Effect of nonionic surfactants on the percutaneous absorption tenoxicam

Safety Assessment of Polyglyceryl Fatty Acid Esters as Used in Cosmetics

The Expert Panel for Cosmetic Ingredient Safety (Panel) assessed the safety of 274 polyglyceryl fatty acid esters. Each of the esters in this group is a polyether comprising 2 to 20 glyceryl residues, end-capped by esterification with simple carboxylic acids, such as fatty acids. Most of these ingredients are reported to function in cosmetics as skin-conditioning agents and/or surfactants. The Panel reviewed the available data and considered conclusions from their relevant previous reports, and determined that these ingredients are safe in cosmetics in the present practices of use and concentration described in this safety assessment when formulated to be non-irritating.

Quality by Design Assisted Optimization and Risk Assessment of Black Cohosh Loaded Ethosomal Gel for Menopause: Investigating Different Formulation and Process Variables

Black cohosh (Cimicifuga racemosa) (CR) is a popular herb and is medically lauded for ameliorating myriad symptoms associated with menopause. However, its pharmaceutical limitations and non-availability of a patient-compliant drug delivery approach have precluded its prevalent use. Henceforth, the current research premise is aimed at developing an ethosomal gel incorporating triterpene enriched fraction (TEF) obtained from CR and evaluating its effectiveness through the transdermal application. TEF-loaded ethosomes were formulated using solvent injection, optimized and characterised. The optimized ethosomes were then dispersed into a polymeric gel base to form ethosomal gel which was further compared with the conventional gel by in-vitro and ex-vivo experiments. Here, the quality by design (QbD) approach was exploited for the optimization and development of ethosomal gel. The elements of QbD comprising initial risk assessment, design of experimentation (DoE), and model validation for the development of formulation have all been described in detail. The optimized ethosomes (F03) showed a nanometric size range, negative zeta potential and good entrapment. The in vitro release profile of gel revealed a burst release pattern following the Korsmeyer Peppas model having Fickian diffusion. The transdermal flux of ethosomal gel was observed to be more than that of conventional gel. Texture analysis and rheological characterization of the gel, revealed good strength showing shear thinning and pseudoplastic behaviour. The confocal microscope investigation revealed the deeper skin permeation of ethosomal gel than conventional gel. This result was further strengthened by DSC, IR and histological assessment of the animal skin (Wistar rat), treated with the optimized formulation. Conclusively, the implementation of QbD in the formulation resulted in a better understanding of the process and the product. It aids in the reduction of product variability and defects, hence improving product development efficiencies. Additionally, the ethosomal gel was found to be a more effective and successful carrier for TEF than the conventional gel through the transdermal route. Moreover, this demands an appropriate animal study, which is underway, for a stronger outcome.

Investigation of partially myristoylated carboxymethyl chitosan, an amphoteric-amphiphilic chitosan derivative, as a new material for cosmetic and dermal application

Background

Cationic amphiphilic chitosan derivatives can form polymeric micelles, which are useful cosmetic materials, but they form polyion complexes with anionic polymers, which can cause formulation difficulties.

Aims

This study aimed to evaluate the usefulness of partially myristoylated carboxymethyl chitosan, an amphoteric‐amphiphilic chitosan derivative, as a new material for cosmetics in the absence of a surfactant comprising an anionic polymer.

Methods

An anionic polymer and 1,2‐decanediol (an antimicrobial agent)‐containing partially myristoylated carboxymethyl chitosan nanoemulsified lotion and glabridin (an antimelanogenic agent)‐containing partially myristoylated carboxymethyl chitosan polymeric micelle were prepared using a pressure homogenization method. The release of interleukin‐1α, cell viability, and melanogenesis inhibition was evaluated on a human skin model. Antimicrobial activity was evaluated using agar dilution method.

Results

A mixture of partially myristoylated carboxymethyl chitosan and carboxyvinyl polymer did not form a polyion complex, but it formed a hydrophilic gel. The anionic polymer‐containing partially myristoylated carboxymethyl chitosan nanoemulsified formulation was stable, with no decrease in cell viability and horny layer exfoliation, which are typically observed with Tween 60. Compared with the formulation with methyl paraben (0.2%), the formulation to which 1,2‐decanediol (0.05%) was added improved the antibacterial activity against methicillin‐resistant Staphylococcus aureus and Propionibacterium acnes; however, no interleukin‐1α upregulation was observed. The glabridin‐containing partially myristoylated carboxymethyl chitosan polymeric micelles enhanced melanogenesis inhibition and percutaneous glabridin delivery to the epidermis compared with conventional emulsified micelles.

Conclusions

These results suggest that partially myristoylated carboxymethyl chitosan‐forming polymeric micelles, in combination with 1,2‐decanediol and glabridin, may be useful for surfactant‐free cosmetic emulsions.

