Transcript Document

PATCHES
TRANSDERMAL DRUG
DELIVERY
Lecturer: ass. prof. Beley N.N.
Plasters or patches
(Emplastra)
are dosage form for external use, which sticks
to the skin, affects on the skin, subcutaneous
tissue and, in some cases, makes the overall
effect on the body.
At room temperature patches look like a solid
mass.
At room temperature emplastic mass is dense, but
on the skin human it becomes soft and sticky.
When the temperature increases further patches
begin to melt, turning into a dens liquid.
For convenience, the patches are applied over the
fabric or paper.
Classification of patches depend
on action and using
1. Epidermatical patches
2. Endermatical patches
3. Diadermatical (transdermal) patches
Epidermatical adhesive plasters don’t
include medicine substances
and they are used:
 to protect any part of the skin from harmful
influences;
 to close the skin defects;
 for bring together the wound edges;
 for fixing the bandages on the skin surface.
They must be sufficiently sticky, firmly to stick to
the skin and not irritate it.
Endermatical adhesive plasters
They include drugs that have therapeutic effect
on patient skin.
This type of patches acts only on the external
layer of the skin (antiseptic action).
Diadermatical (transdermal)
adhesive plasters
They include medicines substances and have
special structure that ensures drug
penetration through the skin.
Medicines substances can penetrate into
deeper layers of the skin or have a general
effect on the body.
Transdermal patches are flexible
pharmaceutical preparations of
varying sizes, containing one or
more active substances.
They are intended to be applied to the
unbroken skin in order to deliver the active
substance(s) to the systemic circulation after
passing through the skin barrier.
Dermal and transdermal drug
delivery
Patches for dermatological drug therapy are intended to
produce desired therapeutic action at specific sites in
the epidermal tissue .
A drug′s ability to penetrate the skins epidermis, dermis,
and subcutaneous fat layers will lead to transdermal
(percutaneous) drug delivery giving rise to systemic
action .
Therefore, the extent the drug can travel through the
different skin layers determine the delivery system.
Advantages of the Transdermal
drug delivery
- Avoiding hepatic first pass effect
- Continuous drug delivery
- Fewer side effect
- Therapy can be terminated at any time
- Improved patient compliances
Disadvantages of the
Transdermal drug delivery:
-
Cosmetically non-appealing
- May display irregular absorption
The fraction of the drug that penetrate
the skin via any route depends on:
1. The physicochemical nature of the drug, specially
its size, solubility and partition coefficient.
2. The site and condition of the skin.
3. The formulation.
4. How vehicle component temporarily change the
properties of the stratum corneum.
Ideal molecular properties for drug
penetration
- A low molecular weight (generally less than 500
Daltons)
- An adequate solubility in oil and water
- A balanced partition coefficient
- A low melting point
- Potent drug (maximum 50 mg/day)
Transdermal patches normally consist
of an outer covering which supports a
preparation which contains the active
substance(s).
The transdermal patches are covered on the site
of the release surface of the preparation by a
protective liner, which is removed before
applying the patch to the skin.
The outer covering is a backing sheet
impermeable to the active substance(s) and
normally impermeable to water, designed to
support and protect the preparation.
The outer covering may have the same dimensions
as the preparation or it may be larger.
In the latter case the overlapping border of the
outer covering is covered by pressure-sensitive
adhesive substances which assure the adhesion
of the patch to the skin.
The patches contain the active substance(s)
together with excipients such as stabilisers,
solubilisers or substances intended to modify
the release rate or to enhance transdermal
absorption.
Application of the patches
When applied to the dried, clean and unbroken
skin, the transdermal patch adheres firmly to
the skin by gentle pressure of the hand or the
fingers and can be peeled off without causing
appreciable injury to the skin or detachment
of the preparation from the outer covering.
The patch must not be irritant or sensitising to
the skin, even after repeated applications.
The protective liner generally consists of a sheet
of plastic or metal material.
When removed, the protective liner does not
detach the preparation (matrix or reservoir) or
the adhesive from the patch.
Transdermal patches are normally individually
enclosed in sealed sachets.
Classification of the adhesive
plasters
1. Depend on the composition:
 ordinary
 rubber,
2. Depend on the technique:
 patches as the mass
 smeared patches
Classification of the ordinary
patches:
Depending on the substances that are
prevalent in emplastic base:
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lead (Diachylon),
Lead-pitch,
Lead-wax,
Pitch-wax patches.
Patches are produced in the
follow forms:
1. Viscose mass on the liner (fabric, paper … )
2. Solid patches mass (cylinders, rods, bars,
sticks)
3. Liquid (skin glue)
4. Foam
5. Films
Composition of the diachylon
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Sunflower oil
Fat purified
Lead oxide
Water
10 parts,
10 parts
10 parts
in sufficient quantity.
