Osmotic Drug Delivery System as a Part of Modified Release Dosage Form

Abstract

Conventional drug delivery systems are known to provide an immediate release of drug, in which one can not control the release of the drug and can not maintain effective concentration at the target site for longer time. Controlled drug delivery systems offer spatial control over the drug release. Osmotic pumps are most promising systems for controlled drug delivery. These systems are used for both oral administration and implantation. Osmotic pumps consist of an inner core containing drug and osmogens, coated with a semipermeable membrane. As the core absorbs water, it expands in volume, which pushes the drug solution out through the delivery ports. Osmotic pumps release drug at a rate that is independent of the pH and hydrodynamics of the dissolution medium. The historical development of osmotic systems includes development of the Rose-Nelson pump, the Higuchi-Leeper pumps, the Alzet and Osmet systems, the elementary osmotic pump, and the push-pull system. Recent advances include development of the controlled porosity osmotic pump, and systems based on asymmetric membranes. This paper highlights the principle of osmosis, materials used for fabrication of pumps, types of pumps, advantages, disadvantages, and marketed products of this system.

Osmogen‐Mediated One‐Step Technique of Fabricating Hollow Microparticles for Encapsulation and Delivery of Bioactive Molecules

“…The osmotic pressure of these osmogens is in the order of NaCl > KCl > sucrose . KCl (5 mg) having 21.6% less osmotic pressure (from above equation) than that of NaCl (5 mg), produced microparticles with comparatively thicker shells and smaller hollow cores (Figure I,J).…”

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“…When device is placed in the aqueous environment the middle push layer which containing the swelling agent swells and the drug is released from the two orifices situated on opposite sides of the tablet and thus these systems can be suitable for drugs prone to cause local irritation of the gastric mucosa 19 .…”

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“…The delay in the gastric emptying after meals rich in fats is mainly caused by saturated fatty acids with chain length of C 10 -C 14 . [37] A coated ion exchange resin bead formulation has been shown to have gastric retentive properties, which was loaded with bicarbonates. Bicarbonate and a negatively charged drug are loaded in ion exchange resins.…”