Journal: Aaps Open

Article Title: Extraction of niclosamide from commercial approved tablets into aqueous buffered solution creates potentially approvable oral and nasal sprays against COVID-19 and other respiratory infections

doi: 10.1186/s41120-023-00072-x

Figure Lengend Snippet: Baseline-corrected, 30 s subtracted spectra over 1–180 min dissolution for 300 µM fresh Yomesan niclosamide in nominal pH 9.35 Tris Buffer. The 30 s scan is shown as the dashed orange line and this 30 s scan was subtracted from each subsequent scan for 1 – 180 min. Each spectrum is an average of three scans (note: legend is ordered as 180 min to blank; graph is blank to 180 min)

Article Snippet: Tris buffer was used mostly at 20 mM buffer concentration. pH buffers were made using the TRIZMA HCl and TRIZMA base buffer system according to recipes at AAT Bioquest (AATbio.com ).

Techniques: Dissolution

Journal: Aaps Open

Article Title: Extraction of niclosamide from commercial approved tablets into aqueous buffered solution creates potentially approvable oral and nasal sprays against COVID-19 and other respiratory infections

doi: 10.1186/s41120-023-00072-x

Figure Lengend Snippet: Comparison between baseline-corrected UV-Vis spectra for Yomesan at the 30 s time point for initial Yomesan niclosamide-equivalent concentrations of 300 µM, 600 µM, and 1 mM in pH 9.35 Tris buffer. A UV-Vis spectra showing the “impurity” peak indicated (black arrow) at 345 nm, and the expected double niclosamide peaks indicated (gray arrows) at 333 and 377 nm. B Relative absorbance at 333 nm vs. initial added Yomesan niclosamide-equivalent concentration (µM) reveals a linear dependence to the “impurity” absorbance with an intercept at an Absorbance of 0.0292 AU, which would be equivalent to a niclosamide concentration of 1.05 µM. C Comparison between the UV-Vis spectra for the 30s “impurity” for 1 mM Yomesan niclosamide and a 12.5 µM vanillin solution, both in pH 9.35 Tris buffer

Article Snippet: Tris buffer was used mostly at 20 mM buffer concentration. pH buffers were made using the TRIZMA HCl and TRIZMA base buffer system according to recipes at AAT Bioquest (AATbio.com ).

Techniques: Comparison, Concentration Assay

Journal: Aaps Open

Article Title: Extraction of niclosamide from commercial approved tablets into aqueous buffered solution creates potentially approvable oral and nasal sprays against COVID-19 and other respiratory infections

doi: 10.1186/s41120-023-00072-x

Figure Lengend Snippet: Dissolution of ~1 mM 200 °C heat-treated Yomesan in nominal pH 9.35 Tris buffer at 23 °C: A 1 to 180 min, final pH 9.32 with logarithmic fit to initial data (dashed line); B comparison between heat-treated Yomesan (black-filled symbols) and untreated Yomesan (gray-filled symbols) from Fig. C in 9.35 TB vs time after addition out to day 2 final pH 9.26. Dotted lines are to guide the eye

Article Snippet: Tris buffer was used mostly at 20 mM buffer concentration. pH buffers were made using the TRIZMA HCl and TRIZMA base buffer system according to recipes at AAT Bioquest (AATbio.com ).

Techniques: Dissolution, Comparison

Journal: Aaps Open

Article Title: Extraction of niclosamide from commercial approved tablets into aqueous buffered solution creates potentially approvable oral and nasal sprays against COVID-19 and other respiratory infections

doi: 10.1186/s41120-023-00072-x

Figure Lengend Snippet: Yomesan-niclosamide dissolution as a function of Tris buffer pH: Maximum niclosamide concentrations from Fig. (filled black circles) vs. supernatant pH, plotted along with pHp theory determined earlier (Needham ) (dotted black line), for anhydrous (AK Sci) niclosamide (pKa 7.12, S w = 2.53 µM). Also shown are the day 2 equilibrated concentrations (gray-filled circles) and pHp theory for the monohydrate (dotted gray line) ( S w = 1 µM) ( S w = intrinsic solubility of the protonated niclosamide acid)

Article Snippet: Tris buffer was used mostly at 20 mM buffer concentration. pH buffers were made using the TRIZMA HCl and TRIZMA base buffer system according to recipes at AAT Bioquest (AATbio.com ).

Techniques: Dissolution, Solubility