Hybrids between H2S-donors and betamethasone 17-valerate or triamcinolone acetonide inhibit mast cell degranulation and promote hyperpolarization of bronchial smooth muscle cells.

Glucocorticoids represent the standard gold treatment of inflammation in asthmatic patients. More recently, H2S has been described to exert positive effect on this disease. Bearing in mind that an improved pharmacological activity and a reduced toxicity can be obtained through hybridization of different molecules, simultaneously modulating multiple targets, we designed and synthesized novel betamethasone 17-valerate and triamcinolone acetonide hybrids with well-known H2S-donor moieties. Synthesized compounds have been evaluated for the potential H2S-releasing profile both in cell-free environment and into the cytosol of bronchial smooth muscle cells (BSMCs). The two hybrids 4b and 5b were investigated by molecular modelling studies and results indicated that the steric accessibility of the isothiocyanate carbon atom can account for their different H2S releasing properties. Furthermore, the most promising derivatives 4b and 5b have been tested for inhibitory effect on mast cell degranulation and for the ability to induce cell membrane hyperpolarization in BSMCs. Significant inhibitory effect on mast cell degranulation was assessed, resulting to reduce ß-hexosaminidase release more efficiently than the corresponding native drugs. Both compounds determined a massive membrane hyperpolarization of BSMCs and proved to be 4-fold more effective compared to reference compound NS1619. These effects represent an enrichment of the pharmacological activity of the native drugs.

Patients preferences for different corticosteroid vehicles are highly variable.

Introduction: Topical corticosteroids, available in an array of vehicles are used to control a variety of inflammatory skin diseases. Patients preferences for different vehicles may affect their willingness to use treatment. We assess corticosteroid vehicle preference and potential impact of topical characteristics on adherence and quality of life in patients with psoriasis.Methods: Subjects with psoriasis were recruited from Wake Forest University Dermatology Clinic. Subjects sampled desoximetasone 0.25% spray, betamethasone valerate 0.1% cream, triamcinolone acetonide 0.1% ointment, fluocinonide 0.05% gel, betamethasone valerate 0.1% lotion, clobetasol propionate 0.05% foam, and fluocinonide 0.05% solution in a predetermined randomized order. Subjects completed a Vehicle Preference Measure, Determinants of Adherence Measure, and a Determinants of Quality of Life Measure.Results: Patients preferences for the various products were highly variable. Regarding Determinants of Adherence, patients perception of absorption of the medication was ranked as 'quite important/extremely important' by 85% of total subjects. A majority of patients rated medication side effects as 'quite important/extremely important' when asked to consider topical characteristics effect on quality of life.Discussion: There was wide variation in patient preference for topical medication vehicles used for treating psoriasis. Several vehicle characteristics were considered important to adherence. Given the marked variation in vehicle preference, topical treatment should be individualized according to patients preferences.

Potential of biocompatible polymeric ultra-thin films, nanosheets, as topical and transdermal drug delivery devices.

The aim of the present study was to assess the potential of biocompatible polymeric nanosheets as topical and transdermal drug-delivery devices. Nanosheets are two-dimensional nanostructures with a thickness in the nanometer order, and their extremely large aspect ratios result in unique properties, including high transparency, flexibility, and adhesiveness. Nanosheet formulations containing betamethasone valerate (BV) as a model drug and consisting of poly (L-lactic acid) or poly (lactic-co-glycolic) acid were fabricated through a spin-coating-assisted layer-by-layer method using a water-soluble sacrificial membrane. The fabricated formulations could incorporate and release higher amounts of BV compared with a commercial ointment, and the amounts could be controlled by the polymers used, the amount of BV added, and the use of controlled-release membranes. The presence of BV had a minimal effect on thickness, transparency, adhesiveness, and moisture permeability of nanosheets, permitting their application to any area of skin for a long period of time. Therefore, this biocompatible polymeric nanosheet formulation represents a novel and promising topical and transdermal drug delivery device, which has potential to deliver drugs regardless of the area of skin.

Urinary detection of corticosteroid in topical treatment of skin disease by 19F MRS.

OBJECTIVE: To investigate if it was feasible to quantify the renal excretion of topically applied corticosteroids by 19F MRS. MATERIALS AND METHODS: Five participants, one healthy and four with skin diseases, were treated with ointment containing betamethasone 17-valerate. Urine samples were collected for up to 87 h after the initial application. A sample of ointment mixed with urine served as a study control. Organic fractions were obtained after sample freeze drying, and resolved in deuterated chloroform prior to acquisition of 19F MR spectra at 470 MHz for typically 8 h. RESULTS: We detected fluorine signals in 40 of the 62 fractions of organic extracts. The corticosteroid was detected in samples from all patients, ranging from 0.1 to 2.8% of the applied steroid. No fluorine signal was obtained in samples from the healthy volunteer. DISCUSSION: 19F MRS can be utilized to detect topically applied corticosteroids in urine. However, more work is required to optimize and control for extraction procedures, complete spectral assignments and reliable quantification.

Hyaluronic acid-modified betamethasone encapsulated polymeric nanoparticles: fabrication, characterisation, in vitro release kinetics, and dermal targeting.

Atopic dermatitis (AD) is a chronically relapsing eczematous skin disease characterised by frequent episodes of rashes, severe flares, and inflammation. Till date, there is no absolute therapy for the treatment of AD; however, topical corticosteroids (TCs) are the majorly prescribed class of drugs for the management of AD in both adults and children. Though, topical route is most preferable; however, limited penetration of therapeutics across the startum cornum (SC) is one of the major challenges for scientists. Therefore, the present study was attempted to fabricate a moderate-potency TC, betamethasone valerate (BMV), in the form of chitosan nanoparticles (CS-NPs) for optimum dermal targeting and improved penetration across the SC. To further improve the targeting efficiency of BMV and to potentiate its therapeutic efficacy, the fabricated BMV-CS-NPs were coated with hyaluronic acid (HA). The prepared NPs were characterised for particle size, zeta potential, polydispersity index (PDI), entrapment efficiency, loading capacity, crystallinity, thermal behaviour, morphology, in vitro release kinetics, drug permeation across the SC, and percentage of drug retained into various skin layers. Results showed that optimised HA-BMV-CS-NPs exhibited optimum physicochemical characteristics including finest particle size (< 300 ± 28 nm), higher zeta potential (+ 58 ± 8 mV), and high entrapment efficiency (86 ± 5.6%) and loading capacity (34 ± 7.2%). The in vitro release study revealed that HA-BMV-CS-NPs displayed Fickian diffusion-type mechanism of release in simulated skin surface (pH 5.5). Drug permeation efficiency of BMV was comparatively higher in case of BMV-CS-NPs; however, the amount of drug retained into the epidermis and the dermis was comparatively higher in case of HA-BMV-CS-NPs, compared to BMV-CS-NPs. Conclusively, we anticipate that HA-BMV-CS-NPs could be a promising nanodelivery system for efficient dermal targeting of BMV and improved anti-AD efficacy.

Nanoencapsulation of betamethasone valerate using high pressure homogenization-solvent evaporation technique: optimization of formulation and process parameters for efficient dermal targeting.

Betamethsone valerate (BMV), a medium potency topical corticosteroid, is one of the most commonly employed pharmacological agents for the management of atopic dermatitis in both adults and children. Despite having remarkable pharmacological efficacy, these agents have limited clinical implication due to poor penetration across the startum cornum (SC). To mitigate issues related to targeted delivery, stability, and solubility as well as to potentiate therapeutic and clinical implication, the nanodelivery systems have gained remarkable recognition. Therefore, this study was aimed to encapsulate BMV into the chitosan nanoparticles (CS-NPs) for optimum dermal targeting and improved penetration across the SC. The prepared NPs were characterized for particle size, zeta potential, polydispersity index, entrapment efficiency, loading capacity, crystallinity, thermal behavior, morphology, in vitro release kinetics, drug permeation across the SC, and percentage of drug retained into various skin layers. Results showed that optimized BMV-CS-NPs exhibited optimum physicochemical characteristics including small particle size (< 250 ± 28 nm), higher zeta potential (+58 ± 8 mV), and high entrapment efficiency (86 ± 5.6%) and loading capacity (34 ± 7.2%). The in vitro release study revealed that BMV-CS-NPs displayed Fickian-diffusion type mechanism of release in simulated skin surface (pH 5.5). Drug permeation efficiency and the amount of BMV retained into the epidermis and the dermis were comparatively higher in case of BMV-CS-NPs compared to BMV solution. Conclusively, we anticipated that BMV-CS-NPs could be a promising nanodelivery system for efficient dermal targeting of BMV and improved anti-AD efficacy.

