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ESEM images of blank MBH with 13% (A), 16% (B), 17% (C) Poloxamer 407 and triptolide-loaded MBH with 16% Poloxamer (D).
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Triptolide is a diterpenoid compound that inhibits the inflammation of rheumatoid arthritis (RA). However, the use of triptolide is limited due to its strong gastrointestinal toxicity. The purpose of this work was to develop a transdermal delivery system for triptolide to reduce this toxicity. A microemulsion-based hydrogel (MBH) was prepared from...
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... this study, ESEM was used to observe the formation and interconnected network structures of the MBH preparations. Fig. 3 shows ESEM images of the blank MBH preparation with different concentrations of Poloxamer 407 (Fig. 3A-C) and the triptolide- loaded MBH preparation with 16% (w/w) Poloxamer 407 (Fig. 3D). Fig. 3A shows that the network structures of the O/W microemulsion containing 13% (w/w) Poloxamer 407 had not been formed completely, and that the ...
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... this study, ESEM was used to observe the formation and interconnected network structures of the MBH preparations. Fig. 3 shows ESEM images of the blank MBH preparation with different concentrations of Poloxamer 407 (Fig. 3A-C) and the triptolide- loaded MBH preparation with 16% (w/w) Poloxamer 407 (Fig. 3D). Fig. 3A shows that the network structures of the O/W microemulsion containing 13% (w/w) Poloxamer 407 had not been formed completely, and that the system was still loose and collosol. We found that as the concentration of Poloxamer 407 increased, the ...
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... this study, ESEM was used to observe the formation and interconnected network structures of the MBH preparations. Fig. 3 shows ESEM images of the blank MBH preparation with different concentrations of Poloxamer 407 (Fig. 3A-C) and the triptolide- loaded MBH preparation with 16% (w/w) Poloxamer 407 (Fig. 3D). Fig. 3A shows that the network structures of the O/W microemulsion containing 13% (w/w) Poloxamer 407 had not been formed completely, and that the system was still loose and collosol. We found that as the concentration of Poloxamer 407 increased, the whole microemulsion would contribute to the formation of the hydrogel. When the ...
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... this study, ESEM was used to observe the formation and interconnected network structures of the MBH preparations. Fig. 3 shows ESEM images of the blank MBH preparation with different concentrations of Poloxamer 407 (Fig. 3A-C) and the triptolide- loaded MBH preparation with 16% (w/w) Poloxamer 407 (Fig. 3D). Fig. 3A shows that the network structures of the O/W microemulsion containing 13% (w/w) Poloxamer 407 had not been formed completely, and that the system was still loose and collosol. We found that as the concentration of Poloxamer 407 increased, the whole microemulsion would contribute to the formation of the hydrogel. When the concentration ...
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... and collosol. We found that as the concentration of Poloxamer 407 increased, the whole microemulsion would contribute to the formation of the hydrogel. When the concentration of Poloxamer 407 was 14% (w/w), the interconnected network structures had been formed. By comparison, the network structures of systems containing 16% (w/w) Poloxamer 407 (Fig. 3B) were more compact and the rheological measurement revealed that the dynamic viscoelasticity of this system was strongest. When the concentration of Poloxamer 407 increased to 17% (w/w) (Fig. 3C), the structures were relatively disorganized. This may be the result of incomplete swelling of the matrix at this concentration. Fig. 3D shows ...
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... was 14% (w/w), the interconnected network structures had been formed. By comparison, the network structures of systems containing 16% (w/w) Poloxamer 407 (Fig. 3B) were more compact and the rheological measurement revealed that the dynamic viscoelasticity of this system was strongest. When the concentration of Poloxamer 407 increased to 17% (w/w) (Fig. 3C), the structures were relatively disorganized. This may be the result of incomplete swelling of the matrix at this concentration. Fig. 3D shows the effect of triptolide on the microstructure of MBH. The concentration of triptolide was fixed at 0.03% (w/w) and the concentration of Poloxamer 407 was 13%, 14%, 15%, 16%, 17%, 18% (w/w). ...
