Physicochemical properties are all the physical and chemical properties of a drug, which are influence the drug performance or action.
Various Physico-Chemical Properties of Drugs
Thermodynamic properties
- Melting and sublimation temperatures
- Internal energy (i.e. structural energy)
- Enthalpy (i.e. heat content)
- Heat capacity
- Entropy
- Free energy and chemical potential
- Thermodynamic activity
- Vapour pressure
- Solubility
Kinetic properties
- Dissolution rate
- Rates of solid state reactions
- Stability
Spectroscopic properties
- Electronic transitions (i.e. ultraviolet visible absorption spectra)
- Vibrational transitions (i.e. infrared absorption spectra and Raman spectra)
- Rotational transitions (i.e. far infrared or microwave absorption spectra)
- Nuclear spin transitions (i.e. nuclear magnetic resonance spectra)
Surface properties
- Surface free energy
- Interfacial tensions
- Habit (i.e. shape)
Mechanical properties
- Hardness
- Tensile strength
- Compressibility
- Handling flow and blending
Packing properties
- Molar volume and density
- Refractive index
- Conductivity electrical and thermal
- Hygroscopicity
If a deficiency is detected, then the project team should decide on the molecular modification(s) that would most likely improve the drug’s properties. Salts, prodrugs, solvates, polymorphs, or even new analogs may emerge from this modification effort.
Read also: