drug delivery

ABSTRACTThe majority of patients find that the oral route of drug administration is the most convenient, easy to follow, non- invasive, and physician-preferred method. However, oral biologic administration is not as beneficial as other routes because of mucosal permeability and various gastrointestinal barriers that limit the systemic absorption of complex macromolecules after ingestion. Patients tend to prefer taking medicines orally as tends to be more convenient; however, oral administration is not currently possible for biologics. The physiological role of the gastrointestinal tract presents multiple barriers that limit the systemic absorption of complex macromolecules after ingestion. Biologics are not only highly sensitive to the harsh environment of the gastrointestinal tract, but, as very large molecules, their permeability across the intestinal mucosa is extremely poor. Research in the area of oral delivery of biologics has a long and rich history and the proliferation of biologics in recent decades has further accelerated the research activity. This article summarizes the main physiological barriers to oral delivery of biologics and discuss different research strategies to enable or improve oral delivery of biologics. Keywords: Absorption enhancers; biologics; drug delivery; gastrointestinal barriers; insulin; micro needle pill.

Microbubbles designate air or gas filled microspheres suspended in a liquid carrier phase which generally results from the introduction of air or gas. The liquid phase contains surfactants to control the surface properties as well as stability of the bubble. Microbubbles have an average size less than that of RBC’s i.e. they are capable of penetrating even into the smallest blood capillaries & releasing drugs or genes, incorporated on their surface, under the action of ultrasound. Microbubbles in general have a wide variety of applications. However in the biomedical field these are primarily used as diagnostic agents in combination with ultrasound for molecular imaging of various organs and even tumors. These are also proposed for drug and gene delivery to targeted regions in combination with various ligands. Most of the physicians today prefer imaging with ultrasound in combination with microbubbles compared to other diagnostic techniques for low cost and rapidity.