Stages of obtaining simple
diachylon:
1. Melting oil and fat
2. Shredding litharge
3. Sifting litharge
4. Mixing litharge with fresh boiling water clean
5. Mixing suspensions of Pb oxide with alloy of oil and
fat
6. Production patches mass
7. Flushing ready mass from glycerol
8. Drying patches
Technology of the simple
diachylon:
In the boiling process, which lasts for 1/2-2 hours, the
original red mixture gradually turns into a whitishgray, and at the end of boiling - to whitish.
In this case, the saponification reaction occurs,
resulting in the formation fatty acid salt of lead (lead
soap).
Consequently, it is chemically diachylon is a mixture of
lead salts of oleic, palmitic and stearic acids with a
significant predominance of the former.
Boiling patch is considered complete when a
small sample at pouring it into cold water,
gives a plastic mass which at the kneading
does not stick to your fingers.
Then, patch is washed off from glycerol.
Ready emplastic mass is rolled out to form
sticks, which enveloping parchment or waxed
paper.
Diachylon itself has no use, but its part are used
to many patches and certain ointments
production.
Elastic patches
Composition:
Natural rubber
Rosin
Zinc oxide
Lanolin anhydrous
Liquid paraffin
Neozonu D
- 25,7 pm
- 20.35 pm
- 32 pm
- 9,9 pm
- 11,3 pm
- 0,75 pm
Hard-lead
(Emplastrum plumbi compositum) is an alloy of diachylon with resinous
substances.
Composition:
 Diachylon simple
85 parts,
 Rosin
10 parts,
 Turpentine
5 parts.
Diachylon and rosin are melted in a boiler with a steam
heating. After that, the turpentine is added, mixed
thoroughly and mass is rolled out or form sticks.
Used as a mild irritant.
Lead-wax patches
Bases in these patches are simple alloys
diachylon with beeswax and lanolin:
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Mercury Patch (Ernplastrum hydrargyri)
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Epilinovy patch (Ernplastrum epilini)
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Akrihinovy patch (Ernplastrum acrichini)
Corn patches is a homogeneous soft,
sticky, but the discrepancy mass yellow
or dark yellow.
The melting point is above 60 ° C.
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Composition:
Salicylic acid
Rosin
Paraffin
Petrolatum
20 parts,
27 parts,
26 parts,
27 parts.
Wax, rosin and petroleum jelly are loaded in the reactor
to alloy with stirring, then salicylic acid is dissolved,
and the obtained mass poured into molds to 3 g.
Rubber (caoutchouc) plaster
Adhesive tape
(Emplastrum adhaesivum elasticum
externum)
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Composition:
Rosin
22.4 parts
Yellow wax
8.4 parts
Zinc oxide
24.4 parts
Anhydrous lanolin
22.4 parts
Rubber
22.4 parts
Gasoline
102 parts
Stages of the Adhesive tape
production
1. Preparation of rubber glue (dissolution of rosin and
rubber in gasoline)
2. Obtaining the mix of substances that prevent aging
(homogenization mixture of lanolin protystarytelem)
3. Preparation of zinc base (homogenization mixture
lanolin, beeswax and zinc oxide)
4. Mixing rubber adhesives, pastes and zinc
substances that prevent aging basis (6 hours)
5. Put plasters mass on a moving belt machines for
plastering of the mass (shpredinh)
Machine for smearing of the
plasters mass on the tape from
fabric
Pepper Patch
(Emplastrum capsici)
Composition:
Soft extract of capsicum
(obtained specifically for the patch)
Soft extracts of belladonna
Tinctures Aralias
- 11,0 %
- 0,3 %
- 0,3 %
They are produced in the form of rectangular pieces of
paper size 12X18, 10x18 cm and 8X18, in each
package are located on two pairs of pieces that ran
in cellophane.
Bactericidal patches
(Emplastrum adhacsivum
bactericidum)
which consists of a gauze pad soaked in
antiseptic solution, which contain:
Frc
- 0.02 %
Sintomitsina
- 0,08 %
Brilliant green in 40% alcohol
- 0,01%
Skin glue or liquid adhesives
(Emplastra Liquida)
Skin glue - liquid, which forms adhesive elastic strong
film at the skin after evaporation of the solvent.
Skin adhesives are otherwise called liquid adhesives,
and relatively widely used as epidermatical and
endermatical patches.
Most often emplastic film is formed by substances
such as collodion, rosin or synthetic.
To provide greater flexibility to the mixture vegetable
oils are added.
Mustard
are rectangular sheets of paper size 8X12, 5
cm, coated on one side of a layer of powder
defatted mustard seeds thickness 0,3-0,55
mm.
Raw materials are seeds Sarepts (Semina
sinapis junceae) and Black (Semina sinapis
nigrae) mustard.
From the resulting skim powder cake mustard
paste is prepared by mixing it with a solution
of rubber in gasoline.
Smearing is produced by emplastic machine.
Stages of the mustard
production:
1) preparation of glue;
2) preparation of mustard mass;
3) smearing of the mass on the paper, drying of
cutting roll and laying mustard patches to the
feet;
4) packing;
5) the recovery of gasoline.