Preparation and formulation of transferosomes containing an antifungal agent for transdermal delivery: Application of Plackett-Burman design to identify significant factors influencing vesicle size.

Transferosomes containing an anti-fungal agent were prepared by Rotary Flask Evaporation -Sonication method. Eight batches were prepared in triplicate and vesicle size of each batch was determined. Plackett-Burman Design was employed to identify significant formulation and process parameters affecting vesicle size. The amount of lipid and surfactant, volume of ethanol and hydration medium as well as hydration time significantly affect the vesicle size.

Transferosomes are also known as Ultradeformable vesicles, Ultradeformable Liposomes or Elastic Vesicles. Transfersome can squeeze itself through a skin pore which is many times smaller than its size owing to its elasticity. Thus, they can increase the skin penetration when applied non-occlusively. The objective of the present study was to identify significant factors influencing vesicle size through the use of Plackett-Burman Design.

Materials and Methods

Preparation of transferosomes

They were prepared by Rotary Flask Evaporation –Sonication Method reported by Gregor et al.[1] Soya phosphatidyl choline, Tween80 and antifungal agent were dissolved in Ethanol. Ethanol was evaporated by flask rotation to deposit the film on the wall of the round bottom flask. The film was hydrated at 45°C using Saline phosphate buffer, pH 6.4 with mild agitation. The Transferosomes formed were allowed to swell for 2 hour at room temperature. Vesicles were subsequently sonicated for 30minutes using bath sonicator. (Model: EN-60US,Make: ELECTROQUIP). Eight batches were prepared as per the Plackett-Burman Design [Table 1].

Table 1

Composition of transferosomes of different batches and their vesicle size

Measurement of vesicle size

Vesicle size was determined using particle size analyzer employing Dynamic Light Scattering Technique (Model: Nano S90, Make: Malvern, USA). Data analysis was carried out using DOE++ Software (Version 1.0.7.2 ID –DS-1, ReliaSoft Corporation, USA).

Result and Discussion

Using Pareto chart [Figure 1] significant and non-significant factors influencing vesicle size were identified. It is evident from the Pareto Chart [Figure 1] as well as P value [Table 1] with respect to vesicle size associated with every variable that the amount of Lipid, amount of Surfactant, volume of Ethanol, volume of Hydration medium and Hydration Time significantly affect the vesicle size.

Figure 1

Pareto chart showing effects of variables on vesicle size

Conclusion

From large number of formulation and process variables involved in making of transferosomes, Plackett-Burman Design can help in identifying significant factors influencing vesicle size. These significant factors may be optimized by employing full factorial design. While employing full factorial design, non-significant factors may be fixed at appropriate level (-1 or +1) employed during Plackett-Burman Design.