Transcript Minal Patel Ppt

MICROBIOLOGICAL ASSAY OF ANTIFUNGAL
CLOTRIMAZOLE AND MICONAZOLE CREAMS
IN THE KENYAN MARKET
BY: PATEL MINAL NARAN
U29/35243/2010
SUPERVISOR: DR. P. M. NJOGU
INTRODUCTION
 Drug therapy is by far the commonly used form of treatment.
 Unfortunately it cannot be supported only by the innovator
drugs especially in the developing countries. Hence the need
for generic drugs due to their low costs.
 Topical antifungal azoles such as clotrimazole and miconazole
are widely used for the treatment of tinea pedis, tinea cruris and
candidiasis.
 Various generics are available in the Kenyan market hence the
need to carry out tests and determine whether the generic
drugs are pharmaceutically equivalent to the innovator drug.
OBJECTIVES
To carry out identification tests of the innovator and
generic brands of clotrimazole and miconazole
creams according to the British Pharmacopeia
2008.
To compare the potency of innovator and generic
brands of clotrimazole and miconazole creams
using microbiological assay method.
EXPERIMENTAL
Three samples of clotrimazole and miconazole creams each
were obtained from the pharmacies within Nairobi City. They
comprised of the innovator drugs Canestan® (clotrimazole)
and Daktarin® (miconazole) and their respective generics that
were either locally manufactured or imported.
Ultra-violet (UV) spectroscopy was used for identity tests. All
samples complied with the British Pharmacopoeia (2008)
specifications for identity of clotrimazole and miconazole.
MICROBIOLOGICAL ASSAY
Agar diffusion method was employed. Sabouraud
dextrose agar was used as growth media and Candida
albicans was used as test micro-organism.
The assay comprised of two dose levels of each standard
and sample. Means of responses to standard test
solutions
were
designated
S(0.25mg/ml)
and
S1(0.5mg/ml) for low and high dose, respectively.
Similarly, mean responses to the sample of unknown
potency were designated T(0.25mg/ml) and T1(0.5mg/ml).
Standard and Sample preparation
 Approximately 5g of clotrimazole cream (1% w/w) samples
and 2.5g of the miconazole nitrate cream (2% w/w) samples
were dissolved in 100ml of dimethylformamide (DMF) to
obtain a concentration of 0.5mg/ml and filtered. The resulting
solutions were diluted with DMF to obtain a second
concentration of 0.25mg/ml.
 Standards were prepared by dissolving approximately 0.05g
of clotrimazole and miconazole in 100ml to obtain a
concentration of 0.5mg/ml. Concentration levels of standard
solutions were prepared by diluting with DMF to obtain
another concentration of 0.25mg/ml.
Sample application
S
S1
T1
C
T
Figure 1. S (0.25mg/ml) and S1 (0.50mg/ml) represent the standard solutions; T
(0.25mg/ml) and T1 (0.50mg/ml) represent the test solutions; C is the negative control
(DMF).
 Figure 2. Zones of inhibition by Daktarin®
POTENCY DETERMINATION
 Potency of each sample was calculated according to the formula:
E= ½ [(T1 – T) + (S1 – S)]
F= ½ [(T1 + T) – (S1 + S)]
b = E/I
antilog M = F/b
Where:
T- Diameter of zones of inhibition for test samples.
S- Diameter of zones of inhibition for standards.
E- Mean difference in response between adjacent dose levels.
F- Difference in response between two preparations.
I- Logarithm of the ratio of adjacent dose levels (0.3)
b- Theoretical mean difference in response arising from a 10-fold increase in dose.
M- Logarithm of the ratio of potencies of test solutions, sample:standard.
RESULTS
Drug
Sample
Clotrimazole
Miconazole
Potency
Label claim (%)
Canestan®
0.712
0.72
Sample A
0.698
0.70
Sample B
0.657
0.66
Daktarin®
0.806
1.61
Sample C
0.754
1.49
Sample D
0.649
1.29
DISCUSSION
 The innovator drugs and generic samples of clotrimazole had similar
potency of approximately 0.7. this implies the generic drugs are
pharmaceutically equivalent to the innovator drug and hence can be
substituted for the innovator drug.
 The innovator drug Daktarin® and one of the generic drugs (sample C)
had potencies that were similar of approximately 0.8. This shows that
sample C is bioequivalent to the innovator drug. The second generic of
miconazole (sample D) had a potency lower than the innovator drug.
This may imply that Sample D is not bioequivalent to Daktarin®.
CONCLUSION
The generic samples of clotrimazole had potencies
equivalent to that of the innovator drug implying that
they are equally potent and hence serve as cheaper
substitutes for treatment of fungal infections.
One of the miconazole generic drug had a lower
potency compared to the brand drug suggesting it
might not be bioequivalent to the innovator drug.
RECOMMENDATIONS
Since microbiological assay for antifungal azole creams is not
an official method, it could be one of the methods that could
be validated for use in determining the potencies and hence
used as a method to study the bioequivalence of various
generics that are available in the market.
Various other fungi could be used to assess the potency of
the creams. Example Saccharomyces cerevisiae, Aspergillus
niger, Trichophyton rubrum, Trichophyton mentagrophytes
and Epidermophyton floccosum.