Advances in phytochemical delivery systems for improved anticancer activity

Natural compounds have significant anticancer pharmacological activities, but often suffer from low bioavailability and selectivity that limit therapeutic use. The present work critically analyzes the latest advances on drug delivery systems designed to enhance pharmacokinetics, targeting, cellular uptake and efficacy of anticancer phytoconstituents. Various phytochemicals, including flavonoids, resveratrol, celastrol, curcumin, berberine and camptothecins, carried by liposomes, nanoparticles, nanoemulsions and films showed promising results. Strategies to avoid drug metabolism, overcome physiological barriers and achieve higher concentration at cancer sites through skin, buccal, nasal, vaginal, pulmonary and colon targeted delivery are presented. Current limitations, challenges and future research directions are also discussed.