Physical-chemical characterization and polymorphism determination of two nimodipine samples deriving from distinct laboratories

Knowing the characteristics of raw materials in pharmaceutical practice is both important and useful. Firstly, evaluating the physical-chemical properties of the substances that will be used must be the primary step for quality control in the pharmacy industry. This work aims at analyzing the physical-chemical characteristics of two nimodipine samples I and II derived from distinct laboratories through thermal analysis (DSC and TG/DTG), HPLC, crystallography, and microscopy. Thermal analysis showed that sample II was more unstable than I. Morphological differences concerning shape, size, and crystallinity of particles were visualized by scanning electron microscopy (SEM) and X-ray powder diffraction. To sum up, the techniques used in this study can be said to have been efficient in the characterization and evaluation of quality control of the raw material.     

Formulation, quality control and shelf life of the experimental cytostatic drug cyclopentenyl cytosine

This paper describes the formulation and quality control of an aqueous sterilized formulation of the experimental cytostatic drug cyclopentenyl cytosine (CPEC) to be used in Phase I/II clinical trials. The raw drug substance was extensively tested. A High Pressure Liquid Chromotography (HPLC) method was validated for the quality control of the formulated product. The aqueous formulation was found to be stable for at least 2 years at 2-8°C. Sterilization (15 min at 121°C) showed no influence on drug stability. The results show that CPEC can be formulated in an aqueous solution. The described HPLC method is a useful tool in the pharmaceutical quality control.     

Formulation,Quality Control and Shelf Life of the Experimental Cytostatic Drug Cyclopentenyl Cytosine

ABSTRACT

This paper describes the formulation and quality control of an aqueous sterilized formulation of the experimental cytostatic drug cyclopentenyl cytosine (CPEC) to be used in Phase I/II clinical trials. The raw drug substance was extensively tested. A High Pressure Liquid Chromotography (HPLC) method was validated for the quality control of the formulated product. The aqueous formulation was found to be stable for at least 2 years at 2–8°C. Sterilization (15 min at 121°C) showed no influence on drug stability. The results show that CPEC can be formulated in an aqueous solution. The described HPLC method is a useful tool in the pharmaceutical quality control.     

溶解乙炔安全生产的工艺性分析

从溶解乙炔的生产实际出发,通过对溶解乙炔及相应的生产原辅料的理化性能的分析,结合溶解乙炔各工段的操作和管理特点,从工艺操作、设备维护到安全管理提出了很多实用的意见和建议。     

Stochastic Processes

In quality control, a proper Phase I analysis is essential to the success of Phase II monitoring. A literature review reveals no distribution-free Phase I multivariate techniques in existence. This research develops a Phase I location control chart for multivariate elliptical processes. The resulting in-control reference sample can then be used to estimate the parameters for Phase II monitoring. Using Monte Carlo simulation, the proposed method is compared with the Hotelling's T² Phase I chart. Although Hotelling's T² chart is preferred when the data are multivariate normal, the proposed method is shown to perform significantly better under nonnormality. This article has supplementary material online.     

Importance of the Casting Process. Comparative Survey of the Commonly Used Ni-Cr Dental Alloys

Mobile or fixed dental prostheses are a common and important part of life. Many noble metal-based alloys have been used in prosthodontics, and they need a correct evaluation of their technical, biological, and clinical properties. The present study proposes a new approach for the manufacturing process. We emphasize the key role of each step for combined process of heating, casting and spin for completing works of Ni-Cr alloys with improved physical-chemical properties, as a protocol for quality of the obtained physiognomic dental restorations. The differences in composition distribution between cast and raw materials were investigated by energy dispersive x-ray spectroscopy (EDX), while the surface morphology was inspected by scanning electron microscopy (SEM). Important aspects related to crystal lattice were revealed through the x-ray diffraction (XRD) method and they are closely related to the centrifugal casting process.     