Palm Olein Emulsion: a Novel Vehicle for Topical Drug Delivery of Betamethasone 17-Valerate.

This study aims to investigate the use of palm olein as the oil phase for betamethasone 17-valerate (BV) emulsions. The physicochemical properties of the formulations were characterized. In vitro drug release study was performed with the Hanson Vertical Diffusion Cell System; the samples were quantified with HPLC and the results were compared with commercial products. Optimized emulsion formulations were subjected to stability studies for 3 months at temperatures of 4, 25, and 40°C; the betamethasone 17-valerate content was analyzed using HPLC. The formulations produced mean particle size of 2-4 µm, viscosities of 50-250 mPa.s, and zeta potential between -45 and -68 mV. The rheological analyses showed that the emulsions exhibited pseudoplastic and viscoelastic behavior. The in vitro release of BV from palm olein emulsion through cellulose acetate was 4.5 times higher than that of commercial products and more BV molecules deposited in rat skin. Less than 4% of the drug was degraded in the formulations during the 3-month period when they were subjected to the three different temperatures. These findings indicate that palm olein-in-water emulsion can be an alternative vehicle for topical drug delivery system with superior permeability.

Preclinical Assessment of Steroidal Nanostructured Lipid Carriers Based Gels for Atopic Dermatitis: Optimization and Product Development.

BACKGROUND: Betamethasone Valerate (BV) is a potent topical corticosteroid. Preparation of nanostructured lipid carriers (NLC) involves process parameters optimization and formulations were developed. It is available in several conventional formulations like creams and ointments which have well-known problems of frequent dosing and consequently additional side effects. The aim is to ascertain the probability of NLC as an exclusive carrier for betamethasone valerate topical application with regard to release modulation and improved therapeutic effect. METHOD: Preparation of BVNLC formulations involves rigorous broad range optimization of process parameters viz. selection of lipids, surfactants, formulation technique, stirring time, stirring speed and homogenization cycles. Accordingly, optimized parameters were selected and formulation table was developed. Characterizations of developed NLC comprise particle shape, size, zeta potential, percent drug entrapment, in vitro drug release studies. The optimized NLC formulation was gelled and evaluated for ex vivo permeation studies and preclinical anti-inflammatory testing. RESULTS: The permeation studies revealed that enhancement ratio of BVNLC based gel was 2.59 folds higher as compared to plain BV gel. Release models indicated anomalous (non-fickian) diffusion viz. drug release is controlled by more than one process i.e. superposition of both phenomenon, the diffusion controlled as well as swelling controlled release. Preclinical studies indicated a significant (P < 0.05) extended anti-inflammatory effect and 16.5% inhibition compared to plain gel. CONCLUSION: The outcome of entire characterization advocates that the developed formulation is efficient as once a day dosing in therapy of atopic dermatitis.

Simultaneous Determination of Cinchocaine Hydrochloride and Betamethasone Valerate in Presence of Their Degradation Products.

Cinchocaine hydrochloride (CIN) and betamethasone valerate (BMV) are co-formulated in pharmaceutical formulations that could be used for local treatment of hemorrhoids. Both drugs are susceptible to hydrolytic degradation. Two sensitive and precise stability-indicating chromatographic methods were developed for the simultaneous determination of both active pharmaceutical ingredients. The developed methods were applied for quantitation of CIN and BMV in their pure forms, in presence of their corresponding degradation products and in their pharmaceutical formulation. The first method was a high performance liquid chromatographic (HPLC) one, separation and quantitation was achieved using a Waters Spheriosorb® 5 µm ODS2 C18 analytical column and an isocratic mobile phase formed of acetonitrile-acetate buffer (pH 6.5 ± 0.1) in a ratio of (55:45, v/v). The mobile phase was pumped at a flow rate of 1.2 mL/min. UV-detection was done at 240 nm using photodiode array detector. The second method was based on thin layer chromatography (TLC) fractionation coupled with densitometric determination. Separation was done on high performance thin layer chromatography (HPTLC) silica gel 60F254 plates using a developing system formed of chloroform-toluene-ethanol-acetic acid in a ratio of (4.5:4.5:1:1, by volume). The separated bands were scanned densitometrically at 240 nm. For the HPLC method, linearity was confirmed over concentration ranges of 4-300 and 4-350 µg/mL for CIN and BMV, respectively. For the HPTLC-densitometric method, the obtained ranges were 0.5-12 and 0.5-10 µg/band for CIN and BMV, respectively. The developed methods were optimized and validated according to the ICH guidelines. CIN acid degradation products were separated and identified by mass spectroscopy. The developed HPLC method was used to study the kinetics of acid and alkali degradation of the both drugs. The results obtained were statistically analyzed and compared with those obtained by applying the official methods for both drugs.

