THE JOURNAL OE INVESTIGATIVE DERMATOLOGY
`Copyright © 1965 by The Williams & Wilkins CO.
`
`VOl. 45, NO. 2
`Printed in U.S.A.
`
`DEPOSITION ON THE SKIN OF PARTICLES OF ANTIMICROBIAL
`AGENTS FROM DETERGENT BASES*
`
`JOHN J. PARRAN, JR., M.S.
`
`containing antimi-
`compositions
`Detergent
`crobial or other
`therapeutic ingredients offer
`convenience and possible enhanced therapeutic
`effectiveness because of simultaneous cleaning
`and treatment. However,
`the combination of
`cleaning and therapeutic effect
`is often diffi-
`cult to obtain because the effectiveness of such
`a
`treatment
`is usually determined by the
`amount of active ingredient
`retained by the
`skin following the washing (1). The substantiv—
`ity of the agent to the skin is usually a matter
`of attraction between charged ions or molecules
`of the agent and the skin, the compound being
`retained by the stratum corneum during the
`washing and rinsing processes.
`Some time ago, another mechanism for the
`retention of an active material by the skin
`was suggested by the problem of soil redeposi—
`tion that occurs during the
`laundering of
`clothes. The soil
`redeposition problem con—
`sists of
`the deposition and retention of
`fine
`charged particles of
`soil on the cloth fibers
`during the washing and rinsing processes
`(2,
`3). This can occur even though the removal of
`lipids
`from the clothing is quite complete.
`Since it was known that fine particles of active
`ingredients are often charged (4),
`it occurred
`to us that the same processes that cause soil
`redeposition might be used to deposit an active
`ingredient on the skin. It seemed that selected
`active
`ingredients which were only slightly
`soluble might be deposited on the skin while
`other soil, especially lipids, was being removed
`by detersive action.
`
`MATERIALS AND METHODS
`
`Antimicrobial powders, meeting the solubility
`requirements, with particle
`size
`less
`than 10
`microns were suspended in unbuffered detergent
`solutions. Each of the antimicrobial-detergent com—
`binations was used as a shampoo by at least four
`subjects. The shampoos were used ad libitum and
`followed by thorough rinsing. After the hair was
`towel dried, the relative concentrations of particles
`
`on the scalp were determined.
`
`Received for publication July 30, 1964.
`* From the Winton Hill Technical Center, The
`Procter & Gamble Co., Cincinnati, Ohio.
`
`cornified epithelium was
`the
`of
`A sample
`obtained by pressing a piece of cellulose adhesive
`tape against the scalp. The tape was then placed
`on a glass slide with the adhesive in contact with
`the glass. The slide was examined With a polarizing
`microscope at approximately 400 diameters with
`polaroids crossed. While the cornified epithelium
`exhibited some degree of birefringence, the highly
`anisotropic properties of most crystalline antimi-
`crobial agents made them readily visible under
`such viewing conditions.
`The cellulose adhesive tape was selected for
`minimal resident particles prior to use, since the
`number of particles on samples of
`tape varied
`with different brands and with different batches of
`a specific brand. Also, when the slide was ex-
`amined for particles with crossed polaroids,
`the
`birefringence
`of
`the
`tape Was minimized by
`rotating the slide on the microscope stage so as to
`yield maximum extinction of light.
`The scalps of a number of
`the subjects were
`examined daily for three days after shampooing.
`RESULTS
`
`Particles of several antimicrobial agents de-
`posited heavily on the scalp. Photomicrographs
`of a moderate degree of particle retention are
`shown in Figure 1.
`The particles could not be removed from the
`scalp by vigorous and prolonged rinsing. The
`number of particles on the scalps gradually
`decreased following the shampoos, but were de-
`tectable on the scalp for as long as two to
`three days after shampooing.
`The amount of particle deposition obtained
`with several
`antimicrobial
`agents when in-
`corporated into solutions of different detergent
`bases is
`shown in Table I. The amount of
`particle deposition varied greatly with different
`antimicrobial agents and with different deter—
`gent bases. There was relatively little variation
`in the amount of particle deposition between
`subjects for any given suspension.
`the
`Users of the shampoos could not detect
`presence of
`the particles on the scalp either
`by feel or by sight.
`
`DISCUSSION
`
`The deposition of particles is reportedly an
`electrokinetic phenomenon and related to the
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`PARTICLE DEPOSITION FROM DETERGENT BASES
`
`87
`
`
`
`the
`typical particle retention by cornified epithelium of
`FIG. 1. Photomicrographs of
`scalp (2% 3,4,4’-trichlorocarbanilide in sodium alkyl benzene sulfonate used as a shampoo).
`A. Normal transmitted illumination, 432x. B. Same field of View and conditions as A,
`except polaroids crossed.