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... Poloxamer 407 (Fig. 3B) were more compact and the rheological measurement revealed that the dynamic viscoelasticity of this system was strongest. When the concentration of Poloxamer 407 increased to 17% (w/w) (Fig. 3C), the structures were relatively disorganized. This may be the result of incomplete swelling of the matrix at this concentration. Fig. 3D shows the effect of triptolide on the microstructure of MBH. The concentration of triptolide was fixed at 0.03% (w/w) and the concentration of Poloxamer 407 was 13%, 14%, 15%, 16%, 17%, 18% (w/w). Compared to the blank MBH preparations, the interconnected network structures of triptolide-loaded MBH preparations were less well defined. ...
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Citations
... A comparison of absolute values of G' and G" points towards improved strength of dispersion with increase in water content. This implies that higher dilution enhanced the stability of microemulsion by forming more elastic structures [46]. Cross-over points were observed at 40 and 45% water content. ...
... Turbidity and lack of homogeneity were resolved by substituting HPMC and Carbomer 934 with Carbomer 940 (47). As described by Chen et al., the reason might be associated with the dissociation of Carbomer 934 and HPMC matrices from the hydrated state by surfactant and co-surfactant in the microemulsion (48). The gels were also evaluated in terms of stickiness, ease of spreading, and coarseness by rubbing a sufficient amount of gels between index and thumb fingers. ...
: Microemulsion-based gels (MBGs) were prepared for transdermal delivery of lidocaine and evaluated for their potential for local anesthesia. Lidocaine solubility was measured in various oils, and phase diagrams were constructed to map the concentration range of oil, surfactant, cosurfactant, and water for oil-in-water (o/w) microemulsion (ME) domains, employing the water titration method at different surfactant/cosurfactant weight ratios. Refractive index, electrical conductivity, droplet size, zeta potential, pH, viscosity, and stability of fluid o/w MEs were evaluated. Carbomer® 940 was incorporated into the fluid drug-loaded MEs as a gelling agent. Microemulsion-based gels were characterized for spreadability, pH, viscosity, and in-vitro drug release measurements, and based on the results obtained, the best MBGs were selected and subsequently subjected to ex-vivo rat skin permeation anesthetic effect and irritation studies. Data indicated the formation of nano-sized droplets of MEs ranging from 20 - 52 nm with a polydispersity of less than 0.5. In-vitro release and ex-vivo permeation studies on MBGs showed significantly higher drug release and permeation in comparison to the marketed topical gel. Developed MBG formulations demonstrated greater potential for transdermal delivery of lidocaine and advantage over the commercially available gel product, and therefore, they may be considered as potential vehicles for the topical delivery of lidocaine.
... And only mild reversible skin irritation signs were observed on the skin of rabbits and guinea pigs. Chen et al. [135] developed another microemulsion-based hydrogel transdermal delivery system for triptolide to avoid its strong gastrointestinal toxicity, which had no irritation on intact skin after a single application or multiple applications. ...
With the increasing epidemiology of autoimmune disease worldwide, there is an urgent need for effective drugs with low cost in clinical treatment. Triptolide, the most potent bioactive compound from traditional Chinese herb Tripterygium Wilfordii Hook F, possesses immunosuppression and anti-inflammatory activity. It is a potential drug for the treatment of various autoimmune diseases, but its clinical application is still restricted due to severe toxicity. In this review, the pharmacodynamic effects and pharmacological mechanisms of triptolide in autoimmune diseases are summarized. Triptolide exerts therapeutic effect by regulating the function of immune cells and the expression of cytokines through inflammatory signaling pathways, as well as maintaining redox balance and gut microbiota homeostasis. Meanwhile, the research progress on toxicity of triptolide to liver, kidney, reproductive system, heart, spleen, lung and gastrointestinal tract has been systematically reviewed. In vivo experiments on different animals and clinical trials demonstrate the dose- and time- dependent toxicity of triptolide through different administration routes. Furthermore, we focus on the strategies to reduce toxicity of triptolide, including chemical structural modification, novel drug delivery systems, and combination pharmacotherapy. This review aims to reveal the potential therapeutic prospect and limitations of triptolide in treating autoimmune diseases, thus providing guiding suggestions for further study and promoting its clinical translation.
