From conventional formulations to nanoparticles in the delivery of Imiquimod: a literature review

Imiquimod (IMQ) is an FDA-approved immune response modifier available as a 5% w/w topical cream (Aldara™) and is extensively utilized in the treatment of superficial basal cell carcinoma and other skin cancers. PubMed and Google Scholar (2006-2026) were searched for original studies on IMQ solubility, clinical trials, and IMQ-loaded nanoparticle formulations. IMQ exhibits poor solubility in pharmaceutical excipients such as Miglyol 812N, solvents (e.g. acetonitrile), and water, which has limited its formulation choices. After conventional formulation administration, IMQ poor deposition in skin tissue requested high initial drug amounts in vehicle but did not allow full potential efficacy in patients. In addition, IMQ high content in formulation to promote more skin deposition has been observed to cause several toxicities in clinical trials, such as erythema. To address these limitations, various nanoformulations have been developed to enhance the solubility, efficacy, safety and delivery of IMQ. This review focuses on the potential and limitations of IMQ delivery, along with recent progress in the development of IMQ-loaded nanoformulations, with particular emphasis on their role in cancer treatment.