In-vitro dissolution testing is a very powerful tool to easily and effectively obtain information about the performance of drug products.

1. IN VITRO DISSOLUTION
AND DRUG RELEASE TESTING
Submitted By: Prachi Pandey, Rahul Pal Submitted To: Dr. Tejpal Yadav
M. Pharm (Pharmaceutics), IInd Sem.
Department of Pharmaceutics, NIMS Institute of Pharmacy, NIMS University Jaipur, Rajasthan
In-vitro dissolution testing is a very powerful tool to
easily and effectively obtain information about the
performance of drug products.

2. DEFINITION
• Dissolution is a process in which a solid substance solubilizes in a given solvent (mass
transfer from the solid surface to the liquid phase.)
• Dissolution testing measures the extent and rate of solution formation from a dosage form,
such as tablet, capsule, ointment, etc.
• The dissolution of a drug is important for its bioavailability and therapeutic effectiveness

3.  NON SINK METHODS
 For poorly water-soluble drugs, pharmaceutical scientists are increasingly applying in vitro dissolution
testing under non-sink conditions for a direct evaluation of their ability to generate and maintain
supersaturation as a predictive surrogate for ensuring product quality and in vivo performance.
 NATURAL CONVECTION NON SINK METHODS:
 a) Klein solvmeter method
 b) Nelson hanging pellet method
 c) Levy static disk method
ALTERNATIVE METHOD OF DISSOLUTION

4.  FORCED CONVECTION NON SINK METHODS:
 Tumbling method
 Levy or Beaker method
 Rotating disk method
 Particle size method
 USP Rotating basket apparatus
 USP Paddle apparatu
NON-SINK METHODS

5.  SINK METHOD
 Sink condition is the ability of the dissolution media to dissolve at least 3 times the amount of drug that
is in your dosage form. Having sink conditions helps your dissolution have more robustness as well as
being more biologically relevant.
 FORCED CONVECTION SINK DEVICES:
 Wurster pollis adsorption method
 Partition method
 Dialysis methods
 Rotating disk apparatus
SINK METHOD

6. SINK METHOD
 CONTINOUS FLOW/FLOW THROUGH METHODS:
 Pernarowski method
 Langenbucher method
 Baun and Walker
 Tingstad and Reigelman
 Modified column apparatus
 Takenaka method

7. NON-SINK METHOD - KLEIN SOLVMETER
METHOD
 KLEIN SOLVMETER METHOD
• Carrier device surrounded by flat and is immersed in
dissolution medium
• When dosage form is placed in the boat the bar moves and
as dosage form dissolves it moves upwards
• Amount of dosage form dissolved is revealed from the
difference in height of bar movemen
Figure (a) Klein solvmeter Method

8.  NELSON HANGING PELLET METHOD
• Aluminum strip having provision for holding dosage form
which is in turn connected perfectly maintained balance arm
of strip
• Dosage form is mounted on aluminium strip with help of
wax .This method can be employed to know Intrinsic
dissolution rate.
• To prevent disintegration further high pressures can be
applied and also constant surface
NELSON HANGING PELLET METHOD
Figure (b) Nelson Hanging Pellet Method

9. LEVY STATIC DISK METHOD
 LEVY STATIC DISK METHOD
• Acrylic holder containing dosage form is inserted into a
known volume of medium through rubber stopper
• The vial is inverted and placed in incubator at 37 C.
• At specific time intervals the vial is removed from incubator
and samples are analysed
• Disadvantages:- effect of conc. On dissolution medium is
ignored and the surface area of dosage form while dissolving
is assumed constant which is not impractical.
Figure (c) Levy Static Disk Method

10. SINK METHOD- WURSTER- POLLI ADSORPTION
METHOD
 WURSTER- POLLI ADSORPTION METHOD
• In this method the dissolved drug is adsorbed by charcoal
or bentonite, care should be taken regarding the
adsorbent, adsorbent should not alter the viscorsity of the
medium.
Figure (d) Wurster- Polli
adsorption method

11.  PARTITION METHOD
• In this device organic phase is employed to remove the
dissolved drug such that the drug would partition
between the lipophilic and hydrophilic phases.
selection of organic phase plays a critical role
PARTITION METHOD
Figure (c) Partition Method

12.  ROTATING FLASK APPARATUS
• In this method a flask containing dissolution
medium is rotated around its horizontal axis in
a water bath kept at a temperature of 37 C.
• The flask has a provision of sampling such that
aliquots can be withdrawn and the fresh
medium can be replaced back.
• This apparatus is best suited for oral solid
dosage forms like tablets and capsules since
they do not require much agitation.
ROTATING FLASK APPARATUS
Figure (c) Receprocating cylinder type

13. FLOW THROUGH DEVICES
 FLOW THROUGH DEVICES
• For the drugs which saturate rapidly in large volumes
of medium, USP apparatus will not serve the purpose.
• For this the suitable device is flow through device. In
this device unlimited quantity of fresh dissolution is
available.
• A dosage form is placed in a small cell and is subjected
to a stream of fresh dissolution media.
Figure (d) Flow through cell Method

14. PERNAROWSKI
 PERNAROWSKI
• It consists of 10 mesh stainless steel basket stirrer assembly
with an adjustable stirrer.
• The chamber is 3 necked flask of 33 mm and the rest two of
20 mm diameter.
• 1 L of medium is employed within the flask.
• The dissolution characteristics are dependent upon the
amount of medium pumped through the dissolution
chamber.

