PARENTERAL FORMULATIONS
Enlist general requirements of parenteral preparation
General requirements of Parenterals:
i) It should be free from foreign particles, fibers
and filaments.
ii) It should be free from all type of microorganisms
iii) The preparation should be isotonic with blood
plasma and body fluids.
iv) It should be free from pyrogen
v) It should be neutral
vi)It should be physically and chemically stable
vii) The specific
gravity of preparation if it is meant for intra spinal route should be same as
spinal fluid
What are different adjutants used in parenteral
preparations.
1)Solubilising agents:
These are used to increase solubility of drugs which
are slightly soluble in water.
Eg surface active agents like tweens and polysorbates
2) Stabilizers :
The drug in the form of solutions are more liable to
deteriorate due to oxidation and hydrolysis. The oxidation can be prevented by
adding antioxidants like thiourea ,ascorbic acids etc and hydrolysis can be
prevented by using non.aq. vehicle or by adjusting pH of the preparation.
2)Antibacterial agent:
These substances are
added in adequate quantity to prevent the growth microorganism during storage,
so these substances act as preservative. Used in Multidose containers and
Single dose products that are not terminally sterilized.
3)Buffering agent :
Many drugs require a certain pH range to maintain
product stability. Parenteral products formulated to possess sufficient buffer
capacity to maintain proper pH.
eg:-Sodium citrate, acetic acid, citric acid, sodium
acetate.
5)Tonicity adjustment agents
Parenteral preparation should be isotonic with blood
plasma and other body fluids. Isotonicity of the solution may be adjusted by
adding sodium chloride , dextrose and boric acid in suitable quantities.
6)Chelating agent:
Chelating agents such as EDTA and its salt, sodium or
potassium salts of citric acid are added in the formulations to chelate the
metallic ions present in the formulation.
7)Suspending, emulsifying and wetting agents :
Suspending agents are
used to improve the viscosity and to suspend the particles for long time. Ex.
Methyl cellulose, carboxymethyl cellulose etc.
Emulsifying agents are used in sterile emulsions.
Ex.lecithin
Wetting agents are
used to reduce the interfacial tension between the solid particles and liquids
8)Vehicle: there are two types of vehicle
Water is used as vehicle for majority of injection
because water is tolerated well by the body and is safest to administer.
a)The aqueous vehicle used is i) Water for injection
ii) Water for injection free from CO2
b) Non aqueous vehicle
are used for stability and sterility. Eg oils like fixed oil ,sesame oil and
alcohol.
Q.
Describe the processing of parental dosage form.
Steps
involved in parental preparation
i)
Cleaning of containers, closures and equipment: All the
containers, closures and
equipment
which are required for the preparation are cleaned thoroughly with detergent
and
washing is done with tap water followed by distilled water and finally rinsed
with
water
for injection. Rubber closures are washed with hot solution of 0.5% sodium
pyrophosphate
in water, than washed with water and rinsed with water for injection.
ii)
Collection of materials: Ingredients of parental preparation are weighed and
collected
in
preparation room all the ingredients has to be of pharmacopeial standards Water
for
injection
which is free from pyrogen has to be used for preparation.
iii)
Preparation of parenteral product: The pharmacist should decide the order
of mixing
and
exact method of preparation to be followed before preparing the parenteral
product, the
parental
preparations must be prepared under strict aseptic conditions.
iv)
Filtration: The
parental solution so formed is passed through bacteria proof filter, the
primary objective is to clarify the solution by removing foreign particles, if
the preparation
has
to be sterilized by filtration than it has to be done in strict aseptic
conditions before it is
transferred
into final container and sealed.
v)
Filling the preparation in final containers: The filtered product is filled
into final
container,
which are cleaned dried and sterilized on small scale hypodermic syringe and
needle
are used and on large scale automatic filling machine are used. The sterile
powders
are
filled into the container by individual weighing or by using automatic or semi
automatic
devices. The filling operation is carried under strict aseptic precautions.
vi)
Sealing the container: Sealing should be done immediately after filling.
