Miconazole

Furthermore, these compounds were tested against the same fourteen fungal strains to evaluate their minimum fungicidal concentration (MFC) and the results are summarized in Table 4. Similarly, the results correlated well with the anti-fungal activity data and most of the compounds displayed MFC values identical to the standard miconazole. In particular, compound 9f showed MFC = 3.9 µg mL⁻¹, compared to the standard (MFC = 7.8 µg mL⁻¹) against C. parapsilosis MTCC 1744 and displayed the same efficacy as miconazole against several other tested fungal strains. On the whole, the results indicate that the compounds possess excellent antifungal potential, in some cases better than and/or equipotent to miconazole.

When Dyclonine and Miconazole were docked into the binding pocket of AChE, we observed different binding modes compared to the other four compounds mentioned above. Interestingly, the two compounds only located at the PAS of AChE. No group inserted into the CAS. This binding mode can support the non-competitive manner from kinetic study. We assumed that it was the length and themolecular shape of these two molecules caused such difference. Compared to the other four compounds, Dyclonine and Miconazole formed more shrink conformations, which made them could not cover the CAS and PAS simultaneously. Additionally, the two compounds were highly hydrophobic, containing multiple aromatic rings or alky chains. This made them were prone to the more hydrophobic PAS of AChE.

The difference in the release pattern is evident in Fig. 3 which is an overlay of release profiles of indomethacin and miconazole nitrate. This may be due to the difference in physicochemical properties of the drugs: indomethacin is weakly acidic (due to the presence of carboxylic acid functional groups) and has a low partition coefficient in octanol–water systems, with log P = 3.4; miconazole nitrate is basic (due to the presence of imidazole ring) and has a high partition coefficient in octanol–water system, with log P = 6.3. These values suggest that miconazole nitrate has higher lipophilicity (and therefore, solubility in the lipid phase) than indomethacin. Thus, one interpretation of the release data is that indomethacin (low partition coefficient) is present predominantly in the shell (i.e. drug-enriched shell model) and released quickly. On the other hand, miconazole nitrate (high partition coefficient) should be solubilized in the molten lipid and crystallize within the lipid core (i.e. drug-enriched core model), thus providing a slower release. These findings support the hypothesis that indomethacin is primarily present in the shell and its release is diffusion-controlled. In contrast, the release of miconazole nitrate, which is predominantly present in the lipid core, is controlled by dissolution and diffusion.