盐酸米诺环素软膏的释放度研究

目的探讨盐酸米诺环素缓释软膏的体外释放度及释药机制。方法制备盐酸米诺环素软膏供试品溶液和盐酸米诺环素标准品溶液。释放度采用桨法（《中国药典》2010版二部附录XD第二法）,以水为释放介质,体积为500 mL,转速为100 r/min,温度为（37.0±0.5）℃,检测波长为274 nm。采用紫外分光光度法测定释放介质中盐酸米诺环素的含量。结果盐酸米诺环素检测浓度在0.99～19.87μg/mL范围内具有良好的线性关系,线性回归方程为A=0.0301C＋0.0004,相关系素r=1,平均回收率为101.6%,相对标准偏差为1.5%。在1、4、7 h的释放度分别为13.91%、29.89%、40.76%,体外释放度有良好的缓释药物行为。体外释放特征显示该软膏制剂具有复合释药的规律,一级释放机制所占比例更大一些。结论盐酸米诺环素软膏制剂具有缓释作用,释放度测定方法操作简便、快速、准确度好。     

Sustained Release of Minocycline From Minocycline-Calcium-Dextran Sulfate Complex Microparticles for Periodontitis Treatment

It is important to address the periodontitis-associated bacteria in the residual subgingival plaque after scaling and root planing to successfully treat periodontitis. In this study, we explored the possibility of exploiting the ion pairing/complexation of minocycline, Ca²⁺, and sulfate/sulfonate-bearing biopolymers to develop an intrapocket delivery system of minocycline as an adjunct to scaling and root planing. Minocycline-calcium-dextran sulfate complex microparticles were synthesized from minocycline, CaCl₂, and dextran sulfate. They were characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. An in vitro release study was conducted to evaluate the release kinetics of minocycline from these microparticles. Agar disk diffusion assays and biofilm-grown bacteria assays were used to assess antibacterial capability. High loading efficiency (96.98% ± 0.12%) and high loading content (44.69% ± 0.03%) for minocycline were observed for these complex microparticles. Mino-Ca-DS microparticles achieved sustained release of minocycline for at least 9 days at pH 7.4 and 18 days at pH 6.4 in phosphate-buffered saline, respectively. They also demonstrated potent antimicrobial effects against Streptococcus mutans and Aggregatibacter actinomycetemcomitans in agar disk diffusion and biofilm assays. These results suggested that the ion pairing/complexation of minocycline, Ca²⁺, and sulfonate/sulfate-bearing biopolymers can be exploited to develop complex microparticles as local delivery systems for periodontitis treatment.     

Measurement of stain on extracted teeth using spectrophotometry and digital image analysis

Abstract: Aim: The aim of this study was to assess the reliability and validate a customized image analysis system, designed for use within clinical trials of general dental hygiene and whitening products, for the measurement of stain levels on extracted teeth and to compare it with reflectance spectrophotometry. Method: Twenty non‐carious extracted teeth were soaked in an artificial saliva, brushed for 1 min using an electric toothbrush and a standard toothpaste, bleached using a 5.3% hydrogen peroxide solution and cycled for 6 h daily through a tea solution. CIE L* values were obtained after each treatment step using the customized image analysis system and a reflectance spectrophotometer. A statistical analysis was carried out in SPSS. Results: Fleiss’ coefficient of reliability for intra‐operator repeatability of the image analysis system and spectrophotometry was 0.996 and 0.946 respectively. CIE L* values were consistently higher using the image analysis compared with spectrophotometry, and t‐tests for each treatment step showed significant differences (P < 0.05) for the two methods. Limits of agreement between the methods were ?27.95 to +2.07, with a 95% confidence of the difference calculated as ?14.26 to ?11.84. The combined results for all treatment steps showed a significant difference between the methods for the CIE L* values (P < 0.05). Conclusion: The image analysis system has proven to be a reliable method for assessment of changes in stain level on extracted teeth. The method has been validated against reflectance spectrophotometry. This method may be used for pilot in vitro studies/trials of oral hygiene and whitening products, before expensive in vivo tests are carried out.     

紫外分光光度法测定蜈蚣甘草散中重金属的含量

目的：测定蜈蚣甘草散中重金属的含量。方法：蜈蚣甘草散灰化后用硫化钠显色,用紫外分光光度法测定蜈蚣甘草散中重金属的含量。灰化温度550℃,时间2h;测定条件：pH3．0-3．5,波长202nm。结果：线性范围0-50μg,平均加样回收率为99．52％,RSD1．82％。结论：本方法可靠,稳定性、重现性好,可作为蜈蚣甘草散中重金属限量控制的方法。     

紫外分光光度法测定川射干总黄酮的含量

目的：建立川射干总黄酮含量的测定方法。方法：采用紫外分光光度法测定川射干药材中的射干苷含量,测定波长为266nm。结果：射干苷在0．002-0．010mg·mL^-1范围内与吸光度呈良好的线性关系,r=0．9991,回收率为97．45％,RSD为0．65％,川射干总黄酮的平均含量为4．17％。结论：该方法操作简便、灵敏、准确、具有良好的重复性和回收率,可作为川射干总黄酮含量测定的方法。     

颠胃酸口服液的消化活力测定

目的 建立颠胃酸口服液消化活力测定方法.方法 用酪氨酸为对照品,牛血红蛋白为底物,水浴温度37℃±0.5℃,紫外分光光度法,测定波长275 nm.结果 颠胃酸口服液平均消化活力为33.8μ·mL-1,高于标示量(24μ·mL-1),回收率为98.2％,RSD为0.96％(n=6).结论 该方法用于颠胃酸口服液的消化活力测定,操作便利,试验条件稳定,结果重复性好.     

