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Doxepin hydrochloride (DOX) is a tricyclic antidepressant drug. Three sensitive spectrofluorimetric methods, namely resonance Rayleigh scattering (RRS), frequency doubling scattering (FDS) and second-order scattering (SOS), were developed and validated for their estimation of doxepin in spiked human plasma and formulation using liquid-liquid extraction method through the formation of an ion pair complex with eosin Y at a pH of 4.5. Various factors affecting fluorescence intensity were optimized, and the reaction kinetics was determined using the Arrhenius equation method. Different scattering methods such as RRS, FDS and SOS were developed at maximum scattering wavelengths λ ex /λ em = 567/567 nm for RRS, 720/360 nm for SOS and 260/520 nm for FDS, respectively. The methods exhibited high sensitivities, and the detection limits for DOX were found to be 0.82, 1.20 and 1.03 ng/ml for RRS, FDS and SOS methods, respectively. The FDS method exhibited the highest sensitivity. The methods were validated using the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines and applied to determine DOX in capsule and spiked human plasma samples.

Background: Hexahydroquinoline as a small molecule was reported for good cytotoxicity and affinity towards Mcl-1. Hence, new compounds were explored as Mcl-1 inhibitors to be potent anticancer agents. Objective: Compounds were synthesized and screened for cytotoxicity. The active compound was evaluated for cell cycle analysis, Mcl-1 inhibition, caspase-3, and caspase-9 activation. Further compounds were docked with Mcl-1 to confirm the mechanism of cytotoxicity. Methods: Compounds were confirmed by spectral techniques and screened for cytotoxicity at National Cancer Institute (USA). The active derivatives were screened by SRB and MTT. In addition, the potent compound was studied for apoptosis and cell cycle analysis by PI staining, Mcl-1 inhibition by TR-FRET assay, and activation assay of caspase-3 and caspase-9 with the Elisa technique. Results: Compounds 6a and 6b exhibited the highest growth inhibition of 86.28% and 93.20% against SR and HOP-62, respectively. Compound 6a showed higher cytotoxicity (IC50 = 0.4 µM) against THP-1 and HL-60. It showed 15-fold higher apoptosis compared to control by arresting cells at the Sub-G1 in the cell cycle. It also showed a potent inhibition with IC50 of 1.5 µM against the anti-apoptotic protein Mcl-1, which may induce apoptosis. Furthermore, apoptosis was evidenced by an increase in cleaved caspase-3 and caspase-9 to 4.20 and 3 folds, respectively higher than control. The docking score of compound 6a was in good agreement with the Mcl-1 inhibition assay. Conclusion: Compound 6a inhibited anti-apoptotic protein Mcl-1 and induced activation of pro-apoptotic proteins caspase-3 and caspase-9. These dual results suggested the mechanism of apoptosis and cytotoxicity.

Background: Fluorine containing Hexahydroquinoline-3-carbonitrile derivatives were found to have potent cytotoxicity. Further, Fluorine can modulate pharmacokinetic and pharmacodynamic profile of drugs. Hence, new derivatives containing fluorine were explored as potential cytotoxic agents. Objective: Difluoro substituted compounds containing aromatic/heteroaromatic rings were designed, synthesized and screened for in vitro cytotoxicity on cancer cell lines. The active compounds were subjected to docking on Mcl-1 and ADME/T prediction. Methods: The synthesized compounds were characterized using various spectral techniques like FT-IR, 1 H NMR, 13C NMR and Mass spectra. Compounds were screened for cytotoxicity on NCI-60 cell lines at National Cancer Institute. The active compounds were evaluated additionally by MTT and SRB assay. Results: Compounds (6l and 6o) showed maximum cytotoxicity with (% GI) of 69 and 63.7 at 10 µM drug concentration respectively. Compound 6i showed potent cytotoxicity with GI50 of 7.2 µM against Ishikawa cell line. Compound 6o was nearly as active as reference with IC50 of 9.39 µM and 13.54 µM against HT-29 and HCT-116 respectively and compound 6l also showed equal potency to that of reference with IC50 of 9.66 µM against Caco-2. Compounds 6i, 6o and 6l showed high docking score suggesting their cytotoxicity. Further, ADME/T prediction revealed that all the compounds have drug likeness properties. Conclusion: Enhanced lipophilic interaction of compounds due to presence of fluorine in compounds 6i and 6l was revealed during docking study. Compound 6i can be explored as a lead molecule against other endometrial cancer in futuristic drug development.

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