In vitro transdermal permeation of fenoterol hydrobromide

A burst of fenoterol excretion during the recovery of a weight loss protocol

Fenoterol is a sympathomimetic β2 receptor agonist primarily used as a bronchodilator. Due to its sympathomimetic actions, the World Anti-Doping Agency (WADA) has banned it. Multiple acute weight loss protocols (WLP) are used by Olympic athletes for sports that segregate athletes by weight; these generally involve caloric and water deprivation combined with heat exposure. Athletes use WLP before weigh-in, then transition to different body acute weight regain protocols (WRP) before competitions. Here, we studied the pharmacokinetics of fenoterol under WLP conditions: energetic dietary restriction, decreased water intake, and exposure to a dry sauna (80 ± 2 °C), followed by a WRP. Five elite-level female judo athletes participated in the study. Four received fenoterol (200 μg; n = 2 or 400 μg; n = 2), while one was a control receiving placebo under identical conditions. We measured excretion of the fenoterol parent molecule and presented qualitative data of its sulfated metabolite using QqQ tandem quadrupole mass spectrometry for 118 h. The fenoterol parent appeared earlier in urine than did its conjugated metabolite; excretion profiles were similar among all subjects. The centers of mass for fenoterol parent curves were (time, fenoterol): athlete A (10.9, 7.3); athlete B (9.2, 27.3); athlete C (8.5, 6.9); athlete D (9.7, 5.0). After initiating WRP, we observed a burst in urinary fenoterol excretion once in complete decay. This trend was observed for all four athletes who received fenoterol. Our results suggest that during hypohydration, some of the unmetabolized fenoterol accumulates in tissues, then is released during rehydration. These findings can be important for detecting fenoterol use in athletes.

Stimuli-Responsive Polymers for Transdermal, Transmucosal and Ocular Drug Delivery

Despite their conventional and widespread use, oral and intravenous routes of drug administration face several limitations. In particular, orally administered drugs undergo enzymatic degradation in the gastrointestinal tract and first-pass metabolism in the liver, which tend to decrease their bioavailability. Intravenous infusions of medications are invasive, painful and stressful for patients and carry the risk of infections, tissue damage and other adverse reactions. In order to account for these disadvantages, alternative routes of drug delivery, such as transdermal, nasal, oromucosal, ocular and others, have been considered. Moreover, drug formulations have been modified in order to improve their storage stability, solubility, absorption and safety. Recently, stimuli-responsive polymers have been shown to achieve controlled release and enhance the bioavailability of multiple drugs. In this review, we discuss the most up-to-date use of stimuli-responsive materials in order to optimize the delivery of medications that are unstable to pH or undergo primary metabolism via transdermal, nasal, oromucosal and ocular routes. Release kinetics, diffusion parameters and permeation rate of the drug via the mucosa or skin are discussed as well.

Formulation optimization and characterization of transdermal film of curcumin by response surface methodology

Objective

India is referred as goldmine of herbal drugs but still lack of optimization of herbal drugs, which has kept us on the back foot. The rationale of the study is to prepare optimized transdermal drug delivery system of curcumin employing response surface methodology to study the collective effect of independent variables like concentration of ethyl cellulose, hydroxyl propyl methyl cellulose and dibutyl phthalate which significantly influenced characteristics like percentage elongation and in vitro drug release.

Method

Twenty formulations containing varying concentrations of polymers and permeation enhancer were prepared using solvent casting technique.

Result

The study revealed that the effect of dibutyl phthalate (DBP) concentration was the highest on percentage elongation (P < 0.0001), while hydroxy propyl methyl cellulose (HPMC) concentration exhibited pronounced effect on drug release (P < 0.0001) through dialysis membrane. Linear model fitted the best for curcumin release and elongation for all formulations. According to Derringer’s desirability prediction tool, the composition of optimized film was found to be 242.14% of HPMC, 109.59% of ethyl cellulose (EC), and 1.03% of DBP. Under these conditions, the optimized patch exhibited a predicted value of %elongation and in vitro drug release of 94.35% and 80.0306%, respectively, which was comparable to the actual values of percent elongation and in vitro drug release i.e. 95.02% and 81.03% respectively. FTIR and thermal studies were also performed which revealed no interaction or complexation between drug and excipients. The ex vivo study performed using rat skin showed that the cumulative drug release from the optimized patch showed flux of (30.68 ± 18) µg/cm²/h.

