Green Spectrophotometric Platforms for Resolving Overlapped Spectral Signals of Recently Approved Antiparkinsonian Drug (Safinamide) in the Presence of Its Synthetic Precursor (4-Hydroxybenzaldehyde): Applying Ecological Appraisal and Comparative Statistical Studies

BACKGROUND

Safinamide, a highly specific inhibitor of monoamine oxidase B, is a new approved prodigious therapy used to cure Parkinson's disease (PD).

OBJECTIVE

Before marketing and selling a medicine, manufacturers must guarantee that the manufacturing process is consistent by monitoring levels of process-related chemicals and drug contaminants. Therefore, five precise, fast, and accurate spectrophotometric techniques were employed and evaluated for the simultaneous measurement of safinamide and its synthetic precursor, 4-hydroxybenzaldehyde.

METHODS

The first derivative, derivative ratio, ratio difference, dual wavelength, and Fourier self-deconvolution methods worked well to resolve spectral overlap of safinamide and its synthetic precursor, 4-hydroxybenzaldehyde.

RESULTS

Safinamide detection limits ranged from 0.598 to 1.315 µg/mL, whereas the 4-hydroxybenzaldehyde detection limit was found to be as low as 0.327 µg/mL.

CONCLUSION

According to International Council for Harmonisation (ICH) criteria, all procedures were verified and confirmed to be accurate, robust, repeatable, and precise within reasonable range. No considerable variation was found when comparing the outcomes of the suggested approaches to the findings of previously published methods. The ecological value of established methods was measured: the national environmental methods index (NEMI), the analytical eco-scale, the analytical greenness metric (AGREE), and the green analytical process index (GAPI) were used.

HIGHLIGHTS

This is the first spectrophotometric determination of safinamide drug in the presence of its synthetic precursor. Five simple and efficient spectrophotometric approaches were employed to determine a newly approved antiparkinsonian drug in the presence of its synthetic precursor simultaneously. Ecological appraisal was performed for the developed methods using four assessment tools.

Simultaneous determination of ergotamine, caffeine and dipyrone in their ternary mixture by applying double divisor and first derivative ratio spectra methods

Two validated methods namely, double divisor ratio spectra derivative spectroscopy and derivative ratio spectroscopy with zero crossing point were applied to assay a ternary mixture of ergotamine tartrate (EGT), caffeine (CAF) and dipyrone sodium (DIP) without any additional separation steps. The linearity ranges using both methods were (1.0 µg/mL-70.0 µg/mL), (60.0 µg/mL - 100.0 µg/mL) and (100.0 µg/mL - 300.0 µg/mL) for EGT, CAF and DIP respectively. Double divisor ratio spectroscopy (method A) depends on dividing the different peak responses of EGT on (summation of peaks responses of CAF and DIP each of 10.0 µg/mL concentration) at λ max=342 nm, 310 nm and 315 nm for EGT, CAF and DIP respectively. Derivative ratio spectroscopy with zero crossing point (method B) depends on dividing the peak responses of two drugs (EGT and CAF) on (10.0 µg/mL of DIP) and dividing the peak response of DIP on peak response of (10.0 µg/mL of EGT). The detection limits of the studied drugs applying method A were (3.54, 12.96 and 8.748 µg/mL), with quantitation limits of (10.73, 39.28 and 26.51 µg/mL) for EGT, CAF and DIP respectively. Regarding method B, the limits of detection and quantitation for EGT were 0.604 µg/mL and 1.829 µg/mL respectively: with corresponding values of 19.44 µg/mL and 58.92 µg/mL for CAF and 20.44 µg/mL and 61.9 µg/mL for DIP. The obtained results were compared to those obtained by published methods and were found to be in accordance.

First derivative ATR-FTIR spectroscopic method as a green tool for the quantitative determination of diclofenac sodium tablets

Background: Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy is a rapid quantitative method which has been applied for pharmaceutical analysis. This work describes the utility of first derivative ATR-FTIR spectroscopy in the quantitative determination of diclofenac sodium tablets.

Methods: This analytical quantitative technique depends on a first derivative measurement of the area of infrared bands corresponding to the CO stretching range of 1550-1605 cm ^-1. The specificity, linearity, detection limits, precision and accuracy of the calibration curve, the infrared analysis and data manipulation were determined in order to validate the method. The statistical results were compared with other methods for the quantification of diclofenac sodium.

Results: The excipients in the commercial tablet preparation did not interfere with the assay. Excellent linearity was found for the drug concentrations in the range 0.2 – 1.5 w/w %.  (r ²= 0.9994). Precision of the method was assessed by the repeated analysis of diclofenac sodium tablets; the results obtained showed small standard deviation and relative standard deviation values, which indicates that the method is quite precise. The high percentage of recovery of diclofenac sodium tablets (99.81, 101.54 and 99.41%) demonstrate the compliance of the obtained recoveries with the pharmacopeial percent recovery. The small limit of detection and limit of quantification values (0.0528 and 0.1599 w/w %, respectively) obtained by this method indicate the high sensitivity of the method.

Conclusions: First derivative ATR-FTIR spectroscopy showed high accuracy and precision, is considered as nondestructive, green, low cost and rapid, and can be applied easily for the pharmaceutical quantitative determination of diclofenac sodium tablet formulations.

Study and application of real-time control strategy based on DO and ORP in nitritation-denitrification SBR start-up

In this study, nitritation-denitrification SBR was successfully begun within 5 days by maintaining a proper condition (pH > 8, DO 0.1-0.5 mg/L and 29.5 ± 0.5°C) and transient excessive aeration would not cause N-NO₃ ^- accumulation. In the start-up stage, FA had an upward trend and reached to 10.98 mg NH₃/L, which could entirely inhibit NOB. On the basis of experimental evidence, DO and ORP showed regular trends of variation and the first derivatives of DO and ORP as process control parameters in a nitritation-denitrification SBR was proposed. During the real-time control period, N-NH₄ ⁺ in the outlet was less than 2 mg N-NH₄ ⁺/L and N-NH₄ ⁺ removal efficiency was 97%, with nitrite accumulation rate (NAR) reaching 98%. After algorithm optimization by using 'Slope', the first derivatives of DO and ORP curves became smooth and interference signals were eliminated. Pre-aeration could promote nitritation rate from 23.76 mg/L/h to 26.27 mg/L/h and increase the transformation rate of N-NH₄ ⁺ to N-NO₂ ^- from 48.% to 79.6%. The 16S rDNA analysis showed that real-time control could cause a significant difference in microbial community. Nitrosomonas was the dominant strain in AOB and its relative abundance increased from 0.13% to 0.786%. Nitrospira was inhibited and washed out in nitritation-denitrification sludge.

First order derivative spectra to determine caffeine and chlorogenic acids in defective and nondefective coffee beans

In this research, the application of the first order derivative spectra was employed to determine the levels of caffeine (CAF) and chlorogenic acids (CGA) in defective (immature, black, and sour) and nondefective coffee beans without using extraction or background correction techniques. The extreme points of first order derivate spectra of these compounds were at the wavelength of 260 and 292 nm enable to quantify the contents of CAF and CGA, respectively. The level of CAF and CGA in coffee beans determined by this method is ranged from 1.2 ± 0.12-1.46 ± 0.47% and 4.04 ± 0.44-4.43 ± 0.43%, respectively. The study results also indicated total contents of CAF and CGA levels discriminate the defective and nondefective coffee beans with higher CAF and CGA contents being observed in defective coffee beans. As the method is extremely rapid, easy, and inexpensive and also requires minimal sample preparation for the quantification of CAF and CGA contents in coffee, it could be a valuable quality control technique.