New Strategies for Improving Budesonide Skin Retention

The aim of this work was to evaluate the ex vivo effect of the combination of two strategies, complexation with cyclodextrin, and poloxamer hydrogels, for improving water solubility in the dermal absorption of budesonide. Two hydrogels containing 20% poloxamer 407, alone or in combination with poloxamer 403, were prepared. Each formulation was loaded with 0.05% budesonide, using either pure budesonide or its inclusion complex with hydroxypropyl-β-cyclodextrin, and applied in finite dose conditions on porcine skin. The obtained results showed that for all formulations, budesonide accumulated preferentially in the epidermis compared to the dermis. The quantity of budesonide recovered in the receptor compartment was, in all cases, lower than the LOQ of the analytical method, suggesting the absence of possible systemic absorption. The use of a binary poloxamer mixture reduced skin retention, in line with the lower release from the vehicle. When the hydrogels were formulated with the inclusion complex, an increase in budesonide skin retention was observed with both hydrogels. Poloxamer hydrogel proved to be a suitable vehicle for cutaneous administration of budesonide.

Hydrogel Films Based on Chitosan and Oxidized Carboxymethylcellulose Optimized for the Controlled Release of Curcumin with Applications in Treating Dermatological Conditions

Cross-linked chitosan (CS) films with aldehyde groups obtained by oxidation of carboxymethyl cellulose (CMC) with NaIO4 were prepared using different molar ratios between the CHO groups from oxidized carboxymethyl cellulose (CMCOx) and NH2 groups from CS (from 0.25:1 to 2:1). Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy demonstrated the aldehyde groups’ presence in the CMCOx. The maximum oxidation degree was 22.9%. In the hydrogel, the amino groups’ conversion index value increased when the -CHO/-NH2 molar ratio, cross-linking temperature, and time increased, while the swelling degree values decreased. The hydrogel films were characterized by scanning electron microscopy (SEM) and FTIR analysis. The curcumin encapsulation efficiency decreases from 56.74% to 16.88% when the cross-linking degree increases. The immobilized curcumin release efficiency (REf%) and skin membrane permeability were evaluated in vitro in two different pH solutions using a Franz diffusion cell, and it was found to decrease when the molar ratio -CH=O/NH2 increases. The curcumin REf% in the receptor compartment was higher at pH = 7.4 (18%- for the sample with a molar ratio of 0.25:1) than at pH = 5.5 (16.5%). The curcumin absorption in the skin membrane at pH = 5.5 (47%) was more intense than at pH = 7.4 (8.6%). The curcumin-loaded films’ antioxidant activity was improved due to the CS presence.

Optimization of Coumarins Extraction from Pterocaulon balansae by Box-Behnken Design and Anti-Trichomonas vaginalis Activity

Trichomonas vaginalis causes trichomoniasis, a nonviral sexually transmitted infection with a high prevalence worldwide. Oral metronidazole is the drug of choice for the treatment of this disease, although high levels of T. vaginalis resistance to this agent are well documented in the literature. This study describes the anti-T. vaginalis activity of an optimized coumarin-rich extract from Pterocaulon balansae. Optimization was performed to maximize extraction of total coumarins by means of a 3-level Box-Behnken design, evaluating the effect of three factors: extraction time, plant : solvent ratio, and ethanol concentration. Optimum conditions were found to be 5 h extraction time and a plant : solvent ratio of 1% (w/v) and 60% (v/v) ethanol, which resulted in approximately 30 mg of total coumarins/g of dry plant. The coumarin-enriched extract exhibited a minimum inhibitory concentration of 30 µg/mL and an IC50 of 3.2 µg/mL against T. vaginalis, a low cytotoxicity, and a high selectivity index (18 for vaginal epithelial cells and 16 for erythrocytes). The coumarins permeation/retention profile through porcine vaginal mucosa was evaluated in Franz-type diffusion cells. After 8 h of kinetics, coumarins were detected in the tissue (4.93 µg/g) without detecting them in the receptor compartment. A significant increase of coumarins in the mucosa layers (8.18 µg/g) and receptor compartment (0.26 µg/g) was detected when a T. vaginalis suspension (2 × 105 trophozoites/mL) was previously added onto the mucosa. No alterations were visualized in the stratified squamous non-keratinized epithelium of the porcine vaginal mucosa after contact with the extract. Overall, these results suggest that the P. balansae coumarin-rich extract may have potential as a treatment for trichomoniasis.

