Encapsulation of tea tree oil by amorphous beta-cyclodextrin powder

Area of Science:

• Pharmaceutical Technology
• Materials Science

Background:

• Tea tree oil (TTO) possesses valuable antimicrobial properties but is prone to degradation and volatilization.
• Encapsulation techniques are crucial for stabilizing TTO and enhancing its delivery.
• Beta-cyclodextrin (β-CD) is a well-established host molecule for encapsulating guest compounds.

Purpose of the Study:

• To investigate an innovative direct complexation method for encapsulating TTO within solid amorphous β-CD.
• To evaluate the impact of water and ethanol addition on the encapsulation efficiency of TTO-β-CD complexes.
• To compare the efficacy of the novel solid encapsulation method with the conventional paste method.

Main Methods:

• Direct complexation of TTO with amorphous β-CD at a fixed ratio (90.5:9.5).
• Modified direct mixing involving the addition of specific moisture content (17% MC) or varying ethanol ratios (1:1 to 1:4 TTO:ethanol).
• Characterization of encapsulation efficiency and complex structure using X-ray diffraction (XRD) and differential scanning calorimetry (DSC).

Main Results:

• Direct mixing yielded the lowest TTO complexation (60.77mg TTO/g β-CD).
• Recrystallization with 17% moisture content achieved high encapsulation (99.63mg TTO/g β-CD).
• Ethanol addition at 1:2 and 1:3 ratios resulted in effective TTO inclusion (94.3 and 98.45mg TTO/g β-CD), comparable to the paste method (95.56mg TTO/g β-CD).
• XRD and DSC confirmed crystallization of the amorphous TTO-β-CD complex upon water or ethanol addition.

Conclusions:

• Solid encapsulation of TTO using direct complexation with β-CD is feasible and effective.
• The addition of water or ethanol significantly enhances TTO encapsulation efficiency.
• This method offers a promising alternative to conventional TTO encapsulation techniques, improving stability and potentially bioavailability.