15. LANGENBUCHER COLUMN TYPE
 LANGENBUCHER COLUMN TYPE
• This device is according to the dissolution basic design.
• The screen is constructed such that the medium flows equally through the
entire cross section in a laminar pattern.
• This is again closed by a secondary screen, filter which prevents the
undissolved drug from being eluted.

16. TINGSTAD AND RIEGELMAN
 TINGSTAD AND RIEGELMAN
• A cylindrical glass cell of 6.1 cm long and 1.9 cm in diameter
constructed with two glass filter funnels is used.
• The dissolution cell has filter membranes which prevents the
solid particles from being analyzed.
• There are also external valves to control the excess flow of
solvent into the system. the air trap averts air bubbles.
• The complete assembly is immersed in a temperature bath kept
at 37°C Figure (e) Tingstad and riegelman

17. MODIFIED COLUMN APPARATUS
Figure (f) Modified Column Apparatus
 MODIFIED COLUMN APPARATUS
• The device consists of filter of 14 M -size made of
nylon.
• The tubing from the pump is connected to the
dissolution cell.
• The Teflon faced stainless steel supports the screen
resting on the bottom half of the filter holder.
• The direction of the flow is such that the particles
do not fall through the screen. the rest of the process
is the same.

18. TAKENAKA
 TAKENAKA
• The release of drug is measured with the aid of in
vitro simulator device consisting of flow type
dissolution container.
• The dosage form is placed in the basket rotating at
94 rpm with 300 ml of medium.
• then the medium is removed by collecting
reservior using peristaltic pump.
• aliquots are withdrawn using syringe and then
filtered using Whatman filter paper and the same
volume is replaced immediately with fresh
medium.
Figure (g) Takenaka

19. IN VITRO DISSOLUTION AND DRUG
RELEASE STUDY INVOLVES
 IN VITRO DISSOLUTION AND DRUG RELEASE STUDY INVOLVES
 Preparation of solutions for calibration curve
 Stock solution
 Sample solution
 Buffer solution
 Determination of absorption maxima
 Preparation of calibration curve
 Dissolution study
 Dissolution procedure was carried out.
 Plot a graph between Time intervals on x-axis vs % of drug release on y-axis.
 Find out the slope, concentration, amount of drug release, percentage of drug release and report it.

20. GRAPHIC REPRESENTATION OF IN VITRO
DISSOLUTION TESTING

21. DRUG RELEASE TESTING
Drug release is the process by which a drug leaves a drug product
 Drug release:
• Immediate release (IR)
• Sustained Release (SR)
• Sustained Action (SA)
• Extended Release (ER)
• Long Acting (LA)
• Prolong Action (PA)
• Controlled Release (CR)
• Timed Release (TR)

22.  Immediate release drug products allow drugs to dissolve with no intention of delaying or prolonging
dissolution or absorption of the drug
 Prolonged-release dosage forms Prolonged-release dosage forms are modified-release dosage forms
showing a slower release of the active substance(s) than that of a conventional-release dosage form
administered by the same route.
 • Delayed release is defined as the release of a drug at a time other than immediately following
administration.
 • Enteric Coated: Intended to delay the release of the drug (or drugs) until the dosage form has passed
through the stomach. Enteric-coated products are delayed-release dosage forms.
DRUG RELEASE

23. • Controlled release includes extended-release and pulsatile-release products
• Extended-release products are formulated to make the drug available over an extended period after
administration.
• Pulsatile release involves the release of finite amounts (or pulses) of drug at distinct time intervals that
are programmed into the drug product.
• Repeat action products contain two single doses of medication; one for immediate release; another one
for modified release
DRUG RELEASE

24.  Targeted release drug release directed toward isolating or concentrating a drug in a body region, tissue
or site of absorption or for drug action Drug release and dissolution
 Modified-release dosage forms include both delayed and extended-release drug productsModified-
release dosage forms are preparations where the rate and/or place of release of the active substance(s) is
different from that of a conventional- release dosage form administered by the same route.
DRUG RELEASE

26.  IN VITRO DRUG RELEASE TESTING
 ROTATING BASKET METHOD:
• In vitro release study was carried out by the rotating basket method.
• Six tablets of each batch were taken and placed in rotating basket, respectively.
• Then the rotating basket was introduced into 900 mL of each dissolution medium (water, 0.1 M HCI
and pH 6.8 phosphate buffer) at 37°C ± 0.5°C with a rotation speed of 100 rpm.
• 5 mL of sample solution was collected a different time intervals (2, 4, 6, 8, 10, 12 h) and filtered
through a 0.45 um hydrophilic membrane.
IN VITRO DRUG RELEASE TESTING

27. • 1.0 mL of subsequent filtrate was taken accurately to add into a 100 mL volumetric flask and diluted
with the corresponding dissolution medium to 100 mL and mixed well.
• The amount of drug dissolved in the dissolution medium was measured using an UV-visible
spectrophotometer at 233 nm.
• The same volume of fresh dissolution medium at the same temperature was added to replace the
amount withdrawn after each sampling.
• The drug amount of cumulative release was calculated with a standard curve.
IN VITRO DRUG RELEASE TESTING