The Effect of Methylsulfonylmethane on Hair Growth Promotion of Magnesium Ascorbyl Phosphate for the Treatment of Alopecia

Home , Methylsulfonylmethane

Biomolecules & Therapeutics, 17(3), 241-248 (2009) ISSN: 1976-9148(print)/2005-4483(online) www.biomolther.org DOI: 10.4062/biomolther.2009.17.3.241

Srinivasan SHANMUGAM, Rengarajan BASKARAN, Santhoshkumar NAGAYYA-SRIRAMAN, Chul-Soon YONG, Han-Gon CHOI, Jong Soo WOO, and Bong-Kyu YOO* College of Pharmacy, Yeungnam University, Kyungsan 712-749, Republic of Korea

(Received April 10, 2009; Revised May 16, 2009; Accepted May 23, 2009)

Abstract － The purpose of this study was to evaluate the effect of methylsulfonylmethane (MSM) on hair growth promotion of magnesium ascorbyl phosphate (MAP) for the treatment of alopecia. Aqueous solutions of MAP 7.5% with or without MSM 1%, 5% or 10% were prepared and applied onto the depilated back skin of the male mice once a day for 20 days. The degree of hair growth was evaluated by visual scoring using hair growth quantification scale (0-5, 0 being initial state and 5 being complete hair growth). In vitro transdermal penetration and intradermal retention studies of MAP were performed with Franz diffusion cell using hairless mice skin. Hair growth in the group treated with the aqueous solution containing MAP 7.5% and MSM 10% was comparable to or better than the result in the group treated with minoxidil 5% solution. Hair growth promotion of MAP was dose-dependently increased by the presence of MSM used in combination with MAP 7.5% solution. The in vitro transdermal penetration of the MAP was decreased in proportion to the concentration of MSM. However, intradermal retention of MAP was profoundly and dose-proportionally increased as a function of MSM concentration, reaching 802 μg/cm2 in the presence of MSM 10% (200-fold increase). The effect of MSM on hair growth promotion of MAP was dose-proportional to the concentration of MSM due to the enhanced intradermal retention of MAP in the presence of MSM. Therefore, topical application of MAP together with MSM appears to be useful for the treatment of alopecia. Keywords: Magnesium ascorbyl phosphate, Methylsulfonylmethane, Alopecia, Hair growth, Skin permeation/accumulation, Permeation enhancer

INTRODUCTION promotion in the treatment of alopecia. However, because of its hydrophilicity MAP has lower ability to penetrate the Magnesium ascorbyl phosphate (MAP) (Fig. 1A), a sta- skin barrier stratum corneum to produce its therapeutic ef- ble phosphate derivative of L-ascorbic acid has been re- fect (Spiclin et al., 2002; Yoo et al., 2008). ported to stimulate growth of dermal papilla cells in vitro (Hata and Senoo, 1989; Takamizawa et al., 2004) and in- duce early conversion of telogen phase to anagen phase of hair cycle in experiment with mice (Sung et al., 2006). Furthermore, MAP treatment resulted in significant elongation of hair shafts in isolated hair follicles. Mechanism re- sponsible for the growth stimulation of dermal papilla cells and elongation of hair shafts has been suggested that MAP induces proliferative and anti-apoptotic effects on dermal papilla cells (Sung et al., 2006). This finding pro- vided a potential that MAP might be useful for hair growth

*Corresponding author Fig. 1. The chemical structures of magnesium ascorbyl pho- Tel: +82-53-810-2822 Fax: +82-53-810-4654 sphate (MAP) and methylsulfonylmethane (MSM). (A) Magnes- E-mail: [email protected] ium ascorbyl phosphate (MAP). (B) Methylsulfonylmethane (MSM). 242 Srinivasan Shanmugam et al.