Safety Assessment of Alkyl PEG/PPG Ethers as Used in Cosmetics

The Cosmetic Ingredient Review (CIR) Expert Panel assessed the safety of 131 alkyl polyethylene glycol (PEG)/polypropylene glycol ethers as used in cosmetics, concluding that these ingredients are safe in the present practices of use and concentration described in this safety assessment when formulated to be nonirritating. Most of the alkyl PEG/PPG ethers included in this review are reported to function in cosmetics as surfactants, skin-conditioning agents, and/or emulsifying agents. The alkyl PEG/PPG ethers share very similar physiochemical properties as the alkyl PEG ethers, which were reviewed previously by the CIR Expert Panel and found safe when formulated to be nonirritating. The alkyl PEG ethers differ by the inclusion of PPG repeat units, which are used to fine-tune the surfactant properties of this group. The Panel relied heavily on data on analogous ingredients, extracted from the alkyl PEG ethers and PPG reports, when making its determination of safety.

Effects of Carbopol® 934 proportion on nanoemulsion gel for topical and transdermal drug delivery: a skin permeation study

Nanoemulsions (NEs) are used as transdermal drug delivery systems for systematic therapeutic purposes. We hypothesized that the skin permeation profile of an NE could be modulated by incorporating it into a hydrogel containing differing proportions of thickening agent. The objectives of this study were as follows: 1) to determine the stability and skin irritability of NE gels (NGs) containing 1%, 2%, and 3% (w/w) Carbopol^® 934 (CP934) (termed NG1, NG2, and NG3, respectively); 2) to compare the skin permeation profiles and drug deposition patterns of the NGs; and 3) to visualize the drug delivery routes of the NGs. Terbinafine and citral were incorporated into the NGs as model drugs. Ex vivo skin permeation tests indicated that the percutaneous flux rates of terbinafine decreased in the order NE (215 μg/cm²) > NG1 (213 μg/cm²) > NG2 (123 μg/cm²) > NG3 (74.3 μg/cm²). The flux rates of citral decreased in the order NE (1,026 μg/cm²) > NG1 (1,021 μg/cm²) > NG2 (541 μg/cm²) > NG3 (353 μg/cm²). The NGs accumulated greater amounts of the drugs in the stratum corneum and less in the epidermis/dermis than did the NE (P<0.05) over a period of 12 h. Laser scanning confocal microscopy indicated that the NGs altered the main drug delivery routes from skin appendages to intercellular paths. Histological images suggested that perturbations to the skin structure, specifically the size of the epidermal intercellular spaces and the separation distance of dermal collagen bundles, could be significantly minimized by increasing the proportion of CP934. These results suggest that adjustments of the CP934 proportions can be used to modulate the skin permeation profiles of NGs for specific therapeutic purposes.

Status of surfactants as penetration enhancers in transdermal drug delivery

Surfactants are found in many existing therapeutic, cosmetic, and agro-chemical preparations. In recent years, surfactants have been employed to enhance the permeation rates of several drugs via transdermal route. The application of transdermal route to a wider range of drugs is limited due to significant barrier to penetration across the skin which is associated with the outermost stratum corneum layer. Surfactants have effects on the permeability characteristics of several biological membranes including skin. They have the potential to solubilize lipids within the stratum corneum. The penetration of the surfactant molecule into the lipid lamellae of the stratum corneum is strongly dependent on the partitioning behavior and solubility of surfactant. Surfactants ranging from hydrophobic agents such as oleic acid to hydrophilic sodium lauryl sulfate have been tested as permeation enhancer to improve drug delivery. This article reviews the status of surfactants as permeation enhancer in transdermal drug delivery of various drugs.

Topical piroxicam in vitro release and in vivo anti-inflammatory and analgesic effects from palm oil esters-based nanocream

INTRODUCTION

During recent years, there has been growing interest in use of topical vehicle systems to assist in drug permeation through the skin. Drugs of interest are usually those that are problematic when given orally, such as piroxicam, a highly effective anti-inflammatory, anti-pyretic, and analgesic, but with the adverse effect of causing gastrointestinal ulcers. The present study investigated the in vitro and in vivo pharmacodynamic activity of a newly synthesized palm oil esters (POEs)-based nanocream containing piroxicam for topical delivery.

METHODS

A ratio of 25:37:38 of POEs: external phase: surfactants (Tween 80:Span 20, in a ratio 80:20), respectively was selected as the basic composition for the production of a nanocream with ideal properties. Various nanocreams were prepared using phosphate-buffered saline as the external phase at three different pH values. The abilities of these formulae to deliver piroxicam were assessed in vitro using a Franz diffusion cell fitted with a cellulose acetate membrane and full thickness rat skin. These formulae were also evaluated in vivo by comparing their anti-inflammatory and analgesic activities with those of the currently marketed gel.

RESULTS

After eight hours, nearly 100% of drug was transferred through the artificial membrane from the prepared formula F3 (phosphate-buffered saline at pH 7.4 as the external phase) and the marketed gel. The steady-state flux through rat skin of all formulae tested was higher than that of the marketed gel. Pharmacodynamically, nanocream formula F3 exhibited the highest anti- inflammatory and analgesic effects as compared with the other formulae.

CONCLUSION

The nanocream containing the newly synthesized POEs was successful for trans-dermal delivery of piroxicam.

