NATURAL BIODEGRADABLE POLYMERS BASED TRANSDERMAL DRUG DELIVERY SYSTEM(TDDS)

Presented By : Deepanjan Datta and Pragya Paramita Pal(B.Pharm) 4thyear/7th Semester

Under The Guidance Of: Mr. Rana Mazumder Asst. Professor, Department of Pharmaceutics

CONTENTS

1.Introdcution.2.Skin as a site for drug infusion.3.Advantages And Disadvantages of TDDS.4.Introduction to Polymers.5.Characteristic Of Ideal Polymers.6.Classification Of Polymers Used For TDDS.7.Biodegradable Polymers.8.Advantages Of Biodegradable Polymers.9.Applications Of Biodegradable Polymers.10.Polymers In Pharmaceutical Applications.RosinCARRAGEENANChitin And ChitosanHyaluronic AcidHydrogels11.Storage, Sterilization And Packaging.12.Conclusion.13.References.

Transdermal drug delivery is defined as self contained, discrete dosage forms which, when applied to the intact skin, deliver the drug, through the skin at controlled rate to the systemic circulation.[1]Transdermal drug delivery system (TDDS) established itself as an integral part of novel drug delivery systems.[1]

INTRODUCTION

Transdermal drug delivery systems (TDDS), also known as “patches,” are dosage forms designed to deliver a therapeutically effective amount of drug across a patient’s skin.[1]

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Transdermal is a route of administration wherein active ingredients are delivered across the skin for systemic distribution. Examples include transdermal patches used for medicine delivery, and transdermal implants  used for medical or aesthetic purposes.[2]Transdermal 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.

Skin as a site for Drug Infusion-

Transdermal implants are a form of  body modification  used both in a  medical and aesthetic context. In either case, they consist of an object placed partially below and partially above the skin, thus transdermal.[2]

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There are two important layers to the human skin: [2](1)the Epidermis and (2)the Dermis. For transdermal delivery, drugs must pass through the two

sublayers of the epidermis to reach the microcirculation of the dermis.

The Stratum corneum is the top layer of the skin and varies in thickness from approximately ten to several hundred micrometres, depending on the region of the body. It is composed of layers of dead, flattened keratinocytes surrounded by a lipid matrix, which together act as a brick-and-mortar system that is difficult to penetrate.[2]

The stratum corneum provides the most significant barrier to diffusion. In fact, the stratum corneum is the barrier to approximately 90% of transdermal drug applications. However, nearly all molecules penetrate it to some minimal degree.

Below the stratum corneum lies the viable epidermis. This layer is about ten times as thick as the stratum corneum; however, diffusion is much faster here due to the greater degree of hydration in the living cells of the viable epidermis.

Below the epidermis lies the dermis, which is approximately one millimeter thick, 100 times the thickness of the stratum corneum. The dermis contains small vessels that distribute drugs into the systemic circulation and to regulate temperature, a system known as the skin's microcirculation.

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Advantages of Transdermal Drug Delivery System-[3]

Delivers a steady infusion of a drug over an extended period of time.Transdermal delivery can increase the therapeutic value of many drugs by avoiding specific problems associated with the drug e.g.-Gastro-intestinal irritation, low absorption, etc.Improved patient compliance and reduced inter & intra – patient variability.Self administration is possible & drug input can be terminated at any point by removing the patch.

Disadvantages of Transdermal Drug Delivery System-[3]Drug must have some desirable physicochemical properties for penetration through Stratum Corneum.Only relatively potent drugs are suitable candidates for TDDS because of the natural limits of drug entry imposed by the skin’s impermeability.Some patients develop contact dermatitis at the site of application.The barrier function of the skin changes from one site to another on the same person, from person to person and with age.

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INTRODUCTION TO POLYMERS

The term "polymer" derives from the ancient Greek word polus, meaning "many, much" and meros, meaning "parts", and refers to a molecule whose structure is composed of multiple repeating units.[4

The term was coined in 1833 by Jons Jacob Berzelius.

