## 1 Introduction  
Gefitinib (GEF; MW: 446.9 \(\mathrm{\SIUnitSymbolMicro m}\)/mole), a water-insoluble anilinequinazoline derivative, is the epidermal growth factor receptor (EGFR) inhibitor and belongs to the family of tyrosine kinase inhibitor. It promotes cell cycle arrest and apoptosis, leading to inhibition of angiogenesis and cell invasion. The angiogenic-pathway is an important target to inhibit tumor growth [1]. It mediates the anti-angiogenesis effect by reducing the expression of pro-angiogenic genes, cell-proliferation and vascular density [2]. It is used to treat non-small-cell lung cancer (NSCLC), especially in patients who already have received chemotherapy [3, 4, 5, 1]. It has poor oral bioavailability (not more than 60%) because of its biopharmaceutical and physicochemical properties [6]. It exhibits poor aqueous solubility (approximately 0.3 mg/mL in ethanol and 0.5 mg/mL in 1:1 \(v\)/\(v\) solution of DMSO and PBS (pH 7.2) [7]. After a single oral dose of 50 mg GEF, only 12.1% of the drug was present in the blood after 240 h post-dose [8]. The absorption of GEF through the oral route is limited due to its low dissolution rate (only around 41.13% from pure-GEF) [8; 9; 10]; hence, it shows high variability in blood concentration and causes low bioavailability [11]. In addition to the low oral bioavailability, only 40-45% of the plasma concentration was found to act on the target tumors [12].  
Therefore, it was mandatory to develop a formulation with better solubility, dissolution and absorption to enhance the oral bioavailability of GEF [5; 13]. The present study focuses on the formulation of GEF with different excipients for evaluation of its impact on their solubility and dissolution rate. TPGS and SLS were used as surfactants to prepare the solid dispersions of GEF. The optimal composition was further encaged into HP \(\beta\)-CD to form ternary SDs.  
TPGS and SLS are non-ionic and anionic surfactants, respectively, which were found to have potential to increase the solubility and dissolution rate of various poorly soluble drugs. These surfactants have shown somewhat mechanistic simulation towards the in vivo solubilization and absorption of some drugs [14; 15; 16]. TPGS is generally regarded as a safe listed excipient that can be taken orally long-term even at high doses [16]. Additionally, vitamin-E-TPGS 1000 (where 1000 denotes the molecular weight of the polyethylene glycol chain) is an FDA-approved drug-solubilizer for oral, topical, nasal and vaginal delivery systems [16; 17]. Cyclodextrin, especially HP \(\beta\)-CD, has been reported to be safe and biocompatible [14; 18]. It is considered as a good solubilizer and bio-enhancer that forms an inclusion complex to improve the solubility and bioavailability of poorly soluble drugs [18]. It has served as an outstanding complexing agent to enhance the solubility, stability and bioavailability of GEF [5; 10].  
In this study, TPGS and SLS surfactant-based binary solid dispersions (SDs) of GEF were prepared. The addition of HP \(\beta\)-CD occurred for the optimal binary SDs to increase the aqueous solubility of GEF. The physicochemical interaction between GEF and the excipients was studied by FTIR and NMR spectroscopy. The morphological changes in the SDs were assessed by SEM, while the flow property was checked by Carr's index and Hausner ratio determination. The DSC was performed to determine the crystalline to amorphous conversion of GEF. The saturation solubility of the SDs was checked at different pH conditions, and dissolution tests were completed in 0.1N HCl (pH 1.2). Finally, the selected binary SDs and ternary SDs were evaluated for cell viability study using the lung cancer cells (A549) to evaluate apoptotic activity comparing GEF pure and untreated cells. The levels of p53 and caspases were also determined to substantiate their apoptotic properties.