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PRACTICAL REPORT ON DISSOLUTION TEST FOR PARACETAMOL
AIM: Evaluation of Dissolution Behavior of 500mg Paracetamol Tablets
by ZENUFA), according to the USP (US. Pharmacopeia) using paddle
INTRODUCTION AND THEORY:
Paracetamol, also known as acetaminophen, or APAP, chemically named N-acetyl-
p-aminophenol, is a widely used over-the-counter analgesic (pain reliever) and
antipyretic (fever reducer). Paracetamol is the International Nonproprietary Name
(INN), Australian Approved Name (AAN) and British Approved Name (BAN),
while acetaminophen is the United States Adopted Name (USAN) and Japanese
Adopted Name (JAN).
Paracetamol is classified as a mild analgesic. It is commonly used for the relief of
headaches and other minor aches and pains and is a major ingredient in numerous
cold and flu remedies. In combination with opioid analgesics, paracetamol can also
be used in the management of more severe pain such as post-surgical pain and
providing palliative care in advanced cancer patients. Though paracetamol is used
to treat inflammatory pain, it is not generally classified as an NSAID because it
exhibits only weak anti-inflammatory activity.
A main purpose of solid dosage form is to make available to the human body a
certain and defined amount of the active substance through the gastrointestinal
system. Studies on the bioavailability of drugs from a given dosage form revealed
that, in many situations, solid dosage forms with the same therapeutic effect. This
fact is ascribed to differences in physical characteristics of the active compound in
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formulation factors or in technological processes used by different manufacturers,
resulting in different bioavailability profiles. Pharmaceutical availability or in vitro
availability is one of aspects of drug bioavailability. Of the tests that can be
performed on drug solid s the DISSOLUTION TEST is considered to be
sensitive, reliable and rational for predicting in vivo drug bioavailability behavior.
DISSOLUTION TEST :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
In vitro drug dissolution data generated from dissolution testing experiments can
be related to in vivo pharmacokinetic data by means of in vitro-in vivo correlations
(IVIVC). A well established predictive IVIVC model can be very helpful for drug
formulation design and post-approval manufacturing changes.
The main objective of developing and evaluating an IVIVC is to establish the
dissolution test as a surrogate for human studies, as stated by the Food and Drug
Administration (FDA). Analytical data from drug dissolution testing are sufficient
in many cases to establish safety and efficacy of a drug product without in vivo
tests, following minor formulation and manufacturing changes. Thus, the
dissolution testing which is conducted in dissolution apparatus must be able to
provide accurate and reproducible results.
Several dissolution apparatuses exist. In United States Pharmacopeia (USP)
General Chapter <711> Dissolution, there are four dissolution apparatuses
standardized and specified. They are:
• USP Dissolution Apparatus 1 - Basket (37°C)
• USP Dissolution Apparatus 2 - Paddle (37°C)
• USP Dissolution Apparatus 3 - Reciprocating Cylinder (37°C)
• USP Dissolution Apparatus 4 - Flow-Through Cell (37°C)
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USP Dissolution Apparatus 2 is the most widely used apparatus among these four.
And one we are going to discuss.
APPARATUS AND MATERIAL USED:
a) 1 cm-3 pipette (or plastic syringe)
b) 1 dm-3
e) 1 dm-3
f) filter paper
l) Filter papers
m) Dissolving machine
n) Analytical scale
o) Dissolution test machine.
Fig.1.Dissolution test machine.
a) 0.1N sodium hydroxide.
b) Phosphate buffer PH- 5.8 .
c) Six paracetamol tablets.500mg(zenadolTM
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According to the US pharmacopeia, the following procedures done during
1) Six Paracentamol tablets were weighed by using analytical balance and their
weights were recorded along with the mean weight M1.
2) 900mls of pH 5.5 phosphate buffer was added in each of the six vessels of
apparatus ii (paddle), at temperature of 370
3) As the machine operated, one tablets was kept in each vessels at (0, 1,
2,3,4,5 minutes intervals respectively) while the machine operated at the
rotation of the paddle speed of 50rpm.
4) After 30 minutes of operation, sample 1( of more than 2mls) was taken from
the1 and 1 minute later, second sample from the vessel 2 and so on until all
vessels had been sampled and put into the corresponding sample beakers
after filtration through using filter papers.
5) Proper dilution was then done using 0.1M Na0H until 100cm3
6) Then these sample solutions were measured using the UV machine for their
7) Total amount of the paracentamol in each specimen was then found using
the equation Beer`s lambert law and dilution law.
8) Then the mean dissolved substances are compared with 0.00075%w/v to
obtain to obtain the percentage of the paracentamol dissolved.
Below is table we which obtain during the experiment.
1 0.5474 0.373
2 0.5848 0.780
3 0.5576 0.627
4 0.5471 0.739
5 0.5569 0.643
6 0.4995 0.596
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Since the data obtained will be affected by extreme values, so that to avoid this
problem, the mean value must be calculated, as follows, the first value among of
the data obtained will be excluded since it is out of the range of the values so the
mean value will start from data number two.
Mean weight, M1 ( of weights) n
But from Beer Lambert Law:
Where A is the absorbance (mean absorbance)
is the molar absorptivity which is 715AU
b is path length which is 1cm.
c is the concentration of the solution used in the experiment (which is the
AM = ( of absorbance) n = (0,780+0.6270+0.739+0.643+0.596) 5=0.677AU
Then, from the formular, c=A/.b0.677/715=9.469x10-4
Then percentage dissolved can be obtained by comparing with the 0.00075%w/v
from the BP.
% dissolved = (9.469x10-4
A paddle machine creates the similar conditions as that of the GIT in terms of the
movement and temperature. This cause the tablets to dissolve as it would have in
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According to the information found in the USP and BP show that paracentamol
dissolve by 80% for 30minutes and that cause the concentration of the solution as
that of ZenadolTM
of Zenufa accepted that it is according to the BP standard in term
of the dissolution characteristics. The paddling machine is used to increase the
dissolution rate by decreasing the diffusion layer thickness,h,also maximize the
dissolution rate by increasing (Cs-C).There is other type of the machine called the
Basket type is used for easily soluble drugs, good examples are the chewable
SOURCES OF ERROR:
1) Poor calibrated machine.
2) Human error which are the parallax errors and the calculation errors.
3) Environmental contamination.
4) Human error due to contamination.
CONCLUSION AND ACKNOWNLEDGEMENT:
According to the experiment done show that the Zenadol of ZENUFA has a
dissolution percentage of 126.2%. Which correspond to that found in the USP and
The in vitro dissolution rate of a drug from a dosage form is very important for the
design and development of an optimum, formation and for the bioequivalence
1) TO MR. EDSON
2) TO. Dr. KAALE
3) TO. MY FELLOW STUDENTS.
4) TO ALL STAFF OF QA LAB.
5) TO MY MOTHER.