In vitro and in vivo characteristics of a thermogelling rectal delivery system of etodolac

Rectal etodolac-Poloxamer gel systems composed of Poloxamer and bioadhesive polymers were developed and evaluated. Hydroxypropylmethyl cellulose, poly)vinyl) pyrrolidone, methyl cellulose, hydroxyethylcellulose, and carbopol were examined as mucoadhesive polymers. The characteristics of the rectal gels differed according to the properties of mucoadhesive polymers. The physicochemical properties such as gelation temperature, gel strength, and bioadhesive force of various formulations were investigated. The analysis of release mechanism showed that the release of etodolac was proportional to the square root of time, indicating that etodolac might be released from the suppositories by Fickian diffusion. The anti-inflammatory effect of etodolac-Poloxamer gel system was also studied in rats. Moreover, liquid suppository of etodolac did not cause any morphological damage to the rectal tissues. These results suggested that in situ gelling liquid suppository with etodolac and mucoadhesive polymer was a physically safe, convenient, and effective rectal dosage form for etodolac.

A light-emitting mouse to image skin inflammation

BACKGROUND

The mouse ear swelling test is a well-accepted method for quantitating the inflammatory response to contact irritants and sensitizing agents. However, this assay measures edema rather than the cellular component of skin inflammation.

OBJECTIVE

To develop a quantitative and noninvasive assay of inflammatory cell infiltration in contact dermatitis.

METHODS

We bred a transgenic bioluminescent mouse that emits light proportional to cutaneous infiltration of inflammatory cells. We characterized this model by correlating luminescence with edema and histologic analysis of affected skin. A mouse strain expressing cyclization recombinase enzyme (cre) recombinase exclusively in myeloid cells was crossed with a reporter strain containing an inactivated form of the luciferase gene. In progeny mice, cre-mediated recombination repaired the luciferase gene, causing light emission from myeloid cells. Light emission and swelling from the inflamed ear was quantitated and compared to the contralateral ear.

RESULTS

Light intensity correlated with the inflammatory cell infiltration in the dermis. In sensitized mice challenged with squaric acid, luminescence increased about 2.2-fold while swelling increased about 1.5-fold.

CONCLUSION

Our model may serve as a useful screening assay for topical antiinflammatory molecules. Moreover, this approach allows real-time imaging of skin infiltration by specific inflammatory cell lineages in living animals.

European Oncology Nursing Society extravasation guidelines

An infrequent, but potential complication of chemotherapy is vesicant chemotherapy extravasation. Vesicants have the potential to cause blistering and ulceration when they extravasate from the vein or are inadvertently administered into the tissue. In 2007, the European Oncology Nursing Society published guidelines for extravasation prevention, detection, and management. Recommended management includes topical heating for plant alkaloid extravasations and topical cooling for anthracycline and other antitumor antibiotic vesicants. For treatment of antracycline extravasations topical dimethylsulfoxide (DMSO), sodium thiosulfate, and hyaluronidase have been described in the literature but due to lack of evidence to support their use as vesicant extravasation antidotes, it is recommended that these agents are studied further. Furthermore, Savene (dexrazoxane) is the only registered drug for the treatment of antracycline extravasation. Nurses need to be aware of current evidence-based guidelines for detecting and managing vesicant extravasations and need to be prepared to administer evidence-based treatment.

Amphiphilic Gels as a Potential Carrier for Topical Drug Delivery

This study involves development of amphiphilic gels consisting solely of nonionic surfactants bearing cyclosporine and characterized for microstructure, gelation temperature, and in vitro drug release into dermis. The formulation is nonirritant and suitable for topical application. Gels consisting of cyclosporine were prepared using different methods by mixing the solid gelator (sorbitan or glyceryl fatty acid esters) and the liquid phase (liquid sorbitan esters or polysorbates) and heating them at 60 degrees C to form a clear isotropic sol phase, and cooling this sol phase to form an opaque semisolid at room temperature. Gel microstructure was examined by phase contrast microscopy while gelation temperatures were measured by melting point apparatus and differential scanning calorimetry. These amphiphilic gels were evaluated in vitro for topical as well as transdermal delivery using rat skin mounted in a Franz diffusion cell. Gel microstructures consisted mainly of clusters of tubules of gelator molecules that had aggregated upon cooling of the sol phase, forming a 3D network throughout the continuous phase. The gels demonstrated thermoreversibility with robust gel network. At temperatures near the skin surface temperature, the gels softened considerably and moreover, it facilitated the drug to accumulate in dermis, thus making an ideal delivery vehicle of cyclosporine topically that can be used in treatment of psoriasis. Thus amphiphilic gels were demonstrated as the ideal vehicle for topical use of cyclosporine.

