Determination of Theophylline in Serum by Ion-Pairing Reversed-Phase High-Performance Liquid Chromatography

HIGH-PERFORMANCE LIQUID CHROMATOGRAPHIC DETERMINATION OF THEOPHYLLINE IN HUMAN SERUM

A simple, rapid and sensitive HPLC method for the determination of theophylline (T) in human serum has been developed. An isocratic system consisting of a /-l Bondapak C18 column, mobile phase of methanol, phosphate buffer (22:78, pH=4.5), and a flow rate of 1.4 mL/min was used. The eluent was detected by UV at 275 nm at room temperature. 8-Chlorotheophylline (8-CT) was used as an internal ...

Determination of urinary oxalate by reversed-phase ion-pair "high-performance" liquid chromatography.

In this liquid-chromatographic method for determination of urinary oxalate, interfering compounds in the urinary samples were eliminated before chromatography by passage through a preparative C18 mini-column (Sep-pak cartridge, Waters Associates). In the reversed-phase system tetrabutyl ammonium was included as a counter ion to enhance the retention of oxalate. The pH of the mobile phase was ke...

Reversed-phase high-performance liquid chromatography.

Reversed-phase High-performance Liquid Chromatography Study of Lipophilicity of Imidazo[2,1-f]theophylline Derivatives.

The present study is a part of our physicochemical and pharmacological studies in a group of tricyclic theophylline derivatives. The investigated compounds exhibit different pharmacological profiles in comparison to theophylline and have been tested as potential antidepressant and/or antipsychotic agents. The differences in pharmacological action between theophylline and their tricyclic derivat...

Separation of Somatropin and Its Degradation Products by High-Performance Liquid Chromatography Using a Reversed-Phase Polymeric Column

The accurate prediction of protein stability is one of the most challenging goals in protein formulation and delivery. In this study, a gradient RP-HPLC method is described for the separation of human growth hormone (hGH) variants as deamidated and oxidized forms. The methodology employed a polymeric poly (styrene-co-divinylbenzene) column and a 1mL/min flow rate of a linear gradient of 0.1% v/...