This POWERPOINT gives detailed explanation of different polymers used in manufacturing of release modified dosage forms.

1. POLYMERS

2. WHAT IS POLYMER?
• “Polymer” word is derived from Greek term “Poly” meaning
many and “Meros” meaning parts.
• Definition : Polymers are long chain organic molecules
assembled from many smaller molecules called as monomers.
• The small repeating units are known as monomers
• Polymers formed from two or more different monomers are
called as copolymers. - [A – B – A – B – A – B] –
• Homopolymer : Polymers formed from bonding of identical
monomers are called as homopolymers. - [A – A – A – A – A]

3. Chemical Structure

4. GRAFT COPOLYMER
• It is obtained by linking a
polymer of one type to another
polymer molecule of a different
composition

6. CHARACTERISTICS OF IDEALPOLYMER

8. Classification of Polymers
1. Classification based on origin of source
2. Classification based on structure
3. Classification based on polymerisation
4. Classification based on molecular force

10. Classification based on origin of source
Natural polymersThe definition of a natural
polymer is a polymer that results from only raw
materials that are found in nature.
Example –
Protein based : Albumin, Collagen, Gelatin
Polysaccharides: Chitosan, cyclodextrins,
alginate, agarose, carrageenan etc
-

13. Synthetic polymers
•Biodegradable polymers:
i. Polyesters- Poly lactic acid, Polyglycolic acid
ii. Polyanhydrides – Poly adipic acid
iii. Polyamides – Polyamino acids
iv. Phosphorous based polyphosphates - Polyphosphagenes
v. Others – Polyurethanes, polyacetals
•Non-biodegradable:
i. Cellulose derivatives- CMC, EC, HPMC, CAP
ii. Silicones – Colloidal silica, polydimethylsiloxane
iii. Acrylic polymers - polymethacylates
iv. Others – PVP, POLOXAMERS, Ethyl vinyl acetate

14. Classification based on structure

15. Classification based on structure

16. Classification based on structure

17. • Slide 10

18. CLASSIFICATION BASED ON MOLECULAR FORCES
• Thermoplastic polymers
• Thermosetting polymers
• Elastomers

19. Thermoplastic Polymers
• These are linear or slightly branched
long chain polymers, softened on
heating & reversibly hardened on
cooling repeatedly.
• Their hardness is a temporary
property & varies with temperature.
• The polymer under heating can
convert one state to another state and
after cooling it can again convert its
original state.
• Example:- PVC, PS, PE, PP
Thermosetting polymers
• Initial mixture of reactive, low
molar mass compounds reacts
upon heating in the mold to form
an insoluble, infusible network.
• Example: Bakelite (formed of
Phenol and formaldehyde
polymerization).
CLASSIFICATION BASED ON MOLECULAR FORCES

20. Thermoplastic Polymers
• Thermoplastics can be synthesises
by the process called Addition
polymerization
• Have secondary bonds between
molecular chains
• Thermoplastics have low melting
points & low tensile strength
• Thermoplastics have low mol.wt.
compared to thermosetting
Thermosetting polymers
• Thermosetting polymers can be
synthesises by the process called
condensation polymerization
• Have primary bonds between
molecular chains and held
together by strong crosslinks
• Have high melting points &
tensile strength
• Thermoplastics have high mol.
wt.
CLASSIFICATION BASED ON MOLECULAR FORCES

22. Classification based on polymerisation
1. Addition polymerization (or) Chain growth
polymerization
2. Condensation polymerization (or) Stepwise
polymerization

24. SYNTHESIS OF POLYMER- ADDITION polymerization
INITIATION
• The first step in chain polymerization- Initiation occurs when free radical
radical catalyst reacts with double bond carbon monomer.
• Each initiating radical has the ability to attack the double bond of a
monomer.
• In this way, the radical is transferred to the monomer and a monomer
radical is produced.
• Addition can occur at either end of the monomer.

25. PROPAGATION
• The monomer radical is also able to attack another monomer
and then another monomer, and so on and so forth.
• This step is called propagation by which a macro radical is
formed.
• The entire propagation reaction usually takes place within a
fraction of a second.

26. TERMINATION
• Chain termination is the chemical reaction that ceases the
formation of reactive intermediates in a chain propagation step in
step in the course of polymerization, effectively bringing it to a
a halt.

