Nanoemulsions as vehicles for transdermal delivery of aceclofenac

Pentyl Gallate Nanoemulsions as Potential Topical Treatment of Herpes Labialis

Previous studies have demonstrated the antiherpes activity of pentyl gallate (PG), suggesting that it could be a promising candidate for the topical treatment of human herpes labialis. PG low aqueous solubility represents a major drawback to its incorporation in topical dosage forms. Hence, the feasibility of incorporating PG into nanoemulsions, the ability to penetrate the skin, to inhibit herpes simplex virus (HSV)-1 replication, and to cause dermal sensitization or toxicity were evaluated. Oil/water nanoemulsions containing 0.5% PG were prepared by spontaneous emulsification. The in vitro PG distribution into porcine ear skin after topical application of nanoemulsions was assessed, and the in vitro antiviral activity against HSV-1 replication was evaluated. Acute dermal toxicity and risk of dermal sensitization were evaluated in rat model. Nanoemulsions presented nanometric particle size (from 124.8 to 143.7 nm), high zeta potential (from -50.1 to -66.1 mV), loading efficiency above 99%, and adequate stability during 12 months. All formulations presented anti-HSV-1 activity. PG was able to reach deeper into the dermis more efficiently from the nanoemulsion F4. This formulation as well as PG were considered safe for topical use. Nanoemulsions seem to be a safe and effective approach for topically delivering PG in the treatment of human herpes labialis infection.

Nanoemulsions: formation, properties and applications

Nanoemulsions are kinetically stable liquid-in-liquid dispersions with droplet sizes on the order of 100 nm. Their small size leads to useful properties such as high surface area per unit volume, robust stability, optically transparent appearance, and tunable rheology. Nanoemulsions are finding application in diverse areas such as drug delivery, food, cosmetics, pharmaceuticals, and material synthesis. Additionally, they serve as model systems to understand nanoscale colloidal dispersions. High and low energy methods are used to prepare nanoemulsions, including high pressure homogenization, ultrasonication, phase inversion temperature and emulsion inversion point, as well as recently developed approaches such as bubble bursting method. In this review article, we summarize the major methods to prepare nanoemulsions, theories to predict droplet size, physical conditions and chemical additives which affect droplet stability, and recent applications.

Design, formulation and optimization of novel soft nano-carriers for transdermal olmesartan medoxomil delivery: In vitro characterization and in vivo pharmacokinetic assessment

Olmesartan is a hydrophobic antihypertensive drug with a short biological half-life, and low bioavailability, presents a challenge with respect to its oral administration. The objective of the work was to formulate, optimize and evaluate the transdermal potential of novel vesicular nano-invasomes, containing above anti-hypertensive agent. To achieve the above purpose, soft carriers (viz. nano-invasomes) of olmesartan with β-citronellene as potential permeation enhancer were developed and optimized using Box-Behnken design. The physicochemical characteristics e.g., vesicle size, shape, entrapment efficiency and skin permeability of the nano-invasomes formulations were evaluated. The optimized formulation was further evaluated for in vitro drug release, confocal microscopy and in vivo pharmacokinetic study. The optimum nano-invasomes formulation showed vesicles size of 83.35±3.25nm, entrapment efficiency of 65.21±2.25% and transdermal flux of 32.78±0.703 (μg/cm(2)/h) which were found in agreement with the predicted value generated by Box-Behnken design. Confocal laser microscopy of rat skin showed that optimized formulation was eventually distributed and permeated deep into the skin. The pharmacokinetic study presented that transdermal nano-invasomes formulation showed 1.15 times improvement in bioavailability of olmesartan with respect to the control formulation in Wistar rats. It was concluded that the response surfaces estimated by Design Expert(®) illustrated obvious relationship between formulation factors and response variables and nano-invasomes were found to be a proficient carrier system for transdermal delivery of olmesartan.

Development of intranasal nanovehicles of itraconazole and their immunological activities for the therapy of rhinovirus infection

Itraconazole (ITZ)-loaded microemulsion (ME) systems for intranasal (IN) delivery were developed for the treatment of human rhinovirus serotype 1B (HRV1B) infection. ITZ was incorporated into the oil-in-water (o/w) ME formulation composed of benzyl alcohol (oil), Cremophor EL (surfactant), Solutol HS15 (cosurfactant), and water. The optimized composition of ME was determined by constructing pseudo-ternary phase diagram. ITZ ME formulation with about 150nm mean diameter and spherical shape was prepared and the solubility of ITZ in blank ME was markedly improved (up to 13.9mg/mL). The initial value of droplet size was maintained with four times dilution in the aqueous buffer and 72h incubation. Released amounts of drug from ME formulation were significantly enhanced compared to drug suspension group (p<0.05). Particularly, ITZ ME group displayed lower levels of inflammatory markers in the lung compared to ITZ suspension group after their IN administration in the HRV1B-infected mouse model (p<0.05). Developed ITZ ME formulation via IN route can be a promising candidate for the treatment of rhinovirus infection.

