Rectal controlled-release formulations

Corticosteroids and adrenocorticotropic hormone have been widely used for the treatment of ulcerative cohtis and Crohn s disease, given parenterally, orally, or rectally. Corticosteroids are believed to modulate the immune system and inhibit production of cytokines and mediators. It is not clear whether the most important steroid effects are systemic or local (mucosal). Budesonide is a corticosteroid that is administered orally in a controlled-release formulation. The drug undergoes extensive first-pass metabolism, so systemic exposure is thought to be minimized. Immunosuppressive agents such as azathioprine, mercaptopurine (a metabolite of azathioprine), methotrexate, or cyclosporine are sometimes used for the treatment of IBD. ... 

A host of bioadhesive controlled release systems have been proposed in recent years. Among the most commonly studied applications of bioadhesive materials is the area of buccal controlled delivery [408], The buccal delivery of small peptides from bioadhesive polymers was studied by Bodde and coworkers [409], and a wide range of compositions based on poly(butyl acrylate) and/or poly(acrylic acid) gave satisfactory performance. Bioadhesive poly(acrylic add)-based formulations have also been used for oral applications [402,410] for the sustained delivery of chlorothiazide [410] and for a thin bioadhesive patch for treatment of gingivitis and periodontal disease [411]. Other bioadhesive applications of polyelectrolytes include materials for ophthalmic vehicles [412,413], and systems for oral [410,414,415-419], rectal [420,421] vaginal [422] and nasal [423] drug delivery. 

Dosages and routes of administration Oxycodone is given by mouth in single doses of 5-10 mg or as controlled release preparations with doses of 40 mg (Cairns, 2001). Rectal administration is also possible. Oral formulations often contain combinations with paracetamol or acetylsalicylic acid. 

Miyake, M., et al. 2004. Development of suppository formulation safely improving rectal absorption of rebamipide, a poorly absorbable drug, by utilizing sodium laurate and taurine. J Control Release 99 63. 

Polyethylene glycols (PEGs) are widely used in a variety of pharmaceutical formulations including parenteral, topical, ophthalmic, oral, and rectal preparations. It has been used experimentally in biodegradable polymeric matrices used in controlled-release systems. 

Morphine is available for oral, rectal, and parenteral administration. Oral formulations include immediate and controlled release tablets, as well as oral solution regular strength and concentrate. Parenterally, it can be administered subcutaneously, intramuscularly, intravenously, or by continuous infusion. It is a drug of abuse and can be nasally insufflated. 

Mesalamine (5-aminosalicylic acid asacol, others) is a salicylate that is used for its local effects in the treatment of inflammatory bowel disease (see Chapter 38). It currently is available as a suppository and rectal suspension enema (rowasa) for treatment of mild-to-moderate proctosigmoiditis Cl rectal suppository (canasa, others) for the treatment of distal ulcerative colitis, proctosigmoiditis, or proctitis. Oral formulations and controlled-release capsule that deliver drug to the lower intestine are efficacious in treatment of inflammatory bowel disease, in particular ulcerative colitis. Sulfasalazine (salicylazosulfapyridine azulfidine) contains mesalamine linked covalently to sulfapyridine (see Chapter 38) it is absorbed poorly after oral administration, but it is cleaved to its active components by bacteria in the colon. The drug is of benefit in the treatment of inflammatory bowel disease, principally because of the local actions of mesalamine. 

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