This document describes the various types of dissolution apparatus as specified by the USP, IP, and BP. It outlines 7 types of USP apparatus including the basket, paddle, reciprocating cylinder, flow through cell, paddle over disc, rotating cylinder, and reciprocating disc. The basket and paddle types are also included in the IP and BP. The key features and uses of each apparatus are provided along with diagrams. Ideal features of dissolution apparatus include precise specifications, simple design, sensitivity to changes, maintenance of sink conditions, and minimal dosage form abrasion.

1. DISSOLUTION APPARATUS
BY-WANI V.B
M.PHARM (SEM-I)
DEPT-PHARMACEUTICS
DR.DY PATIL COLLEGE OF
PHARMACY,AKURDI
GUIDED BY-DR.SHILPA CHAUDHARI
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CONTENTS-
 USP dissolution apparatus:
1:Basket type
2:Paddle type
3:Reciprocating cylinder
4:Flow through cell
5:Paddle over disc
6:Rotating cylinder
7:Reciprocating disc
 IP dissolution apparatus :
1:Paddle type
2:Basket type
 BP dissolution apparatus :
1:Basket type apparatus
2:Paddle type apparatus
3:Flow through cell

3. TYPES OF DISSOLUTION APPARATUS :
USP dissolution apparatus:
1:Basket type
2:Paddle type
3:Reciprocating cylinder
4:Flow through cell
5:Paddle over disc
6:Rotating cylinder
7:Reciprocating disc 3

