Sensitivity Enhanced Ecofriendly UV Spectrophotometric Methods for Quality Control of Telmisartan and Benidipine Formulations: Comparison of Whiteness and Greenness with HPLC Methods

The development of an environmentally friendly analytical technique for simultaneous measurement of medicines with large concentration differences is difficult yet critical for environmental protection. Hence, in this work, new manipulated UV-spectroscopic methods with high scaling factors were established for concurrent quantification of telmisartan (TEL) and benidipine (BEN) in fixed-dose combinations. Two different methods were developed and established by calculation of peak height at zero crossing point of second derivative and the ratio of first derivative spectra with a scaling factor of 200 and 100, respectively. The absorption difference between the peaks and troughs of the ratio spectra, as well as continuous subtraction from ratio spectra, were established as additional methods. In addition, new procedures were validated using ICH recommendations. The proposed methods’ linearity curves were constructed in the range of 0.5–10 µg mL⁻¹ and 1–30 µg mL⁻¹ for BEN and TEL, respectively, under optimized conditions. Furthermore, both the detection (0.088–0.139 µg mL⁻¹ for BEN and 0.256–0.288 µg mL⁻¹ for TEL) and quantification limits (0.293–0.465 µg mL⁻¹ for BEN and 0.801–0.962 µg mL⁻¹ for TEL) were adequate for quantifying both analytes in the formulation ratios. The accuracy and precision were confirmed by the good recovery percent (98.37%–100.6%), with low percent relative error (0.67%–1.70%) and less than 2 percent relative standard deviation, respectively. The specificity of the methods was proven by accurate and precise outcomes from the standard addition method and analysis of laboratory mixed solutions with large differences in concentrations of both analytes. Finally, the BEN and TEL content of the formulations was determined simultaneously without prior separation using these first ever reported spectroscopic methods. Furthermore, developed UV derivative spectroscopic methods demonstrated high greenness and whiteness when compared to the reported HPLC methods. These findings show that the projected methods were effective, practical, and environmentally acceptable for quality control of BEN and TEL in multicomponent formulations.

Comparative Study of the Selectivity Power of Colorimetric Method over Chromatographic Methods for the Analysis of Valaciclovir Hydrochloride

BACKGROUND

Valaciclovir hydrochloride (VAL) is an essential antiviral prodrug utilized to cure various types of herpes. Analysis of VAL by different analytical techniques demonstrates a persuasive aspect that is favorable in quality control application.

OBJECTIVE

This study describes a comparison between colorimetric and chromatographic (RP-HPLC and TLC-densitometric) methods concerning selectivity and specificity for the determination of VAL in existence of all possible degradation products (alkali and acid-induced degradation products, namely aciclovir (ACI) and guanine (GUA), respectively) in their synthetic mixture and pharmaceutical formulations.

METHODS

Colorimetric method was accomplished by forming a highly colored complex with ferric hydroxamate reagent measured at 493 nm in concentration range (0.20-1.60 mg/mL). Both chromatographic methods were successfully applied using UV detection at 256 nm in concentration range (2.00-5.00 µg/mL) for RP-HPLC method and (10.00-900.00 ng/band) for TLC-densitometric method.

RESULTS

The linearity studies, regression equations, assay parameters, and validation sheet of the proposed colorimetric and chromatographic methods to determine VAL were obtained with highly acceptable values.

CONCLUSION

ICH guidelines were followed to validate the described methods and the statistical comparison regarding both accuracy and precision, and satisfactory results were accomplished.

HIGHLIGHTS

In this study, we configure a full comparative study between different analytical methods for the analysis of challengeable mixture containing the drug of interest VAL along with its degradation products, ACI & GUA.

Application of DoE-Based Analytical QRM to Development of the Multipurpose RP-HPLC Method for Estimation of Multiple FDC Products of Telmisartan Using Enhanced AQbD Approach

Telmisartan is an antihypertensive drug and several FDC products of telmisartan are available in the market for the treatment of hypertension. The multipurpose reverse-phase high-performance liquid chromatography (RP-HPLC) method has been developed and validated as economical and eco-friendly alternative to numerous published chromatography methods for synchronous estimation of FDC of telmisartan to save time, cost and solvent for analysis. The analytical quality risk management was initiated with identification of potential method parameters using cause-effect diagram followed by assessment of their risk by risk priority number ranking and filtering method. The risk of critical method parameters was controlled by their optimization using design of experiments-based full-factorial design. The method operable design ranges was identified for high-risk method parameters, and control strategy was set for mitigation of their risk throughout the life cycle of the developed RP-HPLC method. The RP-HPLC method was validated as per the ICH Q2 (R1) guideline. The RP-HPLC method was applied for simultaneous estimation of seven FDC products of telmisartan, and results were found compliance with labeled claim. The developed RP-HPLC method is fulfilling requirements of numerous RP-HPLC and high performance thin layer chromatography methods for the said estimation. It can be used as a multipurpose RP-HPLC method for quality control of FDC products of telmisartan in the pharmaceutical industry to save solvent, cost and time of analysis.

Derivatization of γ-Amino Butyric Acid Analogues for Their Determination in the Biological Samples and Pharmaceutical Preparations: A Comprehensive Review

γ-Aminobutyric acid (GABA) plays an important role in regulating neuronal excitability. Four structurally related drugs to GABA including pregabalin (PGB), gabapentin (GBP), vigabatrin (VGB), and baclofen are used for the treatment of central nervous system disorders. These drugs are small aliphatic molecules having neither fluorescent nor strong absorbance in the ultraviolet/visible region; therefore, direct determination of these analytes by optical methods is difficult. Additionally, their high boiling point makes gas chromatography impossible. Accordingly, the amine or acid moiety in these drugs is derivatized in order to improve their selectivity and sensitivity during determination in the biological samples. This review focuses on derivatization based methods and their different reactions for determination of PGB, GBP, VGB, and baclofen in the biological samples and pharmaceutical preparations reported between 1980 and 2020. High-performance liquid chromatography methods coupled with different detectors are a commonly used methods for determination of GABA analogs after derivatization. These methods cover 38.89% of all developed methods for determination of GABA analogs.

A Fast and Validated Reversed-Phase HPLC Method for Simultaneous Determination of Simvastatin, Atorvastatin, Telmisartan and Irbesartan in Bulk Drugs and Tablet Formulations

The aim of this study was to develop and validate a fast and simple reversed-phase HPLC method for simultaneous determination of four cardiovascular agents-atorvastatin, simvastatin, telmisartan and irbesartan in bulk drugs and tablet oral dosage forms. The chromatographic separation was accomplished by using Symmetry C18 column (75 mm × 4.6 mm; 3.5 μ) with a mobile phase consisting of ammonium acetate buffer (10 mM; pH 4.0) and acetonitrile in a ratio 40:60 v/v. Flow rate was maintained at 1 mL/min up to 3.5 min, and then suddenly changed to 2 mL/min till the end of the run (7.5 min). The data was acquired using ultraviolet detector monitored at 220 nm. The method was validated for linearity, precision, accuracy and specificity. The developed method has shown excellent linearity (R² > 0.999) over the concentration range of 1-16 µg/mL. The limits of detection (LODs) and limits of quantification (LOQs) were in the range of 0.189-0.190 and 0.603-0.630 µg/mL, respectively. Inter-day and intra-day accuracy and precision data were recorded in the acceptable limits. The new method has successfully been applied for quantification of all four drugs in their tablet dosage forms with percent recovery within 100 ± 2%.