`
`TABLE I
`
`Relative concentrations of particles deposited on the scalp from suspensions consisting of 2%
`antimicrobial, 15% detergent, aq.*
`
`Selenium
`Colloidal
`Zinc 2-pyridin- 3,4,4'~Trichlor- Tetrachloro~p—
`Disulfide
`Sulfur
`ethiol—l-oxide
`ocarbanilide
`benzoquinone
`
`
`++
`+
`+ +++
`
`++++
`++++
`+++ +
`
`++
`++
`++++
`
`+
`+
`++++
`
`+++
`Sodium alkyl benzene sulfonate
`+
`Sodium alkyl sulfate
`Polyoxyethylene (20) sorbitan mono- ++++
`oleate, Tween 80
`Polyethylene
`glycol
`ether, Nonic 303
`Benzalkonium chloride
`+++
`++
`++++
`++
`
`
`nonylphenyl
`
`+
`
`—
`
`++
`
`_
`
`+
`
`* — = no deposition; ++++ = heavy deposition.
`
`zeta and psi potentials of the particles and the
`skin (3, 4). Apparently the attraction between
`particles of a number of antimicrobial agents
`and the skin is sufficient to resist removal of the
`
`particles by intensive rinsing.
`There is much variation in the deposition
`tendencies of particles of different materials.
`Also, particle deposition is strongly affected by
`
`the type of detergent base employed. The dep-
`osition of materials that have little tendency
`to deposit can often be improved by careful
`selection of the base detergent.
`While electrophoretic measurements of par—
`ticles and of cornified epithelium have been
`made (4, 5), it is difficult to use such measure-
`ments to predict particle deposition from prac-
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`88
`
`THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
`
`tical detergent formulas. Suspensions of known
`pH and concentration and that contain a rela—
`tively low concentration of
`ions of
`approxi—
`mately equal mobilities are most suitable for
`electrophoretic studies.
`In contrast, practical
`detergent
`formulas usually contain high con—
`centrations of readily ionizable materials with
`ions of great disparity in size and mobility.
`Also,
`the pH and the concentration of deter-
`gent at the particle-skin site continually change
`during washing because of
`the diluting effect
`of the wash water. These changes doubtlessly
`affect
`the zeta and psi potentials of the par-
`ticles and the skin. Because of
`the present
`difficulties
`in obtaining meaningful potentio—
`metric measurements, it does not seem possible
`to delineate accurately the effect of pH and
`ionic strength under practical use conditions.
`For any particular formula, it is relatively easy
`to determine particle deposition by a use test.
`The probable advantages of particle deposi-
`tion as a mechanism for the retention of an
`
`active ingredient on the skin are:
`(1) A relatively large amount of the active
`ingredient can be deposited. However, a very
`heavy deposition cannot be detected by users
`of the formulas because the particles are only
`a few microns in size.
`
`(2) Prolonged effects from a single washing
`can be obtained. The deposited particles act
`as a reservoir, and if they are not excessively
`soluble in the skin secretions, dissolve slowly
`and thereby exert their effect for long periods.
`While antimicrobial agents were used in this
`investigation,
`the particle deposition method
`should be broadly applicable as a method of
`
`depositing other types of active ingredients on
`the skin from detergent bases.
`SUMMARY
`
`The principle of deposition of particulate
`matter was used to achieve selective deposi—
`tion of
`relatively insoluble fine particles of
`antimicrobial agents on the skin while at
`the
`same time soil was being removed from the
`skin
`by
`detersive
`action. When
`detergent
`suspensions of antimicrobial agents were used
`as shampoos, particles of some of
`the anti-
`microbial agents deposited heavily upon the
`scalp. The amount of deposition varied with the
`individual antimicrobial agents and the deter-
`gent employed. The particles adhered tena-
`ciously to the skin and were not removed by
`intensive
`rinsing. They seemed to
`dissolve
`slowly in the skin secretions. It seems therefore
`possible that this mechanism can provide pro-
`longed
`antimicrobial
`action
`from a
`single
`washing.
`
`REFERENCES
`1. Fahlberg, W. J., Swan, J. C. and Seastone,
`C. V.: Studies 011
`the retention of hexa-
`chlorophene (G-ll) in human skin. J. Bact.,
`56: 323,1948.
`2. Schwartz, Anthony M., Perry, James W. and
`Berch, Julian: Surface active agents and de-
`tergents. Vol. 2., New York, Interscience Pub-
`lishers, Inc., 1958.
`3. Stillo, H. S. and Kolat, R. E.: The mode of
`operation of antiredeposition agents in de-
`tergent solutions. Textile Research Journal,
`27: 949,1957.
`4. Schwartz, Anthony M.: The zeta potential and
`its application in cosmetic science. Proc. Sci.
`Sect., Toilet Goods Assoc, No. 39, 16, 1963.
`5. Blank, Irvin H. and Coolidge, Mary H.: De-
`germing the cutaneous surface. I. Quaternary
`ammonium compounds. J. Invest. Derm., 15:
`249, 1950.
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