1. Dissolution and drug release tests measure the rate and extent of drug release from a product under specified conditions. They are important quality control tests linked to in vivo performance. 2. Many factors can affect drug dissolution, including drug properties, formulation excipients, test medium conditions, temperature, and apparatus type and settings. 3. Common apparatuses include baskets, paddles, cylinders and flow cells suited for different drug products like tablets, capsules, suspensions or films. Test conditions are selected based on the product type to simulate gastrointestinal conditions.

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Dissolution and drug release testin
g
Mr:Roshan G Bodhe
Research Scholar, M. Pharm (Pha
rmaceutics)
RCPIPER, Shirpur

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Why do we study dissolution?
Disintegration Dissolution Absorption
Drug in
the blo
od and
the bod
y

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Dissolution and drug release tests
 Dissolution and drug release tests are in-vitro test
s that measure the rate and extent of dissolution
or release of the drug substance from a drug prod
uct, usually in an aqueous medium under specifie
d conditions
 The dissolution test is an important quality control
procedure for the drug product and is often linked
to product performance in vivo.
 In-vitro drug dissolution studies are most often us
ed for monitoring drug product stability and manu
facturing process

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Conditions that May Affect Drug Dissolution
and Release: Drug and formulation related
 Drug substance
 Particle size
 Polymorph
 Surface area
 Chemical stability in dissolution media
 Formulation of drug product
 Excipients (lubricants, suspending agents,
etc)

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Conditions that May Affect Drug Dissolution
and Release: methodology related
 Medium
 Volume
 pH
 Molarity
 Co-solvents, added enzymes/surfactants
 Temperature of medium
 Apparatus
 Hydrodynamics
 Agitation rate
 Shape of dissolution vessel
 Placement of tablet in vessel
 Sinkers (for floating products and products th
at stick to side of vessel)

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Dissolution Apparatus

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Apparatusa Name Drug Product
Apparatus 1 Rotating basket Tablets
Apparatus 2 Paddle Tablets, capsules, modified drug products, suspensions
Apparatus 3 Reciprocating cylinder Extended-release drug products
Apparatus 4 Flow cell Drug products containing low-water-soluble drugs
Apparatus 5 Paddle over disk Transdermal drug products
Apparatus 6 Cylinder Transdermal drug products
Apparatus 7 Reciprocating disk Transdermal drug products
Rotating bottle (Non-USP-NF) Extended-release drug products (beads)
Diffusion cell (Franz) (Non-USP-NF) Ointments, creams, transdermal drug products
Dissolution Apparatus
aApparatus 1–7 refer to compendial dissolution apparatus in USP-NF (Unite
d States Pharmacopeia)

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Rotating basket (Apparatus 1)

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Rotating basket (Apparatus 1)
 In case of none-disintegrating dosa
ge forms this apparatus is superior t
o apparatus 2 since it constraints t
he dosage form in a steady state flu
id flow
 It is inferior for testing dosage form
s which contains gums due to cloggi
ng of screen matrix

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Rotating basket (Apparatus 1)
 In the case of floating dosage forms
this method performs well, but care
should be taken that excepients do
not clog the basket mesh

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Rotating Paddle (Apparatus 2)

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Rotating Paddle (Apparatus 2)
 This apparatus is identical to appara
tus 1 except that the paddle is subs
tituted for the rotating basket
 Frequently used for both disintegrati
ng and non-disintegrating dosage fo
rms

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Reciprocating cylinder (Apparatus 3)

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Reciprocating cylinder (Apparatus 3)
 One advantage of the reciprocating
cylinder is that the gastrointestinal t
ract conditions can be easily simulat
ed, as it is easy to make time depen
dent pH changes
 This apparatus is most suitable for n
ondisintegrating (extended release)
or delayed release (enteric coated)
dosage forms

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Flow cell (Apparatus 4)

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Flow cell (Apparatus 4)
 The advantage of flow through cell
apparatus is the ability to test drugs
of very low aqueous solubility and t
he ability to change the pH convenie
ntly during the test

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Paddle over disk (Apparatus 5)

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Cylinder (Apparatus 6)
 The cylinder method (Appar
atus 6) for testing transder
mal preparation is modified
from the basket method (A
pparatus 1). In place of the
basket, a stainless steel cyli
nder is used to hold the sa
mple.

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Reciprocating Disk Method (Apparatus
7)
 In the reciprocating disk me
thod for testing transderma
l products, a motor drive as
sembly (Apparatus 7) is use
d to reciprocate the system
vertically, and the samples a
re placed on disk-shaped ho
lders using cuprophan supp
orts