Amelioration of FCA induced arthritis on topical application of curcumin in combination with emu oil

OBJECTIVE

The aim of the present study was to investigate the skin penetration potential of emu oil and the possibility of enhancing the antiarthritic potential of lipophilic bioactive curcumin, which has poor permeability through biological membranes.

METHODS

Solubility and ex vivo skin permeation studies were performed with water, corn oil, and emu oil as a vehicle using curcumin as a model drug. Carrageenan induced inflammation and Freund's complete adjuvant-induced arthritic rat models were used to evaluate enhanced antiinflammatory and antiarthritic effect of curcumin in combination of emu oil via topical route.

RESULTS

The skin permeation study resulted in the combination of emu oil with curcumin enhancing the flux 1.84 and 4.25 times through the rat skin compared to corn oil and water, respectively. Results of carrageenan induced rat paw edema model demonstrated that percentage of paw inhibition shown by curcumin-emu oil combination was 1.42-fold more compared to the total effect shown by both groups treated with curcumin aqueous suspension and emu oil per se. In Freund's complete adjuvant-induced arthritic model, the combined treatment was effective in bringing significant changes in the functional, biochemical, histopathologic, and radiologic parameters. Topical application of curcumin-emu oil combination resulted in significant reduced levels of proinflammatory mediators TNF-α, IL-1 β, and IL-6 (P < 0.05, 0.001, and 0.01, respectively) compared to arthritic animals.

CONCLUSION

Topical delivery of curcumin with emu oil holds promise as a noninvasive and efficacious intervention for the treatment of inflammatory arthritis and it assists in further development of a topical formulation of curcumin using emu oil as a vehicle.

Controlling and predicting droplet size of nanoemulsions: scaling relations with experimental validation

Nanoemulsions possess powerful nano-scale properties that make them attractive for diverse applications such as drug delivery, food supplements, nanoparticle synthesis and pharmaceutical formulation. However, there is little knowledge in nanoemulsion literature about controlling and predicting droplet size. In this article, we propose a scaling relation to predict the dependence of nanoemulsion droplet size with physical properties such as viscosity of the droplet phase and continuous phase, and process parameters such as input power density. We validate our proposed scaling with a wide range of droplet size data from nanoemulsions prepared with high pressure homogenization and ultrasonication. Our proposed scaling also compares favorably with experimental data from literature. The scaling relation can serve as a guiding principle for rational design of nanoemulsions.

Intranasal delivery of paroxetine nanoemulsion via the olfactory region for the management of depression: formulation, behavioural and biochemical estimation

Paroxetine is a selective serotonin reuptake inhibitor (SSRI) and is used for the treatment of depression and anxiety problems, but suffers from the drawback of poor oral bioavailability (less than 50%) due to its extensive first pass metabolism. The objective of the present study was to develop a paroxetine loaded nanoemulsion (o/w type) for direct nose-to-brain delivery. Nanoemulsions were prepared by the spontaneous emulsification technique using Capmul MCM, Solutol HS 15 and propylene glycol as oil phase, surfactant and co-surfactant, respectively, for delivery of drug directly to the brain through the nasal route for better management of depression. Formulations were studied for droplet size, polydispersity index (PDI), percentage transmittance, refractive index, viscosity, zeta potential, surface morphology and in vitro permeation study. TEM images of optimized formulation showed spherical droplets with a mean diameter of 58.47 ± 3.02 nm, PDI of 0.339 ± 0.007 and zeta potential values of -33 mV. The formulation showed good results for transmittance (100.60 ± 0.577%), refractive index (1.412 ± 0.003) and viscosity (40.85 ± 6.40 cP). Permeation studies revealed a 2.57-fold enhancement in permeation as compared to the paroxetine suspension. Behavioural studies such as the forced swimming test and locomotor activity test were done on Wistar rats to study the antidepressant effect of the optimized formulation. Treatment of depressed rats with paroxetine nanoemulsion (administered intranasally) significantly improved the behavioural activities in comparison to paroxetine suspension (orally administered). Biochemical estimation results revealed that the prepared nanoemulsion was effective in enhancing the depressed levels of glutathione and decreasing the elevated levels of TBARS.

