Evaluation of Antibacterial Activity of CVS® Ichthammol Ointment
Nasim Eshragh Nia, Alborz Jelvani
Department of Biological Science
Saddleback College
Mission Viejo, CA 92692
Ichthammol, a substance extracted from marine rocks, is known to have
antibacterial activity and has been used for generations for the treatment of ear infection
and skin problems. Although several clinical studies have confirmed the antibacterial
properties of pure ichthammol, this compound is not FDA approved as an antibacterial
agent due to insufficient research on its effectiveness. In this study, it is hypothesized that
CVS® 10% ichthammol ointment exhibits antibacterial activity when applied to the Gram
positive bacteria, Staphylococcus aureus. Ichthammol ointment (I) and a mixture of the
ointment and glycerin (IG) were studied. The zones of inhibition were measured in
millimeters and were analyzed using ANOVA and Bonferroni correction tests. The mean
zones of inhibition for I and IG were 0.78 ± 0.02 mm and 1.08 ± 0.03 mm after 48 hours.
After two weeks, the zone of inhibition for IG increased to 3.79 ± 0.05 mm. There was
significant statistical difference between the groups and the control groups, with IG being
more effective than I (p ≤ 0.0125). The significant inhibitory effect of IG is due to the
inherent antibacterial property of ichthammol and its ability to spread out more effectively
when mixed with glycerin.
Introduction
There are various antibacterial agents worldwide that contribute to the human health. Although these
antibacterial compounds are known to be effective, some can potentially result in allergic reactions, the intensity of
which can vary depending on the individual. Due to the rise of antibacterial resistant bacteria strains, there is a need
for the production of new antibacterial agents. Ichthammol (Ammonium Bituminosulfonate or black drawing salve
with chemical composition of C28H36S3O6(NH4)2) is derived from marine sediments, containing the remains of fish
in Mesozoic era rock formations. Although Ichthammol is rich in hydrogen and carbon atoms and low in nitrogen
atoms, it should not be mistakenly confused with tar (Braun-Falco et al. 1991). Ichthammol is miscible in glycerol, a
compound possessing humectant and moisturizing properties (Bushan et al. 2000). To synthesize Ichthammol, a
certain bituminous shale need to be carbonisinated in a low temperature and distilled, be sulfonated, and then be
neutralized by ammonia, after which it is prepared for medicinal use (Kownatzki et al. 1984).
Based upon various clinical studies, Ichthammol is known to have antibacterial, antiphlogistine, antiinflammatory, antiseborrhoic, antieczematous, antimycetic, antiprurinous and blood flow stimulating effects
(Cholcha et al. 1994). In 1994, Ahmed et al. carried out an experiment on the antibacterial effect of Ichthammol and
Ichthammol-glycerin mixture on different bacteria, including Staph. Epidermidis, Streptococcus pyogenes, and
Staphylococcus aureus as Gram positive, and Pseudomonas aeruginosa and Escherichia coli as Gram negative. This
study showed more inhibition of Gram positive bacteria compared to Gram negative. They also concluded that
Ichthammol alone had a better antibacterial effect, which resulted in the conclusion that the main substance that acts
as the antibacterial agent in Ichthammol-glycerin mixture is in fact Ichthammol (Ahmed et al. 1994). Similar results
were obtained in a different study; Nilssen et al. selected the same microorganisms for his experiment to test
antibacterial effects of Ichthammol (1996). His team found Ichthammol by itself to be more effective than
Ichthammol-glycerin mixture, with glycerin only having a dilutional effect (Nilssen et al. 1996). In Germany, as
well as Australia, Ichthammol ointment with specific concentrations is approved as an antibacterial compound
(Rowe et al. 2007); however, it has not been approved by the U.S. Food and Drug Administration (FDA) due to
undocumented effectiveness and safety.
The antibacterial action of Ichthammol compound as a pure substance has already been established through
various studies, however, comparative studies assessing the antibacterial activity of Ichthammol ointment is sparse.
The present study evaluated the effectiveness of over the counter 10% Ichthammol ointment, using penicillin as the
positive control and sterile water as the negative control. Because the Ichthammol ointment is a viscous material and
is unable to spread properly, a mixture of Ichthammol-glycerin was also studied to allow for better diffusion of the
compound. Comparison was accomplished by means of measuring the zone of inhibition resulting from the
application of compounds on Staphylococcus aureus, a Gram positive bacterium.
Based on the previous body of knowledge, it is expected that Ichthammol ointment, having Ichthammol
among its ingredients, will exhibit significant antibacterial activity.