Environmentally Responsive Ophthalmic Gel Formulation of Carteolol Hydrochloride

Environmentally responsive gel formulation for ocular controlled delivery of carteolol hydrochloride (HCl) was developed in an attempt to improve ocular bioavailability and hence decrease its systemic absorption and side effects. The viscosity and the ability of the prepared formulations to deliver carteolol HCl in vitro and in vivo were monitored and compared with an aqueous commercial solution. The effect of polymer concentration and drug concentration on the in vitro release of carteolol HCl was examined. Gelrite formulations showed pseudoplastic behavior with thixotropic characteristics and the viscosity of the prepared systems increased as the concentration of the polymer increased. At fixed drug concentrations, as the Gelrite concentration increased, the drug release decreased. At fixed polymer concentrations, as the drug concentration increased the release of drug increased. Gelrite formulation (0.4% w/w) containing 1% drug showed significantly improved bioavailability compared with the commercial aqueous solution (Arteoptic 1%). The developed in situ gel formulation showed potential for use as delivery systems with superior ocular bioavailability of carteolol HCl.

Preparation and Evaluation of Sustained Ophthalmic Gel of Enoxacin

The poor bioavailability and therapeutic response exhibited by conventional ophthalmic solutions due to rapid precorneal elimination of the drug may be overcome by the use of a gel system. The present work describes the formulation and evaluation of an ophthalmic delivery system containing an antibacterial agent, enoxacin, based on the concept of ophthalmic sustained gel, in which 2-hydroxypropyl-beta-cyclo-dextrin (HP-beta-CD) was used as a penetration enhancer in combination with hydroxypropylmethylcellulose (Methocel F4M) which acted as a vehicle. The developed formulation was therapeutically efficacious, nonirritant, and provided sustained release of the drug over 8 h period in vitro and 7 h period in vivo. The developed system is a viable alternative to conventional eye drops.

Bicontinuous Water-AOT/Tween85-Isopropyl Myristate Microemulsion: A New Vehicle for Transdermal Delivery of Cyclosporin A

The purpose of this study was to investigate the influence of structure and composition of microemulsions (AOT/Tween85/isopropyl myristate/water) on their transdermal delivery potential of a lipophilic model drug (Cyclosporin A), and to compare the drug delivery potential of microemulsion to the suspension of drug in normal saline containing 20% ethanol. Their type and structure were examined by measuring surface tension, density, viscometry, and electric conductivity; the degree of agreement between the techniques was assessed. Transdermal flux of Cyclosporin A through rat skin was determined in vitro using Franz-type diffusion cells. Results of conducting, viscosity, and surface tension measurement confirmed the prediction transition to a bicontinuous structure. The microemulsions increased transdermal drug delivery of Cyclosporin A up to 10 times compared to the suspension. The increased transdermal delivery was found to be due mainly to water concentration and appeared to be dependent on the structure of the microemulsions.

Management of skin conditions in the older population 2

This is the second of two papers covering assessment and management of elderly skin. Part 1 of this clinical review focused on the importance of a comprehensive assessment of the skin and a detailed clinical history of the patient (Bianchi and Cameron, 2008). This second paper considers some common dermatological conditions seen in the older adult and explores suitable management strategies.