Biocompatible Nanoemulsions for Improved Aceclofenac Skin Delivery: Formulation Approach Using Combined Mixture-Process Experimental Design

We aimed to develop lecithin-based nanoemulsions intended for effective aceclofenac (ACF) skin delivery utilizing sucrose esters [sucrose palmitate (SP) and sucrose stearate (SS)] as additional stabilizers and penetration enhancers. To find the suitable surfactant mixtures and levels of process variables (homogenization pressure and number of cycles - high pressure homogenization manufacturing method) that result in drug-loaded nanoemulsions with minimal droplet size and narrow size distribution, a combined mixture-process experimental design was employed. Based on optimization data, selected nanoemulsions were evaluated regarding morphology, surface charge, drug-excipient interactions, physical stability, and in vivo skin performances (skin penetration and irritation potential). The predicted physicochemical properties and storage stability were proved satisfying for ACF-loaded nanoemulsions containing 2% of SP in the blend with 0%-1% of SS and 1%-2% of egg lecithin (produced at 50°C/20 cycles/800 bar). Additionally, the in vivo tape stripping demonstrated superior ACF skin absorption from these nanoemulsions, particularly from those containing 2% of SP, 0.5% of SS, and 1.5% of egg lecithin, when comparing with the sample costabilized by conventional surfactant - polysorbate 80. In summary, the combined mixture-process experimental design was shown as a feasible tool for formulation development of multisurfactant-based nanosized delivery systems with potentially improved overall product performances.

Enhanced delivery of diclofenac diethylamine loaded Eudragit RL 100® transdermal system against inflammation

A transdermal therapeutic system (TTS) of diclofenac diethylamine (DDE) was developed to obtain a prolonged controlled drug delivery by the solvent evaporation technique. The matrix diffusion controlled systems used various combinations of hydrophilic (polyvinylpyrrolidone K30) and lipophilic (Eudragit RL 100® and Eudragit RS 100®) polymers containing dimethyl sulfoxide (DMSO) (0, 5 and 10% w/w) as a penetration enhancer. In vitro drug release was improved with an increased fraction of hydrophilic polymer. Formulation F8 containing Eudragit RL 100® and polyvinylpyrrolidone K30 in the ratio 40:60 presented the highest drug release (92.45%) and permeation rate (0.0988±0.010 mg/cm2/h) with sustained release action for 48 h. In vivo pharmacodynamic study of DDE-loaded Eudragit RL 100® transdermal system (formulation F8) showed significant higher percent inhibition of rat paw edema compared with the marketed formulation of the drug. Our results suggest that a developed formulation is an efficient system for transdermal diclofenac delivery against inflammation. The optimized formulation was found to be stable and did not show physicochemical interaction. The system is envisaged to be stable for a sufficiently long period (2.52 years) at room temperature.

Influence of Solid Drug Delivery System Formulation on Poorly Water-Soluble Drug Dissolution and Permeability

The majority of drugs have a low dissolution rate, which is a limiting step for their absorption. In this manuscript, solid dispersions (SD), solid self-microemulsifying drug delivery systems (S-SMEDDS) and solid self-nanoemulsifying drug delivery systems (S-SNEDDS) were evaluated as potential formulation strategies to increase the dissolution rate of carbamazepine. Influence of increased dissolution rate on permeability of carbamazepine was evaluated using PAMPA test. In S-SMEDDS and S-SNEDDS formulations, the ratio of liquid SMEDDS/SNEDDS and solid carrier (Neusilin^® UFL2) was varied, and carbamazepine content was constant. In SD formulations, the ratio of carbamazepine and Neusilin^® UFL2, was varied. Formulations that showed the best dissolution rate of carbamazepine (SD_1:6, SMEDDS_1:1, SNEDDS_1:6) were mutually compared, characterization of these formulations was performed by DSC, PXRD and FT-IR analyses, and a PAMPA test was done. All formulations have shown a significant increase in dissolution rate compared to pure carbamazepine and immediate-release carbamazepine tablets. Formulation S-SMEDDS_1:1 showed the fastest release rate and permeability of carbamazepine. DSC, PXRD and FT-IR analyses confirmed that in S-SMEDDS and S-SNEDDS carbamazepine remained in polymorph form III, and that it was converted to an amorphous state in SD formulations. All formulations showed increased permeability of carbamazepine, compared to pure carbamazepine.

Biocompatible lidocaine and prilocaine loaded-nanoemulsion system for enhanced percutaneous absorption: QbD-based optimisation, dermatokinetics and in vivo evaluation

Barrier properties of the skin and physicochemical properties of the drugs are the main hiccups in delivering local anaesthetic molecules topically. The present work endeavours for systematic optimisation and evaluation of nanoemulsions (NEs) of local anaesthetic drugs, lidocaine and prilocaine, employing the systematic approach of Quality by Design. A 3(3) Box-Behnken design was employed for systematic optimisation of the factors obtained from screening studies employing Plackett-Burman design and risk assessment studies. The superior permeation rates, and higher concentrations of the drugs in skin layers from the optimised NE carriers, were achieved in permeation and dermatokinetic studies, when compared to marketed cream. Furthermore, rapid onset of action was demonstrated by the NE system in rabbit eye corneal reflex model and biocompatibility was confirmed from the absence of any marked skin change(s) in the normal skin histology. The developed NE systems demonstrated it as a promising carrier for topical delivery of lidocaine and prilocaine.

