Polymeric Films DONE BY : 1-Fatimah Al –Shehri 2- Hessah Al- Subai 3-Hamdah Al-nubaihei 4-Shoroug Al-Qarni 5-Bayan ba-abdullah 6- Noor Al-Otaibi

History : Reacting organic compounds under high temperatures and high pressures. They set up an experiment to react ethene with benzaldehyde.they found a small amount of a white waxy solid. Polyethene polymer.

What are polymers : Definition : are chemical compounds of natural and synthetic of usually high molecular weight consisting of up to millions of repeated linked units. Polymerization: the way the molecules linked together. Nomenclature : is generally based upon the type of monomer residues comprising the polymer..

1- : 1- homopolymers : Contains only a single type of repeat unit. e.g Polystyrene 2-copolymers : Contains a matrix of repeat units. e.g: Ethylene vinyl acetate.

Types of polymers : 1-natural : CELLULOSE DRERIVATIVES : 1-HPMC 2- sodium CMC 3- cellulose actetate. 4-methyl cellulose. 5-ethyle cellulose. 6-chitosan. 7-sodium carboxymethylquar. 8-sodium alginate. 9-polymerized rosin. 2- synthetics : 1-Polyvinyl alcoholpolyethylene. 2-polyethylene glycol. 3-ethylene vinyl acetate copolymer. 4-silicon rubber. 5-ethyl vinyl acetate.

PROPERTIES OF POLYMERS : 1-microstructure. 2-continuous macroscopic material 3-The physical properties of a polymer are strongly dependent on the size or length of the polymer chain. 4-polymer chains are so long. 5-Different side groups on the polymer can lend the polymer to ionic bonding or hydrogen bonding between its own chains.ionic bondinghydrogen bonding

Polymer architectures Structure has a strong influence on the other properties of a polymer.

Determination of long chain & molcular weight: done by using Chromatographicmethod Like: 1-size exclusion chromatography. 2-Low-angle laser light scattering. 3- viscometry.

Polymeric films : It’s a kind of modification of polymer to provide a certain properties to drug delivery system.

Film preparation : 1) Casting technique : · most simple technique · preparation of relatively thick films >mm 2) Thermal spray processing of polymers : 3) Spin coating: For thin, uniform films to flat substrates Polymer is dissolved in a volatile solvent and the solution is spanned.

Uses of polymeric films : Medical uses : 1- coatings. 2- transdermal drug delivery system. 3- controlled drug delivery system. Non medical uses : 1- packaging material for ( food products & consumer goods & liquid & bulk chemicals & petrochemical products ) 2- household purposes. 3- insulating of wire & cables. 4- production of capacitors.

A- film coating polymers : Properties : 1- solubility : polymer solublility is important to determine the behaviors of the coated product in GIT. 2-Viscosity : Polymer should have relatively low viscosity.

Types of film coating polymers : A- immediate release coatings 1- cellulose derivatives 2- vinyle derivatives 3- aminoalkyle methacrylate copolymers. B- modified release coatings: 1- cellulose derivatives. 2- phathalate esters 3- methacrylic copolymers.

1-hydroxypropyle methyl cellulose : The most widely used of the cellulose polymers Soluble in aqueous media. 2- vinyl derivatives : Has limited use in coatings because of its inherent tackiness 3- Ethylene glycol: Less tacky and extremely flexible.

4- METHYLEMETHACRYLATE COPOLYMERS : -They are esters polymers -Insoluble in water preparation : Varying degree of permeability to render them suitable for extended release applications. These polymers used today as : aqoues polymer dispersions.

Evaluation of polymeric films 1- physical appearance. 2- moisture content. 3- thickness. 4- flatness. 5-folding endurance. 6- tensile strength (percentage elongation at break). 7- drug content.

Ne w applications of polymeric films :

B-TDDS : A transdermal patch or skin patch is a medicated adhesive patch that is placed on the skin to deliver a specific dose of medication through the skin and into the bloodstream. the first application was on : scopolamine in 1979.

