Figure 1:

Dual-peak Lorentzian fitting based on the CEST effects of -NH₂ and -OH in 3TC. (A) Lamivudine (3TC) chemical structure. (B) MTRasym calculated from Z-spectra of 3TC. The CEST effects of –NH₂ and –OH protons are at 2 and 1 ppm, respectively. MTRasym results are extracted from a previous study [11] and adapted for re-analysis. (C) CEST effects of –NH₂ and –OH protons are proportional to 3TC concentration (R²=0.97 and 0.92 for –NH₂ and –OH, respectively). CESTivity (line of slope) is 0.0052 mM⁻¹ for –NH₂ proton of 3TC and 0.0026 for –OH proton of 3TC. (D) Background fitting using a polynomial function. (E) A dual-peak Lorentzian function fits –NH₂ and –OH.