Highly stable phase change material emulsions fabricated by interfacial assembly of amphiphilic block copolymers during phase inversion

This study introduced a robust and promising approach to fabricate highly stable phase change material (PCM) emulsions consisting of n-tetradecane as a dispersed phase and a mixture of meso-2,3-butanediol (m-BDO) and water as a continuous phase. We showed that amphiphilic poly(ethylene oxide)-b-poly(ε-caprolactone) block copolymers assembled to form a flexible but tough polymer membrane at the interface during phase inversion from water-in-oil emulsion to oil-in-water emulsion, thus remarkably improving the emulsion stability. Although the incorporation of m-BDO into the emulsion lowered the phase changing enthalpy, it provided a useful means to elevate the melting temperature of the emulsions near to 15 °C. Interestingly, supercooling was commonly observed in our PCM emulsions. We attributed this to the fact that the PCM molecules confined in submicron-scale droplets could not effectively nucleate to grow molecular crystals. Moreover, the presence of m-BDO in the continuous phase rather dominated the heat emission of the emulsion system during freezing, which made the supercooling more favorable.

Biological investigation of a supersaturated self-nanoemulsifying drug delivery system of Piper cubeba essential oil

In this work, the mechanism ofPiper cubebaessential oil anti-inflammatory activity alone and as a supersaturated self-nanoemulsifying drug delivery system (S-SNEDDS) was evaluated.

Liposomal Aloe vera trans-emulgel drug delivery of naproxen and nimesulide: A study

INTRODUCTION

The present aim of this study was to formulate naproxen and nimesulide liposomal formulation for incorporation in Aloe vera transemulgel and to carry out in vitro and in vivo evaluation of the formulation.

MATERIAL AND METHODS

A. vera gel was prepared and used as a gel base for formulation. Carbopol 934 is used as a gelling agent and Methyl paraben was used as a preservative for the formulation of the gel. Liposomes was formulated by using hydration method. The formulated naproxen and nimesulide liposomal formulation using A. vera trans-emul gel were evaluated for in vitro studies such as drug release, permeation study, and drug content and entrapment efficiency. Paw edema method in Wistar rats induced by carrageenan is used to study in vivo anti-inflammatory action.

RESULT

From the in vitro studies such permeability drug release naproxen 65% (69.6), Nimesulide 65% (61.1), and commercial Nimsulide gel (60.82) at 240 min. In vivo data shows that formulated liposomal transemulgel formulation are superior in their efficacy compared to commercial and A. vera gel. The results are compared with the commercial formulations.

CONCLUSION

From our results, it is concluded that the A. vera trans emul gel using nimesulide and naproxen liposomal formulation is stable and prepared gel base is effective for formulation with high drug release and drug content compared with commercial formulation with significant anti-inflammatory effect.

Tretinoin Nanogel 0.025% Versus Conventional Gel 0.025% in Patients with Acne Vulgaris: A Randomized, Active Controlled, Multicentre, Parallel Group, Phase IV Clinical Trial

BACKGROUND

Conventional topical tretinoin formulation is often associated with local adverse events. Nanogel formulation of tretinoin has good physical stability and enables good penetration of tretinoin into the pilo-sebaceous glands.

AIM

The present study was conducted to assess the efficacy and safety of a nanogel formulation of tretinoin as compared to its conventional gel formulation in the treatment of acne vulgaris of the face.

MATERIALS AND METHODS

This randomized, active controlled, multicentric, phase IV clinical trial evaluated the treatment of patients with acne vulgaris of the face by the two gel formulations locally applied once daily at night for 12 wk. Acne lesion counts (inflammatory, non-inflammatory & total) and severity grading were carried out on the monthly scheduled visits along with the tolerability assessments.

RESULTS

A total of 207 patients were randomized in the study. Reductions in the total (72.9% vs. 65.0%; p = 0.03) and inflammatory (78.1% vs. 66.9%; p = 0.02) acne lesions were reported to be significantly greater with the nanogel formulation as compared to the conventional gel formulation. Local adverse events were significantly less (p = 0.04) in the nanogel group (13.3%) as compared to the conventional gel group (24.7%). Dryness was the most common adverse event reported in both the treatment groups while peeling of skin, burning sensation and photosensitivity were reported in patients using the conventional gel only.

CONCLUSION

In the treatment of acne vulgaris of the face, tretinoin nanogel formulation appears to be more effective and better tolerated than the conventional gel formulation.

