Solubility enhancement of candesartan cilexetil by complexation with CAVAMAX® W7 PHARMA (β ‑Cyclodextrin)

Candesartan cilexetil (CC), a BCS Class II drug, exhibits low aqueous solubility, leading to dissolution-rate limited absorption and poor oral bioavailability. This study aimed to enhance the solubility and dissolution of CC through inclusion complexation with β-cyclodextrin (CAVAMAX® W7 Pharma). Complexes were prepared using physical mixture, kneading, and solvent evaporation methods at drug:carrier ratios of 1:1, 1:2, and 1:3. Prepared formulations were evaluated for solubility, phase-solubility behavior, solid-state characterization (FTIR, PXRD), dissolution studies, and accelerated stability. Phase-solubility analysis produced AL-type diagrams, confirming 1:1 stoichiometry and spontaneous complexation. Apparent solubility studies showed maximum enhancement at the 1:2 ratio, with solvent-evaporated complexes (F8) achieving the highest solubility (0.112 ± 0.007 mg/mL). FTIR and PXRD revealed peak shifts and amorphization, supporting inclusion formation. Dissolution profiles demonstrated improved release rates, with F8 achieving ~99% release within 120 min, compared to 52% for pure CC. Accelerated stability studies over 3 months confirmed formulation stability (f₂ ≥ 70). These findings establish solvent evaporation–based β-CD complexation as a robust strategy for enhancing the solubility, dissolution, and stability of candesartan cilexetil.