Application of quantitative thin-layer chromatography in drug assay and stability testing. Determination of codeine phosphate, noscapine, diphenhydramine hydrochloride, phenylephrine hydrochloride, caffeine, etofyllin, phenobarbital and thiamine hydrochloride by in situ reflectance spectroscopy

A Simple and Rapid Flow-Injection Chemiluminescence Method for the Determination of Noscapine with Ru(phen)32+-Ce(IV) System

A new flow injection chemiluminescence (CL) system was used for the determination of noscapine. This technique is based on the reduction effect of noscapine on the Ru(phen)3(3+), which is produced by reaction between Ru(phen)3(2+) and acidic Ce(IV) solutions, and this rapid reduction produces strong CL. Calibration plots were linear over the range of 3.0 x 10(-7) - 2.0 x 10(-6) mol L(-1) and 2.0 x 10(-6) - 2.0 x 10(-4) mol L(-1). The CL intensity was so high, that it is able to produce a detection limit of 6.6 x 10(-8) M noscapine (3sigma). The relative standard deviation of 2.0 x 10(-6) M noscapine was 1.0% (n=10). The proposed method was successfully applied for the flow injection determination of noscapine in cough and Tonin syrup samples. The results of real sample analyses show good recovery percentages (97.3-102.4%). The minimum sampling rate was 100 samples per hour.

Determination of thiamine by high-performance liquid chromatography

High-performance liquid chromatographic methods for the determination of thiamine (vitamin B1) in foodstuffs or biological tissues and fluids are outlined and discussed. The methods are often similar and interchangeable, sample extraction and clean up procedures being the major difference. Most of the methods use either ultraviolet or fluorescence detection. Fluorescence detection requires either precolumn or postcolumn oxidation of thiamine to thiochrome. A number of methods are recommended and problems with standardization are emphasized.

Determination of the components of analgesic mixtures using high-performance thin-layer chromatography

A spectrodensitometric method is described for the determination of the components of two analgesic mixtures. For the first mixture (paracetamol-ascorbic acid-caffeine-phenylephrine), the pharmaceutically active components were separated from each other and closely related degradation products and impurities on high-performance thin-layer chromatography (F254) plates using methylene chloride-ethyl acetate-ethanol-formic acid (3.5 + 2 + 4 + 0.5) and methylene chloride-ethyl acetate-ethanol (5 + 5 + 1) as the developing systems. The other mixture (phenazone-phenacetin-caffeine) was separated efficiently from the degradation products using the same plates and acetonitrile-chloroform (1 + 1) as the mobile phase. The proposed method was used to determine these mixtures in commercial tablets.