Spectrophotometric dental colour measurement to assess age in living adults

The aim of this study was to evaluate the usefulness of spectrometrically measured colour parameters of teeth for age estimation in living adults. A total of 329 teeth were selected (162 upper central incisors and 167 upper canines) from 52 men and 50 women aged between 20 and 86 years. Colour measurements were performed in vivo on the vestibular surface of the teeth using a portable contact Spectro-color device. Colorimetric variables (L*, a*, b*), chromaticity coordinates (x, y, z), and indexes of whiteness (WIC, Z%, WI) and yellowness (YI) were calculated. The accuracy of colour values to estimate the age was determined by Receiver Operating Characteristic analysis. A more powerful age discrimination was obtained with upper incisors than with upper canines. Areas under the ROC curve ranged from 0.7 to 0.8 for all dental colour parameters measured in upper central incisors except for the variables L* and Z%, with sensitivity values ranging from 56% to 93% and specificity values from 38% to 92%. We conclude that spectrophotometric dental colour measurement may be an objective and useful tool to estimate age and meets medical ethical standards for application in living adults. However, further research is needed to study the effect of ethnicity and other factors on tooth colour.     

云南地区大叶千斤拔不同种质的异黄酮含量比较△

目的:建立大叶千斤拔中异黄酮含量测定方法,对比云南不同地区大叶千斤拔的药材质量,初步明确影响异黄酮含量的因素.方法:以染料木素为对照品,对紫外分光光度法测定大叶千斤拔中异黄酮的含量进行方法学考察,并用此方法测定采自云南不同地区野生及栽培的26份大叶千斤拔中异黄酮的含量.结果:采集野生样品中异黄酮的平均含量为0.990‰,其中屏边县的种质含量最高,为1.553‰,而绿春县(B)的种质含量最低,为0.652‰.分别栽培在3个地点的同一份大叶千斤拔种质,异黄酮含量有明显差异;在同一栽培条件下不同来源的大叶千斤拔种质异黄酮含量也有明显差异.结论:种质和环境因子对大叶千斤拔有效成分的积累均有影响.     

Optimising the methodology of calculating the cerebral blood flow of newborn infants from near infra-red spectrophotometry data

Cerebral blood flow can be measured in neonates by near infra-red spectrophotometry. The tracer is oxyhaemoglobin. The purpose of the study is to compare the test-retest variability of two previously proposed methods (UCH and COP) of analysis, and to investigate the influence of sampling rates, smoothing and integration periods. Under clinical conditions good measurements are often difficult to obtain. Therefore, a second goal is to find ways of determining the quality of individual measurements. 380 cerebral blood flow measurements from 69 infants are analysed. The data set is optimised statistically for the lowest test-retest variability and the following results are obtained. The test-retest variability of measurements at 2 s sampling time data is considerably worse than at 0·5 s sampling time. Smoothing does not change the test retest variability. A 6 s integration period gives higher values and higher test-retest variability than an 8 s integration period. By applying the suggested criteria, a test-retest variability of 17% is achieved, if 50% of the measurements are rejected. The mean cerebral blood flow is 12·2 ml(100 g)⁻¹ min⁻¹ for the UCH method and 97·7 ml(100 g)⁻¹ min⁻¹ for the COP method. The test-retest variability of both methods is comparable for 0·5 s sampling time. For 2 s sampling time the method proposed by Skov et al. is significantly better. These test retest variabilities represent maximum values, part of the observed variability may be due to physiological changes of unknown magnitude.     

Accumulation of toxic metals (Pb and Cd) in the sea urchin Diadema aff. antillarum Philippi, 1845, in an oceanic island (Tenerife,Canary Islands)

This document shows the results obtained from a study on the concentration of toxic heavy metals in the internal tissue and exoskeleton of sea urchins, collected from their natural habitat. The levels of lead and cadmium were measured by Graphite Furnace Atomic Absorption Spectrometry. The mean concentrations of lead and cadmium in the internal tissue were 304.04 and 260.54 μg/kg respectively, whereas in the shell they were 185.02 and 142.48 μg/kg. We also performed a statistical analysis of the differences in the distribution of metals between their exoskeleton and their internal content, a correlation study of the metal content in internal tissue and shell and sampling areas, and a correlation study between the metal content and sample size. Since the sea urchin Diadema antillarum presents a wide range of variation in metal content, this study suggests that this species is an excellent bioindicator of heavy metal contamination. © 2009 Wiley Periodicals, Inc. Environ Toxicol, 2010.