Cyclodextrin – Essential Oil Complexes Studied by Thermal Gravimetry Analysis - Differential Scanning Calorimetry

The results of studies of thermal gravimetry analysis (TGA) and differential scanning calorimetry (DSC) profiles for pure α–cyclodextrin (α–CD), β––cyclodextrin (Β–CD), neem oil, clove oil and their adducts α–CD–clove oil, β––CD–clove oil andα––CD–neem oil in the temperature range of 303 – 773 K have been reported. Even though the thermal data for pure α–/ β––CD, clove/neem oil and their inclusion adducts are still not explored up to the mark. Furthermore, the calculations of specific heat capacity at constant pressure (Cp) as a function of temperature are being made for the inclusion of adducts. It is observed that the calculated Cp values from DSC curves are of low magnitude for α––CD–neemoil adduct as compared to that of individual constituents over the temperature range studied and has been attributed to the partial inclusion of neem oil as a guest in the cavity of α––CD macrocycles. An interesting pattern for the Cp values is found to emerge in the case of α––CD–clove oil and Β––CD–clove oil adducts wherein the calculated Cp values are higher in magnitude than for pure clove oil but are of lower magnitude than that of the pure cyclodextrins. To study the thermal gravimetry analysis behaviour for –cyclodextrin–clove oil, –cyclodextrin–neem oil and –cyclodextrin–clove oil adducts using TGA–DSC. To compute specific heat capacity at constant pressure, as a function of temperature for the studied systems. Such variation in the specific heat capacity values of adducts are attributed to the composition of neem oil (a blend of triglycerides) as well as of clove oil (a blend of phenolic eugenol and eugenol acetate with hydrocarbons), which on a structural basis having limitations to form inclusion complex entities fully due to size and stereochemical constraints. The results are discussed in terms of the encapsulation of non-polar chain and the structural decomposition due to thermal energy. Using thermal methods, the attempt to understand the possibilities of molecular complex formation between cyclodextrins and medicinally important neem oil and clove oil is described. The crystals of inclusion compounds for clove oil and neem oil with –CD and –CD are synthesized. The results of TGA–DSC for the crystals are presented and analysed.