Transdermal Transport In Vitro of Domperidone by Compartmental Modeling Approach

Transdermal delivery can be alternatively chosen for domperidone to improve its low oral bioavailability. Development drugs into transdermal formulation need information about the transport mechanism of the drug. The purpose of this study was to develop models of domperidone transdermal transport in vitro based on compartmental modeling for understanding the domperidone transport mechanism. Domperidone solution (0,5 g/L in a citric buffer, pH 5) was filled into the donor compartment. The comparative study also conducted to examine the effect of different pH on domperidone transdermal transport in pH 1 (4g/L in 0,1 M HCl). The shed snake-skin and cellophane membrane were pretreated for 1 hour with chemical enhancers (oleic acid in propylene glycol) and assembled between the donor and the receptor compartment of the vertical diffusion cell. The receptor compartment was filled in with phosphate-buffered saline at a pH of 6.8. The permeation study was performed for 8 hours. Samples concentration was assayed by the UV-Spectrophotometry method. The cumulative permeation profiles of domperidone were analyzed using WinSAAM. Three and four-compartmental models were proposed with the one lag compartment. The evaluation of the appropriate number of compartments in the transport model was examined based on the visual goodness of fit (GOF) and the Corrected Akaike’s Information Criterion (AICc) values. Four-compartmental models with one lag compartment were the best model describing percutaneous domperidone transport either in pH donor of 5 or pH 1. The model indicates domperidone transport follows into two parallel routes, including a lag compartment.

In Vitro Skin Retention of Crisaborole after Topical Application

Crisaborole, a nonsteroidal phosphodiesterase 4 inhibitor, represents the first nonsteroidal medication approved for the treatment of atopic dermatitis in over a decade. In this work, crisaborole skin permeation and retention was studied in vitro from a 2% ointment using porcine skin as barrier. Crisaborole was also characterized in terms of thermal behavior, solubility, and logP. Control experiments were performed also on tape stripped skin to clarify the role of stratum corneum in drug partitioning and permeation across the skin. The results obtained indicate that crisaborole accumulates into the skin in considerable amounts after application of a topical lipophilic ointment. Crisaborole shows more affinity for the dermis compared to the epidermis despite its relatively high value of partition coefficient; stratum corneum analysis revealed a low affinity of the drug for this skin layer. Skin penetration across hair follicles or sebaceous glands can be a reason for the high dermis retention and is worth further investigation. The comparison with data obtained from a solution in acetonitrile suggests that the formulation plays a certain role in determining the relative distribution of crisaborole in the skin layers and in the receptor compartment.

DESIGN AND PERFORMANCE VERIFICATION OF NEWLY DEVELOPED DISPOSABLE STATIC DIFFUSION CELL FOR DRUG DIFFUSION/PERMEABILITY STUDIES

Objectives: The present study describes a disposable static diffusion cell for in vitro diffusion studies to achieve better results as compared to well existing Franz diffusion cell (FDC) in terms of the absence of bubbles, variable receptor compartment, ease of handling, and faster results.Materials and Methods: The cell consists of a cup-shaped donor compartment made of semi permeable that could be either cellophane membrane or, animal skin fitted to a rigid frame, which is supported on a plastic plate that contains a hole for the sample withdrawal. The receptor compartment is a separate unit, and it could be any container up to 500ml volume capacity. The most preferred receptor compartment is glass beaker. In the present study, goatskin was used as semi-permeable membrane and verification of its performance was carried out through diffusion studies using gel formulations of one each of the four-selected biopharmaceutical classification system (BCS) class drugs. Metronidazole, diclofenac sodium, fluconazole, and sulfadiazine were used as model drugs for BCS Class I, II, III, and IV, respectively.Results: The newly developed diffusion cell (NDDC) was found to provide faster and more reproducible results as compared to FDC. At the time interval of 24 h, the cell was found to exhibit a higher diffusion of metronidazole, diclofenac sodium, fluconazole, and sulfadiazine by 0.65, 0.65, 0.32, and 0.81 folds, respectively. The faster release obtained with NDDC was attributed to a larger surface area of skin as compared to that in FDC.Conclusion: It was concluded that better reproducibility of results could be achieved with NDDC.

