Comparison of four different fuller's earth formulations in skin decontamination.

Industrial accidents, wars and terrorist threats are potential sources of skin contamination by highly toxic chemical warfare agents and manufacturing compounds. We have compared the time-dependent adsorption capacity and decontamination efficiency of fuller's earth (FE) for four different formulations for the molecular tracer, 4-cyanophenol (4-CP), in vitro and ex vivo using water decontamination as standard. The adsorption capacity of FE was assessed in vitro for 4-CP aqueous solutions whereas decontamination efficiency was investigated ex vivo by tracking porcine skin 4-CP content using attenuated total reflectance Fourier transform infrared spectroscopy. Decontamination was performed on short time, exposed porcine skin to 4-CP by application of FE: (1) as free powder; (2) loaded on adhesive tape; (3) on powdered glove; or (4) in suspension. Removal rate of 4-CP from aqueous solutions correlates with the amount of FE and its contact time. Decontamination efficiency estimated by the percentage of 4-CP recovery from contaminated porcine skin, achieved 54% with water, ranged between ~60 and 70% with dry FE and reached ~90% with FE suspension. Successful decontamination of the FE suspension, enabling a dramatic reduction of skin contamination after a brief exposure scenario, appears to be rapid, reliable and should be formulated in a new device ready to use for self-application.

Microemulsion system for topical delivery of thai mango seed kernel extract: development, physicochemical characterisation and ex vivo skin permeation studies.

A microemulsion system containing Thai mango seed kernel extract (MSKE, cultivar "Fahlun") was developed and characterised for the purpose of topical skin delivery. The MSKE-loaded microemulsions were prepared by using the spontaneous emulsification method. Isopropyl myristate (IPM) was selected as the oil phase. A polyoxyethylene sorbitan monooleate and sorbitan monododecanoate (1:1, w/w) system was used as the surfactant phase; an aqueous mixture of different cosurfactants (absolute ethanol, 96.3% v/v ethanol, 1-propanol, 2-propanol or 1,2-propanediol) at a weight ratio of 1:1 was used as the aqueous phase. Among the cosurfactants studied, the 1-propanol aqueous mixture had the largest microemulsion region (48.93%) in the pseudo-ternary phase diagram. Microemulsions containing 1% MSKE demonstrated good physicochemical stability during a six-month study period at 25 ± 2 °C/60% ± 5% RH. The ex vivo skin permeation study demonstrated that the microemulsions exhibited a potent skin enhancement effect allowing MSKE to penetrate skin layers up to 60-fold higher compared with the control. Neither skin irritation nor skin corrosion was observed in ex vivo studies. The present study revealed that IPM-based microemulsion systems may be promising carriers to enhance skin penetration and delivering MSKE for topical treatment.

Chlorhexidine salt-loaded polyurethane orthodontic chains: in vitro release and antibacterial activity studies.

The widespread use of indwelling medical devices has enormously increased the interest in materials incorporating antibiotics and antimicrobial agents as a means to prevent dangerous device-related infections. Recently, chlorhexidine-loaded polyurethane has been proposed as a material suitable for the production of devices which are able to resist microbial contamination. The aim of the present study was to characterize the in vitro release of chlorhexidine from new polymeric orthodontic chains realized with polyurethane loaded with two different chlorhexidine salts: chlorhexidine diacetate or chlorhexidine digluconate. The orthodontic chains constituted of three layers: a middle polyurethane layer loaded with chlorhexidine salt inserted between two layers of unloaded polymer. In vitro release of chlorhexidine diacetate and digluconate from orthodontic chains loaded with 10% or 20% (w/w) chlorhexidine salt was sustained for 42 days and followed Fickian diffusion. The drug diffusion through the polyurethane was found to be dependent not only on chlorhexidine loading, but also on the type of chlorhexidine salt. The antibacterial activity of 0.2% (w/w) chlorhexidine diacetate-loaded orthodontic chain was successfully tested towards clinically isolated biofilm forming ica-positive Staphylococcus epidermidis via agar diffusion test. In conclusion, the chlorhexidine salt-loaded chains could provide an innovative approach in the prevention of oral infections related to the use of orthodontic devices.

Compartmentalization of the human stratum corneum by persistent tight junction-like structures.