Stability of a novel corticosteroid nasal irrigation solution: betamethasone 17-valerate added to extemporaneously prepared nasal irrigation solutions.

BACKGROUND: There are no commercially available nasal irrigation solutions containing corticosteroids. Instead, such preparations are extemporaneously prepared by adding existing corticosteroid formulations to nasal irrigation solutions. The stability of the corticosteroid betamethasone 17-valerate (B17V), in nasal irrigation solutions of different compositions and pH and stored under different temperatures, was studied to determine the optimal choice of solution and storage conditions. METHODS: Triplicate extemporaneous preparations made with B17V were prepared by adding a predetermined volume of B17V lotion to each nasal irrigation solution: normal saline (NS), sodium bicarbonate (NaHCO3 ) powder dissolved in tap water, and a commercially available powder mixture (FLO Sinus Care Powder), dissolved in tap water or pre-boiled tap water. Preparations were stored at 30°C and 4°C. Sampling was carried out at 0, 1, 2, 6, and 24 hours. The concentrations of B17V and its degradation compound, betamethasone 21-valerate (B21V), were determined by high-performance liquid chromatography. RESULTS: Preparations stored at 30°C contained a lower amount of B17V and higher amount of B21V than those stored at 4°C. B17V stability in nasal irrigation solutions decreased in the following order: NS, FLO in fresh tap water, FLO in pre-boiled tap water, and NaHCO3 . The degradation rate of B17V increased with higher storage temperature and higher pH. CONCLUSION: B17V is most stable when added to NS and least stable in NaHCO3 solution. FLO solution prepared with either cooled boiled water or tap water is an alternative if administered immediately. Storage at 4°C can better preserve stability of B17V, over a period of 24 hours.

Formulation factors affecting the isomerization rate of betamethasone-17-valerate in a developmental hydrophilic cream - a HPLC and microscopy based stability study.

The formulation of betamethasone-17-valerate (BV) into topical medicines presents a significant challenge for the formulation chemist. The substance is susceptible to acid and base catalyzed isomerization in aqueous environments, which results in valerate transesterification from carbon 17 to carbon 21 of the steroid ring system. This acyl migration process is of significant clinical importance since the 21-valerate ester possesses only a fraction of the potency of the 17-valerate parent compound. Isomerization of BV should therefore be reduced to a minimum through design of a suitable drug vehicle. In this study, the effect of varying the concentration of several excipient components on the isomerization rate of betamethasone valerate in a model hydrophilic cream has been investigated. These excipients include the emulsifier macrogolstearylether-20/21, the co-emulsifier cetylstearyl alcohol and the thickening agent hydroxyl propyl methylcellulose. Additionally, the influence of pH, the presence of the antioxidant, alpha-tocopherol, as well as the chelating agent, disodium edetate, on the stability of the formulation have been investigated. Trial drug product formulations, which were designed to investigate the influence of the above-mentioned components/parameters were manufactured and their stability was tested according to current ICH Guidelines. The content, purity and crystalline structure of the active substance in these formulations was analyzed by a combination of HPLC and microscopy techniques. The study demonstrates that the rate of isomerization of betamethasone valerate depends significantly on the concentration of emulsifier used in the cream formulation. At higher concentrations of emulsifier the isomerization proceeds rapidly with significant degradation over a period of weeks, whereas at lower concentrations significant degradation may not be observed, even after several years' storage. The influence of the emulsifier has been shown to be independent of the pH value of the aqueous phase of the cream. These findings have not been reported in previous literature reports on this topic, which have tended to focus on the influence of pH. The results are likely to be of interest to pharmaceutical chemists working on the formulation of glucocorticoids as well as to local- and hospital pharmacists who carry out the practice of dilution of proprietary corticoid preparations, where the choice of diluent is likely to be critical for ensuring the stability of the diluted product.

