Optimizing Transferosomal Delivery of RSM

RSM-loaded transferosomes were prepared by thin-film hydration technique to enhance the drug incorporation in the transferosomal vesicles [42 (link)]. In a round-bottom flask, 33.33 mg edge activator (EA), 166.66 mg phosphatidylcholine, and cholesterol, if present, were mixed and dissolved together with 10 mg RSM in 15 mL ethanol. Evaporation of the organic solvent was carried out under vacuum at 50 °C using rotary evaporator (Heidolph VV 2000, Burladingen, Germany) at rotation speed 90 rpm until a thin film was deposited on the inner wall of the round-bottom flask. The formed film was then hydrated with 10 mL phosphate-buffered saline (PBS; pH 7.4) under normal pressure and temperature 50 °C. Following, the obtained dispersions were sonicated (Elmasonic S30H, Singen, Germany) for 2 min to ensure that the formed dispersions were free from any aggregates and then stored overnight at 4 °C. Different transferosomal formulations were prepared by altering the type of EA in presence and absence of cholesterol according to a mixed factorial design (6¹.2¹) (Table 1). Blank transferosomes were prepared concurrently using the same weights but without the addition of drug to eliminate any interactions from the used ingredients [43 (link)].
The construction and analysis of the adopted experimental design were performed using Design-Expert^® software (Stat-Ease, Inc., Minneapolis, MN, USA) so as to ascertain the impact of various variables on the characteristics of the formulated RSM-loaded transferosomes. The desirability function was used in order to determine the optimum preparation condition. The independent variables were the type of EA (sodium cholate, sodium deoxycholate, Pluronic^® F-68, Pluronic^® L-35, Pluronic^® L-31, and Span^® 60) [X1] with the presence/absence of cholesterol [X2]. On the other hand, the dependent variables were VS [Y1], ZP [Y2], and %EE [Y3]. In order to determine the optimized formulation, Y1 had to be minimized, while Y2 and Y3 had to be maximized. The formulation with the highest desirability was considered as the optimum formulation and selected for further study. The composition of the prepared transferosomal formulations is clarified in Table 2.