Reducing the amounts consumed of organic solvents while keeping good chromatographic performance has been a significant step towards the greening of analytical methodologies. When sodium dodecyl sulfate (SDS) and Brij-35 surfactants are combined in a mobile phase, they can be used as a green alternative to organic modifiers. Surfactants have numerous advantages, including low cost and toxicity, safe environmental disposal, and unique selectivity, in addition to high solubilization capabilities. In this research, two highly selective chromatographic methods were adopted for the determination of betahistine (BHS) in the presence of its pharmacopeial impurity 2-(2-hydroxyethyl)pyridine (HEP). A solvent-free HPLC method was validated, in which the mixture was separated using a C18 column (3.5 µm, 75.0 × 4.6 mm) and a mobile phase composed of 0.01 M Brij-35, 0.12 M SDS, and 0.02 M disodium hydrogen phosphate adjusted to a pH of 5.5 using phosphoric acid. The flow rate was 1.5 mL min−1 and the resolved peaks were detected at 260 nm. Another HPTLC-densitometric method was validated using HPTLC aluminum plates coated with silica gel 60 F254 as the stationary phase and a developing system consisting of methylene chloride/methanol/ethyl acetate/ammonia (at a ratio of 5:2:2:0.2 by volume); the separated bands were scanned at 260 nm.
AbstractIn the last few years, the use of surfactants as mobile phase additives in reversed phase liquid chromatography (RPLC) has been steadily developing and improving. Surfactants modify the polarity of the stationary phase which in turn decreases the amount of organic solvent required for elution of the analytes rendering the methodologies linked to them greener and more eco-friendly. Brij-35 is a fatty alcohol ethoxylates non ionic surfactant, which is less widely used as mobile phase additive. Brij-35 can decrease stationary phase polarity while remaining neutral. In this research, Brij-35 was studied in the separation and determination of marketed antihypertensive combination therapy composed of triamterene (TRM) and xipamide (XIP). TRM and XIP are diuretics used for treatment of essential hypertension and associated edema conditions. Chromatographic separation was achieved on RP-C18 column (Kinetix®, 5 µm, 15 cm × 4.6 mm) at flow rate 1 mL min−1 and UV-detection at 254 nm. Isocratic elution was performed using mobile phase composed of 0.1 M Brij-35: methanol (MeOH) (60:40, v/v). The analytes were well separated and quantified within linearity ranges of 5–50 µg mL−1 for both drugs in short retention time (2.6 and 5.3 min. for TRM and XIP, respectively). Since claiming greenness is not enough, Green Analytical Procedure Index (GAPI) was used to demonstrate the superiority of the proposed method over the previously reported methods. GAPI is a new metric for evaluation of the ecological impact of analytical procedures. The proposed method was validated according to ICH guidelines and applied successfully for simultaneous determination of the drugs in their co-formulated tablets.
Pharmaceutical quality control products (QC) demand quick, sensitive, and cost-effective methods to ensure high production at a low cost. Green analytical methods are also becoming more common in pharmaceutical research to cut down on the amount of waste that goes into the environment. Meclizine hydrochloride (MZH) and pyridoxine hydrochloride (PYH) are reported to be excellent for calming down COVID-19. As a result, the amount of MZH and PYH manufactured by multinational pharmaceutical organizations has increased considerably during the last several months. The present work proposes three environmentally friendly, straightforward, and sensitive spectrophotometric procedures for quantification of MZH in the presence of PYH in a pure and marketable formulations. The approaches under examination include ratio subtraction (RSM), induced dual wavelength (IDW), and Fourier self-deconvolution (FSD). PYH, on the other hand, was directly quantified at 290 nm. For both drugs, the procedures follow Beer’s law in the range of (5–50 µg/mL). The RSM, IDW, and FSD methods, as well as the zero-order approach for PYH, have all been verified in accordance with ICH standards. The ecological value of established methodologies was determined using four distinct ways: the national environmental methods index (NEMI), the analytical Eco-scale, the Analytical Greenness Metric (AGREE), and the green analytical process index (GAPI). Comparing the findings to those of the previously described spectrophotometric technique, no major changes were identified.
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