Oral route is the most common and preferred route for the drug administration due to convenience and ease of administration. Technology Catalysts International reported in 2002 that approximately 35-40% of all new chemical compounds suffer from poor aqueous solubility. Therefore, enhancing drug dissolution became one of the major challenges for pharmaceutical scientists over the past decade. Lipid formulations and in particular SMEDDS/ SNEDDS Self- icro emulsifying Drug Delivery Systems can induce a considerable increase in dissolution rate Class II-IV drugs are considered the best candidates for intervention by formulation e.g. in self- mulsifying dosage forms. Aim: Cefdinir is a poorly water-soluble drug with varying bioavailability. The main purpose of present work was to develop self-micro emulsifying drug delivery system (SMEDDS) for enhancing solubility and bioavailability of Cefdinir is indicated for the treatment of bronchitis as well as for the treatment ofear, nose, throatdisorder. Materials and Method: Cefdinir had highest solubility in labrafac with comparison to other lipid vehicles. Emulsification study results were shown that tween 20 has highest solubility capacity of oil was higher (0.8528 ± 0.4075mL) than other surfactant.Sotween 20 was selected as surfactant. From the result were shown that PEG 400 has highest solubility capacity of oil (2.65 ± 1.801 mL). So PEG 400 was selected as cosurfactant. The formulation of Cefdinir SMEDDS was optimized by a simplex lattice design. The optimal formulation of SMEDDS was comprised of 20% oil (Labrafac), 60% surfactant (Tween-80) and 20% co-surfactant (PEG-400). Results and Discussion: Pseudo-ternary phase diagrams were constructed to identify the efficient selfemulsification region. Optimal ratio of surfactant to co-surfactant was selected to be 4:1. A suitable SMEDDS formulation should have a minimum self emulsification time, maximum% Transmittance, maximum time require to 20% of drug release.The individual desirability for each response was calculated and batch F2 showed the highest overall desirability therefore this batch considered to be the best batch. In order to obtain both high %Transmittance and high Cumulative %release, the appropriate ratio of components was chosen for optimized formulation, which consisting of oil (20%), surfactant (60%), co-surfactant (20%).The average globule size of SMEDDS containing Cefdinir was about 87.60 nm when diluted in water. No significant variations in globule size and In vitro diffusion studies showed remarkable increase in dissolution of drug. Order of drug release was F-2> F-4> F-1 > F-7> F-3>F-6 > F-5.  Conclusion: The data suggest use of SMEDDS to provide great potential as an alternative to traditional oral formulations of Cefdinir. 

Keywords: Cefdinir; Self-Micro Emulsifying Drug Delivery System (SMEDDS); Simplex lattice Design; Globule Size.