Several tight junction (TJ) proteins were detected in the living layers of adult human epidermis, and TJ-like membrane ridges were observed at the top of the stratum granulosum (SG) in freeze-fracture studies. We applied standard and immunoelectron microscopy to look for TJ-derived structures in the stratum corneum (SC) of human adult epidermis and in cornified envelopes purified from the plantar SC. Besides confirming claudin-1 labelling in the proximity of SG desmosomes, we also observed immunolocalization near corneodesmosomes in the lower SC. In addition, TJ proteins were consistently detected in the purified cornified envelopes. Lateral but not horizontal walls of the corneocytes showed frequent points of molecular fusion between lipid envelopes. These structural associations were very frequently localized at the top of the lateral corneocyte membranes, thus sealing the extremities of lateral intercorneocyte spaces. We propose that TJ-like structures persist in the SC and contribute to the reinforcement of lateral contacts and to the formation of membrane interdigitations between corneocytes. Their presence could contribute to subdivision of the extracellular spaces of SC into consecutive individualized compartments. Intercellular lipids, enzymes and other (glyco)protein content could thus evolve in the keratinized epidermal layer at different paces, as preprogrammed in the underlying living cells and influenced by the environment, e.g. humidity. Such situation might explain differences in the degradation rates between the 'peripheral' and the 'non-peripheral' corneodesmosomes observed during physiological desquamation, as previously suggested by us and others.

Development and in vitro assay of oxidative stress modifying formulations for wound healing promotion.

Often presented as metabolism byproducts, reactive oxygen species are linked to detrimental effects such as chronic wound, mutagenesis, cancer and skin ageing. However, recent in vitro and in vivo observations suggest that ROS, and mainly hydrogen peroxide, interfere with cell signaling acting like second messenger and inducing adaptive responses. This is particularly observed in skin wound healing where cells are exposed to H2O2 following injury. In this study, we developed and characterized an innovative formulation producing H2O2 at low concentrations, in order to mimic physiological inflammation phase. Then, this pro-oxidative formulation (CAM-GOx) was assayed in vitro on keratinocytes cell culture, compared to the blank formulation (CAM) and the anti-oxidative formulation (CAM-CAT) to assess whether oxidative stress was implied or not in cellular responses.

Glycosylated liposomes against Helicobacter pylori: behavior in acidic conditions.

Helicobacter pylori was isolated in 1982 and confirmed as a gastric pathogenic agent at the end of the 1980s. The present work deals with liposomes formulations in which are incorporated cholesteryl tetraethylene glycol oside as model ligands for H. pylori adhesins. This study is devoted to the behavior of liposomes in gastric conditions. The glycosylated vesicles are stable and the pH of the internal aqueous compartment remains close to 4 even through more acidic conditions are imposed to the external phase (pH 1.2-2). Such a pH gradient depends essentially on the nature of phospholipids used and is not extensively affected by the incorporation of the targeting agent. These aspects are particularly important to the development of liposome formulations against H. pylori, bacteria sensitive to antibiotics which are unstable in very acidic conditions.

Temperature-sensitive microemulsion gel: an effective topical delivery system for simultaneous delivery of vitamins C and E.

Microemulsions (ME)--nanostructured systems composed of water, oil, and surfactants--have frequently been used in attempts to increase cutaneous drug delivery. The primary objective addressed in this work has been the development of temperature-sensitive microemulsion gel (called gel-like ME), as an effective and safe delivery system suitable for simultaneous topical application of a hydrophilic vitamin C and a lipophilic vitamin E. By changing water content of liquid o/w ME (o/w ME), a gel-like ME with temperature-sensitive rheological properties was formed. The temperature-driven changes in its microstructure were confirmed by rotational rheometry, viscosity measurements, and droplet size determination. The release studies have shown that the vitamins' release at skin temperature from gel-like ME were comparable to those from o/w ME and were much faster and more complete than from o/w ME conventionally thickened with polymer (o/w ME carbomer). According to effectiveness in skin delivery of both vitamins, o/w ME was found the most appropriate, followed by gel-like ME and by o/w ME carbomer, indicating that no simple correlation between vitamins release and skin absorption could be found. The cytotoxicity studies revealed good cell viability after exposure to ME and confirmed all tested microemulsions as nonirritant.

Effects of physical and chemical treatments upon biophysical properties and micro-relief of human skin.