Evaluating the nickel content in metal alloys and the threshold for nickel-induced allergic contact dermatitis

Many patients are currently suffering from nickel (Ni)-induced allergic contact dermatitis (ACD). There have been few Korean studies dealing with the threshold of Ni-induced ACD and quantifying the total amount of Ni in the metal alloys. The aim of this study is to evaluate the amount of Ni leached from metal alloys and Ni contents in metal alloys, and to estimate the threshold of Ni-induced ACD. All the earrings we examined leached below 0.5 microg/cm(2)/week, the upper limit of European Union (EU) regulation, but the other metal alloys leached a much higher amount of Ni than the limit. Likewise, all the earrings we examined contained less than 0.05% Ni (500 microg/g), the upper limit of EU regulation, but the other metal alloys exceeded this limit. Twenty Ni-sensitive subjects, who were patch-tested with various concentrations of Ni sulphate, showed positive reactions to 5% and 1% Ni sulphate, 10 subjects showed positive reactions to 0.01%, and the most sensitive subject showed reaction even to 0.0001%. The subjects in this study were more sensitive to Ni than those in the previous studies done in Europe. Taken together, strictly regulating the Ni-containing alloys that are made in Korea is needed to lower the occurrence of Ni-induced ACD.

Characterisation of the chemical and biological properties of molecules with QSAR/QSPR and chemical grouping, and its application to a group of alkyl ethers

This study presents a QSAR/QSPR modelling and chemical grouping (read-across) approach to provide information on the biological properties of a group of aliphatic ethers, with accurate biological predictions restricted to those physico-chemical and (eco)toxicological properties where the performance of QSAR/QSPR has been shown to be acceptable. The mathematical methods used ranged from multivariate regression models to PLS (partial least-squares), SVM (support vector machines) and Sammon's mapping. A novel grouping approach, based on a set of key descriptors, has been proposed to give a compact picture of the structural and biological properties of the compounds, and to provide a more mechanistic basis for the interpretations of chemical groups. Besides being a straightforward case study, the paper also exemplifies the capabilities and limitations of the methods in predictive toxicology on a more general level.

Anti-Inflammatory Activity of Sertaconazole Nitrate Is Mediated via Activation of a p38–COX-2–PGE2 Pathway

Sertaconazole nitrate is an antifungal agent that exhibits anti-inflammatory activity; however, the mechanism for this action was unknown. We investigated the cellular mechanisms by which sertaconazole exerts its anti-inflammatory activity in keratinocytes and human peripheral blood mononuclear cells (PBMCs). Paradoxically, sertaconazole was found to activate the proinflammatory p38 mitogen-activated protein kinase. Treatment with sertaconazole also resulted in the induction of cyclooxygenase-2 (COX-2) and the subsequent release of prostaglandin E2 (PGE2). Knocking down p38 in keratinocytes using small interfering RNA resulted in an inhibition of sertaconazole-induced PGE2 release confirming that activation of p38 was required for PGE2 production. Additionally, in stimulated keratinocytes and human PBMCs, sertaconazole was found to suppress the release of cytokines. Treatment with anti-PGE2 antiserum or the COX-2 inhibitor NS398 reversed the inhibitory effects of sertaconazole on the release of proinflammatory cytokines, linking endogenous PGE2 with the anti-inflammatory effects. Finally, in an in vivo mouse model of tetradecanoyl phorbol acetate (TPA)-induced dermatitis, the sertaconazole-mediated inhibition of TPA-induced ear edema was reversed by NS398. Biochemical analysis of tissue biopsies revealed increase in PGE2 levels in sertaconazole-treated mice. Thus, activation of the p38-COX-2-PGE2 pathway by agents such as sertaconazole provides anti-inflammatory therapeutic benefits.

Solid lipid nanoparticles (SLN) of tretinoin: Potential in topical delivery

The objective of this investigation was to develop solid lipid nanoparticles (SLN) of tretinoin (TRE) with the help of facile and simple emulsification-solvent diffusion (ESD) technique and to evaluate the viability of an SLN based gel in improving topical delivery of TRE. The feasibility of fabricating SLN of TRE by the ESD method was successfully demonstrated in this investigation. The developed SLN were characterized for particle size, polydispersity index, entrapment efficiency of TRE and morphology. Studies were carried out to evaluate the ability of SLN in improving the photostability of TRE as compared to TRE in methanol. Encapsulation of TRE in SLN resulted in a significant improvement in its photostability in comparison to methanolic TRE solution and also prevented its isomerization. Furthermore, the skin irritation studies carried out on rabbits showed that SLN based TRE gel is significantly less irritating to skin as compared to marketed TRE cream and clearly indicated its potential in improving the skin tolerability of TRE. In vitro permeation studies through rat skin indicated that an SLN based TRE gel has permeation profile comparable to that of the marketed TRE cream.