Tretinoin-based formulations - influence of concentration and vehicles on skin penetration

Tretinoin is used in the management of acne and it is part of a gold standard treatment for photoaging. It has also been reported as an agent for superficial chemical peeling in highly concentrated formulations with few considerations about skin penetration. The aim of this study was to evaluate the influence of drug concentration and vehicles currently used on skin penetration of tretinoin. In vitro permeation tests were carried out using Franz diffusion cells fitted with porcine ear skin and 10% aqueous methanol in the receptor compartment. Formulations studied, cream or hydroalcoholic dispersion, containing 0.25%, 1% and 5% of tretinoin were placed in the donor compartment for six hours. Tretinoin concentration in skin layers was measured by high performance liquid chromatography. The largest amount of tretinoin from both vehicles was detected in stratum corneum with significant differences among the three concentrations. The hydroalcoholic dispersion was the best vehicle. Significant amounts of tretinoin were found even in deep layers of epidermis. The formulation with 0.25% tretinoin showed better results when considered the amount of tretinoin on skin in terms of percentage. Finally, skin penetration of tretinoin was influenced by vehicle and concentration of this drug used in formulation.

Permeasi Transdermal Losartan In Vitro dari Larutan dengan Variasi Kadar Losartan dan Propilen Glikol

Abstrak Losartan, senyawa antagonis reseptor angiotensin II, mempunyai bioavailabilitas oral 0.25-0.35. Bioavailabilitas yang rendah ini dapat diatasi dengan penghantaran obat secara transdermal. Enhancer sering ditambahkan ke dalam formula sediaan transdermal, misalnya propilen glikol (PG). Penelitian ini bertujuan mempelajari pengaruh kadar propilen glikol terhadap permeasi transdermal losartan pada kadar obat yang berbeda. Penelitian dilakukan secara in vitro dengan sel difusi tipe vertikal dilakukan terhadap empat formula yaitu 2% potasium losartan (k-los) :15% PG (F1), 10% k-los :15% PG (F2), 2% k-los :20% PG (F3), dan 10% k-los: 20% PG (F4) dengan dapar sitrat pH 5 sebagai mediumnya. Kulit punggung tikus jantan galur wistar digunakan sebagai membran, PBS pH 7,4 sebagai medium kompartemen reseptor, dan HPLC untuk pengukuran kadar k-los dalam kompartemen reseptor dengan detektor UV. Hasil penelitian menunjukkan bahwa peningkatan kadar k-los dari 2% ke 10% pada kadar PG 15% meningkatkan fluks, sedangkan pada kadar 20% tidak berpengaruh terhadap fluks. Peningkatan kadar PG dari 15% ke 20% justru menurunkan fluks pada kadar k-los 2%, dan tidak berpengaruh pada kadar k-los 10%. Nilai lag time tidak berbeda diantara semua fomula. Hal ini berarti penggunaan enhancer PG lebih dari 15% justru merugikan permeasi transdermal. Kata Kunci : transdermal, losartan, propilen glikol, enhancer Abstract Losartan is an angiotensin receptor antagonis which has low oral bioavailability (0.25-0.35). Transdermal drug delivery system is needed as one solution for this low oral bioavailability drug. Propilen glikol (PG), as enhancer, is frequently added in transdermal dosage form. This research was purposed to explore the effect of PG as losartan permeation enhancer in various concentration of potasium losartan (k-los). The research was carried out in vitro using vertical tipe difusion cel for 4 formulas, i.e. 2% potasium losartan (k-los) :15% PG (F1), 10% k-los :15% PG (F2), 2% k-los :20% PG (F3), and 10% k-los: 20% PG (F4) using citric buffer pH 5 as donor medium, while PBS pH 7,4 was used as receptor medium. The dorsal skin of white wistar male rat was used as membrane. HPLC with UV detector was used to determine the concentration of k-los appear in receptor compartment. The results show that increasing of k-los concentration from 2% to 10% can increase the flux if PG concentration is 20%, but it does not have any significant effect to the flux if the PG concentration is 15%. Increasing PG concentration from 15% to 20% decrease the flux permeation in k-los concentration of 2%, and does not have any significant effect in concentration of k-los of 10%. The lag time permeation does not has any significant differencess. It means that PG as enhancer in the concentration above 15% doesn’t have any adventages. Keywords : transdermal, losartan, propilen glycol, enhancer