A new approach for the determination of sunscreen levels in seawater by ultraviolet absorption spectrophotometry

Sunscreen is released into the marine environment and is considered toxic for marine life. The current analytical methods for the quantification of sunscreen are mostly specific to individual chemical ingredients and based on complex analytical and instrumental techniques. A simple, selective, rapid, reproducible and low-cost spectrophotometric procedure for the quantification of commercial sunscreen in seawater is described here. The method is based on the inherent properties of these cosmetics to absorb in the wavelength of 300–400 nm. The absorption at 303 nm wavelength correlates with the concentration of most commercial sunscreens. This method allows the determination of sunscreens in the range of 2.5–1500 mg L-1, it requires no sample pretreatment and offers a precision of up to 0.2%. The spectrophotometric method was applied to quantify sunscreen concentrations at an Atlantic Beach with values ranging from 10 to 96.7 mg L-1 in the unfiltered fraction and from the undetectable value to 75.7 mg L-1 in the dissolved fraction. This method is suggested as a tool for sunscreen quantifications in environmental investigations and monitoring programs.

VALIDATION OF THE SPECTROPHOTOMETRIC PROCEDURE FOR DESLORATADINE ASSAY IN TABLETS APPLYING THE UNCERTAINTY CONCEPT OF THE STATE PHARMACOPOEIA OF UKRAINE

Aim. This work aimed to validate an assay procedure for desloratadine tablets by direct spectrophotometric method. Materials and methods. A pilot-scale batch of the pharmaceutical preparation Alerdez, film-coated tablets containing 5 mg of desloratadine, manufactured by PJSC SIC “Borshchahivskiy CPP”, Ukraine, was used as an object of the study. A UV-Vis spectrophotometer Lambda 25 (Perkin Elmer), analytical balance Mettler Toledo XP 205DR, and class A volumetric apparatus were used in the study. Validation of the procedure was performed following the metrological approach of the State Pharmacopoeia of Ukraine (SPhU), whose requirements for the target uncertainty and bias, which rest on the risk assessment of making incorrect decisions on compliance (a confidence level of 95 %), were translated into criteria for all validation characteristics recommended by ICH. All calculations were made in normalised coordinates. The linearity, accuracy and precision (repeatability) were studied in a single experiment using nine different concentrations that uniformly covered the range of ±30 % from the nominal concentration of desloratadine. For validation of the procedure, an SPhU reference standard of desloratadine was used. Results. The experiment design and validation characteristics being tested were in full compliance with ICH Q2(R1) recommendations. All performance characteristics conformed to the criteria recommended by the SPhU. Requirements for the target uncertainty (1.6 %) and bias for any systematic source of variation (≤0.51 %, negligible in relation to 1.6 %) were established. The analytical procedure was specific – the absorbance from the placebo solution was insignificant (A %=0.36). The procedure met the requirements for linearity, accuracy, and precision at the repeatability level. The residual standard deviation s0 was 0.34 (≤ 0.84); correlation index Rc was 0.9998 (≥0.9991); intercept а was 0.045 (less than its confidence interval ∆a=1.14). The confidence interval for recovery ∆Z, which was used as a precision estimate, was 0.55 % (less than the target uncertainty). The mean recovery, which was used as an accuracy estimate, statistically insignificantly deviated from 100% (|Zmean ‑ 100| = 0.022 %). The confidence interval for the intermediate precision ∆intra was 0.33 % (less than the target uncertainty). The developed analytical procedure was found to be robust. Conclusions. A spectrophotometric procedure suitable for the assay of desloratadine in film-coated tablets Alerdez with content limits of ±5 % was validated by the SPhU approach.

Modern kinetic spectrophotometric procedure for estimation of furosemide drug as bulk form and in pharmaceuticals preparations

A simple, rapid, sensitive, inexpensive and easy to perform kinetic spectrophotometric procedure for the investigation of trace quantities of the drug, furosemide (FRO), as bulk and in the pharmaceutical preparations, has been improved upon. The enhanced method was depended on the fashioning of the Schiff ‘s base by the reaction of the aldehyde group present in the 5-sulfo salicylaldehyde reagent, and the primary amino group present in furosemide. The latter acts as a ligand for the formation of an intense colored complex with Co(II) in an acidic medium, with maximum absorption at 608 nm. In the work, kinetic spectrophotometrics were established through the fixed time method. Moreover, Beer’s law was applied on the range of concentration between 5-100 ppm, while the molar absorptivity and the Sandell sensitivity were 3.9295×104 l.mol−1cm−1, 0.008 μg.cm−2, respectively. The detection limit (LOD) was 2.133 µg/ml−1, and LOQ was 1.105 µg/ml−1. Ideal circumstances for all colour improvement were seen, and the suggested procedure has been effectively employed in investigating amounts of furosemide (FRO) in bulk forms and in pharmaceutical preparations (tablets, injection sample). Additives and general excipient materials did not affect the studied method. A statistical comparison between the results that were obtained from the reference method gave good agreement.