The barrier component and the driving force component of transepidermal water loss and their application to skin irritant tests

BACKGROUND/AIM

According to Fick's law of diffusion, the rate of transepidermal water loss (TEWL) is determined by a barrier component and a driving force component. The objective of this study is to propose novel indicators for the assessment of skin irritation potential from chemicals using these components.

METHODS

Before and after acetone/ether (AE), sodium lauryl sulfate (SLS) and nicotinic acid methyl ester (NME) treatments, the apparent mass transfer coefficient of water, K, of the stratum corneum (SC) and the apparent water vapor pressure, P(d), at the interface between SC and epidermis were estimated as measures of the SC barrier and the driving force, respectively.

RESULTS

After AE treatment, K showed marked increase and P(d) remained approximately constant. All participants reacted to NME with erythema and the laser-Doppler flowmetry (LDF) value peaked at around 30 min. While there was a change in P(d), which parallels with LDF changes, K showed little variation. Repeated SLS treatment induced a slight increase in P(d) besides an increase in K. In the meantime, all participants reacted with subtle erythema.

CONCLUSIONS

Our results suggest that not only the SC barrier but also the driving force determines variations in the TEWL rates during skin irritant tests. Together, K and P(d) will provide us with invaluable information about skin condition.

A dorsal model for cutaneous vesicant injury by 2-chloroethyl ethyl sulfide using C57BL/6 mice

To evaluate stem cell-derived therapeutics for cutaneous vesicant injuries, we developed a dorsal exposure model using C57BL/6 black mice and half-mustard, 2-chloroethyl ethyl sulfide (CEES). The dorsal side of a mouse was exposed to 1-5 microl of CEES for 10 minutes and then decontaminated. The data demonstrate that 3 microl of CEES induced edema and erythema that peaked 24 h post exposure. Histopathology showed a central area of deep injury characterized by severe necrosis of epidermis and dermis. The C57BL/6 is a unique model that can be used to unravel the molecular mechanism of injury, identify the effects of black skin pigmentation, and evaluate the efficacy of stem cell therapeutics for cutaneous vesicant exposure.

Electrical impedance model for evaluation of skin irritation in rabbits and humans

BACKGROUND/AIM

The electrical impedance method has been used as a quantitative technique for evaluating changes in the skin during irritation within the invisible range. The purpose of this study was to apply an electrical model of skin to the interpretation of impedance data after the application of an irritant (SLS) in the skin of humans and rabbits.

METHODS

Investigations were performed on 12 humans and 15 albino rabbits. Responses were evaluated by measuring electrical impedance before irritant exposure and 24 h after its removal and also by visual inspection. Using the raw impedance parameter, a novel index was developed and its value was correlated with visual scoring.

RESULTS

The derived impedance index showed a significant correlation with visual scores and its value decreased (P<0.05) after irritant removal even without macroscopic signs of irritation.

CONCLUSION

The proposed electrical model of skin seems to be suitable for the detection and interpretation of changes in the impedance characteristics of skin induced by SLS in rabbits and humans.

Odor frequency and odor annoyance Part II: dose–response associations and their modification by hedonic tone

OBJECTIVE

Risk-assessment for environmental odors and the development of an appropriate guideline for protection against undue odor annoyance have long been hampered by the difficulties of assessing odor exposure and community annoyance responses. In recent years, however, dose-response associations between frequency of odor events and odor annoyance level in the affected population were established. However, the influence of hedonic tone (pleasantness-unpleasantness) and perceived odor strength (intensity) on the degree of odor annoyance have long been neglected in such studies and accompanying guidelines. In order to close this gap a pertinent field study was conducted in the vicinity of six odor emitting plants, two with pleasant (sweets production, rusk bakery), with neutral (textile production, seed oil production), and with presumably unpleasant odor emissions (fat refinery, cast iron production).