Determination of β-caryophyllene skin permeation/retention from crude copaiba oil (Copaifera multijuga Hayne) and respective oil-based nanoemulsion using a novel HS-GC/MS method

Copaiba oil is largely used in the Amazonian region for the treatment of inflammation, and recent studies demonstrated that one of the major components of the oil, β-caryophyllene (CAR), is a potent anti-inflammatory. The nanoemulsification of this oleoresin, which has unctuous character, converts it in a more acceptable hydrophilic formulation and may improve CAR penetration through the skin due to the small droplet size and the high contact surface afforded by the nanoemulsions. This paper describes the validation of a novel, sensitive, practical and solvent free method that uses gas chromatography in headspace mode coupled with mass spectrometry to evaluate the skin permeation/retention of CAR from the crude copaiba oil and its nanoemulsion. Our results show that the bioanalytic method was fully validated, demonstrating linearity (r(2)>0.99), specificity (no peaks co-eluting with CAR retention time), precision (RSD<15%) and accuracy (recovery>90%) within the accepted parameters and that the copaiba oil nanoemulsion presented a better skin penetration compared to the crude oil, with CAR achieving the most profound layer of the skin, the dermis.

Cavitation technology - a greener processing technique for the generation of pharmaceutical nanoemulsions

Novel nanoemulsion-based drug delivery systems (DDS) have been proposed as alternative and effective approach for the delivery of various types of poorly water-soluble drugs in the last decade. This nanoformulation strategy significantly improves the cell uptake and bioavailability of numerous hydrophobic drugs by increasing their solubility and dissolution rate, maintaining drug concentration within the therapeutic range by controlling the drug release rate, and reducing systemic side effects by targeting to specific disease site, thus offering a better patient compliance. To date, cavitation technology has emerged to be an energy-efficient and promising technique to generate such nanoscale emulsions encapsulating a variety of highly potent pharmaceutical agents that are water-insoluble. The micro-turbulent implosions of cavitation bubbles tear-off primary giant oily emulsion droplets to nano-scale, spontaneously leading to the formation of highly uniform drug contained nanodroplets. A substantial body of recent literatures in the field of nanoemulsions suggests that cavitation is a facile, cost-reducing yet safer generation tool, remarkably highlighting its industrial commercial viability in the development of designing novel nanocarriers or enhancing the properties of existing pharmaceutical products. In this review, the fundamentals of nanoemulsion and the principles involved in their formation are presented. The underlying mechanisms in the generation of pharmaceutical nanoemulsion under acoustic field as well as the advantages of using cavitation compared to the conventional techniques are also highlighted. This review focuses on recent nanoemulsion-based DDS development and how cavitation through ultrasound and hydrodynamic means is useful to generate the pharmaceutical grade nanoemulsions including the complex double or submicron multiple emulsions.

Clindamycin 1% Nano-emulsion Gel Formulation for the Treatment of Acne Vulgaris: Results of a Randomized, Active Controlled, Multicentre, Phase IV Clinical Trial

BACKGROUND

Acne vulgaris of the face is a common dermatological disease with a significant impact on the quality of life, psychosocial development as well as self-esteem of the patients. Nano emulsion gel formulations are said to have various advantages over the conventional formulations.

AIM

The present study was conducted to assess the comparative efficacy and safety of a nano-emulsion gel formulation of clindamycin with its conventional formulation in the treatment of acne vulgaris of the face.

MATERIALS AND METHODS

This prospective, active controlled, multicentric, phase IV clinical trial evaluated the treatment of patients with acne vulgaris of the face by a nano emulsion gel formulation or conventional gel formulation of clindamycin (as phosphate) 1% locally applied twice daily for 12 weeks as per random allocation. Acne lesion counts (inflammatory, non-inflammatory and total) and severity grading were carried out on the monthly scheduled visits along with tolerability assessments.

RESULTS

A total of 200 patients (97 males) were included for Intention to Treat analysis in the trial with 100 patients in each group. Reductions in total (69.3 vs. 51.9%; p<0.001), inflammatory (73.4 vs. 60.6%; p<0.005) and non inflammatory (65.1 vs. 43.7%; p<0.001) acne lesions were reported to be significantly greater with the nano-emulsion gel formulation as compared to the conventional gel formulation. Significantly more reduction in the mean acne severity score was noticeable with the nano-emulsion gel formulation (-1.6 ± 0.9 vs. -1.0 ± 0.8; p<0.001) than the comparator. A trend towards better safety profile of the nano emulsion gel formulation was reported.

CONCLUSION

In the treatment of acne vulgaris of the face, clindamycin nano emulsion gel formulation appears to be more effective than the conventional gel formulation and is also well tolerated.

