Drug-targeting methodologies with applications: A review

Abstract

Targeted drug delivery to solid tumors is a very active research area, focusing mainly on improved drug formulation and associated best delivery methods/devices. Drug-targeting has the potential to greatly improve drug-delivery efficacy, reduce side effects, and lower the treatment costs. However, the vast majority of drug-targeting studies assume that the drug-particles are already at the target site or at least in its direct vicinity. In this review, drug-delivery methodologies, drug types and drug-delivery devices are discussed with examples in two major application areas: (1) inhaled drug-aerosol delivery into human lung-airways; and (2) intravascular drug-delivery for solid tumor targeting. The major problem addressed is how to deliver efficiently the drug-particles from the entry/infusion point to the target site. So far, most experimental results are based on animal studies. Concerning pulmonary drug delivery, the focus is on the pros and cons of three inhaler types, i.e., pressurized metered dose inhaler, dry powder inhaler and nebulizer, in addition to drug-aerosol formulations. Computational fluid-particle dynamics techniques and the underlying methodology for a smart inhaler system are discussed as well. Concerning intravascular drug-delivery for solid tumor targeting, passive and active targeting are reviewed as well as direct drug-targeting, using optimal delivery of radioactive microspheres to liver tumors as an example. The review concludes with suggestions for future work, considereing both pulmonary drug targeting and direct drug delivery to solid tumors in the vascular system.

Keywords: Targeted drug delivery; Pulmonary system; Vascular system; Types of drugs and delivery devices; Computational analysis and experimental evidence; Future work

Core tip: Targeted drug delivery to diseased areas or solid tumors has the great potential to significantly improve treatment efficacy, minimize side-effects, and reduce health-care cost. The major problem addressed is how to deliver efficiently the drug-particles from the entry/infusion point to the target site. Past and present developments in drug formulation and associated drug-delivery devices are discussed. Examples of optimal drug delivery to pulmonary target sites as well as targeting solid tumors in the vascular system are reviewed.