Determination of azide impurity in sartans using reversed-phase HPLC with UV detection

Real-Time Monitoring of Translocation, Dissipation, and Cumulative Risk of Maleic Hydrazide in Potato Plants and Tubers by Ion Exclusion Chromatography

In this paper, a high-performance ion exclusion chromatographic (ICE) method was developed and applied for monitoring maleic hydrazide (MH) translocation in complex potato plant tissue and tuber matrices. After middle leaf uptake, most MH was trapped and dissipated in the middle leaf, and the rest was transported to other parts mainly through the phloem. Soil absorption significantly reduced the uptake efficiency of the root system, in which MH was partitioned to dissipate in root protoplasts or transfer through the xylem and persisted in the plant. Tuber uptake enabled MH to remain in the flesh and maintain stable levels under storage conditions, but during germination, MH was translocated from the flesh to the growing buds, where it dissipated through the short-day photoperiodic regime. The results demonstrated successful application of the ICE method and provided necessary insights for real-time monitoring of MH translocation behavior to effectively improve potato edible safety.

How Azide Ion/Hydrazoic Acid Passes Through Biological Membranes: An Experimental and Computational Study

Hydrazoic acid (HN₃) and its deprotonated form azide ion (N₃^-) (AHA) are toxic because they inhibit the cytochrome c oxidase complex IV (CoX IV) embedded in the inner mitochondrial membrane that forms part of the enzyme complexes involved in cellular respiration. Critical to its toxicity is the inhibition of CoX IV in the central nervous system and cardiovascular system. Hydrazoic acid is an ionizable species and its affinity for membranes, and the associated permeabilities, depend on the pH values of aqueous media on both sides of the membranes. In this article, we address the permeability of AHA through the biological membrane. In order to understand the affinity of the membrane for the neutral and ionized form of azide, we measured the octanol/water partition coefficients at pH values of 2.0 and 8.0, which are 2.01 and 0.00034, respectively. Using a Parallel Artificial Membrane Permeability Assay (PAMPA) experiment, we measured the effective permeability through the membrane, which is logP_e - 4.97 and - 5.26 for pH values of 7.4 and pH 8.0, respectively. Experimental permeability was used to validate theoretical permeability, which was estimated by numerically solving a Smoluchowski equation for AHA diffusion through the membrane. We demonstrated that the rate of permeation through the cell membrane of 8.46·10⁴ s^-1 is much higher than the rate of the chemical step of CoX IV inhibition by azide of 200 s^-1. The results of this study show that transport through the membrane does not represent the rate-limiting step and therefore does not control the rate of CoX IV inhibition in the mitochondria. However, the observed dynamics of azide poisoning is controlled by circulatory transport that takes place on a time scale of minutes.

Determination of Genotoxic Azide Impurity in Cilostazol API by Ion Chromatography with Matrix Elimination

Cilostazol is a commonly used active pharmaceutical ingredient (API) to treat and reduce the symptoms of intermittent claudication in peripheral vascular disease. Recently, it was found to be a potential medicine in the effective treatment of COVID-19. In addition to the positive effects of this API, genotoxic sodium azide is used in the synthesis of cilostazol that can appear in the API. In this work, a method was developed for the determination of sodium azide (as azide anion) in cilostazol API at 7.5 ppm limit level by using ion chromatography (IC) and liquid–liquid extraction (LLE) sample preparation. The liquid–liquid extraction allows the application of high sample concentrations. Because of the low limit concentration (7.5 ppm), 500 mg sample was dissolved in 5 mL solvent. By using LLE for sample preparation, the huge amount of cilostazol was omitted and column overload was avoided. The developed method was validated in accordance with the relevant guidelines. Specificity, accuracy, precision, limit of detection and limit of quantification parameters were evaluated. The calculated limit of detection was 0.52 ppm (S/N:3) and the limit of quantification was 1.73 ppm (S/N:10) for sodium azide. The recovery of the sodium azide was 102.4% and the prepared solutions were stable in the sample holder for 24 h.

A novel simple and precise method for the determination of azide impurity in sartans using headspace gas chromatography with two dissimilar capillary columns and two flame ionization detectors (HS-GC-FID/FID)

Determination of azide as an impurity in medicinal products was performed for the following sartans with tetrazole functional group (synthesized with the use of azide ion): candesartan, losartan, irbesartan, olmesartan medoxomil, and valsartan. This was achieved using headspace gas chromatography using a dual column/dual flame ionization detector (HS-GC-FID/FID). The method was linear in range, from 5.0-30.0 μg/g, with a coefficient of determination of >0.998 (R²). The limit of quantification was 5.0 μg/g and the detection limit was 1.9 μg/g. The sample preparation procedure is fast and simple. The validation procedure was performed in accordance with International Conference on Harmonization (ICH) and Pharmacopeia guidelines. Moreover, besides the content of azide ions, trace quantities of residual solvents (methanol, ethanol, acetone, isopropanol) were found in the majority of sartan tablets.

Analytical Methods for the Determination of Sartans in Pharmaceutical Formulations and Biological Fluids: A Review

Background:

Sartans are mostly used as a part of combination with additional medicines in the therapy of essencial hypertension. Preferred combinations are ARB and thiazide diuretics (Hydrochlorothiazide (HCT) and Chlorthalidone (CHL)) or ARB and calcium antagonists. The number of sartans mostly prescribed by specialists is only seven - Candesartan (CDS), Eprosartan (EPS), Irbesartan (IBS), Losartan (LOS), Olmesartan (OMS), Telmisartan (TMS) and Valsartan (VLS).

Methods:

The widespread use of sartans in the treatment of hypertension requires reliable methods of analysis. Bulk drugs and pharmaceutical preparations should be analyzed to ensure the quality of the medicinal products reaching patients. On the other hand, the analysis of drugs in biological fluids aims to trace and improve patient care by adjusting the therapeutic doses of drugs. According to our knowledge, a review devoted to the analysis of sartans was published in 2014.

Results:

Spectral methods are widely used in the analysis of bulk drugs and pharmaceutical dosage forms due to their relatively simple procedures, low reagent and sample consumption, speed, precision and accuracy combined with accessibility and comparatively low cost of common apparatus. Many papers for determination of sartans in bulk drugs and pharmaceutical preparations based on liquid chromatographic techniques were published in the available literature. Among these methods, HPLC takes the leading place but UPLC and HPTLC are also present.

Conclusion:

The widespread use of sartans in the treatment of hypertension requires reliable methods of analysis. Bulk drugs and pharmaceutical preparations should be analyzed to ensure the quality of the medicinal products reaching patients. On the other hand, the analysis of drugs in biological fluids aims to trace and improve patient care by adjusting the therapeutic doses of drugs. Since 2014, many articles have been published on the sartans analysis and this provoked our interest to summarize the latest applications in the analysis of sartans in pharmaceutical formulations and biological media. Articles published from 2014 to 2018 are covered.