原子荧光光度法测定牛黄解毒片中可溶性砷(Ⅲ)和砷(Ⅴ)

用原子荧光光度法测定牛黄解毒片中可溶性砷(Ⅲ)和砷(Ⅴ)。对牛黄解毒片中可溶性砷的基体效应进行了考查,探讨了HCl酸度、还原剂NaBH4浓度对As(Ⅲ)和As(Ⅴ)的测定影响,确定了在酸性介质HCl质量分数为10％-15％,还原剂NaBH4质量分数为2.0％-2.5％时,用校准曲线法分别测定As(Ⅲ)和As(Ⅴ)与As(Ⅲ)的总量,用差减法测定As(Ⅴ)含量。对同一厂家生产的牛黄解毒片进行6次分析,As(Ⅲ)和As(Ⅴ)的相对标准偏差分别为0.80％和2.90％,As(Ⅲ)和As(Ⅴ)的加标回收率分别96.7％-103.5％和109.0％-116.8％。     

一阶导数差示脉冲极谱法分析土霉素及其制剂

土霉素在水溶液中于—1.536 V(vs Ag/AgCl)处有一良好的一阶导数差示脉冲极谱峰,其峰幅值与土霉素在10～60μg/mL浓度范围内呈线性关系,检测限为6.9×10~(-7)mol/L。本方法简便、快速、灵敏,结果准确。     

Effect of 2-Hydroxypropyl-β-cyclodextrin on Release Rate of Metoprolol from Ternary Metoprolol/2-hydroxypropyl-β-cyclodextrin/Ethylcellulose Tablets

The effect of 2-hydroxypropyl--cyclodextrin (HP--CyD) on the release of a water-soluble ₁-selective adrenoreceptor antagonist, metoprolol (Met), from ternary Met/HP--CyD/ethylcellulose (EC) tablets was investigated. The release rate of Met from the ternary tablets was dependent on amounts of HP--CyD in the tablets, i.e., the rate decreased when small amounts of HP--CyD were added, while large amounts of HP--CyD accelerated the rate. The slowest rate was observed for the tablet consisted of a 30/10/60 weight ratio of Met/HP--CyD/EC. The analyses of the release rates by the Korsmeyer equation and their temperature dependence suggested that Met is released from the EC matrix containing HP--CyD according to the diffusion-controlled mechanism. The water penetration studies and the micro- and macroscopic observations suggested that the retarding effect of HP--CyD is attributable to a viscous gel formation in small pores on the surface of the tablets, where HP--CyD gels may work as a barrier for the water penetration into the tablets and the release of the drug from the tablets. The in-vitro release property of the ternary tablets was reflected in the in-vivo absorption profile in dogs. The results indicated that a combination of HP--CyD and EC is useful for the release control of water-soluble drugs such as Met.     

Spin-lattice relaxation behaviour of water in cellulose materials in relation to the tablet forming ability of microcrystalline cellulose particles

Medical tablet forming ability of microcrystalline cellulose (MCC) was investigated in relation to the mobility of water molecules in MCC particles. For this purpose, the spin-lattice relaxation time T1 of water in the system was measured by 1H-NMR. Over a wide range of water contents (0.02 H2O/cellulose (g/g) 1.79), two different T1 (T1,l and T1,s) values were observed for water in each MCC sample. Below the equilibrium water content, water having these two different T1 values exchange with each other in an MCC particle reaching an equilibrium state within a given time scale (equilibrium constant K). The T1,l, T1,s and K values for water in MCC, estimated at the equilibrium water content, showed fairly good correlations with the hardness of the tablets made by the MCC samples. Sample with a shorter T1, or larger K tended to have a stronger tablet forming ability. In the spin-spin relaxation time T2 measurements for protons in an MCC/D2O system, two T2 components originating from the glassy cellulose solid (T2,G) and the swelling region (T2,l) were observed. It was found that the mole fraction xL of protons with T2,L in the system exhibits a clear linear correlation with K. From these results, a structural model for the distribution of water in MCC particles was propoed by taking the surface of each microfibril and the disordered region within the microfibril into consideration     

Rapid drug-screening of clandestine tablets by MALDI-TOF mass spectrometry

A novel method for the rapid screening of clandestine tablets for drugs by MALDI-TOF mass spectrometry is described. In this method, cetrimonium bromide (CTAB), a surfactant, is added to the conventional α-cyano-4-hydroxycinnamic acid (CHCA) matrix solution used in preparing the MALDI samples. This procedure allows very clean mass spectra to be collected for amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), caffeine, ketamine and tramadol. The method was used successfully in the rapid drug-screening of some actual clandestine tablets, which had been seized from the illicit market, and can serve as a good complementary method to GC/MS for use in forensic analysis.     