Bioavailability of nerodilol-based transdermal therapeutic system of nicorandil in human volunteers

The objective of the present investigation was to design and evaluate a nerodilol-based transdermal therapeutic system (TTS) for finding its ability in providing the desired steady-state plasma concentration of nicorandil in human volunteers. The influence of EVA2825 membrane, adhesive-coated EVA2825 membrane and adhesive-coated EVA2825-rat skin composite on the in vitro permeation of nicorandil from a nerodilol-based HPMC gel drug reservoir was studied against a control (excised rat skin alone). The flux of nicorandil from the nerodilol-based HMPC drug reservoir across excised rat skin (control) was 384.0+/-4.6 microg/cm2 h and this decreased to 222.7+/-7.1 microg/cm2 h when studied across EVA2825 membrane indicating that EVA2825 membrane was effective as rate controlling membrane. The flux of the drug decreased to 183.8+/-5.7 microg/cm2 h on application of a water-based acrylic adhesive (TACKWHITE A 4MED) coat to EVA2825 membrane. However, the flux of nicorandil across adhesive-coated EVA2825-membrane-rat-skin composite was 164.8+/-1.8 microg/cm2 h, which was 1.74-times of the required flux that prompted for preparation of TTS. The nerodilol-based drug reservoir system was sandwiched between a composite of adhesive-coated EVA2825 membrane-release liner and a backing membrane. The resultant sandwich was heat-sealed to produce circle-shaped TTS (20 cm2) that were subjected to bioavailability study in human volunteers against immediate release nicorandil tablet. The nerodilol-based TTS provided a steady-state plasma concentration of 25.5 ng/ml for 24 h in human volunteers. It was concluded that the nerodilol-based TTS of nicorandil provided the desired plasma concentration of the drug for the predetermined period of time with minimal fluctuations.

Formulation of an HPMC Gel Drug Reservoir System with Ethanol-Water as a Solvent System and Limonene as a Penetration Enhancer for Enhancing in vitro Transdermal Delivery of Nicorandil

The objective of the present study was to formulate a hydroxypropyl methylcellulose (HPMC) gel drug reservoir system with ethanol-water as a solvent system and limonene as a penetration enhancer for enhancing the transdermal delivery of nicorandil so as to develop and fabricate a membrane-moderated transdermal therapeutic system (TTS). The in vitro permeation of nicorandil was determined across rat abdominal skin from a solvent system consisting of ethanol or various proportions of ethanol and water. The ethanol-water (70:30 v/v) solvent system that provided an optimal transdermal permeation was used in formulating an HPMC gel drug reservoir system with selected concentrations (0% w/w, 4% w/w, 6% w/w, 8% w/w or 10% w/w) of limonene as a penetration enhancer for further enhancement of transdermal permeation of nicorandil. The amount of nicorandil permeated in 24 h was found increased with an increase in the concentration of limonene in the drug reservoir system up to a concentration of 6% w/w, but beyond this concentration there was no further increase in the amount of drug permeated. The flux of nicorandil was 370.9 +/- 4.2 microg/cm2 x h from the drug reservoir system with 6% w/w of limonene, which is about 2.6 times the required flux to be obtained across rat abdominal skin for producing the desired plasma concentration for the predetermined period in humans. The results of a Fourier Transform Infrared study indicated that limonene enhanced the percutaneous permeation of nicorandil by partially extracting the stratum corneum lipids. It is concluded that the HPMC gel drug reservoir system prepared with a 70:30 v/v ethanol-water solvent system containing 6% w/w of limonene is useful in designing and fabricating a membrane-moderated TTS of nicorandil.

Enhanced percutaneous absoption of piroxicam via salt formation with ethanolamines

PURPOSE

The aim of this work was to prepare piroxicam-ethanolamine salts (PX-EAs) with improved physicochemical properties for transdermal application.

METHODS

The physicochemical properties of prepared salts were investigated by DSC and FT-IR. Their percutaneous absorption characteristics across hairless mouse skin and the effect of various enhancers were studied using a flow-through diffusion cell system.

RESULTS

Three piroxicam-ethanolamine salts were prepared. Piroxicam monoethanolamine salt (PX-MEA) and piroxicam diethanolamine salt (PX-DEA) had higher solubility than piroxicam in most of vehicles tested and a higher permeation rate across the skin. The solubility and permeation rate of piroxicam triethanolamine salt (PX-TEA) was lower than those of piroxicam in most of vehicles tested. However, there was no significant change in octanol/water partition coefficient by salt formation. Salt formation lowered the melting point of piroxicam and, of the systems examined, PX-DEA showed the lowest melting point. When the effect of various enhancers were evaluated, nonionic surfactants having medium HLB, an alkyl chain length of C18 and an ethylene oxide chain were better able to modify the permeability of the stratum corneum and to promote the effective penetration of piroxicam and PX-EAs.

CONCLUSIONS

Piroxicam salt formation with MEA and DEA improved the physicochemical properties and enhanced the skin permeability of piroxicam.