In transdermal drug delivery arena, several approaches enhancing potential among many other permeation have been employed to lessen the barrier function of the enhancer. stratum corneum for enhanced penetration of drug of In this study, we have hypothesized that hair growth pro- choice, and one popular approach has been the use of motion effect of MAP can be improved by co-application trandermal permeation enhancers (Godwin and Michniak, with MSM because of its skin permeation enhancing effect. 1999; Asbill and Michniak, 2000). These are chemical The purpose of this study was (1) to evaluate in vivo hair compounds that reversibly alter the barrier function of the growth promotion effect of MAP (in the absence and pres- skin and enhance penetration. Among various classes of ence of MSM) using alopecia model of C57BL/6N mice permeation enhancers, those that enhance local skin-drug and (2) to substantiate the in vivo result with transdermal concentrations (intradermal) and do not produce sig- penetration and intradermal retention of MAP in vitro. nificant transdermal enhancement (across the skin) are considered ideal permeation enhancers for topical delivery MATERIALS AND METHODS (Asbill and Michniak, 2000; Im et al., 2008). Myriad of researchers reported the possible mechanisms and uses of Materials various penetration enhancers. However, despite major in- Magnesium ascorbyl phosphate, methylsulfonylmethane, terest in this research arena, very few penetration en- and methyl paraben were obtained from Wako Pure hancers have been made commercially available because Chemical Industries (Osaka, Japan). Thioglycolic acid of the limitations on selection based on their efficacy, lack 80% cream (Niclean CreamⓇ, Ildong Pharmaceutical Inc., of toxicity, and compatibility with other components of the Korea) and minoxidil 5% solution (Minoxyl SolutionⓇ, transdermal system (Skelly et al., 1987). One of the ear- Hyundai Pharmaceutical Inc., Korea) were purchased from liest and widely investigated penetration enhancers is a local pharmacy. Sodium phosphate monobasic mono- DMSO (Williams and Barry, 1992). hydrate and sodium phosphate dibasic heptahydrate were Methylsulfonylmethane (MSM), also known as dimethyl purchased from Sigma-Aldrich, Inc., (St. Louis, USA). sulfone or methyl sulfone (Fig. 1B), is an organic sul- Metaphosporic acid and trichloroacetic acid were pur- fur-containing compound that occurs naturally in a variety chased from Junsei Chemical Company Ltd., (Tokyo, of plants and animals including humans (Pearson et al., Japan). Methanol used was HPLC grade and all other 1981; Usha and Naidu, 2004; Ameye and Chee, 2006). chemicals were of analytical grade and used without fur- MSM is a normal oxidative metabolite product of dime- ther purification. thylsulfoxide (DMSO) and has been widely used as a diet- ary supplement for the treatment of several indications Preparation of MAP solutions such as osteoarthritis, seasonal allergic rhinitis, interstitial MAP (7.5 g) was accurately weighed and dissolved into cystitis, and snoring (Childs, 1994; Barrager et al., 2002; 100 ml distilled water. Aliquots of this solution (10 ml) were Blum and Blum, 2004; Kim et al., 2006). Like DMSO, MSM taken and added with 100, 500, or 1,000 mg of MSM to is an aprotic solvent that can dissolve wide range of sol- make 1%, 5%, or 10% MSM in the MAP 7.5% solution. The utes and is miscible with many solvents, and therefore resultant aqueous solutions of MAP 7.5% alone or with could be easily incorporated into pharmaceutical for- MSM 1%, 5% or 10% were thoroughly mixed with mag- mulations (Clark et al., 2008). netic bar and used for in vitro or in vivo studies thereafter. It is well known that much of the unique properties of Compositions of aqueous solution of MAP containing vari- DMSO are related to its characteristic polar O-S bond, ous concentrations of MSM are shown in Table I. which enables the compound to interact strongly with water by forming hydrogen bonds. This interaction with water is thought to be one of the key elements in the mechanism Table I. Compositions of aqueous solution of MAP containing of action of DMSO as a penetration enhancer (Franz et al., various concentrations of MSM 1995). Due to the structural similarity with DMSO, MSM is MAP MSM Solvent expected to act as a skin permeation enhancer for various MAP 7.5% only 7.5% - Distilled water medications by similar mechanisms (Engelen and Engelen, MAP-MSM 1% 7.5% 1% Distilled water 2002). Structural similarity coupled with non-toxicity and MAP-MSM 5% 7.5% 5% Distilled water MAP-MSM 10% 7.5% 10% Distilled water safety (GRAS Notice Number: GRN 229) as an oral nutri- MAP: magnesium ascorbyl phosphate, MSM: methylsulfonylme- tional additive as well as unavailability of prior work, put thane, MAP-MSM: MAP 7.5% in the presence of designated forth MSM a rightful candidate to explore its permeation concentration of MSM. Hair Growth Promotion of Magnesium Ascorbyl Phosphate 243

