anayatollah salimi

This study aimed to develop a microemulsion (ME)-based skin delivery platform containing sildenafil citrate (SC)-ME and evaluate its in vitro skin permeability.

Accurate MEs were prepared using pseudo-ternary phase diagrams and a full factorial design with three variables at two levels. After the design phase, suitable ratios of oil, water, and a mixture of surfactant (S) and cosurfactant (CS) were selected to prepare various SC-ME formulations. These SC-MEs were analyzed for stability, droplet size, in vitro SC release, skin permeability, and viscosity properties.

The droplet size of the ME samples ranged from 6.24 to 32.65 nm, with viscosities between 114 to 239 cps. Release profiles indicated that 26 to 60% of SC was released from the different SC-MEs within 24 hours. All ME formulations significantly enhanced the permeability coefficient (P) through rat skin. Specifically, the flux (Jss) in SC-ME7 increased by approximately 117 times (Jss = 0.0235 mg/cm2.h) compared to the control sample (0.0002 mg/cm2.h).

The study concluded that the proportions of the water or oil phase and the S/CS mixture in the MEs significantly influenced the physicochemical characteristics and permeation parameters. The selected MEs improved both the permeability coefficient and the rate of permeation through rat skin. The enhanced drug delivery through and into deep skin layers is a key attribute of an ideal dermal ME. These findings suggest that MEs could serve as effective transdermal delivery systems for SC and similar drugs. However, in vivo assays and clinical research are needed to confirm the therapeutic efficacy of MEs.

Eczema, a common inflammatory skin condition characterized by itching and dermatitis, can significantly impact the quality of life. While conventional treatments exist, there is interest in exploring natural alternatives. This study investigates the efficacy of a rosehip extract-based cream in mitigating eczema symptoms in a mouse model.

Thirty-five mice were divided into five groups: control, dinitrochlorobenzene (DNCB)-induced eczema (model group), and treatment groups receiving placebo, betamethasone cream (positive control), or rosehip extract cream. Following topical treatment for four weeks, the animals were euthanized, and their skin was evaluated for inflammation, moisture, and thickness. Histopathological analysis was performed using hematoxylin and eosin (H&E) staining.

Compared to the control group, DNCB treatment significantly increased inflammation, erythema (redness), dryness, and epidermal thickness. Notably, topical application of the rosehip extract cream significantly reduced these eczema-associated parameters, demonstrating efficacy comparable to the positive control (betamethasone cream).

This study suggests that a topical cream formulated with rosehip extract may be a promising therapeutic strategy for alleviating eczema symptoms. The anti-inflammatory and potentially regenerative properties of rose extract warrant further investigation for the development of natural eczema treatments.

Limitations in drug penetration are overcome by nanotechnology, particularly liposomes, which enhance targeted administration of ocular medications. Liposomes can augment the therapeutic effects of curcumin, a natural compound with positive impacts on the retina. Treatments for eye diseases can also benefit from the antibacterial properties of ozonated oil liposomes.

This study aims to develop and evaluate ozonated liposomes loaded with curcumin for ocular drug delivery applications, specifically targeting diabetic retinopathy (DR).

Liposomal nanoparticles were prepared using thin-film hydration, incorporating phospholipids, lecithin, cholesterol, ozonated oil, and curcumin. We assessed physicochemical properties including particle size, zeta potential, encapsulation efficiency (EE), and morphology. Drug release profiles and stability studies were also conducted.

The optimized liposomes showed a particle size of 84.77 nm, a zeta potential of -16.8 mV, and an EE of 94.73%. The formulation exhibited sustained curcumin release over 24 hours, reaching 82.09% cumulative release. Stability studies indicated minimal changes in key parameters over three months at room temperature.

The developed ozonated liposomal formulation demonstrates promising characteristics for curcumin delivery, potentially enhancing its therapeutic efficacy in ocular applications, particularly for DR.

