FLOATING / HOLLOW MICROSPHERES: A NOVEL APPROACH FOR GASTRO RETENTION

Abstract

To develop an oral drug delivery system, it is necessary to optimize both release rate of drug and residence time of system within gastrointestinal tract. In oral route difference in gastric physiology such as gastric pH & motility exhibit variability on gastric residence time (GRT) & drug delivery behavior. Several approaches are currently utilized in the prolongation of the GRT including floating drug delivery systems (FDDS), swelling and expanding systems, polymeric bioadhesive systems, high-density systems, modified-shape systems and other delayed gastric emptying devices. One such approach is Floating Microspheres (Hollow Microspheres). Floating microspheres are gastro-retentive drug delivery systems based on non-effervescent approach. Gastroretentive floating microspheres are low-density systems that have sufficient buoyancy to float over gastric contents and remain in stomach for prolonged period. The drug is released slowly at desired rate resulting in increased gastric retention with reduced fluctuations in plasma drug concentration. Floating microspheres improve patient compliance by decreasing dosing frequency and better therapeutic effect of short half-life drugs can be achieved. Floating microspheres are characterized by their micromeritic properties such as particle size, tapped density, compressibility index and flow properties including angle of repose, scanning electron microscopy, in vitro drug release studies and stability studies etc.