Enteric polymers,mechanism, marketed products

1. PHARMACEUTICAL TECHNOLOGY-II

2. INTRODUCTION
 An enteric coating is a barrier that controls the location of oral
medication in the digestive system where it is absorbed.
 The word enteric indicates small intestine,
 Thus enteric coating prevents the release of drug
before it reaches small intestine.
 Materials used for enteric coating are insoluble in
low pH(in stomach) but shows solubility at high pH (in
small intestine).
 Materials used for enteric coatings include CAP,
ACRYLATED POLYMERS(EUDRAGIT L&S),
PVAP and HPMCP,ETC

3. REASONS
 There are four reasons for putting such a
coating on a tablet or capsule ingredient:
PROTECTION OF
DRUGS FROM
STOMACH ACID
Eg: SOME ENZYMES
ANTIBIOTICS
PREVENT GASTRIC
IRRIRATION;NAUSEA
VOMITTING
Eg:ASPIRIN
DELIVER INTENDED
LOCAL ACTION IN
INTESTINE
TO PROVIDE DELAY
RELEASE &
PROLONG ACTION
Eg:DICLOFENAC

4. H+
H+
H+
H+
H+
H+
Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
+ H+
PARITAL CELLS OF STOMACH
ENTERIC COATED
TABLET
PROTON
PUMP
PH=1.5-3.5

5.  [H+]=LOW
 Pthalic acid can donate H+
 Coating dissolved and tablet
become bare
 Tablet disintegration proceed.
INTACT TABLET COATING DISSOLVE BARE SURFACE GRANULES PRIMARY DRUG PARTICLES
ABSORPTION
DEODENUM
PH=5.0-6.5

6. PROPERTIES OF IDEAL ENTERIC
METERIAL:
1. Resist gastric fluid
2. Permeability and suspectibility of intestinal
fluid; should dissolve above PH 5.
3. Compatiblity with most coating solution.
4. Formation of a continuous film
5. Non toxic , low cost , ease applicable.
SL
NO
ENTERIC
POLYMER
OPTIMU
M PH
1 POLYVINYL
ACETATE
PTHALATE
5.0
2 HPMC
PTHALATE
5.5
3 CELLULOSE
ACETATE
PTHALATE
6
4 EUDRAGIT L
AND S
6 AND 7
RESPEC
TIVELY
5 HPMC
ACETATE
PTHALATE
>6.0

7. NAME OF DRUG REASON COMMERCIAL NAME
ASPIRIN(NSAID) PRODUCE NEEDLE
SHAPED SALICYLIC
CRYSTAL, CAUSES
IRRITATION IN GASTRIC
MUCOSA
MICROPIRIN(75mg)
OMEPRAZOLE,
PANTOPRAZOLE
(PROTON PUMP
INHIBATOR)
PROTON PUMP
INHIBITOR THAT RAPID
DEGRADATION IN ACIDIC
PH
OMEZ,OMEZOL
PANTOCID,PANTODAC
ERYTHROMYCIN,
PENICILIN G(ANTIBIOTIC)
INACTIVATION IN ACIDIC
PH
ERY-TAB,ERYSAFE
CRYSTAPEN V
DICLOFENAC (NSAID) ION ENTRAPMENT
;GASTRIC ULCER; LOCAL
ACTION IN INTESTINE.
VOLTAREN,MOVONAC
OMEGAVIA.
OMEGA 3 FATTY ACID DESTROYED IN STRONG
PH

8. REFFERENCES:
◂ Pharmaceutics:the design and manufacturing
of drug; Aulton, Michael E; Pg no-562.
◂ Essential of medical pharmacology ;K.D
Tripathi; page no- 628,727,699.
◂ Wikipedia.