Microemulsions (MEs) are considered for preparing drug delivery carriers, especially transdermal vehicles. Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used to manage chronic and acute pain and inflammatory diseases. However, NSAIDs have drawbacks such as gastrointestinal tract disorders and poor pharmacokinetic properties for oral administration. To address these issues, we evaluated the potential of ME as a transdermal system for locally delivering naproxen (NPX) as an NSAIDs model (NPX-MEs). Phase diagrams were constructed for MEs composed of tween 80, span 80, and propylene glycol (PG) as surfactant (S)/cosurfactant (CS), transcutol ® P (TRC-P), and Labrafac TM PG as oil. The final concentration of NPX in MEs was 1% (w/v). The MEs were analyzed for particle size, refractive index, and viscosity. In vitro permeability studies of NPX-MEs were conducted using Franz diffusion cells on rat skin samples. Additionally, the effects of Eucalyptus oil (EU oil), oleic acid (OLA), and TRC-P as enhancers on the skin permeation of NPX were investigated. The particle size and viscosity values of the NPX-MEs ranged from 7.05 ± 0.03 to 79.56 ± 0.58 nm and 222.4 ± 0.87 to 681.13 ± 1.97, respectively. The optimal formulation, ME-3, consisted of 20% oil, 10% water, and 70% S/C phases. The skin permeation rates of NPX from ME-3 were higher than those of other formulations (D app = 1.36 ± 0.616, ER D =527.989 ± 313.627) with a lower lag time. Additionally, OLA-treated skin showed the highest transdermal permeation rate (ER D = 75.55 ± 23.532). Based on these results, the formulated NPX-ME may be a desirable carrier for transdermal delivery compared to traditional formulations, potentially reducing side effects and improving the therapeutic efficacy of NPX.

The melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae) is one of the important ornamental plant pests in urban regions. In this study, the microemulsion system was developed using cypermethrin insecticide as the active ingredient, xylene as the solvent, and surfactants including Tensiofix 8427 + SDS, and Tensiofix 8427 + SLS, and 1-butanol (cosurfactant), as stabilizer. The optimal microemulsion formulation was determined using a pseudo-ternary phase diagram using the water titration method. The microemulsions mean droplet sizes were in the range 11.2–22.8 nm. The droplets of all three formulations were spherical and uniformly dispersed in water. The mortality percentage was 66.66, 56.66, and 55.00% 24 h after aphids exposure to C1-250 (cypermethrin: Tensiofix 8427 + SDS + 1-butanol: water, at the ratio of 10:20:70), C2-250 (cypermethrin: Tensiofix 8427 + SLS + 1-butanol: water, at the ratio of 10:20:70), and C3-250 (cypermethrin: Tensiofix 8427 + SLS + 1-butanol: water, at the ratio of 15:30:55), which increased to 92.86, 89.29, and 83.94%, 48 h after exposure, respectively. The results revealed that the microemulsion formulation containing cypermethrin 250 g/L was more effective in controlling A. gossypii than cypermethrin technical material and 150 g/L cypermethrin-based microemulsion.

Cetirizine is a second-generation antihistamine with anti-allergy and anti-itching properties. The topical formulation of this medicine is used in androgenic alopecia treatment. Due to the hydrophilic nature of cetirizine, its skin absorption is negligible, so to increase its absorption, various enhancers were examined to see which can be used in the design of a topical formulation. First, the skin was exposed to enhancers, including eucalyptus, menthol, Tween 80, propylene glycol, and oleic acid, for 1 or 2 hours. Then, the permeability parameters of the cetirizine solution and the structural changes of the skin after exposure to enhancers were analyzed by differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR) techniques. The obtained results show that all used enhancers increased the permeability of the drug cetirizine compared to water. Various mechanisms, such as liquefaction of lipids, destruction of lipid structure, and irreversible denaturation of intracellular keratin, are involved in the increase in drug penetration caused by eucalyptus, mint, Tween 80, propylene glycol, and oleic acid. The results showed that among the studied absorption enhancers, eucalyptus and Tween 80 had the strongest, and propylene glycol had the weakest absorption enhancement effect after 2- and 1-hour pre-contact, respectively.

