This document discusses various dissolution apparatus used to test the dissolution of pharmaceutical dosage forms. It describes the 7 main types of apparatus specified in pharmacopeias like USP including basket, paddle, flow-through cell and reciprocating cylinder apparatuses. Each type of apparatus has a specific design and is used to test different dosage forms like tablets, capsules, transdermal patches based on simulating their dissolution environment in the body. Dissolution testing provides critical information for quality control and drug development.

1. DISSOLUTION
APPARATUS
PREPARED BY:
PANKAJ
27/MPH/18
MPH 2ND SEM.
DEPARTMENT OF PHARMACEUTICS

2. What is Dissolution Apparatus ?
Tablet Dissolution is a standardized method
for measuring the rate of drug release from a
dosage form. In the pharmaceutical industry,
drug dissolution testing is routinely used to
provide critical in vitro drug release
information for both quality control purposes,
i.e., to assess batch-to-batch consistency of
solid oral dosage forms such as tablets, and
drug development, i.e., to predict in vivo drug
release profiles.

3. Purposes of Dissolution Apparatus Test:
 Quality-control and quality-assurance purposes
 In early phase drug development
 Assess product stability, monitor formulation changes over time
 Establish in-vitro–in-vivo correlations "IVIVC"
 Regulatory perspective Particularly in the development and
approval of generic dosage forms

4. Different types of dissolution apparatus according to the
pharmacopeia:
I.P U.S.P B.P E.P
TYPE 1 Paddle
Apparatus
Basket
Apparatus
Basket
Apparatus
Paddle
Apparatus
TYPE 2 Basket
Apparatus
Paddle
Apparatus
Paddle
Apparatus
Basket
Apparatus
TYPE 3 Reciprocating
Apparatus
Flow through
Cell Apparatus
Flow through
Cell Apparatus
TYPE 4 Flow through
Cell Apparatus
TYPE 5 Paddle over disc
Apparatus
TYPE 6 Rotating cylinder
TYPE 7 Reciprocating
Holder

5. 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 9
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.

6.  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.
CONTD….

7. USP 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. Water-bath : Maintain at 37±0.5⁰c.
5. Sinkers: Platinum wire used to prevent capsule /tablet from
floating.
Used For: Capsules, Powders, Suspensions, Tablets
(preferred over Apparatus 1)
SINKER
S

8.  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
controlled 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
37ºC, similar to the rotating-basket method.
 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, used to prevent a capsule or tablet from floating.
CONTD...

9. USP Apparatus 3: Reciprocating cylinder
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 for : Extended release tablets

10.  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.
 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.
CONTD….

11. USP Apparatus Type 4: Flow Through Cell
 Design:
1. Reservoir: For Dissolution Medium
2. Pump: Forces Dissolution medium through the cell, holding the sample.
Flow rate 240-960 ml/hr
Laminar flow is maintained.
3. Water bath: Maintain at 37±0.5ºC.
Used for: Tablets, capsules, or granules.

12. Types:
 Closed-mode: where the fluid is re-circulated and, by necessity, is of fixed
volume.
 Open-mode: when there is continuous replenishment of the fluids.
Advantages:
1. Ease of maintaining sink condition during dissolution which is often
required for drugs having limited aqueous solubility.
2. Feasibility of using large volume of dissolution fluid .
3. Feasibility of automation of apparatus.
CONTD..

13. USP APPARATUS TYPE 5: PADDLE OVER DISC
 Vessel
 Shaft
 Stirring elements
 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.
 Volume : 900ml.
 Temperature : 32 ⁰c. 23
Used for: Evaluation of Transdermal products

14. USP APPARATUS TYPE 6: CYLINDER APPARATUS
 Vessel: In place of basket cylinder is used.
 Cylinder: Stainless steel 316.
 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.
 water-bath: Maintain at 32±0.5⁰c
Used for: Transdermal patches can be studied but cannot be cut
into small size. 24

15. USP APPARATUS TYPE 7: RECIPROCATING DISC
The sample are placed on disc shaped holder using inert porous cellulosic
support which reciprocates vertically by means of a drive inside a glass container
containing dissolution medium.
 Vessel: Flat bottom cylindrical vessel -Volume of dissolution
medium 50-200ml.
 Shaft
 Sample: Placed on disk shaped holders.
 Agitation: Reciprocation -Reciprocating frequency 30 cycles/min.
 Water-bath: Maintain at 32±0.5⁰c.
Used for: Transdermal patches and non-disintegrating controlled-
release oral preparations.

16. REFERENCES:
 Aulton’s Pharmaceutics The Design And Manufacture of Medicines 3RD
Edition page No: 17-22.
 https://en.wikipedia.org/wiki/Dissolution_testing
 International Journal of Current Biomedical and Pharmaceutical Research,
Current Sci-Direct Publication
 USP 30 and NF 25. US Pharmacopeial Convention. 2007; Rockville, MD.