The aim of the present study was to determine the attendant effects of physical (tape-stripping) and chemical (three commercial hydrating formulations) treatments upon biophysical and micro-relief properties of human skin. In the first set of experiment, the effects of tape-stripping onto human stratum corneum (SC) biophysical and micro-relief properties were assessed in nine volunteers. Transepidermal water loss (TEWL), skin hydration and micro-relief parameters (including total length of the lines in mm per mm(2); total surface in %; roughness of the skin measured in gray level (Ra); maximum profile valley (Rv) depth; maximum profile peak height (Rp); maximum height (Rt), peak density (Pc) and coefficient of anisotropy) were determined by using SkinEvidence Pro after subsequent tape-stripping of SC. The relevance of roughness determination as gray level by SkinEvidence Pro was confirmed by using surface roughness standards. In the second set of experiment, the effectiveness of three commercial hydrating formulations onto human SC biophysical parameters and micro-relief properties were assessed in six volunteers. TEWL, hydration and micro-relief parameters were assessed onto pre-treated acetone skin and then treated by three commercial hydrating formulations after 2, 4 and 6 h skin exposure. A linear relation between hydration and cutaneous parameters (total length of the lines, Ra and Rp) as function of SC removed was shown. Skin barrier properties evaluated by TEWL measurements, were not modified by topical formulations. However, skin treated by topical formulations showed slightly higher hydration than the one determined in control group, while micro-relief parameters were not modified. In this study was showed that biophysical and micro-relief parameters were closely related in tape-stripping experiment. Efficiency of topical formulations was suggested upon skin hydration but not onto skin micro-relief and barrier function recovering. From both experiments, it appears that different mechanisms relating to skin hydration and potential modification of cutaneous micro-relief were suggested.

Pre-formulation of liposomes against Helicobacter pylori: characterization and interaction with the bacteria.

This paper deals with the formulation of targeted liposome against Helicobacter pylori. We describe the characterization of liposomes loaded with antimicrobial agents (ampicillin and metronidazole) and the quantification of the interactions between such formulations and bacteria. If the encapsulation rate of ampicillin seems not strongly affected by the change of phospholipidic composition, the encapsulation of metronidazole drastically decreased in epikuron 170 liposomes compared to DPPC ones. Furthermore, as observed with X-ray diffraction measurements, the presence of metronidazole results in the disorganisation of the phospholipid bilayers. Concerning the liposome-bacteria interactions, it has been observed that the incorporation of fucosyled glycolipids in the vesicle membrane leads to liposomes that are able to interact with the bacteria either in their spiral or in their coccoid forms. Since coccoid forms are occasionally found in vivo, their recognition by the liposomes we have formulated seems promising in the fight against Helicobacter pylori.

Study on the hydatid cyst membrane: permeation of model molecules and interactions with drug-loaded nanoparticles.

The success of the chemotherapeutic treatment of hydatid disease is based upon the drug ability to operate on the germinal layer and on the protoscolices of the hydatid cyst interior at adequate concentrations for sufficient periods. The goal of this study was to evaluate the ability of the drug diffusion through the cyst membrane from sheep hydatid cysts and the increase of drug concentration in the cyst environment. In the first part of this work, the permeation behaviour through the hydatid cyst membrane was studied with five model molecules, having different molecular descriptors (logP, molecular weight, polar surface area ...) onto static Franz glass diffusion cells. A good correlation has been observed between the permeation coefficient and the partition coefficient, log P (r=0.951). In the second part, albendazole-loaded nanoparticles (about 300 nm) prepared by the emulsion solvent evaporation method have shown a sufficient entrapment efficiency (36.4 +/- 6.4%) to raise the apparent solubility of albendazole. The diffusion of drug from the nanoparticles across the hydatid cyst membrane was also improved compare to albendazole suspension. These results have shown the interest of the albendazole-loaded nanoparticles for the treatment of hydatid cysts in the future.

Qualitative and quantitative comparison of heat separated epidermis and dermatomed skin in percutaneous absorption studies.