In this study, the purpose of preparing CS/PVA nanofibers loaded GRF microemulsion is to increase the solubility of Low soluble drug griseofulvin by using microemulsion nanocarrier, and nanofiber was used as a technique for a new product. This drug is one of the antifungal drugs, and its uses are for skin diseases. Therefore, a topical route can be a good option. Chitosan /polyvinyl alcohol (CS/PVA) nanofiber containing griseofulvin (GRF) loaded microemulsion was obtained. The microemulsion comprised oleic acid and Transcutol P as the oil phase, Span20 and Labrasol as the surfactant, and Plurol oleique as the cosurfactant. Formulations were prepared with a ME(GRF): polymer ratio (30: 70) and (40: 60) and a polymeric solution containing chitosan (2%) and polyvinyl alcohol (10%) at two weight ratio (20: 80) and (10: 90), respectively. The physicochemical characteristics of the GRF-CS/PVA nanofibers were evaluated. The differential scanning calorimetry (DSC) study showed the amorphous state of the GRF-loaded microemulsions and PVA polymer embedded into the nanofibers. The entrapment efficiency percentage of GRF in the mats was approximately 66.67% - 88.89%. Drug release behavior showed controlled and slow release of drugs that are affected by the type of microemulsion formulation and the ratio of polymers used in nanofibers. 

Caffeine is an edible chemical compound obtained from various plants, such as tea and coffee. Caffeine is an alkaloid that is highly hydrophilic and has limited skin permeability. The lipophilic nature of the stratum corneum is a major barrier to the passage of this substance through the skin. Topical drug delivery systems can effectively transfer caffeine to the skin.

This study investigated the effect of pretreatment time with chemical enhancers on caffeine’s skin permeation.

The skin was subjected to additives such as sodium lauryl sulfate, sodium lauryl ethyl sulfate, tynoline, nanoxinol, and lecithin for 5, 15, and 30 minutes. Then, the parameters of caffeine permeability and structural changes in the skin due to additive adsorption were studied using Fourier Transform Infrared (FT-IR) spectrometry.

The enhancers increased the permeation of caffeine through the skin. There are different mechanisms for penetration enhancers, including lipid liquefaction, disruption of lipid bilayers, and irreversible denaturation of intracellular keratin.

Sodium lauryl sulfate can affect the skin permeability of caffeine.

Background and

Minoxidil is one of the agents that can treat hair growth disorders, including alopecia, by increasing the anagen period. Due to the nature of minoxidil, the permeability of the drug to the skin surface is negligible. Therefore, the purpose of this study was to design and evaluate microemulsion formulations in order to increase skin permeability of minoxidil.

Microemulsions containing 2% minoxidil were prepared with an appropriate amount of oil phase, surfactant, and co-surfactant. The medicinal substance was dissolved in the oily phase. The physicochemical properties of the microemulsions, including particle size, viscosity, release, skin permeation through rat skin as well as the rate of drug permeation through rat skin, were evaluated using Franz cells.

The particle size of microemulsions was in the range of 5.45-10.4 nm, viscosity was 113.2-199.2 centipoise. This study showed that the parameters of drug release percentage in the second hour, drug release percentage in the 24th hour, viscosity and Dapp were significantly related to independent variables(P<0.05). Increasing the percentage of water and the percentage of oil has increased the amount of drug release in 24 hours. Increasing the percentage of oil and decreasing the percentage of water can lead to an increase in viscosity, and increasing the percentage of water can increase the amount of Dapp in microemulsions.

The prepared formulations were able to significantly increase the skin permeability of minoxidil.

A microemulsion is a stable, homogeneous pesticide formulation, based on an aqueous solvent, which is considered a suitable alternative to emulsion formulations. In this study, microemulsion formulations of cypermethrin insecticide were designed to control Aphis gossypii Glover (Hemiptera: Aphididae), one of the important pests of many crops and ornamental plants.  Xylene was selected as a suitable solvent based on the higher solubility of cypermethrin. Pseudo-ternary phase diagrams were constructed by the water titration method. The microemulsion system using mixtures composed of cypermethrin, Kenon 10+SDS surfactants, and 1-butanol cosurfactant had the highest microemulsion surface, and the ratio of 50:30:20 was chosen for further experiments. The physical and chemical properties of the obtained microemulsions were also evaluated. Microemulsion formulations were synthesized with 150 and 250 g/L a.i. (active ingredient) of the cypermethrin. The appearance of the microemulsion compounds was transparent and the droplet size of all samples was less than 35 nm. Foliar spraying of compounds including cypermethrin technical material (150 g a.i./L), cypermethrin technical material (250 g a.i./L), cypermethrin microemulsion (150 g a.i./L), and cypermethrin microemulsion (250 g/L a.i.), under greenspace conditions on Hibiscus rosa-sinensis L. (Malvaceae) caused 25.05, 37.54, 60.74, and 83.94% mortality on third instar nymphs 48 hours after treatment, respectively. Therefore, microemulsion formulations had significantly more insecticidal activity against A. gossypii compared to the technical material. In this study, an environment-friendly microemulsion system was designed to improve the efficacy of cypermethrin for controlling populations of A. gossypii. However, further research could be performed to assess the behavior and ultimate fate in the environment prior to commercialization.

