Computer-assisted design for paracetamol masking bitter taste prodrugs

J Mol Model. 2012 Jan;18(1):103-14. doi: 10.1007/s00894-011-1040-5. Epub 2011 Apr 15.

Abstract

It is believed that the bitter taste of paracetamol, a pain killer drug, is due to its hydroxyl group. Hence, it is expected that blocking the hydroxy group with a suitable linker could inhibit the interaction of paracetamol with its bitter taste receptor/s and hence masking its bitterness. Using DFT theoretical calculations we calculated proton transfers in ten different Kirby's enzyme models, 1-10. The calculation results revealed that the reaction rate is linearly correlated with the distance between the two reactive centers (r(GM)) and the angle of the hydrogen bonding (α) formed along the reaction pathway. Based on these results three novel tasteless paracetamol prodrugs were designed and the thermodynamic and kinetic parameters for their proton transfers were calculated. Based on the experimental t(1/2) (the time needed for the conversion of 50% of the reactants to products) and EM (effective molarity) values for processes 1-10 we have calculated the t(1/2) values for the conversion of the three prodrugs to the parental drug, paracetamol. The calculated t(1/2) values for ProD 1-3 were found to be 21.3 hours, 4.7 hours and 8 minutes, respectively. Thus, the rate by which the paracetamol prodrug undergoes cleavage to release paracetamol can be determined according to the nature of the linker of the prodrug (Kirby's enzyme model 1-10). Further, blocking the phenolic hydroxyl group by a linker moiety is believed to hinder the paracetamol bitterness.

MeSH terms

  • Acetaminophen / chemistry*
  • Computer-Aided Design*
  • Drug Design
  • Hydrogen Bonding
  • Hydroxyl Radical / chemistry
  • Models, Chemical*
  • Models, Theoretical
  • Taste*
  • Thermodynamics

Substances

  • Hydroxyl Radical
  • Acetaminophen