This document discusses various pharmaceutical factors that should be considered during preformulation studies to develop safe and effective dosage forms. It outlines 7 key factors: 1) flow properties, determined through angle of repose, Hausner ratio, and Carr's index; 2) density; 3) compressibility; 4) hygroscopicity; 5) electrostatic charge, measured using devices like INOSTAT; 6) rheology, examining viscosity using various techniques; and 7) wettability, determined by contact angle between liquid and solid surface. The preformulation study aims to characterize the physical, chemical and mechanical properties of new drug molecules.

1. Pharmaceutical factors affecting
preformulation study
Presented by,
Pallab Kumar Pal
M.Pharm, 1st
year(Pharmaceutics)
Roll no. 10
Under the guidance of,
Dr. Somasree Ray
Astt. Professor (Department of Pharmaceutics)
Gupta College of Technological Sciences, Asansol

2. INTRODUCTION
Preformulation study is the characterization of physical, chemical and
mechanical properties of new drug molecule in order to develop safe,
effective, and stable dosage form.

3. Pharmaceutical factors

4.  Flow property is an important factor that determines the fate of drug
molecule.
 Sufficient flow is required for uniformity of dosage form. So it is necessary to
judge the flow of material in preformulation stage of the dosage form.
 However extreme increase in flow may improve weight uniformity but may
reduce content uniformity through increased segregation.
1.Flow property
Method of determination
i. Angle of repose
a. Static angle of repose
b. Dynamic angle of repose
c. Drained angle of repose
ii. Hausner ratio
iii. Carr’s index

5. 2. Density
Density =
mass
volume

6.  Compressibility is the ability of powder to decrease in volume under
pressure.
%compressibility = Tapped density – bulk density * 100
Tapped density
% Compressibilty Range Flow Descriptions
5-15 Excellent
12-16 Good
18-21 Fair to passable
23-35 Poor
35-38 Very poor
>40 Extremely poor
3. Compressibility

7.  Hygroscopicity: - It is the tendency of material to absorb moisture from
atmosphere & be dynamic equilibrium with water in the atmosphere.
 Deliquescent: - It is the hygroscopic substance which absorb moisture
from air and they can be liquefied by partially or wholly forming solution
 Efflorescent: - a substance which loses water to form a lower hydrate or
become anhydrous is term as efflorescent.
Keep accurately weighed
sample in various humid
condition for 2 weeks
4. Hygroscopicity

8. .
.  Electrostatic charge is produced by-
i. Separation of positive & negative charge
ii. Mechanical impact
iii. Friction between two surface
iv. Rupturing of particle
v. Separation of solid & liquid surface
Electrostatic charges are the consequence of classic attraction & repulsion
effect between the charges
Method of determination
i. INOSTAT, measures negative charge on the surface in volts/cm,
when material is flowing from hopper.
ii. ELPI(13-stage Electrical Low Pressure Impactor), gives detailed
charge profile of aerosol particles.
iii. Electrostatic testers which consists of electrostatic voltage sensing
probes.
5. Electrostatic charge

9. 6. Rheology

10. Rheogram
i. Capillary viscometer
ii. Falling sphere viscometer
iii. Cup and bob viscometer
iv. Cone and plate viscometer
v. Brook field viscometer
vi. Ultrasonic Shear Rheometer :- For analysing protein solution
rheology.
vii. Instron Capillary Rheometer :- Measures viscosity as a function of
rate of shear & temp at a high rate of shear.
Determination of viscosity

11.  Wettability of a solid is an important property with regards to
formulation of solid dosage form
 Adsorption at solid surface is involved in wetting & detergency
 It may influence granulation of solid, penetration of dissolution fluid
into tablet and granules & adhesion of coating material to tablet
It is determined by contact angle-
The contact angle is the angle between a liquid droplet and the surface over
which it spreads
7. Wettability