 Finasteride is a 5-alpha reductase inhibitor used to treat hair loss and acne. The skin permeation of finasteride is one of the main challenges associated with dermal drug delivery. One way to overcome the skin barrier is to use penetration enhancers. The purpose of this study was to investigate the effect of some penetration enhancers on finasteride permeability on the skin, as well as the effect of pretreatment time on their efficacy.

 In order to determine the effect of penetration enhancers on the skin permeability of finasteride, the skin was exposed to clove oil, urea, and lyophilized powder of grape seed extract (LPGSE) at different pretreatment times (2, 4 h), and then the permeability parameters were determined by passing the drug through the skin.

 The results of this study showed that clove oil, urea, and LPGSE increased the transfer of finasteride from the skin. The highest rate of permeation was observed with clove oil (4 h), and the least permeability was observed with urea (4 h).

 Increasing the pretreatment time with clove oil and LPGSE increases the permeability of finasteride. Meanwhile, the increase in pretreatment time with urea reduces the penetration of finasteride from the skin due to reversible effects.

 This study aimed to examine the uptake of the model therapeutic agent, minoxidil, through the skin, under the influence of different vehicles. Therefore, the effect of different penetration enhancers such as Propylene glycol, water, ethanol, transcutol P, caprylic acid, and Isopropyl alcohol were evaluated on skin permeability of minoxidil through rat skin.

 The skin permeability of minoxidil on rat skin was analyzed through a Franz cell by evaluating the parameters, including Jss, ERflux, ERD, and ERp. The enhancement mechanisms were studied by comparing FT-IR peak intensities for asymmetric and symmetric C-H stretching, ester C=O stretching, and Amide peaks. The mean transition temperature (Tm) and their enthalpies (ΔH) were investigated by the DSC technique.

 Caprylic acid had the highest diffusion coefficient enhancement ratio (ERD), followed by propylene glycol and water. All solvents have ERD flux enhancement ratio. Solubility in the stratum corneum limited partitioning. All carriers enhanced drug permeability from rat skin, according to FTIR and DSC.

 Caprylic acid is an effective topical vehicle for minoxidil due to greater partitioning and diffusion through rat skin.

Tadalafil has gained wide clinical acceptance in treatment of erectile dysfunction due to its long treatment window and lower potential for visual impairment. Transdermal drug delivery prevents systemic elimination, drug-drug and food-drug interactions, and reduces side effects by reducing the dose of the drug. The aim of this study was to evaluate the effect of microemulsion formulation on dermatological drug delivery of Tadalafil in rat skin.

In this laboratory study, Tadalafil microemulsions were prepared using a phase-diagram method with an appropriate ratio of oil and water mixture. Factorial design with three variables in two levels was performed to prepare eight formulations. Microemulsions containing 0.05 Tadalafil were prepared with an appropriate amount of oil phase (Oleic acid, Transcotol P), surfactant (Tween 80 and Span 20), and co-surfactant (Propylene Glycol). The drug was dissolved in the oil phase. The physicochemical properties of these microemulsions were evaluated using Franz Cells.

The droplet size of microemulsions ranged less than 60 nm and the viscosity ranged between 114.2 and 239.2 cpz. Parameters, including pH, drug release percentage in two hour and 24 hours, viscosity, Tlag and Dapp were significantly associated with independent variables (P<0.05).

The release kinetics of the drugs in selected microemulsions showed that compared to the Tadalafil solution, release occurs over time. All microemulsions significantly increase the flux coefficient and skin permeability.

Piroxicam is a non-steroidal anti-inflammatory medication for treating fever, discomfort, and inflammation. In addition, piroxicam inhibits cyclooxygenase and lowers prostaglandin synthesis, resulting in analgesic and anti-inflammatory effects.