Preparation and evaluation of microemulsion-based transdermal delivery of total flavone of rhizoma arisaematis

The aims of the present study were to investigate the skin permeation and cellular uptake of a microemulsion (ME) containing total flavone of rhizoma arisaematis (TFRA), and to evaluate its effects on skin structure. Pseudo-ternary phase diagrams were constructed to evaluate ME regions with various surfactants and cosurfactants. Eight formulations of oil-in-water MEs were selected as vehicles, and in vitro skin-permeation experiments were performed to optimize the ME formulation and to evaluate its permeability, in comparison to that of an aqueous suspension. Laser scanning confocal microscopy and fluorescent-activated cell sorting were used to explore the cellular uptake of rhodamine 110-labeled ME in human epidermal keratinocytes (HaCaT) and human embryonic skin fibroblasts (CCC-ESF-1). The structure of stratum corneum treated with ME was observed using a scanning electron microscope. Furthermore, skin irritation was tested to evaluate the safety of ME. ME formulated with 4% ethyl oleate (weight/weight), 18% Cremophor EL^® (weight/weight), and 18% Transcutol^® P, with 1% Azone to enhance permeation, showed good skin permeability. ME-associated transdermal fluxes of schaftoside and isoschaftoside, two major effective constituents of TFRA, were 3.72-fold and 5.92-fold higher, respectively, than those achieved using aqueous suspensions. In contrast, in vitro studies revealed that uptake by HaCaT and CCC-ESF-1 cells was lower with ME than with an aqueous suspension. Stratum corneum loosening and shedding was observed in nude mouse skin treated with ME, although ME produced no observable skin irritation in rabbits. These findings indicated that ME enhanced transdermal TFRA delivery effectively and showed good biocompatibility with skin tissue.

Topical delivery of aceclofenac: challenges and promises of novel drug delivery systems

Osteoarthritis (OA), a common musculoskeletal disorder, is projected to affect about 60 million people of total world population by 2020. The associated pain and disability impair the quality of life and also pose economic burden to the patient. Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely prescribed in OA, while diclofenac is the most prescribed one. Oral NSAIDs are not very patient friendly, as they cause various gastrointestinal adverse effects like bleeding, ulceration, and perforation. To enhance the tolerability of diclofenac and decrease the common side effects, aceclofenac (ACE) was developed by its chemical modification. As expected, ACE is more well-tolerated than diclofenac and possesses superior efficacy but is not completely devoid of the NSAID-tagged side effects. A series of chemical modifications of already planned drug is unjustified as it consumes quanta of time, efforts, and money, and this approach will also pose stringent regulatory challenges. Therefore, it is justified to deliver ACE employing tools of drug delivery and nanotechnology to refine its safety profile. The present review highlights the constraints related to the topical delivery of ACE and the various attempts made so far for the safe and effective topical delivery employing the novel materials and methods.

Phospholipid microemulsion-based hydrogel for enhanced topical delivery of lidocaine and prilocaine: QbD-based development and evaluation

Topical delivery of local anesthetics has been an area of interest for researchers considering the barrier properties of skin and unfavorable physicochemical properties of drugs. In the present study, efforts have been made to modify the in vivo efficacy of eutectic mixture of lidocaine and prilocaine by exploiting the phospholipid modified microemulsion based delivery systems. The strategic QbD (D-optimal mixture design) enabled systematic optimization approach, after having obtained the isotropic area of interest by ternary phase diagram, has resulted into the system with most desirable attributes. Latter include nano-scale, globular structures with an average size of 40.6 nm, as characterized by TEM and DLS. The optimized microemulsion systems in gel dosage forms revealed the better permeability over commercial cream (CC) through abdominal rat skin. Enhancement in the flux from MOPT-NMP gel was 3.22-folds for prilocaine and 4.94-folds for lidocaine, in comparison to that of CC. This enhanced skin permeability is very well reflected in the in vivo studies, wherein intensity and duration of action was augmented significantly. The skin compliance of the optimized formulation was revealed in histopathological studies. The overall benefit relating to efficacy and safety-compliance could be correlated to the uniqueness of the carriers, composed of phospholipids and other components. Hence, the developed phospholipid-microemulsion based gel formulation has been proposed as more useful alternative for the topical delivery of lidocaine and prilocaine.

Stability of Positively Charged Nanoemulsion Formulation Containing Steroidal Drug for Effective Transdermal Application

This paper emphasizes the formation of a positively charged nanoemulsion system for steroid drugs (hydrocortisone). It is believed that positively charged nanoemulsion provides more effective penetration of the skin. Therefore in our study we focused on the incorporation of phytosphingosine which serves as a positively charged cosurfactant in the nanoemulsion system. Negatively charged nanoemulsions were formulated mainly for comparison. Freshly prepared formulations were formed with particle size less than 300 nm and showed good stability over time. The oil-in-water nanoemulsion also showed good viscosity, conductivity, and pH values. From TEM micrograph, particle size showed consistent results with the measurement using photon correlation spectroscopy. It was concluded that both positively and negatively charged nanoemulsions showed good stability and have great potential in transdermal delivery system. Though, further investigation of the drug release and drug penetration of both positively and negatively charged nanoemulsions will be studied to further prove the efficacy of nanoemulsion with hydrocortisone as a delivery system for dermal application.