Ampoules are
sealed
manually on a small scale, but on a large scale ampoule sealing machine is
used.
Vials
and transfusion bottles are sealed by closing its opening with rubber closures,
and
then
crimping of aluminium cap is done manually or mechanical means.
vii)
Sterilization: The
parental preparation should be immediately sterilized after sealing
any
method of sterilization can be used depending on nature of medicaments present
in the preparation.
vii)Evaluation
of parenteral preparations: The finished products are subjected to
following
tests in order to maintain quality control a) sterility test b) clarity test c)
leakage
test
d) pyrogen test e) Assay
What
is TPN? Why it needed and give the requirement of TPN?
Definition:
Total
parenteral nutrition (TPN),
is the practice of feeding a person intravenously,
bypassing
the usual process of eating and digestion. The person receives nutritional
formulas
containing salts, glucose, amino acids, lipids and added vitamins.
Need:
o
When
the gastrointestinal tract is non-functional because of an interruption in its
continuity
or because its absorptive capacity is impaired.
o
To
treat people suffering the extended consequences of an accident or surgery or
digestive
disorder.
o
Needed
for children born with non-existent or severely deformed guts
Requirement:
o
Normal
calories required for an adult is approximately 2500 kcal /day which can be
supported
by injecting dextrose 25%.
o
TPN
requires water (30 to 40 mL/kg/day), energy (30 to 60 kcal/kg/day,
depending
on energy expenditure), amino acids (1 to 2.0 g/kg/day, depending on
the
degree of catabolism), essential fatty acids, vitamins, and minerals
Q.
Describe different methods of sterility testing.
Sterility
Testing:
Membrane
filtration method:
This method is preferred in case
of an oily preparation, an ointment that put into solution,
non-bacteriostatic solid not
readily soluble in culture medium, a soluble powder or a liquid
that possesses bacteriostatic and
fungistatic properties.
The method involves the
filtration of the sample under test through a membrane filter
having normal porosity of 0.45μ
and a diameter of approximately 47 mm. After the
filtration the membrane is
removed aseptically from the metallic holder and divided into
two halves. The first half is
transferred into 100 ml of culture media meant for fungi and
incubated at 200 to 250 C for not less
than seven days. The other half is transferred into 100
ml of fluid thioglycolate medium
and incubated at 300
to
350 C not less than
7 days
.Observe the growth of media.
Direct
inoculation method:
§ In this method the specified qty of
sample under test is drawn aseptically from
container
& transferred into vessel of culture medium.
§ Mix the liq. With the medium &
incubate for NLT 14 days
§ Observe the turbidity in media.
Result
& interpretation:
§ No evidence of growth – passes the test
for sterility § Evidence of growth – Re-testing.
§ There is evidence of microbial growth.
So isolate and identify the organism.
If
they are not readily distinguishable from those growing in the container
reserved
in first test, the preparation being examined fails the test. They are
readily
distinguishable from those growing in the container reserved in first
test.
The second test is performed using twice the no of samples. Preparation
pass the test if no evidence of microbial growth.
Q. Give the
significance of particulate matter and describe any two methods in its
detection.
Significance:
Presence of particulate matter in
IV solutions may lead to septicemia, fever and
blockage of small blood vessels.
The presence of undissolved particles create doubt
about the quality of product
Methods:
1)Visual method
2) Coulter counter method
3) Filtration method
4) Light blockage
Visual
Method:
It is an old but reliable method.
The filled containers are examined against strong
illuminated screen by holding the
neck and rotating it slowly or inverted it to exclude the
possibility of foreign particles.
If any particulate matter is visible, that container is rejected.
Coulter Counter
Method:
The method is based on the
principle that increase in resistance is observed between two
electrodes, as the particle
approaches and passes through the orifice. An electrolyte is
required to be included in the
preparation before its evaluation. The particles with
diameter below 0.1 /um can be
detected by this method.
