Most of biopharmaceuticals in clinical use today are available in a solution or suspension form and delivered by invasive routes (i.e. injection). However, several attempts have been made in order to develop effective oral formulations of 'biomolecules' characterized by a fragile structure and a low bioavailability. To achieve an efficient delivery of such molecules by non-parenteral route, in particular, via the oral route, novel concepts are needed not only to overcome significant enzymatic and diffusion barriers but also to ensure stability and biological activity. Vaccines and antibodies have a special interest as biomolecules because of their high therapeutic efficacy both in prevention and treatment of several chronic diseases. In this review, we would like to highlight the trends made in the development of pharmaceutical forms to deliver these molecules by the oral route. Hence, we will focus on the description of the different forms (solutions, suspensions, powders, tablets, micro and nanocarriers …) available today or under research study, in which product stability and efficacy are maintained. A special attention will be paid to the formulation strategies that may include the addition of several functional excipients and/or adjuvants, aiming to protect, to functionalize or to modulate their release in the body.
Keywords: Biomolecules; antibodies; delivery systems; formulation; oral administration; vaccines.