A polymer is a large molecule (macromolecules) composed of many

repeated subunits, known as monomers. monomers can be linked

together in various ways to give linear, branched and cross linked

polymers ,etc.[4]

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CHARACTERISTICS OF AN IDEAL POLYMER:[4]

Should be versatile and possess a wide range of mechanical, physical, chemical properties.

Should be non-toxic and have good mechanical strength and should be easily administered.

Should be inexpensive.

Should be easy to fabricate.

Should be inert to host tissue and compatible with environment.

CLASSIFICATION OF POLYMERS USED FOR TDDS[4]:-

NATURAL POLYMERS(Cellulose derivatives, Zein, Gelatin, Shellac, Waxes, Chitosan,etc)

SYNTHETIC ELASTOMERS(Polybutadiene, Hydrin rubber, Polyisobutylene,

Acrylonitrile, Neoprene,etc)

SYNTHETIC POLYMERS(Polyvinylchloride,Polyvinyl-pyrrolidone,

Polymethyl-methacrylate, etc)

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BIODEGRADABLE POLYMERS

Biodegradable polymers are defined as polymers comprised of monomers linked to one another through functional groups and have unstable links in the backbone.[5]

They are broken down into biologically acceptable molecules that are metabolized and removed from the body via normal metabolic pathways.[5]

Based on biodegradability polymers are classified as:

1. Biodegradable polymers

eg: collagen, poly glycolic acid etc.,

2. Non biodegradable polymers

eg: poly vinyl chloride, polyethylene etc.,8

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ADVANTAGES OF BIODEGRADABLE POLYMERSLocalized delivery of drug:- Direct delivery to a target area, thus potentially achieving higher drug concentrations at the desired site of action to minimize systemic side effects[6].Sustained delivery of drug:- Sustained release systems include any drug delivery system that achieves slow release of drug over an extended period of time. The basic goal of therapy is to achieve a steady state blood level that is therapeutically effective and non toxic for an extended period of time.[6] Stabilization of drug:- Drug stability means the ability of the pharmaceutical dosage form to maintain the physical,chemical,therapeutic and microbial properties during the time of storage and usage by the patient.[6]

Decrease in dosing frequency

Reduce side effects

Improved patient compliance

Controllable degradation rate9

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APPLICATIONS OF BIODEGRADABLE POLYMERS

Biodegradable polymer for ocular, tissue engineering, vascular, orthopedic, skin adhesive & surgical glues.

Biodegradable drug system for therapeutic agents such as anti tumor, antipsychotic agent, anti-inflammatory agent.

Polymeric materials are used in and on soil to improve aeration,and promote plant growth and health.

Many biomaterials, especially heart valve replacements and blood vessels, are made of polymers like Dacron, Teflon and polyurethane.[6]

Biodegradable polymers are used commercially in both the tissue engineering and drug delivery field of biomedicine. Specific applications include.[6]Sutures Dental devicesOrthopedic fixation devicesTissue engineering scaffolds

ROSIN It is a film forming biopolymer, used for microencapsulation

for controlled release dosage forms.[7] It is primarily composed of abietic and pimaric acid which

contain 2 reactive centres.[7] Rosin & rosin derivatives are hydrophobic biomaterial which

is biodegradable.[7] Good biocompatibility of rosin is demonstrated by the

absence of necrosis or abscess formation in the surrounding tissues.[7]

11Abietic acid Primaric acid Rosin gum

POLYMERS IN PHARMACEUTICAL APPLICATIONS

CARRAGEENAN Carrageenan is located in the cell wall and intercellular

matrix of the seaweed plant tissue.[9] It is formed by alternate units of D-galactose and 3.6

anhydro-galactose (3.6-AG) joined by α-1,3 and β-1,4 -glycosidic linkage.

There are three main commercial classes of carrageenan: 1)Kappa[rigid gels]; 2)Iota[soft gels] & 3)Lambda[does not form gel].[9]

Carrageenans are extremely potent inhibitors of HPV infection in vitro and in animal challenge models.