This study used Franz diffusion cells made from rat skin primed with sesame, eucalyptus, olive, menthol, clove, and sunflower oils.

Control was hydrated rat skin. Permeability measurements include steady-state flux (Jss), permeability coefficient (Kp), and diffusion coefficient (D). FT-IR was used to compare changes in peak position, differential scanning calorimeter (DSC), mean transition temperature, and the permeability enhancement methods of the penetration enhancer (Tm). The skin acted as a barrier to piroxicam permeability throughout the whole surface, indicating that drug flux was limited by diffusion into the skin.

The steady-state flux (Jss) of all penetration enhancers were not significantly different from control, except for clove and menthol oil (4 hours treated) and olive oil (2 and 4 hours treated).

Penetration enhancers improved drug permeability through rat skin. Sesame oil, menthol oil, and sesame oil were found to have higher ERflux, ERD, and ERP ratios than water-hydrated skin due to lipid fluidization, lipid structure disruption, and irreversible keratin denaturation.

Flavonoids are a large group of phenolic compounds possessing anti-inflammatory and antioxidant effects. NAR is a flavonoid with various pharmacological properties. Using pharmaceutical compounds on skin is one of the routes of administration to achieve local and systemic effects. The aim of this study was to develop a topical formulation of NAR by the preparation of a NAR ME, which was further tested its skin permeability in rats.

Eight 0.5% NAR MEs were prepared by mixing appropriate amounts of surfactant (Tween 80 and Labrasol), cosurfactant (Capryol 90) and the oil phase (oleic acid-Transcutol P in a ratio of 1:10). The drug was dissolved in the oil phase. The physicochemical properties of MEs such as droplet size, viscosity, release, and skin permeability were assessed using Franz Cells diffusion.

Based on the results, the droplet size of MEs ranged between 5.07 and 35.15 nm, and their viscosity was 164-291 cps. Independent factors exhibited a strong relationship with both permeability and drop size. The permeability findings revealed that the diffusion coefficient of NAR by the ME carrier increased compared to the drug saturation solution.

The most validated results were obtained for Jss and particle size. Optimal formulations containing MEs with Jss and particle sizes varying between minimum and maximum amounts are suitable for topical formulations of NAR.

Natural products such as Allium jesdianum (AJ) have pharmacological properties with negligible side effects. However, their therapeutic potential has been limited by their low bioavailability. Nanocarriers improve the bioavailability and stability of flavonoids as the most common polyphenolic antioxidant.

This study aimed to assess the toxic effects of Allium jesdianum extract (AJE) loaded in microemulsion (AJE-ME) on the HT-29 cells, a human colon cancer cell line.

HT-29 cells were exposed to 50µM/mL of AJE or AJE-ME for 24 h. Colony formation, cell viability percentage, flow cytometry, and gene expression studies were carried out to assess the impacts of the AJE-ME.

The AJE-ME with the required characteristics and a slow-release AJE were prepared. AJE-ME significantly diminished the survival percentage and colony formation of HT-29 cells compared to the free AJE. Upregulation of mTOR and downregulation of Beclin1 and Atg5 indicated suppression of autophagy by the AJE-ME. Flow cytometry results showed that AJE-ME significantly increased the percentage of necrosis in the HT-29 cells. AJE-ME upregulated the expression of necroptosis-related genes such as receptorinteracting protein kinase 3(RIP1) and mixed lineage kinase domain-like pseudokinase (MLKL).

These data collectively demonstrated that ME enhanced the toxic effect of AJE against human colon cancer cells by suppressing autophagy and activating necroptosis.