HPLC analysis The concentration of MAP in transdermal penetration and intradermal retention studies, was assayed by HPLC system (Shimadzu, Japan) equipped with Class VP com- puter software, LC 10 AD VP pump, and SPD 10A UV-VIS detector at 240 nm using methyl paraben as internal standard. Column used was Inertsil CN-3 (4.6×250 mm, GL Science Inc, Japan) and mobile phase consisted of a mixture of 0.02 M phosphate buffer and methanol (60:40, v/v) adjusted to pH 2.3 with phosphoric acid. Flow rate was 0.8 ml/min and the injection volume of the sample was 20 μl. Fig. 2. Hair growth quantification scale. 0: initial state, 1: grey to The validation of the HPLC assay was performed by re- black coloration, 2: short visible hair, 3: sparse long hair, 4: dense long hair, 5: complete hair growth. peating five times a day for five consecutive days for MAP concentration range of 50 ng/ml-100 μg/ml. ported by Chen and his colleagues (0: initial state, 1: grey Animals to black coloration, 2: short visible hair, 3: sparse long hair, Animals care and procedures were conducted accord- 4: dense long hair, 5: complete hair growth) (Fig. 2) (Chen ing to the guidelines for animal use in toxicology (Society of et al., 2005). Photographs of all mice in this study were tak- Toxicology USP 1989) and the study protocol was ap- en every five days for 20 days. proved by the Animal Care and Use Committee, College of Pharmacy, Yeungnam University. Six-week-old male mice Transdermal penetration and intradermal retention (C57BL/6N) and six-week-old male hairless mice were ob- studies tained from Orient Bio (Seoul, Korea) and housed in Hairless mice were sacrificed and full-thickness skin groups not exceeding six per cage and maintained under was taken, followed by removal of subcutaneous fat. standard conditions. The acclimation period was two Approximately 3 cm2 of the trimmed skin was placed into weeks before the experimental procedure with a dark/light Franz diffusion cell with effective diffusion area of 2.27 cycle of 12 h/12 h at the temperature of 23 ± 2oC. Food and cm2. For transdermal penetration study, freshly prepared tap water were available ad libitum during the acclimation aqueous solution (0.4 ml) of MAP 7.5% alone or with MSM period. 1%, 5% or 10% was applied on the skin and allowed to spread over the skin. Donor compartment (epidermal layer Evaluation of hair growth promotion using alopecia of the skin) remained unoccluded, but covered with a lid, model in mice and the receptor compartment (dermal layer of the skin) The hair on the back of male C57BL/6N mice was re- was perfused with distilled water maintaining temperature moved by electric clipper and depilated using thioglycolic at 37oC. Serial sampling of the receptor compartment was acid 80% cream (Niclean creamⓇ, Ildong Pharmaceutical performed at predetermined intervals (1.5, 3, 6, 9, and 12 Inc., Korea) one day before applying the samples. About h). Cumulative amount of MAP penetrated through the skin 0.5 g of the cream was applied on the hair-clipped back of was plotted as a function of time. The flux of MAP was cal- the mice and allowed for 2 min. The cream and hair were culated by the slope of the linear portion of the curve, wiped off using cotton for depilation, and the back skin was which was achieved in 6 h. rinsed with plenty of distilled water to remove remaining For intradermal retention study, the effective diffusion thioglycolic acid. The mice without significant wound on the area of the mounted skin was cut off after transdermal pen- back were selected, randomly grouped, and used for hair etration study and washed with distilled water, and stored growth study. Freshly prepared aqueous solution (0.2 ml) in the deep-freezer until HPLC determination. For analysis, of MAP 7.5% alone or with MSM 1%, 5% or 10% was ap- the skin was homogenized with isotonic phosphate buffer plied onto the depilated back of the mice (n=5) and allowed (pH 7.4) for 10 min in an ice bath. To 0.45 ml of the skin ho- to dry. The sample application was done once a day for mogenate, 0.05 ml of internal standard (100 μg/ml) sol- twenty days. Saline solution (0.9%) and MinoxylⓇ (minoxidil ution and 0.5 ml of extraction solvent (10% metaphos- 5% solution) were also used as negative and positive con- phoric acid:20% trichloroacetic acid:distilled water=2:4:4) trol, respectively. The degree of hair growth was evaluated were added, and was subjected to sonication for 10 min by visual scoring of hair growth quantification scale as re- and centrifugation at 16,000 g for 3 min. The clear super- 244 Srinivasan Shanmugam et al.

