pH-targeted and time-released microparticles of quercetin and lycopene for ulcerative colitis treatment: DoE-based formulation development, pharmacokinetics, and <i>in-vivo</i> proof of concept studies

Lycopene (LYC) and quercetin (QRN) exhibit synergistic effects on ulcerative colitis (UC) treatment due to their anti-inflammatory and antioxidant properties. This study aimed to develop a microparticle formulation utilising pH-sensitive and time-release-based polymers, namely Eudragit L and Eudragit RS, respectively, to achieve colon-targeted and controlled-release delivery. Subsequently, pharmacokinetics and UC therapy proof-of-concept studies were conducted. The box-Behnken design was employed to develop and optimise the LYC-QRN microparticles, characterised by particle size and distribution, entrapment efficiency (EE), and drug loading, followed by morphology, molecular, thermal and crystallinity evaluations. The polymers primarily contributed to LYC-QRN encapsulation and loading, while the drug concentration influenced particle size behaviour. The optimised formulation was achieved using 4.10% Eudragit RS, 0.76% Eudragit L, and a drug concentration of 7.82%, resulting in an EE of >50%. QRN and LYC loading were approximately 50 and 25 mg/g, respectively, and the particle size was nearly 1 µm, exhibiting minimal variation. Characterisation demonstrated that the drug in the microparticle dispersed molecularly as an amorphous system, devoid of any chemical interactions. The drug was released at a specific pH-triggering system, enhancing its bioavailability by 3.5-fold. <i>In-vivo</i> evaluation demonstrated that LYC-QRN microparticles effectively cured chronic colon inflammation and protected the gastric mucus layers.