... However, the low viscosity of MEs makes topical administration difficult and inconvenient for patients (Heuschkel et al., 2008;Zhu et al., 2009;Scomoroscenco et al., 2021). To increase the viscosity of MEs, various kinds of gel matrix, such as carbomer, carrageenan, xanthan gum, chitosan, Poloxamer 407, and hyaluronic acid, have been added to MEs to produce microemulsion-based gels (MBGs) (Chen et al., 2006;2013;Starychova et al., 2014;Zhang et al., 2020;Patel et al., 2021). Selecting a suitable gel matrix can improve the adhesion and spreading of MEs to the skin, block the diffusion of drugs in MBGs, and reduce the effective diffusion coefficient, thereby prolonging the action time of drugs (Chen et al., 2006;Zhao et al., 2006;Bachhav and Patravale, 2009). ...
... Subsequently, the viscosity decreased with increasing shear rate, showing a pseudo ductile flow ( Figure 5(c)). The increase in gel matrix dosage may help form a tight network structure and increase the viscosity of the system (Chen et al., 2013). ...
... The effect of drug loading on the rheological properties of MBG was related to both the drug and gel matrix. For example, when poloxamer 407 was used as the gel matrix, the viscosity of triptolideloaded MBG was lower than that of blank MBG (Chen et al., 2013). The viscosity of indomethacin-loaded MBG increased with an increase in indomethacin concentration, indicating that the drug interacted with the polymer chains, which led to the weakening of interactions between them and, consequently, weakening of the whole gel structure. ...
To overcome the poor water solubility of total flavones of Arisaematis rhizoma, microemulsions (MEs) can be used as a carrier for transdermal administration to promote their solubilization and skin permeability. Here, we investigated the physical compatibility of MEs in hydrogels and their skin permeation-enhancing effects. Transparency of microemulsion-based hydrogels (MBGs) was analyzed to evaluate ME compatibility with different hydrogel matrices. Transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy were used to explore the microstructures of MBGs and ME–hydrogel combinations. Uniform and transparent MBG was obtained by adding 1% sodium hyaluronate (SH) to the optimized ME. MBG prepared with SH as a matrix expressed pseudoplastic-fluid and shear-thinning characteristics, making it easy to apply in clinical settings. No new FTIR peak occurred in the MBG compared with ME and hydrogel matrix, indicating a physical combination of ME and the polymer network gel. Nanoscale droplets of ME migrated in the gel network, and the migration capacity and in vitro transdermal permeation flux negatively correlated with SH concentration in the gel system. In conclusion, in MBGs, ME can keep nanoscale droplets migrating in the hydrogel network, thereby enhancing transdermal drug delivery.
... Another type of lipid-based nanoparticle, microemulsion (ME), has been widely studied for transdermal delivery of herbal products, drugs, and pro-drugs [1,[116][117][118] including TPL [119][120][121][122]. Recently, a microemulsion was investigated due to its pancreas accumulation and also pharmacokinetic profiles and tissue distribution. ...
Triptolide (TPL) is a natural compound and active component of Tripterygium wilfordii Hook F., an Asian native woody vine widely used for over 200 years in Chinese medicine. Hot water, ethanol–ethyl acetate, and chloroform–methanol extracts are the first reported TPL preparations in the literature, and since then, several studies for application in inflammation processes and cancer are described due to the antitumor, anti-inflammatory, and immunosuppressive characteristics of the molecule. However, physicochemical properties such as poor solubility and bioavailability are the main concerns regarding the TPL safety and efficacy in clinical studies since trials have reported adverse side effects alongside the excellent TPL therapeutic effects. Here, we review the main TPL applications and issues related to the drug usage, and a comprehensive summary of diseases is provided. Special emphasis is given to drug delivery systems designed to overcome the TPL physicochemical characteristics such as poor drug solubility, and how to increase efficacy and obtain a safe drug profile.