There are indications a carrageenan-based gel may offer some protection against HSV-2  transmission.[9]

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CHITIN AND CHITOSAN

Chitosan is a linear polysaccharide mucopolysaccharide, and the supporting material of crustaceans composed of randomly distributed β-(1-4)-linked D glucosamine (deacetylated unit) and N-acetyl-D glucosamine (acetylated units).[8]

Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D glucosamine (deacetylated unit) and N-acetyl-D glucosamine (acetylated units)[8]

Chitin cotton was applied to trauma and abscesses as a tissue defect filling or wound dressing agent.[8]

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HYALURONIC ACID OR HYALURONAN (HA)

Hyaluronic acid or hyaluronan (HA) is a naturally occurring polysaccharide widely distributed throughout the ECM of all connective tissues.[9]

It consists of multiple disaccharide units of glucuronic acid and N-acetylglucosamine. [9]

Dry, scaly skin (xerosis) such as that caused by atopic dermatitis (eczema) may be treated using sodium hyaluronate as an active ingredient.[9]

Hyaluronan may also be used postoperatively to induce tissue healing, notably after cataract surgery .[9]

14 Chemical Structure of Hyaluronic Acid (HA)

HYDROGELS Hydrogel (also called aqua gel) is a network of polymer

chains that are hydrophilic, found as colloidal dispersions in water.[9]

Hydrogels are highly absorbent (they can contain over 99% water) natural polymers having a high degree of flexibility having similarity to natural tissue.[9]

They are used as reservoirs in topical drug delivery; particularly ionic drugs, as sustained release drug delivery system.

Hydrogels have been used in wound dressings for the treatment diabetic ulcers, burns, skin rejuvenation and anti-wrinkle patch, etc.[9]

15 Hydrogel

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Storage,Sterilization and Packaging

minimize premature polymer degradation during fabrication and storage.[10]moisture can seriously degrade, controlled atmosphere facilities.[10]Sterilization

g-irradiation or ethylene oxide. both methods degrade physical properties. choose lesser of two evils for a given polymer. g-irradiation dose at 2-3 Mrad (standard level to reduce HIV,)

can induce significant backbone damage. ethylene oxide higly toxic.[10]

Packed in airtight, aluminum-backed, plastic foil pouches.Refrigeration may be necessary.[10]

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CONCLUSION

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Numerous synthetic biodegradable polymers are available and still being developed for sustained and targeted drug delivery applications.[10]

Biodegradable polymers have proven their potential for the development of new, advanced and efficient DDS and capable of delivering a wide range of bioactive materials.[10]

However, only few have entered the market since many drugs faces the problem of sensitivity to heat, shear forces and interaction between polymers.[10]

These problems can be overcome by fully understanding the degradation mechanism to adjust the release profile.[10]

REFERENCES1) Cleary GW, Transdermal Delivery Rationale, in Topical Drug Bioavailability,

Bioequivalence, and Penetration, Shah VP, and Maibach HI (eds), New York, Plenum, 1993, 17–68.

2) Jain RA, The manufacturing techniques of various drug loaded biodegradable biomaterials, 2000, 21,2475-2490.

3) http://en.wikipedia.org/wiki/Transdermal_implants4) Vyas SP, Khar RK. Controlled Drug Delivery:Concepts and Advances. Ist

ed.Vallabhprakashan,New Delhi, 2002,156-1895) Ebihara et al.,Controlled release formulations to increase the bioadhesive

properties, Drug Res, 1983,33, 163.6) Huang, JC, Shetty, AS, Wang, MS, Biodegradable plastics: A review,

Advances in Polymer Technology,1990, 10, 1, 23-30.7) ) Satturwar PM, Fulzele SV, Dorle AK,Biodegradation and In Vivo

Biocompatibility of Rosin: a Natural Film-Forming Polymer, AAPS PharmSciTech, 2003, 4, 50- 55.

8)Majeti NV, Ravi Kumar, A review of chitin and chitosan applications,Reactive & Functional Polymers, 2000, 46, 1–27

9) International Journal of Drug Development & Research| April-June 2011 | Vol. 3 | Issue 2-NATURAL BIODEGRADABLE POLYMERS AS MATRICES IN TRANSDERMAL DRUG DELIVERY by Kiran Sharma,Vijender Singh, Alka Arora

10)Schroeter, J,Creating a framework for the widespread use of biodegradable polymers, Polymer Degradation and Stability, 1998, 59, 1, 377-381.