Isotretinoin Oil-Based Capsule Formulation Optimization

The purpose of this study was to develop and optimize an isotretinoin oil-based capsule with specific dissolution pattern. A three-factor-constrained mixture design was used to prepare the systemic model formulations. The independent factors were the components of oil-based capsule including beeswax (X₁), hydrogenated coconut oil (X₂), and soybean oil (X₃). The drug release percentages at 10, 30, 60, and 90 min were selected as responses. The effect of formulation factors including that on responses was inspected by using response surface methodology (RSM). Multiple-response optimization was performed to search for the appropriate formulation with specific release pattern. It was found that the interaction effect of these formulation factors (X₁X₂, X₁X₃, and X₂X₃) showed more potential influence than that of the main factors (X₁, X₂, and X₃). An optimal predicted formulation with Y(10 min), Y(30 min), Y(60 min), and Y(90 min) release values of 12.3%, 36.7%, 73.6%, and 92.7% at X₁, X₂, and X₃ of 5.75, 15.37, and 78.88, respectively, was developed. The new formulation was prepared and performed by the dissolution test. The similarity factor f₂ was 54.8, indicating that the dissolution pattern of the new optimized formulation showed equivalence to the predicted profile.