Effective topical delivery systems for corticosteroids: dermatological and histological evaluations.

Atopic dermatitis (AD) is a chronic and relapsing skin disease with severe eczematous lesions. Long-term topical corticosteroid treatment can induce skin atrophy, hypopigmentation and transepidermal water loss (TEWL) increase. A new treatment approach was needed to reduce the risk by dermal targeting. For this purpose, Betamethasone valerate (BMV)/Diflucortolone valerate (DFV)-loaded liposomes (220-350 nm) were prepared and incorporated into chitosan gel to obtain adequate viscosity (∼13 000 cps). Drugs were localized in stratum corneum + epidermis of rat skin in ex-vivo permeation studies. The toxicity was assessed on human fibroblast cells. In point of in-vivo studies, pharmacodynamic responses, treatment efficacy and skin irritation were evaluated and compared with previously prepared nanoparticles. Liposome/nanoparticle in gel formulations produced higher paw edema inhibition in rats with respect to the commercial cream. Similar skin blanching effect with commercial creams was obtained via liposome in gels although they contain 10 times less drug. Dermatological scoring results, prognostic histological parameters and suppression of mast cell numbers showed higher treatment efficiency of liposome/nanoparticle in gel formulations in AD-induced rats. TEWL and erythema measurements confirmed these results. Overview of obtained results showed that liposomes might be an effective and safe carrier for corticosteroids in skin disease treatment.

Development and validation of an UHPLC method for the determination of betamethasone valerate in cream, gel, ointment and lotion.

An ultra high performance liquid chromatographic method has been developed and validated for the determination of betamethasone valerate (BMV) in topical dermatologic formulations. For the development of the method, response surface methodology based on a three-level full factorial design was used. The eluent composition, the column dimension and the flow rate were chosen as relevant experimental parameters to investigate. The response surface plots revealed an optimum separation by using a RP column (30 mm × 2 mm i.d., 2.2 µm particle size), at 30 °C; isocratic mobile phase consisting of acetonitrile:water (60:40) at a flow rate of 0.2 mL min(-1) and a wavelength set at 254 nm. The proposed method was validated for four types of matrices according to ICH guidelines requirements. Dexamethasone acetate (DMA) was used as internal standard. Linearity was studied in the range of 5-200 µg mL(-1) for BMV in spiked matrix samples. Recoveries were in the range of 95-105% and precision was better than 5% for both analytes, either in cream, gel, ointment, or lotion formulations, when using simple sample preparation. Retention times were 0.95 min for DMA and 1.40 min for BMV, demonstrating a short method run time. The method was successfully applied for routine analysis of dermatological formulations containing betamethasone valerate.

Biophysical elucidation of the mechanism of enhanced drug release and topical delivery from polymeric film-forming systems.

The effect of incorporating the lipidic medium-chain triglyceride (MCT) into polymeric film-forming systems (FFS) for topical drug delivery has been evaluated. First, the in vitro release of betamethasone-17-valerate (BMV), a representative dermatological drug, was determined from FFS comprising either hydrophobic polyacrylate co-polymers, or hydrophilic hydroxypropyl cellulose, with and without MCT. Release was enhanced from both polymers in the presence of MCT. Atomic force microscopy imaging and nanoindentation of FFS with MCT revealed two-phase structured films with softer inclusions (0.5 to 4µm in diameter) surrounded by a more rigid structure. Chemical mapping with Raman micro-spectroscopy showed that MCT was primarily confined to the inclusions within the polymer, which predominated in the surrounding film. BMV was distributed throughout the film but was more concentrated outside the inclusions. Furthermore, while BMV dissolved better into the hydrophobic films, it was more soluble in the MCT inclusions in hydrophilic films, suggesting its increased availability for diffusion from these softer regions of the polymer and explaining the release enhancement observed. Second, ex vivo skin penetration studies clearly revealed that uptake of BMV was higher from hydrophobic FFS than that from the more hydrophilic polymer due, at least in part, to the superior anti-nucleation efficiency of the former. Drug was quickly taken up into the SC from which it then diffused continuously over a sustained period into the lower, viable skin layers. In the presence of MCT, the overall uptake of BMV was increased and provides the basis for further optimisation of FFS as simple, convenient and sustained formulations for topical therapy.