Fig. 4. Hair growth quantification score after application of MAP Fig. 3. Hair growth quantification score after application of MAP 7.5% with or without MSM in alopecia model of C57BL/6N mice in alopecia model of C57BL/6N mice (n=5). MAP: magnesium (n=5). MAP: magnesium ascorbyl phosphate, MSM: methylsul- ascorbyl phosphate, * and ** represent p＜0.05 and ＜0.01 com- fonylmethane, MAP-MSM: MAP 7.5% in the presence of desig- pared to negative control, respectively. nated concentration of MSM, * and ** represent p＜0.05 and ＜0.01 compared to MAP 7.5% only, respectively. natant thus obtained was then analyzed for MAP by HPLC utilizing the method described in HPLC assay section. hair growth quantification score compared to 1.92 ± 0.33 in the group treated with MAP 7.5% solution without MSM. Data analysis After 20 days of treatment, hair growth status in the group All the data obtained were analyzed using SPSS 12.0 treated with MAP 7.5% solution with MSM 5% or 10% was for Windows and a significance level of p＜0.05 was used “complete hair growth”, while it was still in the level of to indicate the statistically significant difference between “dense long hair” in the group treated with MAP 7.5% sol- data sets. ution without MSM (p＜0.01). Furthermore, hair growth rate in the mice treated with MAP 7.5% solution with MSM RESULTS 10% was better than or similar to the mice treated with minoxidil 5% solution. Photographs for hair growth status Aqueous solution (0.2 ml) of MAP was investigated for in all groups tested are shown in Fig. 5. the ability to promote hair growth in the alopecia model of Cumulative amount of MAP penetrated through the hair- C57BL/6N mice. There was no significant difference be- less mice skin during 12 h was 3.89 ± 0.41, 2.23 ± 0.39, tween the MAP-treated groups and control group up to 10th and 1.80 ± 0.24 μg/cm2 in the presence of MSM 1%, 5%, day (Fig. 3). However, in 15th day, hair growth quantifica- and 10%, respectively, while it was 4.17 ± 0.46 μg/cm2 in tion score in the mice treated with MAP 7.5% or above was the absence of MSM (Fig. 6). Lag time for transdermal significantly enhanced compared to control group (p penetration of MAP was about 1.5 h, and MAP was de- ＜0.05), and the hair growth status of the mice was “dense tected in the receptor compartment of the Franz diffusion long hair” in 20th day. MAP 5% also showed hair growth cell after 3 h. When MAP was applied as 7.5% solution with promotion compared to control group in 20th day (p＜0.05), 5% or 10% MSM, transdermal penetration of MAP was only but hair growth status of the mice was in the level of 53.5% and 43.2% of the amount penetrated in the absence “sparse long hair”. Hair growth status in the group treated of MSM, respectively (p＜0.01). Average flux of MAP calcu- with MAP 2.5% was not different from control group even lated by the slope of the linear portion of each curve was − in 20th day. 0.08080 ± .04, 0.0359 ± 0.01, and 0.0313 ± 0.02 μg×cm 2/h The effect of MSM on the hair growth promotion of MAP in the presence of MSM 1%, 5%, and 10%, respectively, − 7.5% solution was investigated in the presence of MSM while it was 0.2205 ± 0.02 μg×cm 2/h in the absence of 1%, 5% or 10% (Fig. 4). MSM 1% did not result in sig- MSM (Table II). The flux of MAP in the presence of MSM nificant additive effect even after 20 days. However, MSM 5% or above was less than one fifth of the flux in the ab- 10% demonstrated statistically significant additive effect sence of MSM. as early as in 10th day (p＜0.05), showing 2.50 ± 0.33 of The amount of MAP remaining in the skin (intradermal Hair Growth Promotion of Magnesium Ascorbyl Phosphate 245

