Formulation, optimization and in vitro characterization of microcapsules of Cymbopogan martini essential oil
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Date
2023-01
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Addis Ababa University
Abstract
Complex coacervation is one of the microencapsulation techniques by which encapsulated
substances release profile improved. This study was conducted by using complex coacervation to
formulate and optimize microcapsules of the Cymbopogan martini essential oil. The preliminary
study was conducted to define the optimal polymeric ratio for the coating materials (gelatin B and
sodium alginate) and the optimal pH for coacervate by taking dry coacervate yield and turbidity
as response variable. In screening study eight factors, total polymeric concentration, Palmarosa oil
concentration, surfactant concentration (Tween 80), reaction time, temperature, stirring speed,
crosslinker concentration (Tannic acid) and crosslinking time were screened by Plackett–Burman
design generated by Minitab software using encapsulation efficiency, microcapsules surface
property, microcapsules size and distribution as response variables.
The three significant factors from screening design, total polymeric concentration, Palmarosa oil
concentration and Surfactant concentration were further optimized by taking encapsulation as
response variable, which had significant relationship with factors in screening design. Finally, the
optimized microcapsules oil release was fitted to zero and first order kinetics models. The optimal
polymeric ratio and optimal pH were 0.3:1 and 3.5, respectively and in the optimization study
quadratic mathematical model (p < 0.0001) was an excellent fit to analyze the relationship between
factors and response variable (R2, R2adj and R2 pred were > 0.9). The optimal encapsulation
efficiency was 96.7% and the zero-order kinetics model (where R2 = 0.9937) was defined the oil
release from microcapsules.
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Keywords
Microencapsulation, Complex coacervation, Palmarosa essential oil, Plackett– Burman screening design, Central composite design, Invitro release