Formulation of nanoemulsion: a comparison between phase inversion composition method and high-pressure homogenization method

There is lot of confusion in the literatures regarding the method of production of nanoemulsion. According to some authors, only the methods using high energy like high-pressure microfluidizer or high-frequency ultra-sonic devices can produce actual nanoemulsions. In contrast to this concept, one research group reported for the first time the preparation of nanoemulsion by a low-energy method. Later on many authors reported about the low-energy emulsification method. The purpose of this work is to formulate, evaluate and compare nanoemulsions prepared using high-energy as well as low-energy method. Nanoemulsions formulated were based on the phase inversion composition technique (low energy method) and were selected from the ternary phase diagram based on the criterion of their being a minimum concentration of S(mix) used in the formulation. For high-pressure homogenization method (high energy method) Design-Expert software was used, and the desirability function was probed to acquire an optimized formulation. No significant difference (p > 0.05) was observed in the globule size of formulations made by each method, but the value of poly-dispersibility index between the two methods was found to be extremely significant (p < 0.001). A very significant difference (p < 0.001) was observed in the drug release from formulations made by each method. More than 60% of the drug was released from all the formulations in the initial 2 h of the dissolution study.

In situ intestinal permeability and in vivo oral bioavailability of celecoxib in supersaturating self-emulsifying drug delivery system

In order to characterize the in situ intestinal permeability and in vivo oral bioavailability of celecoxib (CXB), a poorly water-soluble cyclooxygenase (COX)-2 inhibitor, various formulations including the self-emulsifying drug delivery system (SEDDS) and supersaturating SEDDS (S-SEDDS) were compared. The S-SEDDS formulation was obtained by adding Soluplus as a precipitation inhibitor to SEDDS, composed of Capryol 90 as oil, Tween 20 as surfactant, and Tetraglycol as cosurfactant (1:4.5:4.5 in volume ratio). An in situ single pass intestinal perfusion study in rats was performed with CXB-dissolved solutions at a concentration of 40 μg/mL. The effective permeability (Peff) of CXB in the control solution (2.5 v/v% Tween 20-containing PBS) was 6.39 × 10(-5) cm/s. The Peff value was significantly increased (P < 0.05) by the lipid-based formulation, yielding 1.5- and 2.9-fold increases for the SEDDS and S-SEDDS solutions, respectively, compared to the control solution. After oral administration of various formulations to rats at the equivalent dose of 100 mg/kg of CXB, the plasma drug level was measured by LC-MS/MS. The relative bioavailabilities of SEDDS and S-SEDDS were 263 and 355 %, respectively, compared to the CXB suspension as a reference. In particular, S-SEDDS revealed the highest Cmax and the smallest Tmax, indicating rapid and enhanced absorption with this formulation. This study illustrates the potential use of the S-SEDDS formulation in the oral delivery of poorly water-soluble compounds.

Nebulized oil-in-water nanoemulsion mists for pulmonary delivery: development, physico-chemical characterization and in vitro evaluation

CONTEXT

This study presents novel nanostructured oil-in-water (o/w) mists based on self-nanoemulsifying (SNE) mixtures capable of delivering poorly water-soluble drugs into the lungs.

OBJECTIVE

Formulation development of an o/w nanoemulsion (NE) capable of being nebulized for pulmonary delivery of poorly water-soluble drugs.

MATERIALS AND METHODS

SNE mixtures were prepared and evaluated using Tween 80 and Cremophor RH 40 as surfactants; Transcutol P, Capryol 90 and PEG 400 as cosurfactants; and Labrafac Lipophile Wl 1349 (a medium-chain triglyceride) as an oil. Liquid NEs were analyzed by light scattering, zeta potential, transmission electron microscopy (TEM) and in vitro drug release studies. The aqueous NE was nebulized and assessed by light scattering and TEM. The formulation was aseptically filtered and the sterility validated. In vitro cytotoxicity of the formulations was tested in NIH 3T3 cells. The capability of the formulation to deliver a poorly water-soluble drug was determined using ibuprofen.

RESULTS

Ibuprofen was found to be stable in the NEs. The formulations were neutrally charged with a droplet size of about 20 nm. TEM images displayed 100 nm oil droplets. The aseptic filtration method produced sterile NE. The nebulized mist revealed properties ideal for pulmonary delivery. The biocompatible aerosol has a nanostructure consisting of several oil nanodroplets enclosed within each water drop. Solubility and in vitro drug release studies showed successful incorporation and release of ibuprofen.

CONCLUSION

The developed formulation could be used as an inhalation for delivering material possessing poor water solubility into the lungs.