A Comparative Mineralogical and Physico-Chemical Study of Some Crude Mexican and Pharmaceutical Grade Montmorillonites

All bentonites samples including those used as reference were characterized by x-ray diffraction minerological study, whole chemial analysis (total oxides), ion exchange capacity and physical-chemical properties tests. The x-ray diffraction analysis reveal only slight differences among mexican bentonites raw material. Either Mexican bentonite or the reference material show very similar impurity content. Chemical analysis of bentonites show wide variability in oxide content but results are in close accordance with those reported in the literature (2). The results obtained for reference compared to those of raw bentonites are in good agreement.     

Evaluation of Phase I analysis scenarios on Phase II performance of control charts for autocorrelated observations

Phase I analysis of a control chart implementation comprises parameter estimation, chart design, and outlier filtering, which are performed iteratively until reliable control limits are obtained. These control limits are then used in Phase II for online monitoring and prospective analyses of the process to detect out-of-control states. Although a Phase I study is required only when the true values of the parameters of a process are unknown, this is the case in many practical applications. In the literature, research on the effects of parameter estimation (a component of Phase I analysis) on the control chart performance has gained importance recently. However, these studies consider availability of complete and clean data sets, without outliers and missing observations, for estimation. In this article, we consider AutoRegressive models of order 1 and study the effects of two extreme cases for Phase I analysis; the case where all outliers are filtered from the data set (parameter estimation from incomplete but clean data) and the case where all outliers remain in the data set during estimation. Performance of the maximum likelihood and conditional sum of squares estimators are evaluated and effects on the Phase II use are investigated. Results indicate that the effect of not detecting outliers in Phase I can be severe on the Phase II application of a control chart. A real-world example is provided to illustrate the importance of an appropriate Phase I analysis.     

A Comparative Mineralogical and Physico-Chemical Study of Some Crude Mexican and Pharmaceutical Grade Montmorillonites

Abstract

All bentonites samples including those used as reference were characterized by x-ray diffraction minerological study, whole chemial analysis (total oxides), ion exchange capacity and physical-chemical properties tests. The x-ray diffraction analysis reveal only slight differences among mexican bentonites raw material. Either Mexican bentonite or the reference material show very similar impurity content. Chemical analysis of bentonites show wide variability in oxide content but results are in close accordance with those reported in the literature (2). The results obtained for reference compared to those of raw bentonites are in good agreement.     

On the Performance of Phase I Dispersion Control Charts for Process Monitoring

Control charts are usually implemented in two phases: the retrospective phase (phase I) and the monitoring phase (phase II). The performance of any phase II control chart structure depends on the preciseness of the control limits obtained from the phase I analysis. In statistical process control, the performance of phase I dispersion charts has mainly been investigated for normal or contaminated normal distributions of the quality characteristic of interest. Little work has been carried out to investigate the performance of a wide range of possible phase I dispersion charts for processes following non‐normal distributions. The current study deals with the proper choice of a control chart for the evaluation of process dispersion in phase I. We have analyzed the performance of a wide range of dispersion control charts, including two distribution‐free structures. The performance of the control charts is evaluated in terms of probability to signal, under normal and non‐normal process setups. These results will be useful for quality control practitioners in their selection of a phase I control chart. Copyright © 2014 John Wiley & Sons, Ltd.     

A review of: “Melal Cutting Principles.” By MILTON C. SHAW. (Clarendon Press, 1984.) [Pp. 594.] Price £60.

This paper develops formulas that can be used in the design of multiple criteria sampling plans or charts for fraction nonconforming, with sampling on variables or attributes. Products often have multiple requirements and the usual acceptance tests or charts do not take this into account, and hence the overall quality of the product may be in poor control. We design tests or charts on the basis of probability of Type I and Type II errors (α and β) that refer to acceptable and rejectable levels of the overall fraction of the product that is nonconforming. Further, recognizing that the average proportion of the product that is actually nonconforming on each of the characteristics may vary independently of the other characteristics, our formulas give protection on a ‘worst case’ basis.     