27. Some common addition polymers

28. • This method produce polymers of low mol. Wt. and require high
energy
• Involves 2 different types of bi-functional monomers that react with
one another to form a chain.
• Linear chain without crosslinking or branching are formed.
• Short chain molecules-oligomers
SYNTHESIS OF POLYMER- CONDENSATION polymerization

29. Some common condensation polymers

39. APPLICATIONS OF POLYMERS IN
FORMULATION OF CONTROLLED DRUG
DELIVERY SYSTEM
1. ORAL DRUG DELIVERY SYSTEM:
Here, the drug gets released at controlled rate when
administered orally. For that several mechanisms are involved.
a) Osmotic pressure controlled GI delivery system
b) Gel diffusion controlled GI delivery system
c) Muco-adhesive GI delivery system

43. 2. Transdermal drug delivery system:
• TDDS is defined as self contained, self discrete dosage forms,
which when applied to the intact skin delivers the drug at a
controlled rate to the systemic circulation.
• In this, polymer matrix plays a major role.
• It releases the drug from the device to the skin.

44. 3. Ocular Drug Delivery System
• It allows prolonged contact of drug with corneal surface of eye.
• The example for ODDS is pilocarpine in the treatment of glaucoma.
• In this muco-adhesive polymers are used as barriers to control the
drug release.
• E.g. Polyacrylic acid Co polymers of acetate vinyl & ethyl Others:

45. 4. DRUG DELIVERY OF VARIOUS CONTRACEPTIVES & HORMONES:
• E.g. medroxyprogesterone acetate–vaginal contraceptive ring
• It consists of a drug reservoir & polymer coating material. Through this
layer the drug releases slowly.
5)DRUG DELIVERYAND THE TREATMENT OF DIABETES
• Here the polymer will act as barrier between blood stream & insulin. E.g.
polyacrylamide or N,N-dimethylaminoethylmethacrylate

46. 6) APPLICATIONS OF POLYMERS IN SOLID DOSAGE FORMS:
IN TABLETS
• Polymers like methyl cellulose, hydroxyl ethyl cellulose, hydroxyl ethyl
methyl cellulose are used as binders.
• Polymers like carboxyl methyl cellulose sodium is used as
disintegrating agent. • Polymers like all the cellulose derivative are used
as coating materials.
• Polymers like cellulose acetate phthalate, hydroxyl propyl methyl
cellulose phthalate, polyvinyl acetate phthalate are used as enteric
coating material.
IN CAPSULES
• Gelatin, a natural polymer which is the major ingredient in the
manufacturing of capsules

47. 7) APPLICATIONS OF POLYMERS IN LIQUID DOSAGE FORMS:
IN SUSPENSIONS
• Polymers like Acacia, Tragacanth, Cellulose derivative, Xanthum gum
are used as suspending agents. They should be selected based on their
characters like PH, solubility & concentration. They enhances the
dispersion of solids in liquids.
IN EMULSIONS
• Polymers like Tragacanth, Spans, Tweens are used as emulsifying
agents

48. 8)Polymers can be used as film coatings to mask the unpleasant taste of
a drug & to modify drug release characteristics.
9)Polyanhydrides are used in CDDS because of their unique property of
surfaceerosion.
10)Hyaluronic acid is used in controlled release ophthalmic preparations.
11)Wide variety of polymers like natural gums are using as thickening
agents. E.g. poly ethylene glycol, carbomer
12)Some of the polymers are using as protective colloids to stabilize
suspensions & emulsions. E.g . Sodium alginate
13)Some polymers can be used as suppository bases E.g. poly ethylene
glycol

49. 14)Some polymers are used in uterus therapeutic system
E.g.silicone
15)Copolymers of lactide & glycolide, silicone are using in implantation
therapeutic system.
16)Polyurethanes can be used for elasticity
17)Polymethyl methacrylate for physical strength & transparency.
18)Polyvinyl alcohol for hydrophilicity & strength
19)In addition to polymers being used as excipients, some drugs themselves are
polymers including insulin, heparin & its antagonist, protamine sulfate, plasma
expander like dextran, normal human serum albumin, bulk laxatives like methyl
cellulose & sodium carboxy methyl cellulose

50. 20) Alpha, beta, gamma Cyclodextrins have the ability to alter physical,
chemical and biological properties of drugs through formation of inclusion
complexes in solution or solid state.

51. SMART POLYMERS
• Also known as stimulli responsive or enviornmentally responsive
polymers .
• Smart polymers are materials composed of polymers that respond in
a dramatic way to very slight changes in their environment.
• Environmental stimuli include salt, UV irradiation, temperature, pH or
concentration , chemicals, light, magnetic or electric field, ionic
factors, biological molecules, solvent exchange etc
• PH sensitive polymers : pH sensitive polymers are poly electrolytes
that contains acid(carboxylic or sulphonic ) or basic(ammonium salts)
functional groups in their structure, so in response to change in pH
they can accept or release a protons .
• These groups of smart polymers change its solubility by changing
their electrical charge of the polymer molecule.

