Microencapsulation of alpha-tocopherol using sodium alginate and its controlled release properties

Area of Science:

• Materials Science
• Chemical Engineering
• Pharmaceutical Sciences

Background:

• Microencapsulation is crucial for drug delivery and stability.
• Sodium alginate is a common biopolymer for microcapsule formulation.
• Optimizing microencapsulation parameters is key to achieving desired drug release profiles.

Purpose of the Study:

• To optimize the microencapsulation yield (MY) of sodium alginate (SA) microcapsules containing alpha-TP.
• To determine the optimal conditions for microencapsulation using response surface methodology (RSM).
• To evaluate the in vitro release characteristics of alpha-TP from SA microcapsules in simulated gastric and intestinal fluids.

Main Methods:

• Response surface methodology (RSM) was employed to optimize MY.
• Three independent variables were studied: coating to core material ratio (X1), emulsifier concentration (X2), and CaCl2 concentration (X3).
• In vitro drug release studies were conducted in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF).

Main Results:

• The optimal conditions for SA microcapsule preparation were determined.
• A regression model predicted the microencapsulation yield (MY) as MY(%) = 56.02 + 3.64X2 + 3.18X1X2 - 3.74X2(2).
• The predicted MY under optimal conditions (SA/alpha-TP ratio 6.6:3.4, 1.35% emulsifier, 4.3% CaCl2) was 57.2%.
• Microcapsules released 28.8% of alpha-TP in SGF (pH 1.2) over 24 hours.
• Significantly higher alpha-TP release (81.5%) was observed in SIF (pH 7.4).
• The time to release 50% (T50%) and 70% (T70%) of alpha-TP was calculated as 3.8 and 12.3 hours, respectively.

Conclusions:

• Sodium alginate microcapsules demonstrate structural stability in acidic environments.
• The microcapsules facilitate rapid release of the core material (alpha-TP) under mildly alkaline conditions.
• Optimized SA microcapsules hold potential for controlled drug delivery applications.