The goal of this research is the localization of hydroquinone (HQ) to the epidermis for the treatment of hyperpigmentation in rat skin. For this purpose, nanostructured lipid carrier (NLC) was selected for the dermal delivery of HQ. A 23 factorial design was used in this study, and eight NLCs were prepared with a cold homogenization technique. HQ entrapment efficiency (EE %), particle size, morphology, thermal behavior of NLCs, and permeability parameters through rat skin with NLC in comparison with HQ aqueous solution (HQ-S) with Franz diffusion cells were evaluated. Based on the optimization technique, the best NLC was selected and in the in vivo experiment, the depigmentation effect of optimized NLC in comparison with that of HQ-S was evaluated. The results showed that the main problem for HQ permeability was fast permeation and low concentration in the site of action. Partitioning from aqueous donor phase into skin rate was the limiting step for drug flux, and this can be solved using NLC. The decrease in maximum flux obtained by NLC was according to formulation 8. Regression analysis suggested a significant and direct effect of the S/L ratio and the percentage of liquid lipids on the drug loading. NLC decreased drug permeation through rat skin basically due to sustained release properties.

Cystic echinococcosis (CE) is a serious contemporary public health problem. Different CE treatment methods are of considerable importance, with albendazole (ABZ) being one of the most preferred drugs for CE treatment and prophylaxis. In this study, we evaluated the nephrotoxicity caused by ABZ and ABZ-loaded solid lipid nanoparticles (SLNs) in mice with experimental hydatid cyst.

ABZ-loaded SLNs were produced by micro-emulsification and a high shear homogenization technique. Thereafter, we evaluated the physicochemical characterization of the product. Live protoscolices were injected into mice to induce experimental hydatidosis. Mice were then treated with ABZ and ABZ-loaded SLNs. The nephrotoxicity effects were evaluated by biochemical and histopathological surveys.

Significantly different blood urea nitrogen (BUN) levels were observed between the two infected groups (ABZ treatment and ABZ-loaded SLN treatment) and the control group. The kidney malondialdehyde (MDA) and glutathione (GSH) levels of the infected groups were not significantly different from those of the control group. The histopathological study revealed nephropathic and pathologic changes in the ABZ and ABZ-loaded SLN groups.

ABZ formulated for ABZ-loaded SLNs had a more prominent chemoprophylactic efficacy on CE and fewer side effects than ABZ alone. Neither ABZ nor ABZ-loaded SLNs caused significant biochemical and histopathological defects on the kidney, and all functional biochemical markers stayed within the normal range. Therefore, ABZ-loaded SLNs could be a potential new product for CE treatment.

vulvovaginal candidiasis (VVC) caused by Candida albicans and other Candida species are high-risk event in patients admitted to hospital. Ziziphus genus is a rich source of medicinal compounds, effective for the treatment or prevention of some diseases. This study aimed to evaluate the antifungal effect of topical microemulsion containing Ziziphus spina-christi L (ZSC) extracts against Candida spp. Z. Spina-Christi was collected and extracted in a Soxhlet apparatus using the ethanol and methanol solvents. Microemulsions were formulated by varying the composition of surfactant (Tween 80) along with cosurfactant (propylene glycol), oil, and water and were characterized regarding their stability. The microemulsion without extract as placebo and the active microemulsion containing ZSC extract as active formulation were applied to test the antifungal activity against C. albicans, C. parapsilosis and C. krusei using well diffusion test. The optimal microemulsion was selected and then analyzed for average diameter of droplets, pH, viscosity and zeta potential. The microemulsion containing ZSC ethanolic extract had a significant inhibitory effect on the different species of Candida, but the most inhibitory effect was found against C. albicans. The results of this study indicate that the ethanol extract has interesting antimicrobial properties and can used for the treatment of fungal infections. More research is required to check this plant performance to treat the Candidiasis.

Transdermal permeability refers to the delivery of medication to the body through the skin for local or systemic treatment. Transdermal drug delivery systems have not liver first pass effect and gastrointestinal adverse reaction. The use of chemical penetration enhancers and physical absorption systems are obsolete because there are expensive and changes of the skin structure, and the future look at the use of novel drug delivery systems. Nano-carriers is one of the most important new technologies in the field of novel drug delivery. Nanoparticle formulations have about 10 to 100 nanometers. Smaller particles are absorbing more easily than the surface of the skin.

In the present study, a review of previous studies on the use of Nano technology in transdermal drug delivery systems introduced them and their transdermal permeability was paid.

Nanotechnology in different routes and formulations has the ability to increase the permeability of therapeutic drugs depending on their characteristics, the physicochemical characteristics of the drugs, and the therapeutic goals one can choose.