An RP-HPLC Method for the Stability-Indicating Analysis of Impurities of Both Fusidic Acid and Betamethasone-17-Valerate in a Semi-Solid Pharmaceutical Dosage Form.

A topical pharmaceutical cream containing the active pharmaceutical ingredients (APIs) betamethasone-17-valerate and fusidic acid has been developed for the treatment of inflammatory skin conditions and associated secondary infections. In this work, a novel stability-indicating RP-HPLC method has been developed for the simultaneous quantitation of impurities of both APIs present in this cream. The HPLC column was a 150 mm × 4.6 mm I.D. YMC-Pack Pro C18 column with 3 µm particles. The column-oven temperature was maintained at 40°C and UV detection at 235 nm was used. A gradient programme was employed at a flow rate of 0.7 mL/min. Mobile phase A comprised of a 16:21:21:42 (v/v/v/v) mixture of methanol, 10 g/L phosphoric acid, HPLC grade water and acetonitrile. Mobile phase B comprised of a 24:5:5:66 (v/v/v/v) mixture of methanol, 10 g/L phosphoric acid, HPLC grade water and acetonitrile. The method has been validated according to current International Conference on Harmonisation (ICH) guidelines and applied during formulation development and stability studies. The procedure has been shown to be stability-indicating for the topical cream.

Formulation considerations in the design of topical, polymeric film-forming systems for sustained drug delivery to the skin.

Polymeric film-forming systems (FFSs) are potential drug delivery systems for topical application to the skin. The FFSs form thin and transparent polymeric films in situ upon solvent evaporation. Their application convenience and cosmetic attributes, superior to conventional semi-solids, may offer improved patient compliance. This study represents the first phase of an investigation into the use of FFSs for prolonged dermal drug delivery. FFS formulations were distinguished based on their ability to sustain the release of betamethasone 17-valerate (BMV) in vitro over 72 h. The effect of film-forming polymer (hydrophilic: hydroxypropyl cellulose (Klucel™ LF); hydrophobic: polymethacrylate copolymers (Eudragit® NE and Eudragit® RS), and polyacrylate copolymer (Dermacryl® 79) was first determined, and then the impact of incorporation of plasticisers (triethyl citrate, tributyl citrate, and dibutyl sebacate) was examined. The Klucel film released a significantly higher amount of BMV than the hydrophobic FFS, 42 versus 4 µg/cm(2), respectively. The release was increased when a plasticiser was incorporated, and with higher enhancement ratios achieved with the more lipophilic plasticisers. In conclusion, the results show that FFSs can sustain drug release (hence representing useful systems for prolonged dermal therapy) and emphasise the importance of the formulation on drug delivery, with the type of polymer being of greatest significance.

Development and validation of a novel stability-indicating HPLC method for the simultaneous assay of betamethasone-17-valerate, fusidic acid, potassium sorbate, methylparaben and propylparaben in a topical cream preparation.

A novel stability-indicating reversed phase high performance liquid chromatographic (RP-HPLC) method for the simultaneous assay of betamethasone-17-valerate, fusidic acid and potassium sorbate as well as methyl- and propylparaben in a topical cream preparation has been developed. A 100mm×3.0mm ID. Ascentis Express C18 column maintained at 30°C and UV detection at 240nm were used. A gradient programme was employed at a flow-rate of 0.75ml/min. Mobile phase A comprised of an 83:17 (v/v) mixture of acetonitrile and methanol and mobile phase B of a 10g/l solution of 85% phosphoric acid in purified water. The method has been validated according to current International Conference on Harmonisation (ICH) guidelines and applied during formulation development and stability studies. The procedure has been shown to be stability-indicating for the topical cream.

Topical corticosteroid delivery into human skin using hydrofluoroalkane metered dose aerosol sprays.

