Recent advances in oral delivery of peptide hormones.

INTRODUCTION: Oral delivery of therapeutic peptide hormones offers the promise of greater patient compliance when compared to parenteral administration routes. However, it is a huge challenge in the pharmaceutical field. Due to increasing demand for oral delivery of peptide hormones such as insulin, gonadotropin-releasing hormones, and calcitonin, various technologies have been explored to overcome the associated hurdles. AREAS COVERED: This review article summarizes the physiological barriers to the oral delivery of peptide hormones and some of the key strategies to circumvent these barriers and enhance peptide hormones' oral bioavailability. In addition, recent advances in oral formulation strategies of peptide hormones, under development and within the clinical trial stages, are discussed. EXPERT OPINION: The pharmaceutical industry has devoted much effort to develop new, and often complex peptide hormone products based on formulation strategy. Use of the native structure of the peptide hormones in oral formulations could result in an unpredictable pharmacokinetic profile. Authors believe that considering chemical modification prior to formulation is essential to achieve orally active products. Although no major breakthrough has been achieved for effective oral delivery of peptides hormones yet, the substantial efforts by industrial and academic laboratories might yield successful results in near future.