Background: Olmesartan medoxomil is an angiotensin II receptor blocker
antihypertensive drug, which has low oral bioavailability because of poor aqueous solubility.
Objective: The objective of the present research is the development and optimization of Olmesartan
medoxomil loaded self-micro emulsifying drug delivery system by D-optimal mixture design to
improve its dissolution rate.
Methods: Solubility of Olmesartan medoxomil was determined in different oils, surfactants and cosurfactants.
The pseudo ternary diagram was constructed for the identification of self-micro
emulsification region. The D-optimal mixture design was employed for the optimization of SMEDDS
formulations wherein the factors optimized were the concentration of oil (X1), surfactant (X2), and
co-surfactant (X3) and the response was globule size (Y1) and dissolution rate (Y2). Developed selfmicroemulsifying
drug delivery system was further assessed for self-emulsification time, drug
loading capacity, transparency, globule size, in vitro dissolution and comparative in vitro dissolution
testing of optimized formulation with pure medicament and commercially available product.
Results: The application of D-optimal mixture design resulted in 14 batches out of which F-5 was
found to be the optimized batch which contained Olmesartan medoxomil (20 mg), Capmul MCM
EP (23% v/v), Kolliphore EL (49% v/v) and Transcutol P (28% v/v) having globule size of 105 nm,
94.7% dissolution within 30 minutes. In vitro dissolution rate of the drug from SMEDDS was
appreciably higher than that of pure drug and marketed products.
Conclusion: Olmesartan medoxomil self-microemulsifying drug delivery system was successfully
developed and this approach could prove to be suitable for the improvement of the dissolution rate
of BCS II class drugs.