Development and in vitro evaluation of a nanoemulsion for transcutaneous delivery

OBJECTIVE

The purpose of this study is to develop a nanoemulsion formulation for its use as a transcutaneous vaccine delivery system.

MATERIALS AND METHODS

With bovine albumin-fluorescein isothiocyanate conjugate (FITC-BSA) as a vaccine model, formulations were selected with the construction of pseudo-ternary phase diagrams and a short-term stability study. The size of the emulsion droplets was furthered optimized with high-pressure homogenization. The optimized formulation was evaluated for its skin permeation efficiency. In vitro skin permeation studies were conducted with shaved BALB/c mice skin samples with a Franz diffusion cell system. Different drug concentrations were compared, and the effect of the nanoemulsion excipients on the permeation of the FITC-BSA was also studied.

RESULTS

The optimum homogenization regime was determined to be five passes at 20 000 psi, with no evidence of protein degradation during processing. With these conditions, the particle diameter was 85.2 nm ± 15.5 nm with a polydispersity index of 0.186 ± 0.026 and viscosity of 14.6 cP ± 1.2 cP. The optimized formulation proved stable for 1 year at 4 °C. In vitro skin diffusion studies show that the optimized formulation improves the permeation of FITC-BSA through skin with an enhancement ratio of 4.2 compared to a neat control solution. Finally, a comparison of the skin permeation of the nanoemulsion versus only the surfactant excipients resulted in a steady state flux of 23.44 μg/cm(2)/h for the nanoemulsion as opposed to 6.10 μg/cm(2)/h for the emulsifiers.

CONCLUSION

A novel nanoemulsion with optimized physical characteristics and superior skin permeation compared to control solution was manufactured. The formulation proposed in this study has the flexibility for the incorporation of a variety of active ingredients and warrants further development as a transcutaneous vaccine delivery vehicle.

SNEDDS Containing Poorly Water Soluble Cinnarizine; Development and in Vitro Characterization of Dispersion, Digestion and Solubilization

Self-Nanoemulsifying Drug Delivery Systems (SNEDDSs) were developed using well-defined excipients with the objective of mimicking digested SNEDDSs without the use of enzymes and in vitro lipolysis models and thereby enabling studies of the morphology and size of nanoemulsions as well as digested nanoemulsions by Cryo-TEM imaging and Dynamic Light Scattering. Four SNEDDSs (I-IV) were developed. Going from SNEDDS I to IV lipid content and solubility of the model drug cinnarizine decreased, which was also the case for dispersion time and droplet size. Droplet size of all SNEDDS was evaluated at 1% (w/w) dispersion under different conditions. Cinnarizine incorporation increased the droplet size of SNEDDSs I and II whereas for SNEDDSs III and IV no difference was observed. At low pH cinnarizine had no effect on droplet size, probably due to increased aqueous solubility and partitioning into the aqueous phase. Dispersion of the SNEDDSs in Simulated Intestinal Media (SIM) containing bile salts and phospholipids resulted in a decrease in droplet size for all SNEDDS, as compared to dispersion in buffer. Increasing the bile salt/phospholipid content in the SIM decreased the droplet sizes further. Mimicked digested SNEDDS with highest lipid content (I and II) formed smaller nanoemulsion droplet sizes upon dispersion in SIM, whereas droplet size from III and IV were virtually unchanged by digestion. Increasing the bile acid/phosphatidylcholine content in the SIM generally decreased droplet size, due to the solubilizing power of the endogenous surfactants. Digestion of SNEDDSs II resulted in formation of vesicles or micelles in fasted and fed state SIM, respectively. The developed and characterized SNEDDS provide for a better knowledge of the colloid phases generated during digestion of SNEDDS and therefore will enable studies that may yield a more detailed understanding of SNEDDS performance.

Nanoemulsions as potential vehicles for transdermal and dermal delivery of hydrophobic compounds: an overview

INTRODUCTION

In recent years, nanoemulsions have been investigated as potential drug delivery vehicles for transdermal and dermal delivery of many compounds especially hydrophobic compounds in order to avoid clinical adverse effects associated with oral delivery of the same compounds. Droplet size and surface properties of nanoemulsions play an important role in the biological behavior of the formulation.

AREAS COVERED

In this review, current literature of transdermal and dermal delivery of hydrophobic compounds both in vitro as well as in vivo has been summarized and analyzed.

EXPERT OPINION

Nanoemulsions have been formulated using a variety of pharmaceutically acceptable excipients. In many cases of dermal and transdermal nanoemulsions, the skin irritation or skin toxicity issues on human beings have not been considered which needs to be evaluated properly. In the last decade, much attention has been made in exploring new types of nanoemulsion-based drug delivery system for dermal and transdermal delivery of many hydrophobic compounds. This area of research would be very advantageous for formulation scientists in order to develop some nanoemulsion-based formulations for their commercial exploitation and clinical applications.