Transepidermal water loss (TEWL), mainly regulated by the stratum corneum, was quantitatively correlated to percutaneous absorption of compounds in human and suggested for the ex vivo assessment of skin integrity. The present study investigated qualitatively and quantitatively the relevance of 100-microm heat separated epidermis (HSE) in percutaneous absorption studies as compared to 500-microm dermatomed skin by dual complementary approaches. Percutaneous absorption of caffeine delivered from aqueous solution through dermatomed skin or HSE specimens (n = 9) was measured using vertical static diffusion cells coupled with an unventilated evaporimeter enabling the assessment of TEWL and skin integrity for 21 h. Permeation of caffeine exhibited different finite dose-like profiles ranged according to the thickness of skin specimens (cumulative dose absorbed up to 21 h: 11.5 +/- 11.5 microg/cm(2) and 29.4 +/- 36.2 microg/cm(2) through dermatomed skin and HSE, respectively). Normalized TEWL and caffeine fluxes were similar through dermatomed skin and HSE suggesting that the intrinsic permeability properties of both models were undifferentiated over time. Interestingly, a significant relationship was shown between TEWL and caffeine fluxes, suggesting the usefulness of TEWL measurement as an element in the estimation of percutaneous drug absorption. In conclusion, the present showed that percutaneous absorption through HSE was qualitatively and quantitatively similar to dermatomed skin when TEWL as endogenous standard and skin thickness were considered in permeability data comparisons.

Liposomes and niosomes as potential carriers for dermal delivery of minoxidil.

The aim of this work was to formulate minoxidil loaded liposome and niosome formulations to improve skin drug delivery. Multilamellar liposomes were prepared using soy phosphatidylcholine at different purity degrees (Phospholipon 90, 90% purity, soy lecithin (SL), 75% purity) and cholesterol (Chol), whereas niosomes were made with two different commercial mixtures of alkylpolyglucoside (APG) surfactants (Oramix NS10, Oramix CG110), Chol and dicetylphosphate. Minoxidil skin penetration and permeation experiments were performed in vitro using vertical diffusion Franz cells and human skin treated with either drug vesicular systems or propylene glycol-water-ethanol solution (control). Penetration of minoxidil in epidermal and dermal layers was greater with liposomes than with niosomal formulations and the control solution. These differences might be attributed to the smaller size and the greater potential targeting to skin and skin appendages of liposomal carriers, which enhanced globally the skin drug delivery. The greatest skin accumulation was always obtained with non-dialysed vesicular formulations. No permeation of minoxidil through the whole skin thickness was detected in the present study irrespective of the existence of hair follicles. Alcohol-free liposomal formulations would constitute a promising approach for the topical delivery of minoxidil in hair loss treatment.

Bioadhesive film for dermal and transdermal drug delivery.

This paper describes an innovative transdermal drug delivery system, a monolaminated bioadhesive film in which the usual constituents of transdermal patches (backing, drug and adhesive) have been condensed in one single layer, denominated Patch-non-Patch. The main characteristics of the film is that it is not self-adhesive in the dry state but becomes adhesive only when applied on wet skin. This characteristic is due to the presence of a small amount of adhesive, unable to make the system self-adhesive, but capable of restoring the adhesiveness in contact with a small amount of water. From the results obtained to date, it appears that the technology Patch-non-Patch has the potentiality to be successfully applied to the pharmaceutical and cosmetic market. On the skin the film is flexible, invisible and adapts to all skin irregularities. The system has been shown to be highly efficient, releasing a high percentage of the active included in most cases. Additionally, the inclusion of other excipients can modulate drug delivery, thus improving the versatility of the product. Finally, the second generation Patch-non-Patch, made occlusive on the skin surface, can further broaden the potential application.

Sustained antibacterial effect of a hand rub gel incorporating chlorhexdine-loaded nanocapsules (Nanochlorex).

In the present study, an original chlorhexidine-loaded nanocapsule-based gel (Nanochlorex) was tested as hand rub gel against the resident skin flora in comparison with 2-propanol 60% (v/v) and 62% (v/v) ethanol-based gel (Purell). After 30-s hand rub, the immediate bactericidal effect of Nanochlorex was found comparable to 2-propanol 60% (v/v) (reduction factor, RF: 0.30+/-0.35 versus 0.38+/-0.55, P>0.05) against aerobic bacteria, whereas the post-values of surviving anaerobes were shown significantly lower from Nanochlorex (P<0.001) and insignificant from 2-propanol 60% (v/v) (P>0.05). Sustained antibacterial effect of Nanochlorex was confirmed against the resident and transient hand flora in two sets of experiment. In the first, the results obtained with the glove-juice technique showed that the bactericidal effect induced by Nanochlorex hand rub persisted throughout 3-h period, while Purell failed to reduce significantly the post-values of surviving bacteria. In the second, repeated artificial contaminations with Staphylococcus epidermidis was carried out onto ex vivo human skin pre-treated by either Nanochlorex or Purell for 5min, then maintained in cell diffusion apparatus for 4h. The log(10) reduction of surviving bacteria was significantly higher with Nanochlorex than that determined with Purell after three successive contaminations (from approximately 5.5 to 1.5 log(10) reduction for Nanochlorex between the first and the third contamination; approximately 1log(10) reduction for Purell throughout the experiment), confirming the sustained antibacterial effect of chlorhexidine-loaded nanocapsule-based gel. The immediate and sustained antibacterial effect of Nanochlorex was explained by chlorhexidine carrier system which improved the drug targeting to bacteria and reduced from osmotic gel further bacterial growth on the skin. Nanochlorex) might constitute a promising approach for hygienic hand disinfection in care practice performing multiple procedures.