Filtration
method:
The liquid sample is passed
through a filter and the material collected on the surface of
the
filter. It is examined under microscope
Light blockage
method:
It allows a stream of the fluid
under test to pass between a bright white light source and
photodiode sensor. It is possible
to detect cross sectional area in this instrument because it
blocks the path of light and size
of the particle is consider as a diameter of a circle of
equivalent
area
Q. Describe LAL
test and rabbit test for identification of pyrogens.
LAL Test:
LAL test is used for the
detection and quantification of bacterial endotoxins:
Limulus amebocyte lysate (LAL) is
an aqueous extract of blood cells (amoebocytes) from
the horseshoe crab, Limulus
polyphemus. LAL reacts with bacterial endotoxin or
lipopolysaccharide (LPS), which
is a membrane component of Gram negative bacteria.
The solution of endotoxins
containing preparation is added to the lysate derived from
heamolymph cells of horseshoe
crab (limulus polymhemus). The result of the reaction is
turbidity or precipitation or
gelation of the mixture. This is used as a quantitative measure
to estimate the endotoxin
content. The rate of reaction depends upon conc. of endotoxins,
pH,
temperature and presence of clotting enzyme system and clottable proteins from
lysate.
Rabbit Test:
Principle:
The test involves the measurement
of the rise in the body temperature of rabbit following
i.v. injection of a sterile
solution of a substance being examined. Rabbits are used to
perform this test because they
are more sensitive to pyrogen.
Method of
testing :
Sham Test: Pyrogen
testing done on rabbit: The test involves the measurement of rise in
body temp of rabbit following
intravenous injection of a sterile solution of a substance
being
examined. Three healthy rabbits, each weighing not less than 1.5 kg are
selected
They are kept on balanced
diet.& are not showing any loss in body weight .The solution
under test is injected slowly
through ear vein in a volume of 0.5 to 10 ml/body weight.
Record the temperature of each
rabbit in an interval of 30 mins for three hrs. after the
injection. The difference between
initial temp & the maximum recorded as response. If no
rabbit shows an individual rise
in temperature of 0.6 °C or more above its respective
control temperature, and if the
sum of the 3 temperature rises does not exceed 1.4 °C, the
tested material meets the
requirements for the absence of pyrogen. If 1 or 2 rabbits show a
temperature rise of 0.6 °C or
more, or if the sum of the temperature rises exceeds 1.4 °C,
continue the test using 5 other
rabbits If not more than 3 of the 8 rabbits show individual
rises in temperature of 0.6 °C or
and sum of group maximum temp rises doesn’t exceed
3.7°c.
Q. Find the
amount of sodium chloride required make 50 ml isotonic solution containing
0.5 % ephedrine
hydrochloride and 0.5 % chlorobutal.
Give:
i. F.P. 1% w/v
ephedrine hydrochloride = -0.1650c.
ii. F.P. 1%w/v
chlorobutal = 0.1380c.
Ans:
As the concentration of ephedrine
hydrochloride in the preparation is 0.5% w/v, the
depression in freezing point of
ephedrine hydrochloride = 0.165 X 0.5 = 0.0825oC
As the concentration of
chlorobutol in the preparation is 0.5% w/v, the depression in
freezing point of chlorobutol =
0.138 X 0.5 = 0.069o
C
Therefore, total depression in
freezing point of both the substance = 0.0825 + 0.69 =
0.1515
Percentage w/v of sodium chloride
required = 0.52 – 0.1515/
0.576
= 0.644% w/v
Weight of sodium chloride
required to make 100 ml of solution = 0.644 g
Weight
of sodium chloride required to make 50 ml of solution = 0.322 g
Q. Define pyrogen. Explain principle and method for
pyrogen testing
Definition:
Pyrogens are by-product of bacterial metabolism,
pyrogens are polysaccharides, thermostable, soluble in water, unaffected by
bactericide and can pass through bacterial proof filters
Principle:
The test involves the measurement of the rise in the
body temperature of rabbit following i.v. injection of a sterile solution of a
substance being examined. Rabbits are used to perform this test because they
are more sensitive to pyrogen.
Material Used:
Temperature recording device, glass wares,
syringe& needles.
Three healthy adult rabbits of either sex, each
weighing not less than 1.5kg. Do not use any rabbit having a temperature higher
than 39.8°c.