Octyl methoxycinnamate is one of the ingredients in sunscreen products. The main aim of this study was to investigate the effect of different enhancers of in vitro skin permeability of Octyl methoxycinnamate. Octyl methoxycinnamate permeability parameters were evaluated through the whole skin of the rat with and without chemical enhancers including eucalyptus oil, urea, menthol and olive oil by Franz cell diffusion. The effects of enhancers on skin structure were also studied using DSC and FT-IR techniques. The skin prevented the permeability of Octyl methoxycinnamate so that after 24 hours less than 3% of the substance passed through the skin. The results of this study showed that by increasing the time, it is possible to increase the skin permeation and the highest rate of skin absorption were corresponded to olive oil (ERflux=63.074), eucalyptus oil (ERflux=48.78) and menthol (ERflux=33.5), respectively while the least amount of skin absorption was related to urea (ERflux=29.53). Chemical penetration enhancers are substances that interfere with the complex structure of the skin and protein lipids. Two endothermic transitions were obtained at about 67 (Tm1) and 112 ° C (Tm2) in thermogram of the hydrated whole rat skin. Tm1 and Tm2 seems to be due to the melting of the lipids and the irreversible intracellular keratin or melting of the lipid-protein (keratin) complex, respectively. The amount of Tm1, ΔH1 and ΔH2 were decreased by all penetration enhancers compared to the hydrated skin. The FT-IR results suggested the mechanism of increasing absorption effect by lipid fluidization and lipid extraction. All of penetration enhancers used in this study significantly increased the skin permeability of Octyl methoxycinnamate.

Azelaic acid is a natural keratolytic, comedolytic, and antibacterial drug that is used to treat acne. The topical application of azelaic acid is associated with problems such as irritation and low permeability. For dissolving, the problem is that microemulsion (ME) is used as a drug carrier. The aim of this study was to increase the azelaic acid affinity in the follicular pathway through ME.

Azelaic acid-loaded MEs were prepared by the water titration method. The properties of the MEs included formulation stability, particle size, drug release profile, thermal behavior of MEs, the diffusion coefficient of the MEs and skin permeability in the non-hairy ear skin and hairy abdominal skin of guinea pig were studied in situ.

The MEs demonstrated a mean droplet size between 5 to 150 nm. In the higher ratios of surfactant/co-surfactant, a more extensive ME zone was found. All MEs increased the azelaic acid flux through both hairy and non-hairy skin compared with an aqueous solution of azelaic acid as a control. This effect of the ME was mainly dependent on the droplet diffusion coefficient and hydrodynamic radius. MEs with a higher diffusion coefficient demonstrated higher azelaic acid flux through hairy and non-hairy skin. Drug flux through both skins was affected by the surfactant/co-surfactant ratio in that the higher ratio increased the azelaic acid affinity into the follicular pathway.

Finally, the ME with the highest droplet diffusion coefficient and the lowest surfactant/co-surfactant ratio was the best ME for azelaic acid delivery into the follicular pathway

Finasteride is a pharmaceutical agent that treats hair loss and acne with hormonalpatterns. Due to its poor water solubility, and the smaller surface area in comparison to totalskin surface area, penetration of the drug into hair follicles and skin is low. The aim of thisresearch was to formulate, characterize and evaluate in vitro skin permeability of finasteridemicroemulsions (MEs).

Finasteride MEs were prepared using a pseudo-ternary phase diagram method withan appropriate ratio of oil mixture, surfactant-co-surfactant mixture and water. MEs containing1% finasteride were prepared with a suitable amount of oily phase and surfactant and cosurfactant.The physicochemical properties of these MEs and in vitro skin permeability of MEswere evaluated.

The results showed that the mean droplet size range of ME samples was 5–17 nm andpH was 5.1–5.7. The viscosity of MEs ranged from 86.4–209.6 cps. The drug release profileshowed that 49.510% of the drug was released (ME-F-6) over the 24 hours of the experiment.The kinetics of drug release from all selected MEs were approximately described by Higuchiand first-order modeling. All ME formulations with different compositions and propertiessignificantly increased flux and permeability coefficient from rat skin. The selected MEs exhibit99.9% finasteride after six months of storage.

This study showed that any change in the content and composition of MEs couldchange the physical and chemical properties in addition to ME permeability parameters. TheMEs increased permeability of the skin to finasteride.