Conclusion

It can be concluded that in future if proper optimization of herbal formulations is carried out, they can become the first choice for patients as compare to synthetic drugs.

Enhanced Skin Permeation of Estradiol by Dimethyl Sulfoxide Containing Transdermal Patches

Dimethyl sulfoxide is a well-known and widely used dermal penetration enhancer. Its incorporation in transdermal patches would be highly desirable; however, due to its volatility this is extremely challenging. Here, we report on the feasibility of a dimethyl sulfoxide (DMSO) containing transdermal system containing estradiol as a model compound. Transdermal patches were prepared from duro-tak® 387-2510 containing various DMSO concentrations at different drying temperatures. The resulting patches were analyzed for DMSO content, estradiol and DMSO release, estradiol and DMSO permeation through excised porcine skin, and recrystallization during stability testing. Drying conditions in the range of 35° to 40° allowed a complete polymer solvents removal while retaining significant amounts of DMSO (≤10 mg/patch). Estradiol skin permeation increased 4-fold (Jss = 4.12 µg/cm-2·h-1) compared to DMSO-negative control (Jss = 1.1 ± 0.2 µg/cm-2·h-1). As additional benefit, estradiol recrystallization was inhibited by DMSO at even lowest solvent concentrations. Storage stability was limited to 6 months at 25 °C with a surprising discrepancy between DMSO content (significantly lower) and flux (not significantly different). Although the technical feasibility range is relatively narrow, such DMSO-containing matrix-type patches are able to significantly enhance drug permeation through the skin while ameliorating the product stability against recrystallization.

Enhancement strategies for transdermal drug delivery systems: current trends and applications

Transdermal drug delivery systems have become an intriguing research topic in pharmaceutical technology area and one of the most frequently developed pharmaceutical products in global market. The use of these systems can overcome associated drawbacks of other delivery routes, such as oral and parenteral. The authors will review current trends, and future applications of transdermal technologies, with specific focus on providing a comprehensive understanding of transdermal drug delivery systems and enhancement strategies. This article will initially discuss each transdermal enhancement method used in the development of first-generation transdermal products. These methods include drug/vehicle interactions, vesicles and particles, stratum corneum modification, energy-driven methods and stratum corneum bypassing techniques. Through suitable design and implementation of active stratum corneum bypassing methods, notably microneedle technology, transdermal delivery systems have been shown to deliver both low and high molecular weight drugs. Microneedle technology platforms have proven themselves to be more versatile than other transdermal systems with opportunities for intradermal delivery of drugs/biotherapeutics and therapeutic drug monitoring. These have shown that microneedles have been a prospective strategy for improving transdermal delivery systems.

Novel Herbal Topical Patch Containing Curcumin and Arnica montana for the Treatment of Osteoarthritis

BACKGROUND

Osteoarthritis (OA) ranks fifth among all forms of disability affecting 10% of the world population. Current treatments available are associated with multiple side effects and do not slow down the progression of the disease. Moreover, no such effective treatment is available to date in various systems of medicine to treat osteoarthritis. Curcumin and Arnica have shown evident clinical advances in the treatment of osteoarthritis.

OBJECTIVE

The aim of the present study was to design, optimize and characterize novel herbal transdermal patches of curcumin and Arnica montana using factorial design.

METHODS

A multiple factorial design was employed to investigate the effect of hydroxypropyl methyl cellulose, ethyl cellulose and jojoba oil on elongation and drug release. Transdermal patches were evaluated by FTIR, DSC, FESEM, ex vivo drug permeation, anti osteoarthritic activity and analgesic activity.

RESULTS

Independent variables exhibited a significant effect on the physicochemical properties of the prepared formulations. The higher values of drug release and elongation were observed with the higher concentration of hydroxypropyl methylcellulose and jojoba oil. Anti osteoarthritic activity was assessed by complete Freund's adjuvant arthritis model; using rats and analgesic activity by Eddy's hot plate method, using mice. Combination patch exhibited good anti osteoarthritic and analgesic activity as compare to individual drug patches.