Composition of TDDS: 1. Polymer matrix. 2. Drug. 3. Permeation enhancers. 4. Pressure sensitive adhesives (PSA). 5. Backing membrane. 6. Release liner. 7. Other excipients.

Preparation of Transdermal Film Method used : casting technique. Polymer and drug was dissolved in the mixture of Dichloromethane: Ethanol mixed with magnetic stirrer for 30 mins. Propylene glycol 30% v/v is added finally as a plasticizer. The prepared solution was casted in glass surface in ‘O’ shaped ring and allowed to dried at room temperature for 48 hours.

Casting technique : :Preparation of casting solutions For ethyl cellulose and PVP The casting solutions were prepared by dissolving weighed quantities of polymers in chloroform. The drug was dissolved in chloroform and added to the above polymer solution along with propylene glycol, as plasticizer, thoroughly mixed to form a homogeneous mixture.

Casting technique : Film –forming dispersions were poured into each Teflon petri dish. Dried at 35C for 15 h in a convection oven Evaporation of exx water. The film is peeled off from the plates and Kept in a closed reservoir at constant relative humidity.

Properties of drugs used in TDDS: 1-Low molecular weight. 2-low melting point. 3- extensive first pass metaboilsm. 4- narrow therapeutic windows. 5- short half life.

Examples of patches prepared by solvent evaporation method: Plasticizer Permreation enhancer SolventPolymerDrug WATERPEG Theophylline and salbutamol SPAN 80PEGDichloromet han Eudragit RS NAPROXAN Di-n-butyl phthalate ChloroformEthylcellulo se: Polyvinyl pyrrolidone and Eudragit RL100: Eudragit RS100 3-Carvedilol

Plasticizers : Added to polymers to modify physical properties of the polymers. Interpose between the polymer molecules so increasing free volume and facilitate chain motion. E.g: Polyols- fractionated coconut oil.

Mechanism of Action of Transdermal Patch Mechanism of Action of Transdermal Patch

Types of Transdermal Patch: 1. Single-layer Drug-in-Adhesive: The adhesive layer of this system also contains the drug. In this type of patch the adhesive layer not only serves to adhere the various layers together, along with the entire system to the skin, but is also responsible for the releasing of the drug. The adhesive layer is surrounded by a temporary liner and a backing. 2. Multi-layer Drug-in-Adhesive: The multi-layer drug-in adhesive patch is similar to the single-layer system in that both adhesive layers are also responsible for the releasing of the drug. The multi-layer system is different however that it adds another layer of drug-in-adhesive, usually separated by a membrane (but not in all cases). This patch also has a temporary liner- layer and a permanent backing.

3. Reservoir: Unlike the Single-layer and Multi-layer Drug-in-adhesive systems the reservoir transdermal system has a separate drug layer. The drug layer is a liquid compartment containing a drug solution or suspension separated by the adhesive layer. This patch is also backed by the backing layer. In this type of system the rate of release is zero order. 4. Matrix The Matrix system has a drug layer of a semisolid matrix containing a drug solution or suspension. The adhesive layer in this patch surrounds the drug layer partially overlaying it. 5. Vapour Patch: In this type of patch the adhesive layer not only serves to adhere the various layers together but also to release vapour. The vapour patches are new on the market and they release essential oils for up to 6 hours. The vapours patches release essential oils and are used in cases of decongestion mainly. Other vapour patches on the market are controller vapour patches that improve the quality of sleep. Vapour patches that reduce the quantity of cigarettes that one smokes in a month are also available on the market

Limitations: (1)Cure for acute pain is required. (2) Where rapid dose titration is required. (3) Where requirement of dose is equal to or less then 30 mg/24 hrs.

Advantages : 1- TDDS provides steady infusion of drug over extended period of time. 2-improve patient compliance. 3-decreased inter and intra patient variability. 4-Therapeutic failure or adverse effects can be avoided. 5-Self administration. 6-Pain, inconvenience of injections can be overcomed. 7-avoiding the first pass metabolism.

Applications : 1- transdermal nitroglycerine 2- transdermal estradiol 3- transdermal contraceptives 4- transdermal clonidine 5- transdermal fentanly 6- transdermal nicotine 7-transdermal testosterone