase (33,000 dalton) isolated from human kidney cells using tissue culture techniques was used in the stability studies. Quantitative determination of Urokinase was accomplished by either amidolytic or fibrinolytic activity assay methods. The degradation of Urokinase in solution at 55 °C follows pseudo-first order kinetics at several pH values. The pH range for maximum stability has been determined to be about 6 to 7.

The stability of Urokinase is very sensitive to the quantity of residual moisture in the lyophilized formulation. Rubber stoppers used as closures for the glass vials were identified as a major source of moisture. The loss of activity from freeze dried formulations was inversely related to the specific activity of tissue culture derived Urokinase. Similar relationship was also observed for the adsorption of Urokinase from 5% dextrose diluent to the surface of polyvinyl chloride large volume parenteral diluent bags. Initial degradation rates (zero order) for freeze dried urokinase formulations with and without the addition of human serum albumin (HSA) as a stabilizer determined at 50, 40 and 30 °C demonstrated that loss of urokinase followed the Arrhenius relationship with an apparent energy of activation (Ea) of 15 kcal per mol. The addition of HSA resulted in an increase in stability by about a factor of four. However, the apparent Ea for the formulations with and without HSA was not significantly different as evident from parallel slopes in the Arrhenius plots.     

Urokinase: Stability Studies in Solution and Lyophilized Formulations

Abstract

Urokinase - a serine protease - is used clinically as a thrombolytic agent to dissolve blood clots. Low molecular weight Urokinase (33,000 dalton) isolated from human kidney cells using tissue culture techniques was used in the stability studies. Quantitative determination of Urokinase was accomplished by either amidolytic or fibrinolytic activity assay methods. The degradation of Urokinase in solution at 55 °C follows pseudo-first order kinetics at several pH values. The pH range for maximum stability has been determined to be about 6 to 7.

The stability of Urokinase is very sensitive to the quantity of residual moisture in the lyophilized formulation. Rubber stoppers used as closures for the glass vials were identified as a major source of moisture. The loss of activity from freeze dried formulations was inversely related to the specific activity of tissue culture derived Urokinase. Similar relationship was also observed for the adsorption of Urokinase from 5% dextrose diluent to the surface of polyvinyl chloride large volume parenteral diluent bags. Initial degradation rates (zero order) for freeze dried urokinase formulations with and without the addition of human serum albumin (HSA) as a stabilizer determined at 50, 40 and 30 °C demonstrated that loss of urokinase followed the Arrhenius relationship with an apparent energy of activation (Ea) of 15 kcal per mol. The addition of HSA resulted in an increase in stability by about a factor of four. However, the apparent Ea for the formulations with and without HSA was not significantly different as evident from parallel slopes in the Arrhenius plots.     

稀土对化学镀镍溶液稳定性的影响

运用正交试验、结合氯化钯稳定性试验，沉积速度、稳定常数等试验指标来综合评价和分析了4种稀土元素（La,Eu,Nd,Y)对镀液稳定性的影响。结果表明，适量的稀土能大大大提高镀液的稳定性及沉积速度。利用X-射线衍射仪、显微硬度计等研究了在复合稀土化学镀镍液中得到的镀层，结果硬度有较大提高，但镀层中不含稀土元素。测得最佳复合稀土组合方式下的镀液的使用寿命可达11个周期，探讨了稀土在溶液中的作用机理。     

化学镀铜溶液稳定性和沉铜速率的研究

采用单因素试验法研究了影响化学镀铜镀速和溶液稳定性的各因素,根据实验确定了适宜的化学镀铜液配方及工艺规范。优选出的镀液稳定性高,沉铜速率达2．5－3．0μm/20min。镀层延展性好,平整、外观良好,可用于印制线路板的孔金属化及其他塑料电镀。     

分散剂对纳米LiBr溶液稳定性的影响

文章在论述分散剂增强纳米流体分散稳定性的基础上,通过添加E414和C6H5O7（NH4）,验证分散剂增强纳米LiBr溶液的分散稳定性,通过测量分别添加异辛醇（C8H18O）、壬醇（C9H20O）和癸醇（C10H220）基液的表面张力,发现分散剂也能增强纳米LiBr溶液表面张力的稳定性,主要因为表面张力和汽化成核临界功之间存在相关性,因此,分散剂同样能增强纳米LiBr溶液沸腾温度的稳定性。     

酸性镀锡液稳定性的研究进展

分析了酸性镀锡溶液不稳定的原因;讨论了pH值、温度、杂质等因素对酸性镀锡液稳定性的影响;认为提高镀液稳定性最有效的方法是加入适当的稳定剂,同时介绍了目前国内稳定剂的研究状况.