Materials and Methods
Thirty nutrient agar plates (Criterion Inc., Lot #12158) were prepared and inoculated with Staphylococcus
aureus via the lawn spread method on November 8, 2013. Each plate was divided into four sections and labeled as
follows: I (Ichthammol only), IG (Ichthammol and glycerin), P (Penicillin), W (water). CVS® Ichthammol ointment
was purchased from CVS pharmacy, Rancho Santa Margarita CA. A mixture of Ichthammol and glycerin was
prepared by mixing 1 gram of Ichthammol in 10 mL of glycerin. Thirty-three sterile filter paper disks were dipped in
sterile water, Ichthammol, and Ichthammol-glycerin mixture separately. The prepared sterile chads and 10 µg
penicillin disks (Penicillin Susceptibility Disks) were placed on their appropriate spot on the agar plate and the
plates were inoculated at 37°C for 48 hours to allow bacterial growth. After the incubation period, the zone of
inhibition was measured for each disk with a metric ruler by measuring the diameter of the entire inhibited area. All
data were transferred to MS Excel (Microsoft Corporation, Redmond, Washington) for comparison between the four
groups. Based on ANOVA and Bonferroni correction, statistical difference was considered significant when p ≤
0.0125.
Results
Figure 1. The graph of comparison of the zone of
inhibition between different types of antibacterial
reagents. There is a difference in the inhibitory activity
of Ichthammol, Ichthammol and glycerin, penicillin and
water (p=2.70×10-151, ANOVA & Bonferroni
Correction). Error bars are Mean ± SEM.
Discussion
Zone of Inhibition (mm)
Following the incubation period and measuring the zone of inhibition for each of the four groups, the mean
difference in antibacterial activity was 1.08 ± 0.03 (±SEM, N=33) for the IG group, 0.78 ± 0.02 (±SEM, N=33) for
the I group, and 5.21 ± 0.02 (±SEM, N=33) for the P group. No antibacterial activity was observed in the W group.
ANOVA and Bonferroni correction tests revealed that there was a significant difference in inhibitory activity
between all groups (p ≤ 0.0125), with penicillin having the greatest zone of inhibition, and the IG group exhibiting a
more significant zone of inhibition compared to that of the I group. The results are shown in figure 1.
6
5
4
3
2
1
This study was designed to evaluate the
antibacterial activity of 10% Ichthammol ointment.
0
The penicillin and water results are consistent with the
Ichthammol Ichthammol Penicillin (+) Water (-)
expected positive and negative control behavior, with
& Glycerin
Control
Control
penicillin causing the most significant amount of
Type of Antibacterial Reagent
inhibition, with an average of 5.2 mm, and water
showing no inhibition of bacterial growth. Moreover,
while both Ichthammol ointment alone (I) and Ichthammol-glycerin mixture (IG) showed inhibitory activity, with
0.78 mm and 1.1 mm of inhibition respectively, IG produced a larger zone of inhibition, thus showing a greater
extent of antibacterial activity, which is in contrast with that of all previous studies. According Jamalullah et al., all
previous studies used Ichthammol in the form of an ammonium bituminosulfonate chemical (2012); however, the
present study was carried out using Ichthammol in the form of an ointment. The unexpected results can be explained
by the fact that the 10% Ichthammol ointment was unable to spread effectively due to its viscous nature. Because
Ichthammol is miscible in glycerin, upon mixing the two compounds, Ichthammol diffused better on the plates,
creating a larger zone of inhibition. Hence, the Ichthammol-glycerin mixture acted as a better antibacterial agent
against Staphylococcus aureus.
In a clinical study, Abid et al. compared the effectiveness of glycerin/Ichthammol with steroid/antibiotic
drops in relieving the pain, inflammation, and infection caused by otitis externa and media. Their study conducted
on 324 patients proved that glycerin/Ichthammol was more effective than Neomycin/Betamethasone application and
caused earlier relief of symptoms (2012).
Whilst clinical studies do support the antibacterial and anti-inflammatory activity of Ichthammol
compound, the evidence do not appear sufficient for it to be approved by the FDA.
In an efficacy and safety study of Ichthammol, Schmid et al. found out that Ichthammol did not appear to
have any carcinogenic or mutagenic effects when it is administered topically or orally (1996). Since Ichthammol is a
well-tolerated substance for long term treatment, it is considered safer than tar preparations due to its purity.
Through more research, this study can be extended by incorporating a Gram negative reagent with Ichthammol to
increase its spectrum of activity against high resistant bacterial strains; in the meantime, the new anti-Gram negative
agent should not cause any major skin reactions.
Literature Cited
Abid, O., Khan, Z., Hakim, A., and Gul, A. 2012.
COMPARISION OF EFFICACY OF TOPICAL
GLYCEROL/ICHTHAMMOL WICK WITH
NEOMYCIN/BETAMETHASONE WICK IN
BACTERIAL OTITIS EXTERNA. The Journal of
Medical Sciences. 20: 108-111.
Ahmed, K., Roberts, M., and Mannion, P. 1994.