Current and new strategies for the delivery of antiseptic agents.

The present mini-review explores the current methods used for the delivery of antiseptics and topical antimicrobials. Relevance of hand scrub with antiseptic liquid soap (e.g. chlorhexidine, PVP-iodine, triclosan) and alcohol-based hand rub is discussed and compared in terms of bactericidal activity, skin tolerance, and medical staff observance. New strategies for antibacterial delivery focus on the challenge of colloidal drug carrier such as liposomes, micro- and nanoparticles enabling sustained bactericidal effect and effective bacterial targeting.

The influence of microemulsion structure on their skin irritation and phototoxicity potential.

The purpose of this study was to examine skin irritation and phototoxicity potentials of several microemulsions (ME), all comprising approximately the same percentage of surfactant mixture, but varying oil/water content and consequently inner structure being either droplet-like (o/w ME, o/w ME carbomer, w/o ME and w/o ME white wax) or lamellar (gel-like ME). Two different in vitro methods were used: MTT assay (performed either on reconstructed human epidermis (RHE) or NCTC 2544 cells) and pig ear test. Neither assay revealed the difference among ME with droplet-like structure. Then again, pig ear test and MTT assay performed on RHE indicated that gel-like ME is more irritant compared to other tested ME, whereas no difference among formulations were observed by MTT assay on NCTC 2544 cells. The reasonable explanation is destruction and consequently uniform structure of ME upon dilution that is inevitable for testing on cell cultures. The results of phototoxicity test again indicated the increased potential of gel-like ME to cause adverse effects on skin. It can be concluded that for ME consisting of the same amount of identical surfactants but having different structure the latter represent a crucial factor that determines their dermal toxicity.

Evaluation of pig esophageal mucosa as a permeability barrier model for buccal tissue.

Porcine buccal mucosa is frequently used for in vitro drug absorption studies as its structure and permeability characteristics are close to those of human tissue. However, this tissue model suffers from practical disadvantages, including a limited surface area, damage caused by mastication, and a fastidious and time-consuming excision procedure. It has been hypothesized that such limitations may be overcome by replacing the buccal tissue with the pig esophageal mucosa. The latter has a very similar structure and is easier to separate from the underlying tissue; furthermore, its surface area is greater and is generally intact. The aims of this work, therefore, were (i) to perform histological studies on the two membranes; (ii) to compare the transport of fentanyl citrate across buccal and esophageal mucosae; and (iii) to evaluate the effects of freezing on the tissue permeability. The results show that their histology is comparable, that the permeability of fentanyl citrate across the two epithelial barriers is similar, and that freezing the tissues did not alter their permeability.

Comparison of the lipid composition of porcine buccal and esophageal permeability barriers.

Pig esophageal mucosa has been shown to be a useful and practical substitute for buccal mucosa in in vitro permeability studies in that it offers a larger surface area and it is much easier to prepare. Further, the tissues demonstrate similar histological characteristics. The objectives of this work were to characterize the lipid composition of the esophageal mucosa, to compare it to that of the buccal tissue, and to correlate lipid composition with the membranes' permeability to fentanyl. The major lipid classes of buccal and esophageal epithelia were separated and analysed by automated multiple development high-performance thin-layer chromatography (AMD-HPTLC). The two epithelia presented a very similar lipid pattern. In general, there were more polar lipids than non-polar; glycosylceramides were relatively abundant whereas the amount of ceramides present was very small. The flux of fentanyl applied as the citrate in aqueous solution was comparable across the buccal and esophageal barriers. Lipid extraction provoked a significant increase in permeability. In conclusion, this research confirms the suitability of the esophageal mucosa as a model for buccal permeability studies.

Oxidative stress-independent depletion of epidermal vitamin A by UVA.