Development of an analytical method for the determination of valsartan in commercial drug and sewage sludge samples by HPLC and evaluation of its stability under simulated gastric conditions

An analytical method was developed for determination of valsartan in commercial drug and sewage sludge samples by HPLC–UV using a single wavelength (250 nm). The effect of different environmental storage conditions on the stability of valsartan was examined for a period of 85 days, after which no degradation was observed. The post oral administration stability of the valsartan was also investigated by testing valsartan under simulated gastric conditions. Results obtained showed that the structure of valsartan was conserved over 3.5-h period. The calibration plot of the study was linear over a wide concentration range with a correlation coefficient of 0.9999. The limit of detection and limit of quantitation were found to be 0.014 and 0.046 µ g mL^?1, respectively. The percentage recovery of valsartan from sewage sludge was found to be 99.8%.     

A modularized tablet-based approach to preparation for remedial mathematics

Basic arithmetic forms the foundation of the math courses that students will face in their undergraduate careers. It is therefore crucial that students have a solid understanding of these fundamental concepts. At an open-access university offering both two-year and four-year degrees, incoming freshmen who were identified as lacking in basic arithmetic skills were engaged in an experimental technology-enhanced workshop designed to provide them with a deeper understanding of arithmetic prior to their initial remedial coursework. Customized online content was created specifically for this experiment, and the first implementation (n = 27) yielded statistically significant improvement, not only from pre-test to post-test, but also in the subsequent remedial course. This paper also analyses the accuracy of students’ self-assessment from pre-test to post-test, as well as student attitudes about this experimental approach.     

高效液相色谱法测定灭尔痛片的组分含量

采用高效液相色谱法同时测定灭尔痛片中对乙酰氨基酚、异丙基安替比林、及咖啡因３种成分的含量。色谱条件为：ＯＤＳ柱，甲醇＋水（６０＋４０）为流动相，检测波长为２５４ｎｍ。方法线性范围分别为：２４～１２０ｍｇ／Ｌ（ｒ＝０９９７６）；１２～６０ｍｇ／Ｌ（ｒ＝０９９９４）；４～２０ｍｇ／Ｌ（ｒ＝０９９９４）。各组分的平均回收率（ｎ＝６）分别为：１００３％，ＲＳＤ＝０４２％；９９７％，ＲＳＤ＝０６９％；９９２％，ＲＳＤ＝０４６％。该法操作简便、快捷，结果准确。     

药物控制释放方法

药物控制释放方法是目前药物学发展的一个重要领域，本文从贮库型和基质型两方面较为详细地综述了高分子药物控制释放的方法。     

Method development and validation: quantitation of telmisartan bulk drug and its tablet formulation by 1H NMR spectroscopy

The quantitative NMR (qNMR) spectroscopy is nowadays a new tool for the determination of pharmaceutical potent biologically active molecules in bulk drug and its tablet formulation than the other analytical techniques. Herein, qNMR method was developed for an anti‐hypertensive drug, telmisartan in bulk drug and its tablet formulation. The precise method was developed by using malononitrile as an internal standard. The methylene signal of telmisartan appeared at δ = 5.46 ppm (singlet) relative to the signal of malononitrile at δ = 3.59 ppm (singlet) in CDCl₃, as an NMR solvent. The development and validation of the method were carried out as per International Conference on Harmonization guidelines. The method was found to be linear (r² = 0.9999) for 0.5 to 3.5 mg/ml in the drug concentration range. The relative standard deviation for accuracy and precession was not more than 2.0%. The sensitivity of the method was carried out by limit of detection and a limit of quantification, at 0.05 and 0.2 mg/ml, respectively, concentration. The robustness of the method was studied by changing parameters as well as different solvent manufacturer company. The result shows that method was accurately developed for quantification of telmisartan in pharmaceutical dosage form. The developed method by ¹H NMR spectroscopy is comparatively easy and more precise with respect to the other analytical tools. Copyright © 2016 John Wiley & Sons, Ltd.