Organic and Medicinal Chemistry International Journal ISSN 2474-7610 Review Article Organic & Medicinal Chem IJ Volume 7 Issue 2 - June 2018 Copyright © All rights are reserved by Nidhi Sharma DOI: 10.19080/OMCIJ.2018.07.555707 A Brief Review on Transdermal Patches Nidhi Sharma* HIMT College of Pharmacy, Greater Noida, India Submission: May 12, 2018; Published: June 05, 2018 *Corresponding author: Nidhi Sharma, HIMT College of Pharmacy, Greater Noida, India, Email: Abstract healingTransdermal to an injured drug area delivery of the system body. was An presentedadvantage toof overcome a transdermal the difficulties drug delivery of drug route delivery over especiallyother types oral of route. delivery A transdermal system such patch as oral, is a topical,medicated i.v., adhesive i.m., etc. ispatch that that the patchis placed provides on the askin controlled to deliver release a specific of the dose medication of medication into the through patient, the usually skin and through into the either bloodstream. a porous It membrane promotes covering a reservoir of medication or through body heat melting thin layers of medication embedded in the adhesive. The main disadvantage to transdermal delivery systems stems from the fact that the skin is a very effective barrier, as a result, only medications whose molecules are small can easily penetrate the skin, so it can be delivered by this method. This review article describes the overall introduction of transdermal patches including type of transdermal patches, method of preparation of transdermal patches and factor affecting etc. Keywords: Transdermal drug delivery system; Hydrin rubber; Silicon rubber; Polyvinylalcohol; Transdermal patch; Polyvinylchloride; Di-N- butylphthalate; Triethylcitrate Abbreviations: PE: Polyethelene; EVAC: Ethylene Vinyl Acetate Copolymer; PSA: Pressure Sensitive Adhesive Introduction Oral route is the most popular route of drug delivery system Types of Transdermal Drug Delivery System In this type of patch drug degradation etc in gastrointestinal tract due to enzymes, pH Single-layer Drug-in-Adhesive System: but it has some disadvantages including first pass metabolism, the adhesive layer of this system contains the drug. The adhesive etc. To overcome these problems, a novel drug delivery system layer not only serves to adhere the various layers together, along was developed by Chien in 1992, Banker in 1990, Guy in 1996. It with the entire system to the skin, but it is also responsible for was Transdermal patches or Transdermal delivery system. In this the releasing the drug. The adhesive layer is surrounded by a system medicated adhesive patches are prepared which deliver temporary liner and a backing (Figure 1). therapeutically effective amount of drug across the skin when it placed on skin. They are available in different sizes & having more than one ingredient. Once they apply on unbroken skin they deliver active ingredients into systemic circulation passing via skin barriers. A transdermal patch containing high dose of drug inside which is retained on the skin for prolonged period of time,Drug which can penetrate get enters through into blood skin flow via threevia diffusion pathways- process. a) Through hair follicals. b) Through sebaceous glands. c) Through sweat duct. Figure 1. Transdermal drug delivery systems are used in various skin disorders, also in the management of angina pectoris, pains, Reservoir System: In this System the drug reservoir is kept smoking cessation & neurological disorders such as Parkinson’s in between backing layer and a rate controlling membrane. disease [1,2]. And drug releases through microporous rate controlled membrane. Drug can be in the form of a solution, suspension, Organic & Medicinal Chem IJ 7(2): OMCIJ.MS.ID.555707 (2018) 001 Organic and Medicinal Chemistry International Journal or gel or dispersed in a solid polymer matrix in the reservoir polyacrylate, polyamide, polyurea, polyvinylpyrrolidone, compartment. polymethylmethacrylate etc [6,7]. Matrix System: This system is of Two type Drugs: Some of ideal properties of drug & some factors to a) Drug-in-Adhesive System: For the formation of drug be consider during preparation of Transdermal patches are as reservoir, the drug dispersed in an adhesive polymer and follows: then spreading the medicated polymer adhesive by solvent a. Ideal Properties of Drugs: (Table 1) casting or by melting the adhesive (in the case of hot-melt Table 1. adhesives) on to an impervious backing layer. S. No. Parameter Properties b) Matrix-Dispersion System: In this system the drug Should be Low in weight (less than is dispersed homogeneously in a hydrophilic or lipophilic 1 Dose 20mg/day). polymer matrix. And this containing polymer along with 2 Half- life 10/less (hrs). fabricated from a drug- impermeable backing layer. In this 3 Molecular weight <400da. drug is fixed onto an occlusive base plate in a compartment system the adhesive is spread along the circumference Skin permeability instead of applying on the face of drug reservoir to form a 4 >0.5*10-3cm/h. strip of adhesive rim [3]. 