Simultaneous Estimation of Telmisartan, Chlorthalidone, Amlodipine Besylate and Atorvastatin by RP-HPLC Method for Synchronous Assay of Multiple FDC Products Using Analytical FMCEA-Based AQbD Approach.

Numerous reversed-phase high-pressure liquid chromatography (RP-HPLC) and high-performance thin-layer chromatography (HPTLC) techniques have been published for the estimation of fixed-dose combinations (FDCs) of telmisartan (TEL). No published literature has been reported to date which described the synchronous estimation of FDCs of TEL using a single chromatography condition. Hence, the RP-HPLC method has been developed and validated for synchronous analysis of FDCs of TEL using an enhanced analytical quality by design (AQbD) approach to save time, cost and solvent for analysis. The implementation of AQbD was initiated with the identification of failure modes (FMs) using the Ishikawa diagram, and their critical effect analysis was carried out by risk priority number ranking and filtering method. The identified critical FMs were optimized by design of experiments-based response surface modeling using the Box-Behnken design. The method operable design region was navigated and control strategy was framed to mitigate the risk of critical FM. The RP-HPLC method was developed using Shim-Pack octadecyl silane C18 column and acetonitrile: 1.0%v/v triethylamine (pH 6.5 adjusted using perchloric acid; 42:58, %v/v). The developed method was found to be validated as per the International Council For Harmonization Q2 (R1) guideline. The method was applied for the synchronous assay of seven different FDCs of TEL and assay results were found in good compliance with the respective labeled claim.

Electrospun orally disintegrating film formulation of telmisartan.

Telmisartan (TEL) is an antihypertensive BCS class II drug with low solubility at physiological pH. However, the solubility of TEL increases with the presence of an alkalizer. Electrospinning is one of the most recent techniques for the solubility enhancement studies. In this study, an electrospun orally disintegrating film (ODF) formulation of TEL was developed with L-arginine and polyvinylpyrrolidone K90 (PVP), and its characterization studies were performed. Preformulation studies were performed to investigate possible incompatibilities in the components of formulation with differential scanning calorimetry (DSC) and Fourier transform infrared spectrometer (FT-IR) analyses. ODFs were characterized in terms of drug content and uniformity, mechanical properties, fiber shape and diameter and in vitro dissolution profile. Smooth nanofibers without any beads were obtained. The dissolution rate of the TEL significantly increased. The chosen formulation had acceptable mechanical properties with much faster dissolution compared to the commercially available product. Developed ODF and marketed product were compared with a dissolution study in phosphate-buffered solution (pH 7.4). ODF and marketed product both reached 100% release in the 45th minute, and ODF results showed that ODF had much faster release than marketed product. In this study, TEL ODF formulation was successfully produced and characterized.

QbD-based development of an extraction procedure for simultaneous quantification of telmisartan, amlodipine besylate and chlorthalidone in combination complex matrix formulation.

The main objective of this study was to establish an efficient extraction procedure for the estimation of telmisartan, amlodipine and chlorthalidone from their combination in sample matrix using an analytical quality by design approach. Initial screening studies were performed for optimization of a suitable diluent to extract active components from sample matrix. Further, the same study was extended for the identification of critical method attributes and the factors affecting the analytical target profile. This study also explains the rugged and robust quantitative determination of combinations drugs with a shorter run time. The design of experimental studies confirms that the current center point parameters are well suited to recoveries. The chromatographic separation was achieved with an X-Terra RP8, 150 × 4.6 mm, 3.5 µm column with an isocratic mobile phase (mixture of 20 mm aqueous ammonium acetate and acetonitrile). To demonstrate the stability-indicating nature of the optimized method, forced degradation studies were conducted and proved. The optimized method was validated according to International Conference on Harmonization guidelines.

Quantitative investigation of hepatobiliary transport of [11C]telmisartan in humans by PET imaging.

The pharmacokinetics of telmisartan are nonlinear within the clinical dose range. To identify the underlying mechanism of this nonlinearity, we conducted a PET study in healthy subjects using [11C]telmisartan. Eight healthy male subjects were enrolled in a 2-way crossover study. PET imaging was performed after intravenous administration of [11C]telmisartan with or without a 1-h oral predose of two 40 mg Micardis® tablets. About 60% of the injected [11C]telmisartan accumulated in the liver within 10 min after injection. With predosing of 80 mg telmisartan, the systemic elimination of [11C]telmisartan was slightly delayed, but the liver exposure started to decrease earlier and biliary excretion was greatly enhanced. Hepatic uptake clearance of the radioactivity was not changed by telmisartan predosing, whereas the biliary clearance of radioactivity from the liver was significantly increased. Thus, the alteration in the pharmacokinetics of the radioactivity could not be explained simply by the saturation of hepatic uptake. Therefore, other mechanisms, such as the saturation of intracellular binding of telmisartan and/or its glucuronide, and the glucuronidation of telmisartan by uridine 5'-diphospho-glucuronosyltransferases, should be considered. This is the first reported human PET study using [11C]telmisartan, the results of which can assist understanding of the hepatobiliary transport of telmisartan in humans.