Drug delivery systems for thyroid disease treatment: a mini review on current therapies and alternative approaches

Thyroid hormones play an important role in many metabolic processes in the human body. However, these processes can often be disrupted by an over or underactivity of the thyroid gland which, if undiagnosed or untreated, can result in serious illness. Currently, therapeutic management of an underactive thyroid gland (hypothyroidism) is typically achieved via replacement therapy with levothyroxine (LEVO), a synthetic form of thyroxine. Conversely, anti-thyroid drugs (ATDs), radioactive iodine or thyroidectomy are established approaches in treating hyperthyroidism. With respect to the route of the administration, drugs to treat hypo and hyperthyroidism can typically be administered through oral (PO), intravenous (IV), and rectal (PR) routes. Despite the fact that thyroid disorders have been successfully treated for many years, several problems still exist in the conventional treatment approach. Due to issues such as poor patient compliance and concordance, poor gastrointestinal (GI) absorption when taken incorrectly, and interactions with food and other medications, the administration of these drugs often results in sub-optimal dosing with accompanying serious illness if not corrected. Other forms of drug delivery are currently being studied to overcome the dosing complications that frequently occur with LEVO and ATDs with a view to increasing both patient compliance and bioavailability of the drugs in question. This review will examine why there remains a need for novel approaches and discuss studies that have been carried out with regards to this.