Graphical abstract
... A second glass plate of known weight was put over the first one followed by weight of 5 g. The increase in diameter was noted [33]. ...
BACKGROUND: Treatment of fungal infection through oral route is avoided since topical delivery has ease of application and improved patient compliance. Topical drug delivery is used for local administration of drug directly to the affected area, resulting in localization of drug. OBJECTIVE: The objective of the present study was to prepare and evaluate fluconazole (FLZ) loaded microemulsion (ME) based gel for topical delivery. METHODS: Triacetin as the oil phase, tween 80 as surfactant and ethanol as cosurfactant were screened as microemulsion components. Pseudoternary phase diagrams were constructed by titration method and various MEs was prepared and evaluated for parameters like globule size, poly dispersibilty index (PDI), viscosity, pH, and stability. Finally, optimized microemulsion (ME9) was selected to prepare various gels and evaluated for drug content, viscosity, pH and spreadability. Optimized microemulsion based hydrogel containing carbopol 934 (MBH6) was compared with marketed formulation or ex vivo permeation study using rat skin. The optimized MBH6 and marketed formulation were also evaluated for antifungal activity against fungal strain Microsporum fulvum (MTCC 16446) as well as for skin irritation studies. RESULTS: The studied optimized MBH6 showed a good stability over a period of 6 months. The average globule size of optimized ME9 was found 36.17 nm. The antifungal activity of MBH6 was found comparable to the marketed formulation. CONCLUSION: It was concluded that the proposed microemulsion based hydrogel (MBH6) is a promising delivery vehicle for topical delivery of FLZ.
... [35] Microemulsion (ME) is a clear, thermodynamically stable, isotropic mixture of oil, water and surfactant, frequently in combination with a cosurfactant. [36] Advantages of emulsion-based formulations Examples of nanoparticle herbal formulations for anticancer use: Curcumin, Triptolide, Docataxel, Berberine [37][38][39][40] www.wjpr.net ...
Herbal medicines have been used since ages for the treatment of
various diseases since the ancient times. The demand of the herbal
medicines has increased in the recent years because of their ability to
treat different diseases with fewer side effects. The side effects of
chemotherapy in cancer treatment are a major concern and hence the
need of the day is to find the treatment which is effective with fewer
side effects. There is a need to attain the effective drug delivery of
herbal medicines. The development of novel drug delivery system
(NDDS) plays a major role to overcome various constraints like poor
bioavailability, in vivo stability, aqueous insolubility, intestinal absorption and unspecific site of action. The integration of NDDS in
traditional system of medicine enriches the potential of herbal drugs
for treating chronic diseases such as cancer. The formulations such as phytosomes, polymeric nanoparticles, liposomes, microspheres, solid lipid nanoparticles and microemulsions have a great potential to deliver herbal medicines effectively. The current review summarizes
various NDDS that have been studied for the delivery of herbal medicines, for the treatment of cancer and are gaining more attention for improved therapeutic response and bioavailability.
KEYWORDS: Herbal medicine, Novel drug delivery system, Cancer.
... 2,39 Poloxamer 407 gels are pseudoplastic and as shear rate increases, their apparent viscosity decreases. Few recent studies considered the use of poloxamer 407 as a gelling agent in nonionic surfactants-based microemulsions for topical application of chloramphenicol, 40 triptolide, 41 and diclofenac epolamine. 37 Zhao et al. 40 described a preparation of the viscoelastic temperature-sensitive gels from microemulsion systems and assumed that aggregates of the copolymer micelles enabled the formation of the gel, although they coexist with partly preserved microemulsion structure with the oil droplets immobilized in the copolymer-based structure. ...