4. IP dissolution apparatus :
1:Paddle type
2:Basket type
BP dissolution apparatus :
1:Basket type apparatus
2:Paddle type apparatus
3:Flow through cell
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5. IDEAL FEATURES
OF DISSOLUTION APPARATUS
BETTER DSIGN,BETTER RESULT
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6.  The fabrication dimensions and positioning of all components
must be precisely specified and reproducible.
 Must be simply design easy to operate and useable under
variety of conditions.
 Must be sensitive to reveal process changes and formulations
differences but still yield repeatable results under identical
conditions.
 The apparatus in, most cases , should permit controlled but
variable intensity of ; mild uniform non turbulent liquid
agitation. Uniform flow is very essential because changes in
hydrodynamic flow will modify dissolution.
 Nearly perfect sink conditions should be maintained.
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7.  Apparatus should provide easy means of introducing the
dosage form into dissolution medium and holding it, once
immersed in a regular and reliable fashion.
 It should provide minimum abrasion to the dosage form
during test period to avoid disruption of the
microenvironment surrounding the dissolving form.
 Special care should be taken that medium must not evaporate
from container of apparatus.
 Sample should be easily withdrawn for automatic or manual
analysis without interrupting the flow characteristics of
liquid.
 Apparatus should capable of allowing the evaluation of
disintegrating, on disintegrating, floating tablets or capsules,
finely powdered drugs and novel solid dosage forms.
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9. USP dissolution apparatus :
USP Apparatus 1 :Basket type
a)Vessel :-Made up of borosilicate glass -Semi hemispherical
bottom -Capacity 1000ml
b)Shaft : -Stainless steel 316 -Rotates smoothly without
significance wobble
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10. c)Basket :- Stainless steel 316 -Gold
coatings up to 0.0001 inch.
d) Water bath : Maintained at 37±0.5⁰c.
Used for: Capsules, tablets, delayed
release, suppositories, floating dosage
forms.
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11.  The rotating basket apparatus consists of a cylindrical basket
held by a motor shaft.
 The basket holds the sample and rotates in a round flask
containing the dissolution medium.
 The entire flask is immersed in a constant-temperature bath
set at 37°C.
 The rotating speed and the position of the basket must meet
specific requirements set forth in the current USP.
 The most common rotating speed for the basket method is
100 rpm.
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12. APPARATUS 2: PADDLE TYPE-
1.Vessel
2.Shaft: The blade passes through shaft so that bottom of
blade fuses with bottom of shaft.
3.Stirring elements : Made of Teflon For laboratory purpose -
Stainless steel.
4.Waterbath : Maintain at 37±0.5⁰c.
5.Sinkers: Platinum wire used to prevent capsule /tablet
from floating.
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14.  The paddle apparatus consists of a special, coated paddle that
minimizes turbulence due to stirring.
 The paddle is attached vertically to a variable-speed motor that
rotates at a controlled40 speed.
 The tablet or capsule is placed into the round-bottom
dissolution flask, which minimizes turbulence of the dissolution
medium.
 The apparatus is housed in a constant-temperature water hall
maintained at 370C, similar to the rotating-basket method.
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15.  The position and alignment of the paddle are specified in
the USP. The paddle method is very sensitive to tilting.
Improper alignment may drastically affect the dissolution
results with some drug products.
 The most common operating speed for Apparatus II are 50
rpm for solid oral dosage forms and 25 rpm for
suspensions.
 Apparatus II is generally preferred for tablets. A sinker,
such as a few turns of platinum wire. may be used to
prevent a capsule or tablet from floating.
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16. USP Apparatus III (Reciprocating Cylinder)
Design:
1.Vessel :Cylindrical flat bottom glass vessel.
2.Agitation type: Reciprocating -Generally 5-35 rpm.
3.Volume of dissolution fluids :200-250 ml.
4.Water bath: Maintain at 37±0.5⁰c.
Use : Extended release.
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18.  The USP Apparatus III is considered as the first line apparatus
in product development of controlled-release preparations,
because of its usefulness and convenience in exposing
products to mechanical as well as a variety of
physicochemical conditions which may influence the release
of products in the GI tract.
 The particular advantage of this apparatus is the technically
easy and problem free use of test solutions with different pH
values for each time interval.
 It also avoids cone formation for disintegrating (immediate
release) products, which can be encountered with the USP
apparatus II.
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19.  An additional advantage of apparatus III includes the
feasibility of drug-release testing of chewable tablets.
Chewable tablets for human use do not contain
disintegrants , so they need to undergo physiological
grinding (i.e., chewing) prior to dissolution
 For example, enteric-coated/sustained release dosage
forms, and also offers the advantages of mimicking the
changes in physiochemical conditions and extraordinarily
strong mechanical forces experienced by the drug
products in the mouth or at certain locations in the GI
tract, such as the pylorus and the ileocecal valve.
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20. APPARATUS 4:FLOW THROUGH CELL
Design :
1.Reservoir :For dissolution medium.
2.Pump :-Forces dissolution medium through cell -holding a
sample -Flow rate 10-100 ml/min -Laminar flow is maintained.
3.Water bath : Maintain at 37±0.5⁰c.
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21. Fig: flow through cell
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22. It is of two types:
(a) Open system- The open system has a
configuration where fresh medium is pumped
through the cell and the fractions are collected.
(b) Closed system- The closed system is a
configuration in which medium is pumped in circle
and not replaced by fresh medium.
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23. APPARATUS 5:PADDLE OVER DISK
1.Vessel
2.Shaft
3.Stirring elements
4.Sample holder : Disk assembly that hold the product in such a
way that release surface is parallel with paddle. Paddle is directly
attached over disk assembly. Samples are drawn away b/w the
surface of medium and top of paddle blade.
5.Volume :900ml.
6.Temperature : 32 ⁰c.
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24. APPARATUS 6:ROTATING CYLINDER :
1.Vessel :In place of basket cylinder is used.
2.Cylinder :Stainless steel 316.
3.Sample : Mounted to cuprophan (inner porous cellulosic
material) an entire system is adhere to cylinder. -Dosage unit is
place in cylinder and released from outside.
4.waterbath : Maintain at 32±0.5⁰c Disadvantage : Transdermal
patches can be studied but cannot be cut into small size.
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26. APPARATUS 7:RECIPROCATING DISK
1.Vessel :Flat bottom cylindrical vessel -Volume of dissolution
medium 50-200ml.
2.Shaft
3.Sample :Placed on disk shaped holders.
4.Agitation :-Reciprocation -Reciprocating frequency 30 cycles/min.
5.Waterbath : Maintain at 32±0.5⁰c.
Use : Transdermal patches.
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27. FIG: RECEPROCATING DISC
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28. REFERENCES-
1.Aulton’s Pharmaceutics The Design And Manufacture of
Medicines 3RD Edition page No: 17-22.
2. https://en.wikipedia.org/wiki/Dissolution_testing.
3.International Journal of Current Biomedical and
Pharmaceutical Research, Current Sci Direct Publication.
4.USP 30 and NF 25. US Pharmacopeial Convention. 2007;
Rockville, MD.
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