Surface Free Energies Of Some Antiretroviral Drugs From Spectrophotometric Data And Possible Application To HIV-Infected Lymphocytes

Abstract Antiretroviral drugs are usually used for the treatment of Human Immunodeficiency Virus HIV. This virus specifically attacks the lymphocytes so the antiretroviral drugs are designed specifically to block the virus from penetrating into the interior of the cell. The attachment of the virus on the surface of the lymphocyte will cause a change in the surface area of the cell. Such surface area change is followed by change in surface free energy. This work attempted to estimate the surface free energies of five antiretroviral drugs from absorbance data and their possible effects on the surfaces of the lymphocytes. The absorbance values were measured and using modified form of Lifshitz equation through the concept of Hamaker constants surface energies were calculated. Coating effectiveness studies showed that the drugs preferentially coated the surfaces of lymphocytes as expected. The surface free energies for the drugs varied from 48.9 mJm2 for drug 1 to 37.7 mJm2 for drug 4. This means that drug 4 that has the lowest surface free energy is more hydrophobic than drug 1. The surface free energies of HIV-infected lymphocytes varied from 9.3 mJm2 for drug 3 to 13.9 mJm2 for drug 2 being lower than for uninfected lymphocytes by up to a factor of 77 with drug 1 and 62 with drug 4 in blood of patients without previous drug treatment confirming the surface energy-reducing capacity of HIV. The low value of the free energy in drug 4 of 39.5mJm2 is in line with effectiveness value 0.0245 for drug 4 which is the lowest as shown in table 3. It is interesting to observe that drug 1 which has the highest coating effectiveness 0.5102 also has the highest surface free energy 47.5mJm2 confirming the existence of some relationship between drug coating of the surface of the blood cell and the cell surface free energy. It is interesting to note that Ozoihu 2014 reported the surface free energy of infected lymphocyte as 31.812.36 mJm2 and that of uninfected cell as 39.942.82 mJm2. While the values for uninfected cell are close to within 3.2 of each other the values for infected are widely different up to 19.5. The findings of this research work suggest possible existence of a thermodynamic criterion for HIV-drug interaction prediction that will be a valuable tool in HIV-blood interaction study. This work gives more understanding on the surface properties of antiretroviral drugs and the effects of HIV on the surface energies of blood samples.