[Validation of an HPLC method for the analysis of decomposition products in injectable diazepam]. / Validácia HPLC metódy na analýzu rozkladných produktov diazepamu v injekciách diazepamu.

Diazepam is an important drug from the group of benzodiazepines, used in clinical practice for its sedative, hypnotic, anticonvulsive, myorelaxant, and primarily anxiolytic effects. Several kinetic studies have been published which show that diazepam is a drug sensitive to hydrolysis both in acid and alkaline media. The present study aimed to elaborate and validate a simple and rapid HPLC/UV method for simultaneous analysis of three decomposition products of diazepam in the presence of diazepam and to apply it also on the control of stability of the injectional solution of diazepam. The optimization of chromatographic conditions resulted in the use of the high-performance chromatographic column Zorbax ODS, the mobile phase represented by a mixture of acetonitrile/water in a ratio of 60/40 (w/w, %), flow rate 1.5 ml/min, and spectrophotometric detection at 242 nm. The elaborated method and the employed chromatographic system were successfully validated and they can be used in practice in the control of stability of injection solution of diazepam.

[A study of the stability of dioxopromethazine in aqueous solutions and ophthalmic instillation]. / Stúdium stability dioxoprometazínu vo vodných roztokoch a v ocnej instilácii metódou HPLC.

Dioxopromethazine began to be used in therapy as a modern antihistamine agent in the 1970s. A dioxopromethazine-containing ophthalmic instillation and a gel were employed until the end of the 1990s. The paper deals with the examination of the stability of the drug dioxopromethazine in aqueous solutions and the ophthalmic instillation Promefrin stored under different conditions. High-performance liquid chromatography with spectrophotometrical and electrochemical detection and HPLC connected on-line with mass spectrometry were employed for analysis. Dioxopromethazine in aqueous solutions and in ophthalmic instillations stored in direct sunlight was found not to be stable. However, the cover of the ophthalmic instillation, a brown-glass prescription bottle, and observation of storing conditions sufficiently protect the active ingredient from decomposition processes.

[Modern HPLC in drug analysis]. / Moderná HPLC v analýze lieciv.

High performance liquid chromatography found wide-spread utilization almost in all fields of pharmaceutical analysis since the 1980s. The article summarizes the new knowledge and interesting findings about HPLC used in the analysis of drugs during the last three years with a supplement of particular applications in pharmaceutical analysis.

[Validation of the HPLC method in the determination of dioxopromethazine and phenylephrine in eye drops]. / Validácia HPLC metódy pre stanovenie dioxoprometazínu a fenylefrínu v ocnej instilácii.

The present paper introduces a rapid HPLC method for the determination of dioxopromethazine and phenylephrine in eye drops. The method uses a modified C18 stationary phase optimized for the separation of basic compounds and a methanol/1.5 mM phosphoric acid (60/40 v/v, pH 3.02) mobile phase. The flow rate is set to 2 ml/min, sample volume 20 microliters, and compounds are detected at 275 nm. Prior to analysis, the eye drops are diluted with water in a ratio of 1:50. The elaborated HPLC method and the chromatographic system were validated according to the procedure for the validation of chromatographic systems and methods.

[Determination of residual trifluralin in the herbal drug Mentha piperita L]. / Stanovenie rezíduí trifluralinu v droge Mentha piperita L.

A HPLC/UV method was worked out to determine the residues of the herbicide trifluralin in the vegetable drug of the peppermint (M. piperita L.). The yield of the method, determined in model samples, was at least 70%, the determination limit of the method being 0.07 mg.kg-1. The content of trifluralin residues in the vegetable drug of the peppermint plant after application of the preparation Treflan 48 EC (in a dose of administration of 2 kg.ha-1) for the treatment of the growth in a small-plot experiment was below the detection limit of the analytical method.