The document discusses preformulation in pharmacy. Preformulation involves characterizing the physical and chemical properties of a drug substance alone and when combined with excipients. It aims to generate information for developing stable and bioavailable dosage forms. The key steps in preformulation include assessing properties like solubility, stability, solid state compatibility, physico-chemical characteristics, and in vitro availability. Organoleptic properties like color, odor, taste, shape and size are also evaluated to understand sensory characteristics.
2. CONTENTS :-
DEFINATION AND IMPORTANCE OF
PREFORMULATION IN PHARMACY.
STEPS INVOLVED IN PREFORMULTION.
ORGANOLEPTIC PROPERTIES.
PURITY, PARTICLE SIZE SHAPE AND
SURFACE AREA.
SOLUBILITY AND DISSOLUTION OF DRUG
SUBSTANCE
CHEMICAL REACTION INVOLVING DRUG
EXCIPIENT INTERACTIONS AND FACTORS
AFFECTING ABSORPTION OF DRUGS.
3. DEFINATION OF PREFORMULATION:-
“PREFORMULATION IS A BRANCH OF PHARMACY
WHICH DEALS WITH THE INVESTIGATION OF
PHYSICAL AND CHEMICAL PROPERTIES OF A
DRUG SUBSTANCE ALONE OR WHEN COMBINED
WITH EXCIPIENTS”
It is
the characterization of
the physical and
chemical properties of a
drug, especially a newly
discovered drug.
4. IMPORTANCE OF PREFORMULATION IN
PHARMACY:-
It was introduced at 1960
Preformulation testing is the first step in the rational
development of dosage form of a drug substance.
Preformulation forms an indespensible part of the
inovator companey as well as generic companies.
Preformulation testing generate information useful to
the formulator in developing stable and bioavilable
dosage forms.
The necessity of preformulation is not only
acknowledged by most companies it is to a certain
extent prerequisite and forms back bone for R&D.
5. INFORMATION THAT A PREFORMULATOR OF
PHARMACEUTICAL COMPANEY MUST SUPPLY
Solubility, dissolution, partition coefficient,
ionization constant, pka and kp values of the
drug.
Crystall properties and polymorphism.
Density, hygroscopicity, flowability, wetability
and stability studies.
Micromeritics considerations such as – shape,
size, surface area, crystal habits etc..
Compatibility with other compounds .
Purity conformation by methods like-
9. “PREFORMULATION MAY INCLUDE SAVERAL STEPS
IN ORDER TO SATSFY THE LAVELS OF QUALITY
AND PURITY, OF THE PREFORMULATION PROCESS”
“THE STEPS IN PREFORMULATION ENSURE ITS
EFFICIENCY”
10. Steps in Preformulation Process Pharmaceutical Research
1. Stability i. Solubility
a. Solid State (1) Water and Other Solvents
(1) Temperature (2) pH-Solubility Profile
(2) Light (3) Salt Forms
(3) Humidity (4) Cosolvents
b. Solution (5) Complexation
(1) Solvent (6) Prodrug
(2) pH j. Effect of pH on UV Spectra
(3) Light k. Ionization Constant
2, Solid State Compatibility l. Volatility
a. TLC Analysis m. Optical Activity
b. DRS Analysis n. Polymorphism Potential
3. Physico-chemical Properties o. Solvate Formation
a. Molecular Structure and Weight 4. Physico-mechanical Properties
b. Color a. Bulk and Tapped Density
c. Odor b. Compressibility
d. Particle size, Shape, and Crystallinity c. Photomicrograph
e. Melting Point 5. In Vitro Availability Properties
f. Thermal Analysis Profile a. Dissolution of Drug Crystal Per sec.
(1) DTA b. Dissolution of Pure Drug Pellet
(2) DSC c. Dissolution Analysis of Pure Drug
(3) TGA d. Rat Everted Gut Technique
g. Hygroscopicity Potential 6. Other Studies
h. Absorbance Spectra a. Plasma Protein Binding
(1) UV b. Effect of Compatible Excipients
(2) IR on Dissolution
c. Kinetic Studies of Solution
Degradation
d. Use of Radio-labeled Drug
11. The formal preformulation study should start at
the point after biological screening, a decision is
made for further development of the compound in
clinical trials.
Before embarking upon a formal program, the
preformulation scientist must consider the
following:
1. The available physicochemical data (including
chemical structure, different salts available)
2. The therapeutic class of the compound and
anticipated dose
3. The supply situation and the development
schedule (i.e., the time available)
4. The availability of a stability-indicating assay
5. The nature of the information the formulator
should have or would like to have
13. 1. ORGANOLEPTIC PROPERTIES
“Organoleptic Properties are those properties
which are evaluated after an impression on the
organs of sense”
It refers to the evaluation of drugs by properties
like –colour, odour, taste, size, shape and special
features like touch, texture, etc..it is a technique of
qualitative evaluation based on the study of
morphological and sensory profile of whole drugs.
The aromatic odour of fruits, sweet taste of
liquorice, the ovoid tears of gum acacia are some
examples of this type of evaluation.
14. SOME EXAMPLE OF ORGANOLEPTIC
EVAULATION:-
RIBBONS OF TRAGACANTH DISC SHAPE OF NUX
VOMICA
15. COLOUR
Colour can be useful, while describing different
batches of drug, it can sometimes be used as an
indicator of solvent presence or more importantly
of degradation.
In addition subtle difference in colour due to
particle size distribution.
Colour of various drug formulation may indicate
the degradation process,the colour of certain
types of formulation can be improved by adding
certain dyes.
16. ODOUR
Odour plays an important role in drug formulation
and any strong odour should not be present for
consumers acceptance of the consumers finished
product.(such as capsules, tablets, syrups etc..)
Odour prrovides an indication of the quality of
formulation.eg:-characteristic odour of acetic acid in
degradation of aspirin.
Presence of odour may also be the characteristic of
the drug.eg:- vitamins
17. TASTE:
Taste of the formulated drug plays an important role
in consumers acceptance.
Unpalatable drugs which donot have good taste,
problem may be solved by incorporation of-
Flovouring agents.
Excipients.
Coating.
