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This study investigates into the pharmacological potential of three solvent extracts (ethyl acetate, methanol, and water) of two Ajuga species (Ajuga chamaepitys subsp. chia var. chia and Ajuga bom...

Ciclopirox olamine is an antifungal agent widely used in dermatological formulations for topical application. The methods described for its determination usually present time-consuming sample treatment or require major human participation. Here we present a rapid flow system for the determination of ciclopirox olamine, based on the use of sequential injection analysis with terbium-sensitized luminescence detection. The reaction between terbium and the analyte is carried out on-line, recording the analytical signal at 300/545 nm (λex/λem). A detection limit of 15 µg L−1 and a R.S.D. of 3% (n = 10) were obtained. It is worth mentioning that the method here presented is the only one that uses a flow system for the determination of ciclopirox olamine. The flow system was applied to the analysis of different pharmaceutical preparations available in the Spanish Pharmacopoeia. A recovery study was performed, obtaining satisfactory results. The high solution throughput obtained, 50 samples per hour, makes the met...

This paper deals with the photo-induced fluorimetric determination of the insecticide fipronil using a sequential-injection flow assembly provided with an on-line photoreactor. The fluorescent photoproduct generated after UV irradiation for 20 s of the insecticide at 0.01 M NaOH solution is monitored at 245/450 nm/nm (λexc/λem). A detection limit of 0.17 µg mL−1 and a sample throughput of 18 samples per hour were obtained. The proposed method was satisfactorily applied to the determination of the analyte in phytosanitary and veterinary products with minimum pretreatment. In addition, a recovery study was performed in all the analyzed samples, observing recoveries between 95 and 100%, with R.S.D. lower than 3% in all cases.

In this paper, the conversion of tigecycline, a first-in-class glycylcycline antibiotic, into a fluorescent degradation product with quantitative purposes by UV irradiation and its fluorimetric determination are reported for the first time through the presentation of a spectroscopic method for the determination of this compound. A multicommutated flow-assembly employing three-way solenoid valves is used for the analysis, with the entire procedure being computer-controlled. The degradation product is measured at excitation and emission wavelengths of 333 and 453 nm, respectively, obtaining 33 µg L−1 as the detection limit, a linear dynamic range between 0.1–2 µg mL−1, and a R.S.D. of 2.8% (n = 10).

A rapid, sensitive and simple spectrophotometric method for the determination of amiloride in pharmaceutical preparation and urine is described in this paper. The method is based on the sorption of amiloride on a cation-exchange resin (Sephadex SP C-25) at pH 4.0 and the direct measurement of its intrinsic UV absorbance in the solid phase at 362 nm (the maximum absorption wavelength) and 412 nm (wavelength at which only the solid support absorbs light). The calibration graphs were linear from 0.8 to 7, 0.08 to 0.7 and 0.02 to 0.15 µg mL−1 with detection limits of 0.2, 0.02 and 0.006 µg mL−1 for 10, 100 and 500 mL sample volumes, respectively. The relative standard deviations for ten independent determinations were better than 3.46%. The one step method was satisfactorily applied to the rapid determination of amiloride in pharmaceutical preparations and urine without any pre-treatment of the samples.