drug delivery

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DRUG DELIVERY DRUG DELIVERY Mohamed Adam.k

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Drug Delivery delivering the drug at the right place, at the right concentration for the right period of time. Obstacles low drug solubility, degradation (environmental or enzymatic), fast clearance rates, non-specific toxicity, inability to cross biological barriers etc., Drug is a chemical substance used in the treatment, cure, prevention, or diagnosis of disease or used to enhance physical or mental well-being. Drug Drug Delivery Obstacles

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Drug delivery systems are required to be compatible with processes in the body (biocompatibility) as well as with the drug to be delivered. Drug delivery system (DDS), the association of the drug with a carrier. Most of the polymers are used as drug carriers Drug delivery system

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Types of polymers used for controlled release Diffusion-controlled systems Solvent-activated systems Chemically controlled systems Types of polymers used for controlled release Reservoir and Matrix Osmotically controlled system Swelling controlled system Pendant chain system Bioerodible system

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Swelling controlled drug delivery system Hydrogels are three dimensional networks of hydrophilic polymers that are insoluble in water at a physiological temperature and pH but swells. Hydrogels

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Hydrogel Hydrogel It can be Slab, Microparticle , Nanoparticle , Coating, Film. Has ability to maintain their original shape during & after swelling (Isotropic swelling). Hydrophilicity due to the presence of hydroxylic , carboxylic, amidic, sulponic groups. The diffusion characters also depends the monomer composition and relative amount of multi polymer.

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Classifications of hydrogels Classifications of hydrogels

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Mechanism of drug delivery Mechanism of drug delivery

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Stimuli-responsive hydrogels in drug delivery Stimuli-responsive hydrogels in drug delivery

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Stimuli-responsive hydrogels in drug delivery Stimuli-responsive hydrogels in drug delivery

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Characterization parameters for Hydrogels Characterization parameters for Hydrogels

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Comparison between different types of hydrogel networks Comparison between different types of hydrogel networks

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Preparation of Hydrogels Preparation of Hydrogels

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Preparation of Hydrogel based DDS Preparation of Hydrogel based DDS

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Requirements to use as a DDS Requirements to use as a DDS Inert Comfortable for the patient Capable of achieving high drug loading Readily processable Safe from accidental release Simple to administer and remove Easy to fabricate Free of leachable impurities

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Swellable device containing DDS Swellable device containing DDS As the soluble cap erodes, the hydrogel swells and pushes out the drug. The hydration rate depends on the hydrogel size, the length of the plug and the fit ratio (plug diameter to body diameter).

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The gel expands at high pH and shrinks at low pH. The gel contains Polymethacrylic acid Polyethylene glycol Hydrogel – Molecular Gate Hydrogel – Molecular Gate

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Routes of drug administration Routes of drug administration General factors to consider: Chemical properties of the drug (e.g. pH, fat/H2O soluble) Proper medium to carry drug (e.g. oil , H2O) Desired duration of drug effects User variables: age, sex, weight (e.g. fat tissue ,muscle) Specific medical conditions of user (e.g. conscious or not) Factors related to GI tract(e.g. Condition of liver, kidney) Other: cost, pain etc., The path by which a drug is taken into the body.

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Absorption of drug through walls of GI tract & into blood vessels Advantages: Disadvantages: Convenient - portable, safe, no pain, easy to take. Cheap - no need to sterilize , compact. Variety of dosage forms available. Only part of the dose may be absorbed Unconscious patients are unable to swallow solid dosage forms. Oral drug delivery Oral drug delivery

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Liver is by-passed thus there is no loss of drug Rapid absorption - Because of the good blood supply Drug stability - pH in mouth relatively neutral Advantages: Disadvantages: Inconvenient to hold in mouth Drug taste Buccal and Sublingual Buccal and Sublingual

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Hydrogel can be used due to Its mechanical stability , favorable refractive index and high Oxygen permeability. Ocular drug delivery Ocular drug delivery

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Advantages: By - pass the liver. Absorption of gases is efficient and rapid. Drugs absorbed through the mucous membranes of the respiratory tract, producing a relatively limited effect, or systemic effect Inhalation Inhalation

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Can deposit in the lungs, and subsequently undergo swelling Slow degredation , and drug release Slow delivery into the alveolar fluid, and at a controlled rate into the blood stream Minimizing possible toxic responses of exposed cells to an excessively high concentration of the drug. Without the majority of the particles being phagocytosed by alveolar macrophages. Hydrogels in Inhalation

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A quick response is possible . The whole dose is delivered to the blood stream. Veins relatively insensitive - to irritate by irritant drugs (But not in IM ) Advantages: Disadvantages: Difficult to find a suitable vein(in IV ). Toxicity can be a problem with rapid drug administrations. Parentaral drug delivery Parentaral drug delivery

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Generally absorption is quite slow Advantages: Disadvantages: Can provide prolonged or controlled drug delivery Skin irritation Decreased frequency of administration Transdermal drug delivery

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Hydrogels in Transdermal Prevent fluid lose Provide extra moisture Prevent micro organism entry Absorbs contaminating bacteria & debris Maintaining an optimum healing temperature Transparency to view the wound Reduce friction & pressure Easy to apply, painless removal Allow water vapor to pass out Breakdown necrotic tissue Promote re- epithalisation

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Thank You….