... The latter observation was in contrast to the release profiles of different drugs from poloxamer 407 gels and poloxamer 407-based microemulsion gels, which have shown that drug release rates as well as diffusion coefficients were retarded as the copolymer content increased. 40,41,46,47 On the contrary, related investigations 48,49 of the microemulsions based only on the mixtures of nonionic surfactants showed that they may suffer from inadequate drug solubilization capacity upon aqueous media dilution and carrier disturbance and deviation from zero-order release kinetics. The assumed presence of large hydrophilic molecules of poloxamer 407, in the sample M3, affects the geometry of the interface and significantly decreases capacity for the drug solubilization, thus the partition of the drug into the aqueous phase from this carrier become more favorable in comparison with the other investigated microemulsions. ...
Nonionic surfactants (caprylocaproyl macrogol-8 glycerides, octoxynol-12, polysorbate-20, and polyethylene glycol-40 hydrogenated castor oil) (47.03%, w/w), costabilizer (poloxamer 407) (12%-20%, w/w), oil (isopropyl myristate) (5.22%, w/w), water (q.s. ad 100%, w/w), and ibuprofen (5%, w/w) were used to develop oil-in-water microemulsions with Newtonian flow behavior, low viscosity (from 368 ± 38 to 916 ± 46 mPa·s), and average droplet size from 14.79 ± 0.31 to 16.54 ± 0.75 nm. Ibuprofen in vitro release from the microemulsions was in accordance with zero-order kinetics (R0 (2) > 0.99) for at least 12 h. The maximum drug release rate (3.55%h(-1) ) was from the microemulsion M3 comprising 16%, w/w of poloxamer 407. The release rate of ibuprofen from the reference hydrogel followed Higuchi kinetics (RH (2) > 0.99), and drug amount released after the 6th hour was negligible. In a rat model of inflammation, the microemulsion M3 was significantly more efficacious than the reference hydrogel in exerting antihyperalgesic effects in prophylactic topical treatment, whereas they were comparable in therapeutic treatment as well as in producing antiedematous effect in both protocols. No obvious skin irritation was observed in in vivo studies. The developed nonionic surfactants-based microemulsions containing the optimal concentration of poloxamer 407 could be promising carriers for sustained regional delivery of ibuprofen via topical administration. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci.
© 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.
... Mei et al. developed SLN and microemulsions of TP and observed skin delivery [77]. Chen et al. also developed TP-loaded microemulsion hydrogel, and higher permeation through mouse skin as compared to the aqueous solution [78]. ...
Introduction:
Psoriasis is a T-cell mediated autoimmune inflammatory skin disease recognized by skin surface inflammation, epidermal proliferation, hyperkeratosis, angiogenesis and anomalous keratinization. Currently, various pharmacotherapies are available for it; however, pharmacotherapy based on conventional formulations can provide therapeutic benefits only to a limited extent. Recent advancement in nanotechnology-based nanomedicines has led to the possibility of improving the efficacy and safety of pharmacotherapeutic agents for psoriasis.
Areas covered:
This review covers the brief pathophysiology of psoriasis, available medications and its associated challenges in treatment. Collective accounts of various drugs acting on different molecular targets of psoriasis and the role of nanomedicines in their effective targeting are discussed. Moreover, newer approaches in psoriatic therapy such as combination drug targeting and physical techniques of topical permeation enhancement along with nanomedicines are also discussed.
Expert opinion:
Novel nanomedicines (such as liposomes, polymeric nanoparticles, etc.) have shown their potential in improving therapeutic benefits of antipsoriatic drugs by increasing their therapeutic efficacy with minimal toxicity. Nevertheless, while the results on animal models using nanomedicine-based drug targeting of psoriasis via different route seem promising, lack of sufficient evidence in a clinical setup is a constraint and more clinical studies on the efficacy and safety of nanomedicines in psoriasis therapy are required.
