Spectrophotometric method for the determination of paracetamol and phenacetin

A rapid, sensitive and simple spectrophotometric method is proposed for the determination of hydrolysis products of paracetamol (PRL) and phenacetin (PHN) with sodium 1,2-naphthoquinone-4-sulphonate and cetyltrimethyl ammonium bromide (CTA) in alkaline medium. The absorbances are measured at 570 and 500 nm and the molar absorptivities found to be 1.118×10⁴ and 4.54×10³ l mol⁻¹ cm⁻¹ for PRL and PHN, respectively. The coloured species conforms to Beer's law over the range 1–20 μg ml⁻¹ for PRL and 2–24 μg ml⁻¹ of PHN. The sensitivity is enhanced by the addition of CTA. The method is successfully employed for determination of PRL or PHN in various pharmaceutical preparations and laboratory made tablets and results have been statistically compared with those obtained by the official method.     

尿炎清片的鉴别及盐酸小檗碱的含量测定

目的 鉴别尿炎清片并测定盐酸小檗碱的含量.方法 采用TCL法对处方中黄柏、广金钱草、泽泻进行定性鉴别;采用HPLC法测定片剂中盐酸小檗碱的含量.结果 在薄层色谱中可检出黄柏、广金钱草、泽泻;盐酸小檗碱在39.28～78.56μg范围内与峰面积呈良好的线性关系(r=0.9999),平均加样回收率为98.3%,RSD=1.87%(n=5).结论 所建方法简便、准确、可靠,可用于该制剂的质量控制.     

Spectrophotometric method for quantitative determination of total anthocyanins and quality characteristics of roselle (Hibiscus sabdariffa)

A simple, rapid and cost-saving method for the determination of total anthocyanins in roselle has been developed. The method was based on pH-differential spectrophotometry. The calibration curve of the major anthocyanin in roselle, delphinidin 3-sambubioside (Dp-3-sam), was constructed by using methyl orange and their correlation factor. The reliability of this developed method was comparable to the direct method using standard Dp-3-sam and the HPLC method. Quality characteristics of roselle produced in Thailand were also reported. Its physical quality met the required specifications. The overall chemical quality was herein surveyed for the first time and it was found to be the important parameter corresponded to the commercial grading of roselle. Total contents of anthocyanins and phenolics were proportional to the antiradical capacity.     

三元离子对－氯仿萃取分光光度法测定片剂中盐酸黄连素的含量

报道三元离子对－氯仿萃取分光光度法测定片剂中盐酸黄连素含量。在ｐＨ６．７介质中，黄连素与溴酚蓝和奎宁反应形成三元离子对。萃取入氯仿后，在６１０ｎｍ处有最大吸收。盐酸黄连素浓度在０～５．０μｇ／ｍｌ范围内，线性关系良好（ｒ＝０．９９９７）。平均回收率为９７．０％，相对标准偏差（ＲＳＤ）小于１．０％。     

Spectrophotometric method for the determination of carbidopa using neotetrazolium chloride.

A new high-sensitive spectrophotometric method for the determination of microquantities of carbidopa is described. The method is based on the reduction of neotetrazolium chloride by carbidopa in an alkaline ethanolic medium. The formazan formed exhibits an absorption maximum at lambda = 507 nm, with an apparent molar absorptivity of epsilon = 6.63 x 10(4) M-1 cm-1 and a corresponding Sandell's sensitivity of 3.68 ng cm-2. Beer's law is obeyed over the range of 0.10-6.0 micrograms mL-1 while the optimum concentration range is 0.125-5.0 micrograms mL-1. The regression line equation was calculated as: A = 0.271C + 0.0023 with a correlation coefficient of 1.0000 (n = 28). The accuracy and the precision of the method were considered as very satisfactory. The results obtained from the determination of carbidopa using both the described procedure and the corresponding USP. XXII and BP 1988 clinical methods were statistically compared by means of Student's t-test as well as by the variance ratio F-test, and no significant difference was observed.     

A high-throughput method for the quantitative determination of alliin

The quality of most garlic (Allium sativum L., Alliaceae) preparations made from garlic powder or garlic dry extract is determined by their content of alliin. Therefore, a comprehensive documentation of alliin concentration beginning with the crude material up to the final remedy is required. The newly developed analytical method described in this paper was designed in order to fulfill these demands. In contrast to conventional HPLC methods, neither a pre-column derivatization nor a chromatographic separation are involved in this analytical procedure allowing a high throughput of samples. The currently investigated technique is based on immobilized alliinase (EC 4.4.1.4) which was combined with a two-channel flow injection analyser (FIA) coupled to an ammonia detecting device. A high specificity for alliin could be demonstrated and a variety of garlic samples including garlic powders, dry extracts, and garlic preparations was analysed. The results were in good correlation with those obtained by conventional HPLC methods.     

用RP-HPLC法同时测定氯黄软膏中氯霉素和盐酸小檗碱的含量

目的：建立同时测定氯黄软膏中氯霉素和盐酸小檗碱含量的RP-HPLC法。方法：色谱柱为Kromasil-C18柱（150mm×4.6mm,5μm）,流动相为乙腈-0.033mol/L磷酸二氢钾溶液（30：70）,检测波长265nm,流速1.0ml/min,柱温为室温,进样量20μl。结果：氯霉素和盐酸小檗碱的线性范围分别为0.82～26.25μg/ml（r=0.9999）和0.79～25.35μg/ml（r=0.9999）,平均回收率分别为（96.53±0.89）%（n=3）和（99.58±3.50）%（n=3）。3批样品中氯霉素和盐酸小檗碱的平均含量分别为标示量的（95.75±0.52）%和（98.54±0.66）%。结论：该方法简便、准确,适用于氯黄软膏中氯霉素和盐酸小檗碱的质量控制。