Abstract: The rectal route serves as a valuable and effective method for both localized and sys-temic drug administration, offering several advantages compared to other delivery pathways. This route benefits from a relatively stable rectal environment with low enzymatic activity, mak-ing it particularly suitable for drugs that face challenges such as poor oral bioavailability, exten-sive first-pass metabolism, gastrointestinal instability, or gastric irritation. It is also an ideal op-tion for individuals who have difficulty swallowing, suffer from nausea or vomiting, or need tar-geted drug delivery to the lower gastrointestinal tract. Several physiological and pharmaceutical factors influence how well drugs are absorbed and how effective they are when administered rec-tally. This review delves into the anatomy and physiology of the rectum, common rectal disor-ders, and key formulation aspects that impact rectal drug delivery. It also discusses various rectal dosage forms, including suppositories, suspensions, microspheres, nanoparticles, liposomes, tab-lets, and hydrogels, and explains their mechanisms of action and potential therapeutic uses. Moreover, the review includes a comprehensive table summarizing clinical trials that assess the safety and effectiveness of rectal formulations, offering insights into the latest developments and future directions in this field.
Islam et al. (Tue,) studied this question.