The various methods required for the evaluation of nail polishes are as follows.
EVALUATION OF NAIL LACQUERS
The various methods required for the evaluation of nail
polishes are as follows.
1.
Test For Non-Volatile Content:
The test is done in order to check
the quantity of the non-volatile content in the preparation. The method is
known as dish method and involves a simple process described below:
The sample is spread on a flat plate
as a circle 8 cms in diameter.
The quantity is weighed and kept in
an oven at a temperature o 105 for l hr.
The quantity of substance remaining
on the plate is weighed arid this constitutes the non-volatile content.
2. Rate Of Drying:
The test is done in order to check the rate of evaporation
of the preparation. It involves a
simple process in which the film is applied with an applicator on to a
completely non-porous surface. It is kept at 25°C and 50% RH and the time
required to dry is noted by touching it with finger. When no matter is adhered
to the finger tip, then the product is said to be completely dried.
3.
Colour Of The Product:
The colour of the product is tested
by comparing it with, a standard
colour. This can be done by applying the standard colour on one nail and the
prepared product on the adjacent nail. From this comparison, the contrast in
the colours can then be easily noted.
4.
Test For Smoothness Of The Film:
The smoothness is the most important
characteristic of the film. The
surface property can be studied by the microscopic analysis. The film should
not contain any foreign matter or particles of the coating material. It should
also be free from the orange peel effect when seen under microscope.
5.
Estimation Of Gloss:
The gloss of the product can be determined by the use of an instrument that works on the principle
of reflection of light.
6.
Test For Hardness Of The Film:
The test is done in order to measure
the extent of hardness of the
substance.
It is done by spreading the film on a glass plate and then
drying it for 48 hrs at 25°C.
It is then further dried at 70°C for 2hrs.
It is then cooled at 25°C for 48 hrs.
The hardness is then checked by applying mechanical force
externally.
7.
Test For Adhesive Property:
This is done in order to measure the
extent of adhesion of the film with
adhering material. This is done by the following method.
The film is spread on metal surface and allowed to settle
for some time.
The adhesion character is then determined by measuring the
mechanical force applied externally to remove the film.
8.
Test For Resistance To Abrasion:
This is done by applying mechanical
abrasive forces externally on the
film surface. The surface characteristic of the film before and after the
application of abrasive force are then studied.
9.
Test For Resistance To Water Permeability:
This is a measure of resistance of
the film towards absorption of
water. This is done as follows.
A continuous film is spread on the surface of a metal plate.
The plate is then immersed in water.
The weight of the film before and after the immersio n into
water is noted.
An increase in the weight is calculated. The lesser the
increase in weight, the greater is the water resistance.
10.
Test Application Property:
It is a measure of ease of
application of the product. It is carried
out more reliably by applying on nails. The degree of evenness and smoothness
of brushing and the presence of any air bubbles are checked out.
11.
Test for Viscosity:
It is the most important parameter
that determines the evenness of application.
The viscosity can be measured by
using Brookfield‘s viscometer.
It can be easily carried out by checking the flow of product
from the applicator and comparing it with standard product.
12.
Test For Stability:
It is it measure of long lasting ability of the product. It
can be done by using the acceleration
stability test.
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