METHODS

A standardized sensory method was developed (described in Part I in the accompanying paper) to quantify intensity and hedonic tone within the assessment of odor exposure by systematic field inspection with trained observers. Additionally, exposure-information, the degree of annoyance, and the frequency of general health complaints and irritation symptoms were collected from the exposed residents through direct interviews. Multiple logistic regression analysis was used to establish dose-response associations between odor frequency, intensity and hedonic tone as independent variables and annoyance or symptom reporting as the dependent variable.

RESULTS

It is shown that exposure-annoyance as well as exposure-symptom associations are strongly influenced by odor hedonic. Whereas pleasant odors induced little to no annoyance, both neutral and unpleasant ones did. Additional inclusion of odor intensity did not improve the prediction of odor annoyance. Frequency of reported symptoms was found to be exclusively mediated by annoyance. The results are discussed in terms of environmental stress emphasizing the WHO-definition of health.

CONCLUSIONS

Based on these findings the existing German guideline against undue odor annoyance was modified.

The Comparison Study of Lipo PGE1 Preparations

The comparison study was performed with 3 kinds of Lipo PGE(1) (5 microg/ml) preparations (Formulation A, B, and C), which are now used in clinical. Under alkali condition, Lipo PGE(1) (5 microg/ml) preparations in combination with physiological solution containing calcium ion were susceptible to stop dropping because of the formation of aggregates. There was a difference of feasibility to form aggregates among these preparations. The percentage of PGE(1) in the LM (lipid microspheres) was 68.8% (Formulation A) when determined by filtration with the pore size of 0.1 microm, and the respective value (%) of Formulation B and Formulation C was 43.0% and 13.9%. This indicates that the latter formulations were significantly susceptible to leak from the LM. PGE(1) can induce an extensive irritation. The potency of irritation was the most in Formulation C. This seems similar with the result of LM retention of PGE(1). PGE(1) increased the blood flow. Formulation A reached the peak by 2.27 fold, which was significantly higher than Formulation C and PGE(1) alone (PGE(1)-cyclodextrin, PGE(1)-CD). The peak was also significantly higher in Formulation B than that of PGE(1)-CD. The AUC value of blood flow rate showed a significant increase in Formulation A and Formulation B as compared to that of PGE(1)-CD. Drug retention in the LM can be a determinant factor for drug distribution and pharmacological effect. This study indicates that there can be some differences among Lipo PGE(1) preparations, which have the same drug dose.

Evaluation of lotion formulations on irritation using the modified forearm-controlled application test method

BACKGROUND/PURPOSE

Cold and allergy sufferers often develop irritation around the nostrils as a result of repeated and frequent rubbing of the skin site with facial tissues. This irritation is a combination of the inherent irritant properties of the tissue components (chemical irritation), and mechanical irritation from friction. Lotion-coated facial tissues are being developed to provide soothing, skin benefits, and to promote healing of this type of irritation. The objective of these studies was to evaluate the efficacy of different lotion formulations on facial tissues in preventing irritation, or aiding in the healing of irritation.

METHODS

The modified forearm-controlled application test (Modified FCAT) was adapted as a means of quickly evaluating the relative skin benefits of various lotion formulations used to coat facial tissues. The test was conducted on the volar surface of the forearms of volunteer subjects. Test sites were pretreated with 24 h occlusive patches of sodium lauryl sulfate (SLS) to induce mild or moderate skin irritation. This was followed by repeated wiping of the lotion-coated tissues. Irritation was evaluated using visual scoring for erythema and dryness. Lotion formulation options were compared in the model. Comparisons included assessments of the type of fatty alcohol in the formulation (stearyl and cetearyl alcohol), the presence of silicone and the base formulation (mineral oil, petrolatum of a proprietary formula).

RESULTS

Differences in the degree of erythema and dryness were detected among various formulation options. No differences were found between formulations containing stearyl or cetearyl alcohol. Low levels of silicone produced benefits in one of two experiments. The proprietary base formula produced greater reductions in erythema following treatment of SLS-irritated skin compared with mineral oil and petrolatum bases.

CONCLUSIONS

The results indicated that this modification of the FCAT can be used to compare various lotion formulations for skin benefits and healing properties, and to rank qualitatively the benefits of various formulation options.