Fig. 5. Photographs of hair growth status during treatment with MAP in the absence or presence of MSM. MAP: magnesium ascorbyl phosphate, MSM: methylsulfonylmethane, MAP-MSM: MAP 7.5% in the presence of designated concentration of MSM, NC: negative control (0.9% saline solution), PC: positive control (minoxidil 5% solution). retention) after 12 h of transdermal penetration study was nally the resting phase (telogen) that lasts for five to 12 10.5 ± 12.1, 62.0 ± 34.6, and 801.7 ± 156.0 μg/cm2 in the weeks (Ellis et al., 2002). MAP was reported to enhance presence of MSM 1%, 5%, and 10%, respectively. It was the hair growth through anagen induction, which is consid- only 4.2 ± 5.9 μg/cm2 when MAP was applied without MSM ered one of the most effective strategies for treating hair (Fig. 7). Intradermal retention of MAP was exponentially in- loss (Paus, 2006). creased in the presence of MSM, reaching about 200-fold As a preliminary study, we investigated hair growth pro- when MAP was applied with MSM 10%. motion effect of MAP in alopecia model using black-haired mice (C57BL/6N). Concentrations of MAP tested in this DISCUSSION study were 2.5%, 5%, 7.5%, and 10%, because previous researchers reported that MAP induced early conversion Hair growth in animals periodically undergoes a con- from telogen phase to anagen phase of hair growth cycle tinuous hair cycle, during which the hair follicle switches at 250 mM concentration, which is equivalent to about between phases of growth and regression (Paus, 2006). 7.25% of MAP (Sung et al., 2006). Hair growth quantifica- During the hair cycle, the growth phase (anagen) lasts for tion score in the groups treated with MAP was in proportion two to seven years followed by transition and involution to the concentration of MAP up to 7.5% and plateaued phase (catagen), which lasts for one to two weeks, and fi- above this concentration. This result is consistent with the 246 Srinivasan Shanmugam et al.

Table II. Average flux of MAP in the skin penetration study (n=6) MAP 7.5% only MAP-MSM 1% MAP-MSM 5% MAP-MSM 10% Average flux (μg×cm−2/h) 0.2205 ± 0.02 0.0808 ± 0.04a 0.0359 ± 0.01a 0.0313 ± 0.02a MAP: magnesium ascorbyl phosphate, MSM: methylsulfonylemethane, MAP-MSM: MAP 7.5% in the presence of designated concentration of MSM, ap＜0.01 compared to MAP 7.5% only.