5 Skincoefficient Reaction Non irritating, Non sensitizing Micro-Reservoir System: This system is a combination 6 Oral bioavailability Low. of reservoir and matrix- dispersion systems. In which drug is suspended in an aqueous solution of water-soluble polymer b. Factors Affecting: (Table 2) and then dispersing the solution homogeneously in a lipophilic Table 2. polymer to form thousands of unleachable, microscopic spheres of drug reservoirs [4]. Physicochemical Pharmacokinetic Biological Components of Transdermal Drug Delivery System Solubility Half- life Skin toxicity Volume of Crystalinity Site of application a) Polymer matrix/ Drug reservoir distribution b) Drug Molecular weight Total body clearance Allergic Reaction c) Permeation enhancers. Theraputic plasma Polarity Skin metabolism conc. d) Pressure sensitive adhesive (PSA). Meting point Bioavailable factor e) Backing laminate. The chemical compounds that f) Release liner. Permeation Enhancers: enhance the permeability of stratum corneum so as to attain g) Other excipients like plasticizers and solvents [5]. therapeutic levels of the drug candidate. They improve the permeability by interacting with Stratum corneum. Polymer Matrix/ Drug Reservoir: It is prepared by dispersing the drug in liquid or solid state synthetic polymer base. a) Ideal Properties of Permeation Enhancers It should have biocompatibility and chemical compatibility with i. They should be non-irritating, non-toxic & non- allergic. the drug and other components of the system such as penetration enhancers. Additionally they should provide consistent and ii. They should not bind to receptor site i.e. not showing effective delivery of a drug throughout the product’s intended any pharmacological activity. shelf life and should be of safe status. Polymers used in iii. They should be cosmetically acceptable with an appropriate skin feel. [8] Transdermala) Natural drug deliveryPolymers: systems e.g. arecellulose classified derivatives, as- zein, It helps to increase the gelatin, shellac, waxes, gums, natural rubber and chitosan Pressure Sensitive Adhesive (PSA): adherence of transdermal patch to the skin surface. It can easily etc. remove from the smooth surface without leaving a residue on it. b) Synthetic Elastomers: e.g. polybutadiene, hydrin a) Polyacrylates rubber, silicon rubber, polyisobutylene, acrylonitrile, neoprene, butyl rubber etc. b) Polyisobutylene c) Synthetic Polymers: e.g. polyvinylalcohol, c) silicon based adhesives polyvinylchloride, polyethylene, polypropylene, 002 How to cite this article: Nidhi S. A Brief Review on Transdermal Patches. Organic & Medicinal Chem IJ. 2018; 7(2): 555707. DOI: 10.19080/OMCIJ.2018.07.555707. Organic and Medicinal Chemistry International Journal Backing Laminate: It is a supportive material which is Circular Teflon Mould Method: It was discovered by Baker impermeable to drugs and also to permeation enhancers. They and Heller in 1989. Polymeric solution in various proportions is should chemically compatible with the drug, enhancer, adhesive used as an organic solvent. Then that solution is divided in two and other excipients. parts. In one parts calculated amount of drug is dissolved & in another part enhancers in different concentration are dissolved, and then two parts mixed together. Then plasticizer (e.g., Di-N- Ex:Release Vinyl, Liner: Polyethylene This is andthe Polyesterprimary packaging films [9]. material that butylphthalate) is added into the drug polymer solution. The can protect the patch during application. It is made up of base total contents are to be stirred for 12 hrs and then poured into a layer which may be surface and covered with inverted funnel to control solvent a) Non-occlusive (e.g. paper fabric) circular Teflon mould. The moulds are to be placed on a levelled OR 0.5 m/s. The solvent is allowed to evaporate for 24 h. After which vaporization in a laminar flow hood model with an air speed of b) Occlusive (e.g. polyethylene, polyvinylchloride) 25±0.5°C in a desiccators containing silica gel before evaluation a dried film formed & that is to be stored for another 24 h at to eliminate aging effects. chemically inert & it should be permeable to drug, penetration It is made up of silicon or Teflon. Release liner should be In this method drug & enhancers & water. Mercury Substrate Method: plasticizer get dissolved in polymeric solution. It stirred for 10- Other Excipients Like Plasticizers and Solvents 15 min to produce