铀矿地质样品中天然放射性核素比对分析结果的利用

以实验室日常分析副样为原料,经过配料、研磨、均匀性检查和多家实验室间比对验证,获得了8个铀矿地质样品（ALBRIUG-1～ALBRIUG-8）中总α、总β、238U、232Th、226Ra、210Po和40K比活度值。采用最小称样量（50 mg）的ICP-MS检查均匀性时,2个铀矿地质样品（ALBRIUG-1和ALBRIUG-8）的均匀性较好,符合标准物质要求,可作为实验室天然放射性核素分析质量控制样品使用;其余6个样品（ ALBRIUG-2～ALBRIUG-7）均匀性未达到标准物质要求,但样品放射性核素基本处于平衡状态,其铀镭平衡系数在0.988～1.079之间,可用于取样量较大（大于150g）的物理分析质量控制参考。     

激光加工中光化学作用的检测分析方法

在基于激光加工各种材料过程中存在的光热作用和光化学作用的基础上,综述了激光加工过程中光化学作用的检测分析方法.对光化学作用结果的检测主要通过对激光作用后材料表面的结构、成分、微观形貌、物理化学特性等的变化进行分析;而对光化学作用过程的检测则采用具有时间分辨尺度的质谱仪或光谱仪等对激光加工过程中产生的分子碎片和带电离子的...     

Finite element analysis of a center crack specimen warm pre-stressed under different modes of loading

Load bearing capacity of cracked specimens can be improved following pre-loading procedures like warm pre-stressing (WPS). In this paper, the effects of modes I and II pre-loading on fracture load of a central angled crack specimen are studied by finite element analysis. The specimen is reloaded either in mode I or in mode II. To predict the fracture load of cracked specimen after pre-loading, the maximum tensile stress (MTS) and maximum shear stress (MSS) criteria are used. It is shown that mode II fracture load is independent of pre-loading but the mode I fracture load is highly improved after warm pre-stressing. The mode mixity of the specimen is also changed when the pre-loading and reloading modes are not identical. An increase in the fracture load of the specimen following pre-loading may be due to change of failure mode as predicted by finite element analysis in this work.     

Production of carbon black acrylic composite as an electrophotographic toner using emulsion aggregation method: Investigation the effect of agitation rate

Toner as a composite of colorant, polymer and additives is a primary component of electrophotographic printing and copying processes. It can be produced by conventional mechanical milling or by more recently developed chemical polymerization methods. The emulsion aggregation is a popular chemical method that allows tight control on the size, size distribution and shape of the synthesized toner particles. These characteristics are important for producing high quality, high-resolution printed images. This research investigated the effect of agitation speed on toner synthesis using emulsion aggregation method. Particle size analysis, scanning electron microscopy, and field emission scanning electron microscopy were used to study the size, shape, and morphology of toner particles. It was found that toner particles synthesized using emulsion aggregation method is spherical in shape and decrease in size as agitation speed increases. Differential scanning calorimetry and spectrophotometric analyses results showed that the toner synthesized by this method had appropriate thermal and colorimetric characteristics as compared to an industrial toner.     

聚碳酸酯的非光气合成法

以双酚A（BPA）,碳酸二丁酯（DBC）为原料,制备出双酚A单丁基碳酸酯（I）和双酚A二丁基碳酸酯（II）,用核磁共振波谱表征其结构。通过I、II的熔融自缩聚及II与BPA酯交换反应合成了双酚A型聚碳酸酯（PC）,用凝胶渗透色谱法（GPC）和热失重法（TGA）对PC的分子量和热力学性质进行分析。研究发现,II自缩聚更易...     