CONCLUSION

The design results revealed that the combination patch exhibited good physicochemical, anti osteoarthritic and analgesic activity for the treatment of osteoarthritis in animals. More plants and their combinations should be explored to get reliable, safe and effective formulations that can compete with synthetic drugs.

Tuning the Transdermal Delivery of Hydroquinone upon Formulation with Novel Permeation Enhancers

Hydroquinone (HQ) is an anti-hyperpigmentation agent with poor physicochemical stability. HQ formulations are currently elaborated by compounding in local pharmacies. Variability in the characteristics of HQ topical formulations can lead to remarkable differences in terms of their stability, efficacy, and toxicity. Four different semisolid O/W formulations with 5% HQ were prepared using: (i) Beeler´s base plus antioxidants (F1), (ii) Beeler´s base and dimethyl isosorbide (DMI) as solubiliser (F2), (iii) olive oil and DMI (F3), and (iv) Nourivan^®, a skin-moisturising and antioxidant base, along with DMI (F4). Amongst the four formulations, F3 showed the greatest physicochemical stability with less tendency to coalescence but with marked chromatic aberrations. An inverse correlation was established by multivariate analysis between the mean droplet size in volume and the steady-state flux, which explains why F3, with the smallest droplet size and the most hydrophobic excipients, exhibited the highest permeation across both types of membranes with enhancement ratios of 2.26 and 5.67-fold across Strat-M^® and mouse skin, respectively, compared to F1. It is crucial to understand how the HQ is formulated, bearing in mind that the use of different excipients can tune the transdermal delivery of HQ significantly.

Matrix-type transdermal films to enhance simvastatin ex vivo skin permeability

This study aimed at employing Plackett-Burman design in screening formulation variables that affect quality of matrix-type simvastatin (SMV) transdermal film. To achieve this goal, 12 formulations were prepared by casting method. The investigated variables were Eudragit RL percentage, polymer mixture percentage, plasticizer type, plasticizer percentage, enhancer type, enhancer percentage and dichloromethane fraction in organic phase. The films were evaluated for physicochemical properties and ex vivo SMV permeation. SMV initial, delayed flux, diffusivity and permeability coefficient were calculated on the delayed flux phase with constraint to minimize the initial flux and approaching steady-state flux. The obtained results revealed flat films with homogeneous distribution of SMV within the films. Thickness values changed from 65 to 180 μm by changing the factors' combinations. Most of the permeation profiles showed sustained release feature with fast permeation phase followed by slow phase. Analysis of variance (ANOVA) showed significant effects (p < 0.05) of the investigated variables on the responses with Prob > F values of 0.0147, 0.0814, 0.0063 and 0.0142 for the initial and delayed fluxes, permeability coefficients and diffusivities, respectively. The findings of screening study showed the importance of the significant variables to be scaled up for full optimization study as a promising alternative drug delivery system.

Intranasal immunization in mice with non-ionic surfactants vesicles containing HSV immunogens: a preliminary study as possible vaccine against genital herpes

The purpose of this study was to investigate the potential of intranasal immunization with non-ionic surfactant vesicles (NISV) containing either the secretory recombinant form of glycoprotein B (gBs) of herpes simplex virus type 1 or a related polylysine reach peptides (DTK) for induction of protective immunity against genital herpes infection in mice. NISV were prepared by lipid film hydration method. The mean diameter of vesicles was around 390 nm for DTK-containing NISV (DTK-NISV) and 320 nm for gB1s-containing NISV (gB1s-NISV). The encapsulation efficiency of the molecules was comprised between 57% and 70%. After 7-14 day NISV maintained stable dimensions and a drug encapsulation higher than 48%. We showed that intranasal immunization with gB1s-NISV induces gB-specific IgG antibody and lymphoproliferative responses, whereas vaccination with DTK-NISV was not able to generate a gB-specific immune response. Our results indicate that vaccination of BALB/c mice with gB1s-NISV induced Th1 responses, as characterized by increased titre of IG2a in plasma and IFN-production in CD4+ splenic cells. Intranasal immunization with gB1s-NISV could elicit 90% (almost complete) protection against a heterologous lethal vaginal challenge with herpes simplex virus type 2. These data may have implications for the development of a mucosal vaccine against genital herpes.