Fig. 7. Amount of MAP accumulated in hairless mice skin (n=5). MAP: magnesium ascorbyl phosphate, MSM: methylsulfonyl- Fig. 6. Amount of MAP penetrated through hairless mice skin (n=5). MAP: magnesium ascorbyl phosphate, MSM: methylsul- methane, MAP-MSM: MAP 7.5% in the presence of designated ＜＜ fonylmethane, MAP-MSM: MAP 7.5% in the presence of de- concentration of MSM, ** and *** represent p 0.01 and 0.001 signated concentration of MSM, * and ** represent p＜0.05 and compared to MAP 7.5% only, respectively. ＜0.01 compared to MAP 7.5% only, respectively. growth with increasing MSM concentration implied sig- previous researchers’ finding that MAP promotes hair nificant role of MSM as a penetration enhancer, which growth (Sung et al., 2006). could have exerted its additive effect on the hair growth of Hair growth status in the group treated with combination MAP 7.5% solution by enhancing transdermal delivery of of MAP 7.5% solution and MSM 5% or 10% was sig- MAP to hair follicles in the dermis layer of the skin. nificantly better than the result found in the group treated In the present study, based on the speculation above with MAP 7.5% solution only (p＜0.01). Notably, hair growth (enhanced transdermal delivery of MAP with the aid of in the group treated with MAP 7.5% solution and MSM MSM), we performed transdermal penetration study of 10% showed better than or similar to the group treated with MAP 7.5% solution in the presence of MSM (1, 5, and minoxidil 5% solution (positive control), which is consid- 10%) using Franz diffusion cell. We expected that trans- ered a standard topical therapy for the treatment of dermal penetration of MAP would be significantly in- alopecia. Also remarkably, the hair growth status was in creased in the presence of MSM, because MSM is struc- proportion to the concentration of MSM, suggesting that turally very similar to dimethyl sulfoxide, a very strong skin MSM played a role as a hair growth promotion agent. Due permeation enhancer (van Engelen and van Engelen, to its high sulfur content, MSM has been believed to nour- 2002). Unexpectedly, in this experiment, the transdermal ish skin, hair, and finger nails (Richmond, 1986). So, we penetration of MAP was significantly decreased when performed a preliminary experiment to see if MSM itself MAP was applied with MSM concentrations of 5% or has hair growth promotion effect in the concentration above (Fig. 5) compared to control. This unexpected result range of 1-10% using mice alopecia model. The experi- led us take into consideration that transdermal permeation ment, however, did not show any hair growth promotion ef- enhancers might be subdivided into several classes. In fect of MSM in the concentration range tested. These find- fact, Asbill and his colleagues have categorized the en- ings ruled out the probable hair growth ability of MSM and hancers into those that enhance transdermal penetration demonstrated that the observed hair growth promotion in across the skin, those enhance intradermal retention into MAP and MSM treated mice was only due to MAP. the skin, and those enhance both (Asbill and Michniak, However, the dose-dependent enhancement in hair 2000). In fact, accumulation of drug within skin without sig- Hair Growth Promotion of Magnesium Ascorbyl Phosphate 247 nificant systemic appearance is the objective of any means mechanism by which MSM exerts its skin accumulation of topical delivery (Trommer and Neubert, 2006). enhancing effect. Accordingly, as an attempt to substantiate the possibility Despite the fact that the data reported do not directly re- of accumulation of MAP within the skin by MSM, we meas- veal mechanistic information on percutaneous penetration ured the amount of MAP remaining in the skin (intradermal and enhanced intradermal accumulation, they do provide a retention) after 12 h of transdermal penetration study. clear correlation of effect of MSM on the hair growth pro- Surprisingly, we found that the amount of MAP in the skin motion effect of MAP in vivo and substantial intradermal was profoundly and dose-proportionally increased as a accumulation of MAP in vitro, which was the primary ob- function of MSM concentration. The increase was almost jective of this study. Furthermore, this finding could be uti- about 200-fold in the presence of MSM 10%, compared to lized for optimization and exploitation of intradermal drug the result in the absence of MSM (Fig. 7). Though, the ex- delivery of MAP for the treatment of alopecia. act mechanism by which MSM enhances intradermal per- In conclusion, the results of the present study indicate meation of MAP is unclear now, MSM might have followed that topical application of magnesium ascorbyl phosphate the similar mechanism of DMSO due to the structural sim- (MAP) and methylsulfonylmethane (MSM) is effective in ilarity, principally with the possession of characteristic po- promoting hair growth in C57BL/6N mice in vivo. Authors, lar O-S bond, which enables the compound to interact first time to our knowledge report that, MSM could be used strongly with water by forming hydrogen bonds. The hydro- as a penetration enhancer that augments hair growth pro- gen-bonding ability of a substance is a major determinant motion of MAP in vivo through higher dermal accumulation of penetration. Therefore, the hydrogen-bonding groups of of MAP demonstrated by in vitro skin study. The pene- the enhancers could indeed modify the penetration tration enhancing effect of MSM was found to be dose-de- (Abraham et al., 1995; Potts and Guy, 1995). Although pendent, both in vivo and in vitro. Overall, topical applica- DMSO is considered a strong permeation enhancer, its tion of MAP together with MSM appears to be useful for the permeation enhancing effect is dose-dependent and in treatment of alopecia. general, more than 60% DMSO is needed for optimal permeation enhancing effect. Nevertheless, at such high con- ACKNOWLEDGMENTS centrations, DMSO is reported to cause erythema and wheals of the stratum corneum and may denature skin pro- This work was supported by Korea Research Foundation tein (Williams and Barry, 2003). Grant funded by the Korean Government (MOEHRD, Basic It is worth noting that MSM possesses two polar O-S Research Promotion Fund) (KRF-2007-314-E00246). groups (Fig. 1B) that could have efficiently bound to water of stratum corneum forming hydrogen bonds and aided REFERENCES penetration of the solutes. Probably, the same reason could be applicable for its penetration effectiveness even Abraham, M. H., Chadha, H. S. and Mitchell, R. C. (1995). The at low concentration of about 10% or less compared factors that influences skin penetration of solutes. J. Pharm. DMSO. It is possible that the high hydrogen bonding ability Pharmacol. 47, 8-16. of MSM might have perturbed the stratum corneum suffi- Ameye, L. G. and Chee, W. S. (2006). Osteoarthritis and ciently for the fast entry of MAP into the skin, while the low nutrition. From nutraceuticals to functional foods: a systematic review of the scientific evidence. Arthritis Res. 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