Real-time process monitoring using kernel distances

Real-time monitoring is an important task in process control. It often relies on estimation of process parameters in Phase I and Phase II and aims to identify significant differences between the estimates when triggering signals. Real-time contrast (RTC) control charts use classification methods to separate the Phase I and Phase II data and monitor the classification probabilities. However, since the classification probability statistics take discretely distributed values, the corresponding RTC charts become less efficient in the detection ability. In this paper, we propose to use distance-based RTC statistics for process monitoring, which are related to the distance from observations to the classification boundary. We illustrate our idea using the kernel linear discriminant analysis (KLDA) method and develop three distance-based KLDA statistics for RTC monitoring. The performance of the KLDA distance-based charting methods is compared with the classification probability-based control charts. Our results indicate that the distance-based RTC charts are more efficient than the class of probability-based control charts. A real example is used to illustrate the performance of the proposed method.     

A Copula Markov CUSUM Chart for Monitoring the Bivariate Auto‐correlated Binary Observations

Although in the statistical process control (SPC) literature, there are considerable number of researches related to the multivariates variables control charting (focusing on the variable quality characteristics), fewer investigations could be found regarding the multivariate attributes control charts (relying on the attribute quality characteristics). More specifically considering the multivariate attributes control charting, it would be more interesting to monitor the auto‐correlated data, since the real‐world processes usually include the data based on an auto‐correlation structure. Ignoring the auto‐correlation structure in developing a multivariate control chart increases the type I and type II errors simultaneously and consequently reduces the performance of the chart. The most important difficulty with developing multivariate attributes control charts is the absence of the joint distribution for the quality characteristics. This deficiency can be dispelled through the use of the copula approach for developing the joint distribution. In this paper, we use the Markov approach for modeling the auto‐correlated data. Then, the copula approach is used to make the joint distribution of two auto‐correlated binary data series. Finally, based on this joint distribution, we develop a cumulative sum (CUSUM) chart. Hence, the proposed chart is entitled the copula Markov CUSUM chart. The proposed control chart is compared with the most recent and effective existing one in the literature. Based on the average number of observations to signal (ANOS) measure, it is considered that the developed control chart performs better than the other one. In addition, a real case study related to two correlated diseases such as the Type 2 Diabetes Mellitus and the Obesity, in which each has an auto‐correlated structure, is investigated to verify the applicability of the control chart. Copyright © 2012 John Wiley & Sons, Ltd.     

A case study on monitoring polynomial profiles in the automotive industry

In some statistical process control applications, the quality of a process or product can be characterized by a relationship between a response variable and one explanatory variable, which is referred to as profile. We give an example here of a profile that can be described using a polynomial model. This example comes from the automotive industry, where one of the most important quality characteristics of an automobile engine is the relationship between the torque produced by an engine and the engine speed in revolutions per minute. We find for this data set that a second‐order polynomial works well. In addition, we show that there is autocorrelation within each profile, thus an ordinary least‐square method that ignores the autocorrelation is inappropriate. We propose a linear mixed model method as an alternative approach. After the reduction of the data to a series of parameter estimates, we then conduct a step‐by‐step Phase I analysis of the polynomial profiles monitoring using a T²‐based procedure to check the stability of the process and whether or not there are outlying profiles. The remaining profiles are used to form the estimated mean vector and variance–covariance matrix to be used in Phase II studies. Finally, a brief discussion is presented to show how one can use these parameters in Phase II. Copyright © 2009 John Wiley & Sons, Ltd.     

Developing unified rheological curves for polymermodified asphalts-part II. Experimental verification

The theoretical analysis in Part I of the paper has shown that unified curves can be obtained, in principle, if the rheological data obtained by measurements on the dynamic shear rheometer (DSR) are normalized through the use of the material's volumetric-flow rate (MVR) generated from a simple flow measurement device (FMD). In Part II of the paper, experimental verification of the unification process is done through systematic data analysis on selected polymer-modified asphalts. The unified curves have far-reaching implications and these have been brought out explicitly. Since MVR is so simple to determine quite accurately on a relatively inexpensive, easy-to-use flow measurement device (FMD), this parameter can be generated on paving sites or at refineries. The MVR can be used as a quality control/quality assurance parameter to ensure batch-to-batch invariance and also as an excellent indicator of the fundamental rheological parameters through the use of the unified curves.