Stability Indicating RP-HPLC-DAD method for simultaneous estimation of tadalafil and macitentan in synthetic mixture for treatment of pulmonary arterial hypertension

OBJECTIVE

High Performance liquid chromatography is an integral analytical tool in assessing drug product stability. A simple, selective, precise, accurate and stability indicating RP-HPLC method was developed and validated for analysis of Tadalafil and Macitentan in synthetic mixture.

MATERIAL AND METHOD

Chromatographic separation was performed using Phenomex Gemini C18 (25cm×4.6nm, 5μm) Column. The mobile phase consists of (10mM Ammonium Acetate in water and [Methanol: ACN 20: 80% v/v]) (40: 60% v/v). The flow rate was set to be 1.0mL/min. The injection volume was 10.00μL. The detection was carried out at 260nm at column temperature 35°C.

RESULTS

The method was validating according to ICH Q2R1 guideline for accuracy, precision, reproducibility, specificity, robustness and detection and quantification limits. Stability testing was performed on Tadalafil and Macitentan and it was found that these degraded sufficiently in all applied chemical and physical conditions. Linearity for Tadalafil and Macitentan was observed 0.4-100μg/mL and 0.1-25μg/mL with correlation coefficient at 0.9999. LOD and LOQ 0.008μg/mL and 0.024μg/mL and 0.001μg/mL and 0.0029μg/mL for Tadalafil and Macitentan respectively.

CONCLUSION

The developed RP-HPLC method was found to be suitable for the determination of both the drugs.

Development and validation of stability indicating RP-HPLC method for simultaneous estimation of silodosin and mirabegron in synthetic mixture

The study focuses to validate and develop a precise, simple and accurate stability indicating RP-HPLC method for estimation simultaneously of and silodosin and mirabegron in synthetic mixture. The chromatographic separation was achieved by using Shimpack Solar C18 column (250×4.5mm, 5μm) with acetonitrile: 5mM ammonium acetate in ratio of 90:10% v/v as a mobile phase at a constant flow rate of about 1.2mL/min. The development and validation were carried out at detection wavelength of 229nm. We developed a robust RP-HPLC method, validated for linearity, precision, accuracy, specificity, and system suitability. The method demonstrated excellent linearity with correlation coefficient value r2 was nearly 0.998 with linearity range 8-18μg/mL for Silodosin and 24-54μg/mL for mirabegron. LOD and LOQ were found to be lower; hence, the method is sensitive. Percentage recovery was obtained 99.97% and 99.99% for silodosin and mirabegron, respectively. In case of precision, robustness and repeatability, RSD was found to be less than 2. The validated and developed RP-HPLC method offers an efficient and practical approach for the simultaneous quantification of silodosin and mirabegron in pharmaceutical formulations, making it a valuable tool for quality control and pharmaceutical research.

Development and validation of derivative UV spectroscopic method for simultaneous estimation of nicotinamide and tretinoin in their binary mixtures and pharmaceutical preparations

An accurate, precise, sensitive, and simple spectroscopic method was developed and validated for simultaneous quantification analysis of tretinoin (TRT) and nicotinamide (NCT) with a ratio of 1:40 (TRT: NCT) in a synthetic mixture from dermal pharmaceutical preparations (solution and cream). Wavelengths were chosen in the first and second-order derivatives which are valid for the determination of NCT with the existence of TRT and excipients of the tested pharmaceutical preparations. Wavelength 253 nm was picked for the first-order derivative. Wavelengths 245 and 269 nm were picked for the second derivative. All previous wavelengths were zero-crossing points for TRT and its pharmaceutical preparations. Zero-order spectroscopy was used to determine TRT at the wavelength 348 nm, where no interference with NCT or any substance in the previous pharmaceutical preparation. The linearity range was studied and found to be 20–120 μg/mL and 0.5–5.0 μg/mL for NCT and TRT respectively. The correlation coefficient was 0.9995–0.9999 for NCT and 0.9998–0.9999 for TRT. The limit of detection (LOD) and the limit of quantification (LOQ) of NCT were 1.510 μg/mL and 4.590 μg/mL respectively at the wavelength 269 nm of the second-order derivative.

Application of activated carbon functionalized with graphene oxide for efficient removal of COVID-19 treatment-related pharmaceuticals from water

Currently, the COVID-19 pandemic has been increasing the consumption of some drugs, such as chloroquine (CQN) and dipyrone (DIP), which are continuously discharged into water resources through domestic sewage treatment systems. The presence of these drugs in water bodies is worrisome due to their high toxicity, which makes crucial their monitoring and removal, especially by means of advanced technologies. Given this scenario, a new adsorbent material was synthesized through the combination of babassu coconut activated carbon and graphene oxide (GAC-GO). This study was evaluated in batch adsorption processes, aiming at the treatment of water contaminated with CQN and DIP. Characterization analyzes using physicochemical and spectroscopic techniques indicated that the GAC-GO functionalization was successfully performed. The equilibrium time of the adsorption process was 18 and 12 h for CQN and DIP, respectively. Kinetic and isothermal data better fitted to pseudo-second-order and Langmuir models for both drugs. Thermodynamic parameters showed that the process is endothermic and the maximum adsorption capacities of CQN and DIP were 37.65 and 62.43 mg g-1, respectively, both at 318 K. The study of the effect of ionic strength, which simulates a real effluent, demonstrated that the synthesized adsorbent has potential application for the treatment of effluents. Furthermore, satisfactory removal rates were verified for the removal of other contaminants in both simple solutions and synthetic mixtures, evidencing the versatile profile of the adsorbent.

Simultaneous spectrophotometric determination of glimepiride and pioglitazone in binary mixture and combined dosage form using chemometric-assisted techniques

In the present work, pioglitazone and glimepiride, 2 widely used antidiabetics, were simultaneously determined by a chemometric-assisted UV-spectrophotometric method which was applied to a binary synthetic mixture and a pharmaceutical preparation containing both drugs. Three chemometric techniques - Concentration residual augmented classical least-squares (CRACLS), principal component regression (PCR), and partial least-squares (PLS) were implemented by using the synthetic mixtures containing the two drugs in acetonitrile. The absorbance data matrix corresponding to the concentration data matrix was obtained by the measurements of absorbencies in the range between 215 and 235nm in the intervals with Δλ=0.4nm in their zero-order spectra. Then, calibration or regression was obtained by using the absorbance data matrix and concentration data matrix for the prediction of the unknown concentrations of pioglitazone and glimepiride in their mixtures. The described techniques have been validated by analyzing synthetic mixtures containing the two drugs showing good mean recovery values lying between 98 and 100%. In addition, accuracy and precision of the three methods have been assured by recovery values lying between 98 and 102% and R.S.D. % ˂0.6 for intra-day precision and ˂1.2 for inter-day precision. The proposed chemometric techniques were successfully applied to a pharmaceutical preparation containing a combination of pioglitazone and glimepiride in the ratio of 30: 4, showing good recovery values. Finally, statistical analysis was carried out to add a value to the verification of the proposed methods. It was carried out by an intrinsic comparison between the 3 chemometric techniques and by comparing values of present methods with those obtained by implementing reference pharmacopeial methods for each of pioglitazone and glimepiride.