Lofepramine exhibits diverse bioactivity profiles and some degree of pharmacokinetic complexity. It has a high partition coefficient (LogD = 4.58) and a slightly acidic pKa of 6.7, indicating possible pH-dependent solubility changes with a delta logD of -0.32 from pH 6.5 to 7.4. Despite these characteristics, its oral bioavailability in humans is low, with F ≤ 20.0%.
This compound functions as an inhibitor across multiple biological targets. It inhibits acid sphingomyelinase (ASM) in human H4 cells (90.5% residual activity at 10 μM), Tyrosyl-DNA Phosphodiesterase (TDP1) with a potency of 44668.4 nM, and Bacillus subtilis Sfp phosphopantetheinyl transferase (PPTase) with potencies ranging from 15848.9 nM to 50118.7 nM. It also inhibits Histone Lysine Methyltransferase G9a (1258.9 nM), the vitamin D receptor (VDR) (35481.3-39810.7 nM), delayed death in malarial parasite plastid (12589.3-15101.4 nM), USP1/UAF1 (35481.3 nM), and induces DNA re-replication in various cell lines (33498.3 nM).
However, it shows weak inhibitory activity in kinase assays against GST-RET proteins (IC50 > 20000.0 nM), and low potency in blocking uptake of substrates in human BSEP, MRP2, MRP3, and MRP4 transport proteins (IC50 > 133000.0 nM).
In terms of antimicrobial activity, Lofepramine does not show significant effectiveness against Candida albicans, Cryptococcus neoformans, and various bacteria including Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus MRSA (MIC > 10000.0 nM). It also exhibits a high CC50 value for cytotoxicity against HEK293 cells (CC50 > 10000.0 nM).
Despite moderate activity in certain viability assays against SARS-CoV-2-infected Vero E6 cells (inhibition index = 0.7416), it shows antiviral activity manifested by a 17.72% inhibition of SARS-CoV-2 cytotoxicity in Caco-2 cells at 10 μM after 48 hours and 64.61% inhibition of SARS-CoV-2 3CL-Pro protease at 20 μM. The IC50 value for VERO-6 cell cytotoxicity inhibition is greater than 20000.0 nM, indicating moderate to low potency.
Lofepramine's activity includes 35.11% inhibition of human HDAC6 with a commercial substrate and 0.27% with a custom substrate, alongside various binding affinities and activities towards SLC6A2, SLC6A4, HRH1, DRD2, OPRK1, CHRM2, CNR1, NR1I2, HRH2, Ptgs1, and PDE4D.
Liver toxicity has been associated with Lofepramine, including moderate hepatotoxicity (46.5% of cases), and acute liver toxicity characterized by cytolytic and choleostatic effects, though severe chronic liver diseases and secondary liver conditions are not significantly linked.
Overall, Lofepramine shows potential as a multi-target inhibitor, with notable activity in certain pathways and processes, yet limited oral bioavailability and specific safety concerns necessitate cautious therapeutic consideration..
Note: Summary generated by AI. Data source: ChEMBL 