Method of testing :
Sham Test: Pyrogen testing done on rabbit: The test
involves the measurement of rise in body temp of rabbit following intravenous
injection of a sterile solution of a substance being examined. Three healthy rabbits
,each weighing not less than 1.5 kg are selected. They are kept on balanced
diet.& are not showing any loss in body weight .The solution under test is
injected slowly through ear vein in a volume of 0.5 to 10 ml/body weight.
Record the temperature of each rabbit in an interval of 30 mins for three hrs.
after the injection. The difference between initial temp & the maximum
recorded as response. If no rabbit shows an individual rise in temperature of
0.6 °C or more above its respective control temperature, and if the sum of the
3 temperature rises does not exceed 1.4 °C, the tested material meets the
requirements for the absence of pyrogen. If 1 or 2 rabbits show a temperature
rise of 0.6 °C or more, or if the sum of the temperature rises exceeds 1.4 °C,
continue the test using 5 other rabbits If not more than 3 of the 8 rabbits
show individual rises in temperature of 0.6 °C or and sum of group maximum temp
rises doesn’t exceed 3.7°c.
LAL test is
used for the detection and quantification of bacterial endotoxins. Limulus
amebocyte lysate (LAL) is an aqueous extract of blood cells (amoebocytes) from
the horseshoe crab, Limulus polyphemus. LAL reacts with bacterial endotoxin or
lipopolysaccharide (LPS), which is a membrane component of Gram negative bacteria.
The solution of endotoxins containing
preparation is added to the lysate derived from heamolymph cells of horseshoe
crab (limulus Polyphemus). The result of the reaction is turbidity or
precipitation or gelation of the mixture. This is used as a quantitative
measure to estimate the endotoxin content. The rate of reaction depends upon
conc. of endotoxins, pH, temperature and presence of clotting enzyme system and
clottable proteins from lysate
Q.Describe
the layout of sterile area in parenteral formulation Mfg.
Clean up area:-In such area
cleaning and steaming of packing materials and utensils is
done therefore the walls and
ceiling are constructed in such a way, that they withstand the
effects of steam and chemicals.
Generally, epoxy or vinyl paint is coated to solve the
purpose. This area must be kept
clean by washing it regularly. Precaution must be taken to
prevent the growth of
microorganism and collection of dust.
Compounding
area:-It
is nothing but a “preparation” area, where the formula is
compounded, and not necessarily
aseptic. There should be strict control it that these should
not catch dust. The cabinets and
counters should be of stainless steel. Ceiling wall and floor
should be sealed and can be
coated with Epoxy paint. Adequate sink and counter space
should be provided.
Aseptic Area: - It is an
entirely sealed area from outside atmosphere to keep aseptic
environment free from physical
and biological contamination. Therefore, at the time of
designing and constructing the
aseptic area civil work can compose to HVAC (High ventilating and air
conditioning) system including the electrical wire fittings and switches.
The walls facing outside should
have double walled glass partition. Epoxy paints should be
used.to prevent wall, ceiling ,and
floor from the accumulation of dust and microorganisms
The air in the aseptic area
should be free from fibers ,,dust and microorganism. This can be
achieved by the use of high
efficiency particulate air filers (HEPA) which can remove
particles upto 0.3 um. HEPA
filters are fitted in laminar air flow system in which air free
from dust and microorganism flows
with uniform velocity.The air is supplied under
positive pressure which prevents
particulate contamination from sweeping from adjoining
areas .Ultraviolet lamps are
fitted to maintain sterility. The personnel enter in this area
through air lock door. Movement
should be minimum and restricted during filling
procedure.
Quarantine
area:- Approved
batches from QC department can be kept here before
labelling and packing.It must
contain space that separates ‘Approved batches’ and ‘In
process
batches’.
Labelling and
packing area:-Adequate
space is required for installation of printing
devices and packaging machines In
this area, label printing and labelling can be take place.
Storage and its
disposal:- The
finished product are stored under specified storage
condition
and dispensed off.