Antimicrobial activity of glycerin-ichthammol in
otitis externa. Clinical Otoloaryngology & Allied
Science. 20(3): 201-3.
Braun-Falco, O., Plewig, G., Wolff, H. and
Winkelmann, R. 1991. Journal of Dermatology.
Berlin: Springer Verlag 1149.
Bushan, M., and Griffiths, C. 2000. Brook of
Manchester. British Journal of Dermatology. 143(1):
26-9.
Cholcha, W., Leuschner, J., and Leuschner F. 1994.
Safety studies of dark sulfonated shale oil following
local and systemic application. Medicament
Research/ Drug Research. 44(11): 844-49.
Jamalullah, M., Rafique, A., and Ahmed, R. 2011.
COMPARISON OF EFFICAIES OF 10%
ICHTHAMMOL GLYCERINE AND 3%
CIPROFLOXACIN – 1% DEXAMETHASONE BY
MEANS OF SUSTAINED RELEASE OF DRUG
BY WICK METHOD IN TREATMENT OF OTITIS
EXTERNA. Isra Medical Journal. 3: 94-6.
Kownatzki, E., Uhrich, S., and Schopf, E. 1984. The
effect of a sulfonated shale oil extract (ichthyol) on
the migration of human neutrophilic granulocytes in
Vitro. Archives of Dermatological Research. 276:
235-39.
Nilssen, E., Wormald, P.J., and Oliver, S. 1996.
Glycerol and ichthammol-medicinal solution or
mythical potion? The Journal of Laryngology and
Otology. 110: 319-21.
Rowe, S., Hilmi, S., Wood, F. 2007. The use of
ichthammol glycerin in burn wound care: a literature
review. 15: 29-32.
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Review Form
Department of Biological Sciences
Saddleback College, Mission Viejo, CA 92692
Author (s):_ Nasim Eshragh Nia, Alborz Jelvani
Title:_ Evaluation of Antibacterial Activity of CVS® Ichthammol Ointment
Summary
Summarize the paper succinctly and dispassionately. Do not criticize here, just show that you understood the paper.
The study sought to determine the antibacterial effectiveness of 10% Ichthammol ointment on a
culture of Gram positive Staphylococcus aureus. Ichthammol is a substance chemically derived
from marine fossils and is known to have antibacterial properties. This study compared the
radius of bacterial inhibition between the Ichthammol ointment, an Ichthammol/glycerol mixture,
Penicillin as a positive inhibition control, and water as a negative inhibition control on nutrient
agar plates. The reason an Ichthammol/glycerol mixture was used alongside the ointment is
because Ichthammol is easily miscible in glycerol which allowed for better diffusion of the
compound on the agar plates. The ointment was very viscous so it was unable to spread properly
so the glycerol mixture provided another variable for comparison. ANOVA and Bonferroni
correction tests were run which showed that there was indeed bacterial inhibition with the
ointment and the glycerol mixture, however, the glycerol mixture had a significantly larger zone
of inhibition which is contrary to all previous studies that were read. All of the other studies
used Ichthammol as an ammonium bituminosulfonate chemical while this study used it as an
ointment. Also, the ointment was unable to spread properly on the agar plate while the glycerol
mix diffused better on the plates. Future studies would test the inhibition of Gram negative
bacteria strains.
General Comments
Generally explain the paper’s strengths and weaknesses and whether they are serious, or important to our current
state of knowledge.
This paper was very professional and very well written. It was mostly free of grammatical errors
and it contained all the important information needed without any extra/filler information. The
authors’ knowledge on this subject is apparent. There was plenty of relevant research done
regarding this study which greatly supported their findings, although they did differ from the
other studies slightly. The only weakness aside from the very few grammatical mistakes is that I
was unable to find any aspect of the paper I thought I could justify any changes be made to
which makes it look like I didn’t read or pay attention to the paper at all, which is untrue. I read
it though 3 times straight and only caught the few grammar mistakes and then read through each
part again to write the summary. Without having more extensive knowledge on the presented
subject I can’t disagree with their methods, and the rest of the paper is written in agreement with
all the requirements. The authors obviously proofread and made sure they understood their
research. Very good job all around.
Technical Criticism
Review technical issues, organization and clarity. Provide a table of typographical errors, grammatical errors, and
minor textual problems. It's not the reviewer's job to copy Edit the paper, mark the manuscript.
This paper was a final version
This paper was a rough draft
Either say “on November 8, 2013” or “on the 8 of November, 2013” just not “on 8 November
2013.”
About 50% of the Ichthammols were capitalized and 50% were not capitalized. Choose either to
capitalize or not capitalize and stay consistent with all of them.
Two of the literature cited articles had the titles in all caps and they should be changed.
Recommendation
 This paper should be published as is
 This paper should be published with revision
 This paper should not be published