transdermal drug delivery system

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4.  Transdermal drug delivery system is defined as self
containing,discrete dosage forms which when applied to
the intact skin,deliver the drugs through the skin at a
controlled rate to the systemic circulation.
 Transdermal delivery represents an attractive alternative
to oral delivery of drugs and is poised to provide an
alternative to hypodermic injection too.
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5.  Avoid gastrointestinal drug absorption difficulties caused
by gasrtointestinal pH, enzymatic activity, drug
interaction.
 Substitute for oral administration of medication.
 Avoid first pass effect.
 Noninvasive in nature.
 Extended therapy with a single application.
 Improving compliance.
 May be terminated rapidly.
 Easily and rapidly identified in emergencies.
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6.  Many drugs especially drugs with hydrophilic structures
permeate the skin too slowly may not achieve therapeutic
level.
 The drug, the adhesive or other excipients in the patch
formulation can cause erythema, itching and local
edema.
 The barrier function of the skin changes from one site to
another on the same person, from person to person and
also with age.
 Drug that require high blood levels cannot be
administered
 Adhesive may not adhere well to all types of skin
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7. Bioactivity of drug
Skin characteristics
Formulation
Adhesion
System design
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8.  Release of the medicament from the vehicle.
 Penetration through the skin barrier.
› Skin structure and its properties
› The penetrating molecule and its physical-chemical
relationship to skin and the delivery platform
› The platform or delivery system carrying the
penetrant
› The combination of skin, penetrant, and delivery
system
 Activation of pharmacological response.
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9. o Biological factors –
o Skin condition
o Skin age
o Blood flow
o Regional skin sites
o Skin metabolism
o Species differences
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10.  Physicochemical factors –
 Skin hydration
 Temperature and pH
 Diffusion coefficient
 Drug concentration
 Partition coefficient
 Molecular shape and size
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12. 1.Through stratum
corneum
2.Transfollicular
3.Through sweat
gland
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13.  The drug
 Polymer matrix
 Permeation enhancers
 Adhesive
 Backing layer.
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14. The drug is in direct contact with release liner.
 Ex: Nicotine, Methotrexate, and Oestrogen.
 Some of the desirable properties of a drug for
transdermal delivery:
 Should possess an adequate solubility in oil and water.
 Should have a molecular weight less than approximately
1000 daltons.
 Require a balanced partition coefficient to penetrate the
stratum corneum.
 Should have low melting point.
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15. These polymers control the release of the drug from the
drug reservoir.
 Natural polymers: shellac, gelatin, waxes, gums, starch
etc.
 Synthetic polymers: polyvinyl alcohol, polyamide,
polyethylene, polypropylene, Polyurea, polymethyl
methacrylate.
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16.  Substances exist which temporarily diminish the
impermeability of the skin are known as accelarants or
sorption promoters or penetration enhancers.
 These include water, pyrolidones, fatty acids and
alcohols, azone and its derivatives, alcohols and glycols,
essential oils, terpenes and derivatives, sulfoxides like
dimethyl sulfoximide and their derivatives, urea and
surfactants
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17.  Serves to adhere the patch to the skin for systemic drug
delivery of the drug
 Ex: Silicones, Polyisobutylene
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18.  Backing layer protects patch from outer environment.
 Ex: Cellulose derivatives, Polypropylene silicon rubber
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20. There are main four types of TDDS
 Membrane moderated system
 Adhesive diffusion controlled system
 Matrix dispersion system
 Micro reservoir system.
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25. Drug Trade Name Type of Device Indication
Scopolamine Transderm scop Reservoir Motion sickness
Nitroglycerine Transderm nitro Reservoir Angina
Nitro dur Monolithic
Nitro disc Monolithic
Estradiol Estraderm Reservoir Hormone
treatment
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26. 1. Prausnitz MR, Mitragotri S, Langer R. Current status
and future potential of transdermal drug delivery.t Rev
Drug Discov. 2004;3:115–124.
2. Bronaugh RL, Maibach HI, editors. Edn. 4th. New York:
Marcel Dekker; 2005. Percutaneous Absorption.
3. Jain N.K. ,Pharmaceutical Product Development, First
edition,CBS publishers
4. Aulton.M.E, Pharmaceutics; The science of dosage form
design, second edition, Marcel Dekker;2002.502-505.
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27. 5. Allen L.V.; Ansel.H.C ;Popovich.N.G ,Pharmaceutical
dosage forms and drug delivery systems, Ninth edition,
Lippincott Williams and Wilkins publication,2011,295.
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