53. SMART POLYMERS
The major benefits of smart polymer-based drug delivery
systems includes
• reduced dosing frequency,
• ease of preparation,
• maintenance of desired therapeutic concentration with single
dose,
• prolonged release of incorporated drug,
• reduced side effects and improved stability

54. • ENVIORNMENTALLY RESPONSIVE POLYMERS: . [* also known as
SMART Polymers or STIMULI Responsive Polymers .] PHASE sensitive
polymers : Phase sensitive smart polymers are mainly used to prepare
biocompatible formulations of proteins for controlled delivery in biologically
active and confarmationally stable form. EG: a water insoluble
biodegradable polymer such as poly(D,L-lactide) and poly(D,L- lactide-co-
glycoide) dissolve in pharmaceutically accepted solvent to which a drug is
added forming a solution . After injecting the formulation into the body the
water miscible organic solvent dissipates and water penetrates into the
organic phase. This causes the phase separation and precipitation of the
polymer forming a depot at the site of injection . PH sensitive polymers :
pH sensitive polymers are poly electrolytes that contains acid(carboxylic or
sulphonic ) or basic(ammonium salts) functional groups in their structure,
so in response to change in ph they can accept or release a protons
.These groups of smart polymers change its solubility by changing their
electrical charge of the polymer molecule.

55. • Smart Polymers • Smart polymers are the ones that show a change with the change in environmental factors • The factors can include pH change, temperature,
light, and pressure difference • Designing of CRDDS using smart polymers leads to accurate and programmable delivery of a drug. These offer a drug delivery
platform that can be utilized to deliver drugs at a controlled rate and in a stable and biologically active form Smart Polymers various stimuli responsible for
controlling drug release from smart polymeric drug delivery systems
• 13. • A stimuli-sensitive or smart polymer undergoes an abrupt change in its physical properties in response to a small environmental stimulus • These polymers
are also called as intelligent polymers because small changes occurs in response to an external trigger until a critical point is reached, and they have the ability to
return to their original shape after trigger is removed • The exclusivity of these polymers lies in their nonlinear response triggered by a very small stimulus and which
produces a noticeable macroscopic alterations in their structure • These transitions are reversible and include changes in physical state, shape and solubility,
solvent interactions, hydrophilic and lipophilic balances and conductivity • The driving forces behind these transitions include neutralization of charged groups by
the addition of oppositely charged polymers or by pH shift, and change in the hydrophilic/lipophilic balance or changes in hydrogen bonding due to increase or
decrease in temperature • The major benefits of smart polymer-based drug delivery systems includes reduced dosing frequency, ease of preparation, maintenance
of desired therapeutic concentration with single dose, prolonged release of incorporated drug, reduced side effects and improved stability smart polymer
continue….
• 14. • These stimuli can be subsumed into discrete classifications of physical or chemical nature • Physical stimuli (i.e., temperature, ultrasound, light, and magnetic
and electrical fields) directly modulate the energy level of the polymer/solvent system and induce a polymer response at some critical energy level. • Chemical
stimuli (i.e., pH, redox potential, ionic strength, and chemical agents) induce a response by altering molecular interactions between polymer and solvent (adjusting
hydrophobic/hydrophilic balance) or between polymer chains (influencing crosslink or backbone integrity, proclivity for hydrophobic association, or electrostatic
repulsion) Stimuli
• 15. Various smart polymeric drug delivery systems
• 16. smart polymeric drug delivery systems continue…..
• 17. • These types of polymers have either an acidic or basic group in their architectural configuration, which in response to an environmental change accepts or
donates a proton • The pH-sensitive polymers have the ability to release the drug either in the intestine or stomach for therapeutic response generation • Materials
may swell, collapse or change depending on the pH of their environment due to the presence of functional groups in the polymer chain • These polymers can be
designed with many different architectures for different applications. Key uses of pH sensitive polymers are controlled drug delivery systems, biomimetics,
micromechanical systems, separation processes, and surface functionalization • pH sensitive polymers can be broken into two categories: those with acidic groups
(such as -COOH and -SO3H) and those with basic groups (-NH2). The mechanism of response is the same for both, only the stimulus varies. The general form of
the polymer is a backbone with functional "pendant groups" that hang off of it. When these functional groups become ionized in certain pH levels, they acquire a
charge (+/-) pH-SENSITIVE POLYMER