Spectrofluorimetric Study on Inclusion Interaction of β- Cyclodextrin with Bimatoprost: Challenging to Green Analytical Applications

Abstract

Fluorescence study on inclusion interaction of bimatoprost in absence and presence of β-cyclodextrin shows significant increase in native fluorescence of bimatoprost in the presence of β-cyclodextrin. Fluorescence spectroscopy of host-guest interaction between bimatoprost and β-cyclodextrin shows formation of inclusion complex with 1:1 stoichiometric ratio. The changes of native fluorescence of bimatoprost on inclusion in the hydrophobic β-cyclodextrin cavity is used to calculate the association constant.The fluorimetric method was used for determination of bimatoprost in absence and presence of 1% (w/v) β-cyclodextrin. The studied drug shows native fluorescence at λem 285 after excitation at λex 217 nm in water. The quantum yield [QY] was calculated in absence and presence of β-CD and it was found to be increased from 0.26 to 0.31. The different experimental parameters affecting the fluorescence of the drug was carefully studied and optimized. Linearity was over the range of 25 – 250 ng/mL and 5 – 50 ng/mL in absence and presence of β-CD, respectively with detection limits of 0.05 and 0.006 ng/mL, and quantitation limits of 0.18, and 0.02 ng/mL in absence and presence of β-CD, respectively. The proposed methods were validated as per ICH guidelines, and were effectively applied to analysis of studied drug in its ophthalmic formulation. The results obtained were statistically compared with the reported method revealing high accuracy and good precision. The proposed methods are challenging to green. Qualitative and quantitative metrics revealed excellent eco-friendly fluorimetric method for application in QC laboratories.