In hairless mice, epidermal vitamin A (retinol and retinyl esters) is strongly decreased following a single exposure to UVB. Here, using the same mouse model, we studied the effects of UVA on epidermal vitamin A content, lipid peroxidation, and CRBP-I expression, as well as the putative prevention of vitamin A depletion or lipid peroxidation by topical alpha-tocopherol. An acute exposure to UVA completely depleted epidermal vitamin A with EC50 of 0.25 and 0.5 J per cm2 for retinyl esters and retinol, respectively; these values were 0.1 J per cm2 for both retinoids under UVB exposure. CRBP-I expression was increased 2-fold 8 h following UVA exposure (10 J per cm2), and this increase persisted for at least 16 h. A single UVA exposure induced a concentration-dependent epidermal lipid peroxidation (EC50 = 3.5 J per cm2) giving rise to 55.4 +/- 4.2 nmol lipid peroxides per g at 20 J per cm2, whereas UVB, up to 1 J per cm2, did not increase the basal concentration of 6.7 +/- 0.9 nmol lipid peroxides per g. On the other hand, topical menadione induced a concentration-dependent lipid peroxidation, but did not affect vitamin A content. Pretreatment with alpha-tocopherol (i) did not inhibit UV-induced vitamin A depletion, (ii) completely inhibited the increased lipid peroxidation induced by UVA or menadione, and (iii) accelerated reconstitution of epidermal vitamin A after UVB but not UVA induced depletion. Thus acute UVA induced both epidermal vitamin A depletion and lipid peroxidation, UVB induced only vitamin A depletion, and menadione induced only a lipid peroxidation; topical alpha-tocopherol prevented lipid peroxidation but not vitamin A depletion. These observations indicate (i) that CRBP-I neither provides protection to UVB- and UVA-induced epidermal vitamin A depletion, nor interferes significantly with reconstitution, and (ii) that the UV-induced vitamin A depletion and lipid peroxidation in mouse epidermis are unrelated processes. UV light does not destroy epidermal vitamin A through an oxidative stress but probably by a photochemical reaction in which UV radiations at about 325 nm give the corresponding activation energy.

Sustained ex vivo skin antiseptic activity of chlorhexidine in poly(epsilon-caprolactone) nanocapsule encapsulated form and as a digluconate.

In this work, the sustained bactericidal activity of chlorhexidine base loaded poly(epsilon-caprolactone), PCL, nanocapsules against Staphylococcus epidermidis inoculated onto porcine ear skin was investigated. Drug loaded nanocapsules were prepared by the interfacial polymer deposition following solvent displacement method, then characterized by photon correlation spectroscopy, electrophoretic measurements, transmission and scanning electron microscopy. Antimicrobial activity of these colloidal carriers was evaluated (i) in vitro against eight strains of bacteria, and (ii) ex vivo against Staphylococcus epidermidis inoculated for 12 h onto porcine ear skin surface treated for 3 min either with 0.6% chlorhexidine base loaded or unloaded nanocapsules suspended in hydrogel, or 1% chlorhexidine digluconate aqueous solution. Chlorhexidine absorption into the stratum corneum (SC) was evaluated by the tape-stripping method. The results showed that chlorhexidine nanocapsules in aqueous suspension having a 200-300 nm size and a positive charge exhibited similar minimum inhibitory concentrations against several bacteria with chlorhexidine digluconate aqueous solution. Ex vivo, there was a significant reduction in the number of colony forming units (CFUs) from 3-min treated skin with chlorhexidine nanocapsule suspension (5 to <1 log(10)) compared to chlorhexidine digluconate solution (5 to 2.02 log(10)) after a 8-h artificial contamination. After a 12-h artificial contamination, both formulations failed to achieve a 5 log(10) reduction. Furthermore, from a 3-min treatment with an identical applied dose and a subsequent 12-h artificial contamination, a residual chlorhexidine concentration in the SC was found to be three-fold higher with chlorhexidine nanocapsule suspension than with chlorhexidine digluconate solution. Interestingly, nanocapsules were shown in porcine skin follicles. Consequently, a topical application of chlorhexidine base-loaded positively charged nanocapsules in an aqueous gel achieved a sustained release of bactericide against Staphylococcus epidermidis for at least 8 h. Enhancement of drug delivery by mediating a more direct and prolonged contact between the carrier and (i) bacteria, (ii) skin surface, and (iii) skin follicles was assumed.