Bi-layer tablets with sitagliptin phosphate as a Immediate Release (IR) layer and metformin HCl as a Sustained Release (SR) layer were developed for hypoglycemic control. The IR formulations were formulated using Aegle marmelos gum (natural antidiabetic agent and disintegrant) by direct compression method and was found to have good pre- and post-compression properties. Disintegeration time for SP3 (2.5 mg of gum) was found to be 128 seconds. Among the IR formulations, SP3 drug release was found to be 99.31% within 10 minutes, aligning with the marketed product Januvia. For sustained release layer optimization, 3² full factorial design was used to study the effects of sustained release polymers X1 - calcium starch (matrix forming polymer) and X2 - HPMC K100 on drug release of metformin at 1, 6, and 12 hours. Metformin SR layer was evaluated for weight variation, hardness, friability and dissolution. MF7 was selected as optimized formulation by factorial design and it achieved 98.52% release over 12 hours similar to marketed product Glycomet. Sustained drug release followed first-order kinetics (R2 = 0.9832) with non-Fickian diffusion (n = 0.765). Further bi-layer tablets were punched and characterized. Bi-layer tablet having MF7 and SP3 as sustained and immediate release layer was considered as optimized and evaluated. Immediate IR layer from the bi-layer tablet had shown 96.15% of sitagliptin release in 10 min and Metformin SR layer have sustained drug release 97.16% up to 12 similar to Innovator bilayer tablet (Istamet). Compatibility studies (FT-IR) showed no component interactions. Bi-layer tablet formulation had shown promising release profiles, offering effective glycemic control and improved patient compliance.