Rapid Stability Indicating Uv-Assay of Methenamine Mandelate In Tablets Using Solid Phase Extraction

Abstract

A rapid stability-indicating method was developed to quantitatively determine methenamine mandelate in tablets. After dissolution of the sample in water methenamine is separated from its decomposition product formaldehyde by the use of solid-phase extraction. the determination of methenamine may then be carried out by several procedures. A spectrophotometric assay following hydrolysis of methenamine to formaldehyde appeared to be most suitable.

The simplicity and accuracy of the method compares favourable with the U.S.P. XXI method. the procedure can be advantageously used in stability and quality control studies of methenamine containing dosage forms.

Precision and accuracy were checked by comparing the results of 10 identical raw material samples and 10 tablet samples that were both assayed by this method and the USP XXI procedure (Tables 4 and 5).

The assay values for methenamine and the relative standard deviations were similar for both procedures in both raw material and tablets.

Above results show that the SPE procedures give accurate, precise and reliable values for the methenamine assay. Since no titrant standardizations or lengthly sample pretreatments have to be carried out the method is fast, which makes it very suitable for industrial quality control purposes. the method is also economical. No precious instruments are necessary; a simple colorimetric device is sufficient.

The extraction columns can be reused several times. Even after 10 regenerations the columns did not show any deterioration.     

The Determination of Methenamine and its Salts in Tablet Dosage Forms Using Ion-Pair Extraction

Abstract

This paper reports a simple, accurate, reproducible, stability-indicating procedure which may be used to quantitatively determine methenamine base, methenamine mandelate or methenamine hippurate in tablet dosage forms. The procedure initially involves the separation of methenamine from the dosage form and from formaldehyde, the decomposition product, by a cartridge ion-pair extraction process. The methenamine may then be assayed by a number of methods. In this paper the methenamine was hydrolyzed to formaldehyde and the formaldehyde determined by the Nash procedure. The method compares favorably with the USP XXI procedure for methenamine tablets. Advantages of the procedure include the ability to use a single method for the base and salt forms of the drug and the potential application to stability and quality control studies of methenamine dosage forms.     

环氧氯丙烷类阳离子改性絮凝剂的合成及性能研究

为提高环氧氯丙烷胺类絮凝剂的絮凝性能,选用六次甲基四胺为交联剂,以环氧氯丙烷、二甲胺为主要原料,合成了环氧氯丙烷-二甲胺-六次甲基四胺(HMTA)季铵盐阳离子改性絮凝剂,其在辽河油田废水处理中表现出优异的絮凝性能,并研究了絮凝剂用量和温度对HMTA絮凝剂絮凝性能的影响。结果表明,使用HMTA絮凝剂的合适温度为45℃,最佳用量为20mg/L,除浊率可达98. 1%,除油率达到35. 1%。红外光谱和核磁共振谱的表征结果证实六次甲基四胺在聚合物中发挥了交联剂的作用,有效提高了环氧氯丙烷胺类絮凝剂的絮凝性能。