Drug loaded hydrofluoroalkane (HFA) sprays can generate effective pharmaceutical formulations, but a deeper understanding of the manner in which these dynamic systems drive the process of in situ semi-solid dosage form assembly is required. The aim of this study was to investigate the effect of the matrix assembly and composition on drug localisation in human skin. Comparing the characteristics of sprays constituting HFA 134a, ethanol (EtOH), poly(vinyl pyrrolidone) K90, isopropyl myristate (IPM), and poly(ethylene glycol) (PEG) demonstrated that the addition of non-volatile solvents acted to delay EtOH evaporation, control the degree of drug saturation (DS) and enhance the corticosteroid delivery from HFA spray formulations. In a dose matched skin penetration study the HFA sprays containing only EtOH as a co-solvent delivered 2.1 µg BMV (DS 13.5) into the tissue, adding IPM to the EtOH HFA delivered 4.03 µg BMV (DS 11.2), whist adding PEG to the EtOH HFA delivered 6.1 µg BMV (DS 0.3). Compared to commercial cream (delivering 0.91 µg BMV) the EtOH/PEG HFA spray deposited over 6 times (p<0.05) more drug into the skin. Post spray deposition characterisation of the semi-solid suggested that the superior performance of the EtOH/PEG HFA spray was a consequence of retarding EtOH evaporation and presenting the drug in an EtOH rich PEG residual phase, which promoted BMV passage through the SC and into epidermis.

Comparison of PLGA and lecithin/chitosan nanoparticles for dermal targeting of betamethasone valerate.

Poly(lactide-co-glycolide) (PLGA) and lecithin/chitosan (LC) nanoparticles were prepared to evaluate the difference in the behavior upon administration on skin, for steroidal treatment. For this purpose, betamethasone-17-valerate (BMV)-loaded nanoparticles with a narrow size distribution and high entrapment efficiency were prepared. Permeation studies showed that both polymeric nanoparticles enhanced the amount of BMV in epidermis, which is the target site of topical steroidal treatment, when compared with commercial formulation. 1.58-Fold increase was determined in the epidermis concentration of BMV by LC nanoparticles with respect to PLGA nanoparticles. Nanoparticles were diluted in chitosan gel (10%, w/w) to prepare suitable formulation for topical application. Accumulation from both gel formulations were found significantly higher than commercial formulation in skin layers (p < 0.05). In addition, pharmacodynamic responses were also investigated as anti-inflammatory and skin-blanching parameters. Both formulations significantly improved these parameters although they contained 10 times less amount of BMV than commercial cream. Moreover, TEWL measurement exhibited no barrier function changes upon the application of nanoparticles on skin. Overall, both nanoparticles improved the localization of BMV within skin layers; but when compared with PLGA nanoparticles, the LC nanoparticles could be classified as a better candidate for topical delivery vehicle in the treatment of various dermatological inflammatory diseases.

Photodegradation and stabilization of betamethasone-17 valerate in aqueous/organic solvents and topical formulations.

The effects of solvent [acetonitrile, methanol, and acetonitrile/water mixture (20:80, v/v)], buffer concentration (phosphate buffer, pH 7.5), ionic strength and commonly employed adjuvants on the photodegradation of betamethasone-17 valerate in cream and gel formulations have been studied on exposure to UV light (300-400 nm). A validated high-performance liquid chromatography method has been used to determine the parent compound and its photodegraded products. The photodegradation data in the studied solvents showed greater decomposition of the drug in solvents with a lower dielectric constant. A comparatively higher rate of photodegradation was observed in the cream formulation compared to that for the gel formulation. The kinetic treatment of the photodegradation data revealed that the degradation of the drug follows first-order kinetics and the apparent first-order rate constants for the photodegradation reactions, in the media studied, range from 1.62 to 11.30×10(-3) min(-1). The values of the rate constants decrease with increasing phosphate concentration and ionic strength which could be due to the deactivation of the excited state and radical quenching. The second-order rate constant (k') for the phosphate ion-inhibited reactions at pH 7.5 has been found to be 5.22×10(-2) M(-1) s(-1). An effective photostabilization of the drug has been achieved in cream and gel formulations with titanium dioxide (33.5-42.5%), vanillin (21.6-28.7%), and butyl hydroxytoluene (18.2-21.6%).