Determination of the R-enantiomer of valsartan in pharmaceutical formulation by capillary electrophoresis

Applications of electrophoresis for small enantiomeric drugs in real-world samples: Recent trends and future perspectives

Separation and identification of chiral molecules is a topic widely discussed in the literature and of fundamental importance, especially in the pharmaceutical and food fields, both from industrial and laboratory points of view. Several techniques are used to carry out these analyses, but high-performance liquid chromatography is often the "gold standard." The high costs of chiral columns, necessary for this technique, led researchers to look for an alternative, and capillary electrophoresis (CE) is a technique capable of overcoming some of the disadvantages of liquid chromatography, often providing comparable results in terms of sensitivity and robustness. We addressed this topic, already widely discussed in the literature, providing an overview of the last 6 years of the most frequent and recent applications of CE. To make the manuscript more effective, we decided to divide it into paragraphs that represent the main field of application, from enantioseparation in complex matrices (pharmacokinetic studies or toxicological dosage of drugs, analysis of environmental pollutants, and analyses of foods) to quality control analyses on pharmaceutical formulas. About these, which are the fields of most meaningful use, we mentioned some of the most innovative and performing methods, with a look to the future on the application of new materials used, such as chiral selectors, that can make these types of analyses accessible to all, reducing cost, time, and excessive use of toxic solvents.

Development and validation of a stability-indicating, single HPLC method for sacubitril-valsartan and their stereoisomers and identification of forced degradation products using LC-MS/MS

The aim of this research work was to develop and validate a stability-indicating, single reversed-phase HPLC method for the separation of five impurities, including enantiomers, diastereomers, and degradation products in sacubitril-valsartan tablets. The method was developed using a Chiralcel OJ-RH column (150 × 4.6 mm, 5 μm) at 45°C with a gradient program of (T/%B) 0.01/25, 10.0/25, 25/38, 37.0/45, 39.0/25, and 45.0/25 at a flow rate of 0.8 ml/min. Mobile phase A consisted of 1 ml of trifluoroacetic acid in 1000 ml of Milli-Q water. Mobile phase B consisted of 1 ml of trifluoroacetic acid in a mixture of acetonitrile and methanol in the ratio of 950:50 (v/v). Sacubitril, valsartan, and their five impurities were monitored at 254 nm. Degradation was not observed when sacubitril-valsartan was subjected to heat, light, hydrolytic, and oxidation conditions. In acid degradation study (1 N HCl/60°C/2 h) impurity 1 (m/z 383.44) was formed, and in base degradation study (0.1 N NaOH/40°C/1 h) impurities 1 and 5 (m/z 265.35) were formed; both impurities were confirmed using LC-MS. The degradation products, enantiomers, and diastereomers were well separated from sacubitril and valsartan, proving the stability-indicating power of the method. The developed method was validated per the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines. The inter- and intra-day percentage relative standard deviation for sacubitril, valsartan, and their five impurities was less than 5.2%, recovery of the five impurities was between 93 and 105%, and linearity was ≥0.999. The limit of detection was 0.030-0.048 μg/ml, and the limit of quantification was 0.100-0.160 μg/ml.

Study on Co-Crystallization of LCZ696 Using In Situ ATR-FTIR and Imaging

In situ ATR-FTIR spectroscopy and imaging and image analysis were applied to the study of the multicomponent co-crystallization process involving S-valsartan and sacubitril in which LCZ696 crystals were formed. LCZ696 is a combination drug for use in heart failure that was approved by the FDA in 2015 following development by Novartis Pharmaceuticals. Though much work was reported on LCZ696 about its pharmacokinetic and pharmacodynamic effects in the evaluation and clinical testing, less attention was paid to study on the co-crystallization process. LCZ696 crystals have shown difficulties in filtration mainly due to the small particle size. In this work, LCZ696 crystals were prepared successfully by S-valsartan and sacubitril, and characterized by SEM, XRPD, TG-DSC and ATR-FTIR. ATR-FTIR and imaging and image analysis were used to monitoring solution concentration and investigating the co-crystallization mechanism. It revealed that the nucleation process was very slow compared with the transformation process, which is indication that the co-crystallization was controlled by nucleation. LCZ696 crystals are composed of very thin hexagonal plates, which seems indicating that LCZ696 crystals grow mainly in two size dimensions. Stirrer speed and crystal seeds were found to have noticeable effect on the induction time, transformation time and crystal size distribution. The Johnson-Mehl-Avrami equation was found to be able to describe the co-crystallization process.

Capillary electrophoretic methods for quality control analyses of pharmaceuticals: A review

Capillary electrophoresis represents a promising technique in the field of pharmaceutical analysis. The presented review provides a summary of capillary electrophoretic methods suitable for routine quality control analyses of small molecule drugs published since 2015. In total, more than 80 discussed methods are sorted into three main sections according to the applied electroseparation modes (capillary zone electrophoresis, electrokinetic chromatography, and micellar, microemulsion, and liposome-electrokinetic chromatography) and further subsections according to the applied detection techniques (UV, capacitively coupled contactless conductivity detection, and mass spectrometry). Key parameters of the procedures are summarized in four concise tables. The presented applications cover analyses of active pharmaceutical ingredients and their related substances such as degradation products or enantiomeric impurities. The contribution of reported results to the current knowledge of separation science and general aspects of the practical applications of capillary electrophoretic methods are also discussed.

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.