MODERN STATE OF CREATION, PRODUCTION AND RESEARCH OF DRUGS. Message 24. Osmotic drug release and delivery systems: design, characterization and classification

Introduction. Development of new drugs is a priority direction of modern pharmaceutical technology in the world. Modified release drugs that characterized by changes in the mechanism and type of release of active pharmaceutical ingredients (APIs) of the dosage form are perspective concerning development. The drug release can be modulated by different ways but the most of novel drug delivery systems are prepared using matrix, reservoir or osmotic principle. Osmotic drug delivery technique is the most interesting and widely acceptable among all other technologies used for the same. Osmotic drug delivery systems use offer distinct and practical advantages over other means of delivery. The following advantages have contributed to the popularity of osmotic drug delivery systems. • The delivery rate of zero-order is achievable with osmotic systems. • Delivery may be delayed or pulsed, if desired. • Higher release rates are possible with osmotic systems compared with conventional diffusion-controlled drug delivery systems. • The release rate of osmotic systems is highly predictable and can be programmed by modulating the release control parameters. • For oral osmotic systems, drug release is independent of gastric pH and hydrodynamic conditions. • The release from osmotic systems is minimally affected by the presence of food in gastrointestinal tract. Disadvantages of osmotically controlled drug delivery system are expensive, chances of toxicity due to dose duping, rapid development of tolerance, hypersensitivity reaction may occur, integrity and consistency are difficult, release of drug depends on size of hole, thickness of membrane, surface area, composition of membrane. Development of osmotic drug delivery systems was pioneered by Alza and it holds major number of the patents analyzed and also markets several products based on osmotic principle. These systems can be used for both route of administration i.e. oral and parenterals. Oral osmotic systems are known as gastro-intestinal therapeutic systems. Parenteral osmotic drug delivery includes implantable pumps. Oral osmotically driven systems have primarily evolved from being device concepts for the delivery of veterinary medicines, namely Rose-Nelson, Higuchi-Leeper and Higuchi-Theeuwes pumps. Using osmotic pressure as the energy source, the semi-permeable membrane controls water inflow, generating hydrodynamic pressure inside the device and, thereby controlling drug delivery. All these technologies have in common the semi-permeable membrane controlling the drug delivery rate. Basic components of osmotically drug delivery system are drug, osmotic agent, semi permeable membrane, pore forming agents, plasticizers. Osmogent are essential ingredient of osmotic pump, usually is ionic compounds consisting of either inorganic salts or hydrophilic polymers and carbohydrates. Generally combination of osmogent is used to achieve desired osmotic pressure within the device. The semi permeable membrane should be a stable both to the outer inner environment of the device. The membrane must be sufficiently rigid so as to retain its dimensional integrity during the operational lifetime of the device. Factors affecting the release rate of drug from osmotic drug delivery system are solubility, osmotic pressure, delivery orifice, membrane type. In recent years, controlled drug delivery system has been recognized as an attractive niche for the pharmaceutical and health industry. Conclusions. Classification, basic requirements, approaches to the development of osmotic drug release and delivery systems are considered