Nanocarriers outperform traditional medication dosage forms in terms of efficacy, safety, and tolerability because of their small size, large surface area, and potential for precise targeting. More and more researchers are looking to produce nanocarriers that can be used to treat a variety of illnesses. Dendrimers, liposomal nanoparticles, polymersomes, polymer–drug conjugates and peptide nanoparticles are only some of the nanocarriers that have been developed for drug delivery. Other nanocarriers include carbon nanotubes, nanoshells and carbon dioxide nanoparticles. Nanocarriers have been characterised using a variety of approaches during the past few decades, both in vitro and in vivo. Most nanocarriers are characterised using fundamental in vitro, ex vivo, ex situ, and in situ techniques, which emphasise their advantages and limitations as well as regulatory and manufacturing issues that hinder the transfer of nanocarriers from laboratory to clinical use, as described in this review. There is also a discussion of the integration of artificial intelligence with nanotechnology and the advantages and disadvantages of artificial intelligence in the creation and optimization of nanocarriers, along with future prospects.