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Transcript of GITS
it is the hydrostatic pressure naturally occurring in the GIT due to the difference in the concentration of the solute Oral route is the most extensively used routes of drug
administration because of its advantages:
ease of administration
improved patient compliance
convenience Because of this, researchers experimented various techniques
and technologies to further increase efficiency of drug absorption in the body through the gastro-intestinal system. One of this is the
Gastro-intestinal Therapeutic System (GITS). Destination NO. 2 Formulation 1. Consist of two-layered core of active ingredients and osmotic polymer surrounded by a semi-permeable membrane.
The membrane is designed with a laser-drilled hole known as the ORIFICE. When the tablet is swallowed , water is absorbed from the gastrointestinal tract (GIT) through the semipermeable membrane and the active-ingredient containing core is extruded through the orifice at a constant rate by the expanding polymer core layer. Semipermeable Membrane and Polymer Used in drugs:
polyorthoesters Destination N0. 3 Advantages and Disadvantages Advantages: improved treatment tolerability
zero-order delivery rate
delivery maybe delayed or pulsed
drug release is independent of gastric pH
easy to characterized and understood
release mechanism mechanism are not dependent on drug Disadvantages: used of special equipment to make the orifice
risk of film defects in coating
size hole is critical Shortcut way : Factors and Parameters 1. Orifice Size * orifice must be smaller than the minimum size to minimize premature drug release Methods to create orifice:
laser drill - normally CO2 laser beam is used producing sub millimeter size of hole in the tablet.
Indention - made in core tablets using modified punches with needle on the upper punch
used of leachable substances in the semi-permeable coating e.g. controlled porosity osmotic pump 2. Solubility * faster solubility of the drug means faster response
to the body. low solubility drugs have alternate methods to be employed
1. addition of swellable polymers
2. compression of drug with other excipients which improves solubility e.g. cyclodextrin GITS GITS GITS GITS GITS GITS GITS 3. Osmotic Pressure * osmotic pressure directly affect the release rate of the active ingredients.
to be uniform, osmotic pressure must be constant to achieve a zero-order delivery of the drug.
addition of osmotic agents that enhances osmotic pressure are used also e.g. bicarbonate salts 4. Semi-permeable membrane *Since semipermeable membrane used permits only water and not ions, the release rate is essentially independent to the pH of the environment. BASIC COMPONENTS OF GITS Semi-permeable Membrane Polymeric membrane selection is the key to osmotic delivery formulation.
1.impermeability to other ingredients other than water.
3.maintain its dimensional integrity Any polymer that is permeable to water and impermeable to solute can be used as a coating to osmotic devices:
2.cellulose acetate butyrate
4.ethyl cellulose Osmotic Agents Osmotic Agents generates driving force the uptake of water and assist in maintaining drug uniformity release.
potassium bicarbonate Flux Regulators Drug delivery system can be designed to regulate the permeability of the fluid by adding flux regulators such as polyethylene glycols and polyhydric alcohols. Wicking Agents a material that has the ability to draw out water in the porous network. They can be swellable and non-swellable in nature.
examples: SLS and PVP COATING SOLVENTS -solvent suitable for making polymeric solution that is essential in manufacturing the wall of the osmotic device like methylene chloride, acetone, methanol, ethanol. Plasticizers this material have the ability to change the visco-elastic property of the polymeric material which further increase the permeability of water to the device e.g. polyethylene glycol, ethylene glycol monoacetate and triethyl citrate. TREASURE GITS 1. Nifedifine
These drugs are used to treat high blood pressure and chest pain. 2. GLIPIZIDE
These drugs decreases blood sugar level; anti-diabetic agents. 3.DOXAZOSIN
These drugs treats hypertension and improve urination in man with benign prostatic hyperplasia.(enlarged prostate gland). THANK YOU!!!!!!!!!!