The possibility of obtaining continuous analytical signal excluding any pre-treatment of sample is the most environmental friendly method of analysis. In the current manuscript, a solid contact sensor was fabricated for dual purpose; firstly, determination of valaciclovir hydrochloride (VAL) in existence of its acid induced degradation product, Guanine (GUA) and secondly, real time acquisition of the dissolution profile from its pharmaceutical formulations (Valtrex) and (Valysernex). The sensing membrane was fabricated using a polyvinyl chloride (PVC), sodium tetraphenyl borate as a cation exchanger with bis (2-ethylhexyl) sebacate as a plasticizer. The proposed sensor displayed fast, stable Nernstian responses across VAL concentration range (1 × 10 −5 M to 1 × 10 −2 M). The opportunities of the proposed sensor with respect to other off-line classical techniques originates from being in-line, time saving, cost-effective, green and simple. ICH guidelines were followed to ensure validation of the proposed method concerning accuracy and precision.

Background: Four rapid, accurate, and validated stability-indicating spectrophotometric methods have been described in the present work for the analysis of trimebutine maleate (TM) in existence of its degradation products in its authentic form and in pharmaceutical formulations excluding any separation steps. Results: These methods were a dual-wavelength (DW) method which allows the determination of TM in existence of its degradation products at 243 nm and 269 nm, second derivative (D 2) method measured at peak amplitude at 268 nm, ratio difference (RD) method at 242 nm and 278 nm, and constant center coupled with spectrum subtraction (CC-SS) method at 242 nm and 278 nm versus 278 nm. By applying the suggested methods, TM could be quantified in the range of 5.0-60.0 μg/mL with percentage recoveries 99.97 ± 0.40, 100.36 ± 0.58, 99.90 ± 0.42, and 100.15 ± 0.45 for DW, D 2 , RD, and CC-SS methods, respectively. International Conference on Harmonization guidelines were followed for validation of the described methods, and the application of laboratory-prepared mixtures along with different pharmaceutical drugs including the target drug showed favorable results without any contribution from additives. Conclusions: Statistical comparison was used to compare the proposed and official methods, and satisfactory results for both accuracy and precision were obtained. The results confirm the applicability of the suggested methods for the determination of TM in quality control laboratories.

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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.

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