Localized delivery of paclitaxel using elastic liposomes: Formulation development and evaluation

Paclitaxel-loaded elastic liposomes synthesised by microfluidics technique for enhance transdermal delivery

The inherent flexibility of elastic liposomes (EL) allows them to penetrate the small skin pores and reach the dermal region, making them an optimum candidate for topical drug delivery. Loading chemotherapy in ELs could improve chemotherapy's topical delivery and localise its effect on skin carcinogenic tissues. Chemotherapy-loaded EL can overcome the limitations of conventional administration of chemotherapies and control the distribution to specific areas of the skin. In the current studies, Paclitaxel was utilised to develop Paclitaxel-loaded EL. As an alternative to the conventional manufacturing methods of EL, this study is one of the novel investigations utilising microfluidic systems to examine the potential to enhance and optimise the quality of Els by the microfluidics method. The primary aim was to achieve EL with a size of < 200 nm, high homogeneity, high encapsulation efficiency, and good stability. A phospholipid (DOPC) combined with neutral and anionic edge activators (Tween 80 and sodium taurocholate hydrate) at various lipid-to-edge activator ratios, was used for the manufacturing of the ELs. A preliminary study was performed to study the size, polydispersity (PDI), and stability to determine the optimum microfluidic parameters and lipid-to-edge activator for paclitaxel encapsulation. Furthermore, physiochemical characterisation was performed on the optimised Paclitaxel-loaded EL using a variety of methods, including Dynamic Light Scattering, Fourier Transform Infrared Spectroscopy, Atomic force microscopy, elasticity, encapsulation efficiency, and In vitro release. The results reveal the microfluidics' significant impact in enhancing the EL characteristics of EL, especially small and controllable size, Low PDI, and high encapsulation efficiency. Moreover, the edge activator type and concentration highly affect the EL characteristics. The Tween 80 formulations with optimised concentration provide the most suitable size and higher encapsulation efficiency. The release profile of the formulations showed more immediate release from the EL with higher edge activator concentration and a higher % of the released dug from the Tween 80 formulations.

Anti-lung cancer effect of paclitaxel solid lipid nanoparticles delivery system with curcumin as co-loading partner in vitro and in vivo

The main aim of this study was to improve the therapeutic potential of a paclitaxel (PTX) and curcumin (CU) combination regimen using solid lipid nanoparticles (SLNs). PTX and CU were successfully co-encapsulated at a predetermined ratio in SLNs (PC-SLNs) with high encapsulation efficiency (CU: 97.6%, PTX: 95.8%), appropriate particle size (121.8 ± 1.69 nm), small PDI (0.267 ± 0.023), and negative zeta potential (–30.4 ± 1.25 mV). Compared with PTX or the combination of CU and PTX (CU + PTX), PC-SLNs can greatly reduce the dose of PTX while still achieving the same therapeutic effect on four cancer cell lines, among which the inhibitory effect on A549 lung cancer cells was the strongest. PC-SLNs improved the area under the curve (CU: 1.40-fold; PTX: 2.88-fold), prolonged the residence time (CU: 6.94-fold; PTX: 2.51-fold), and increased the half-life (CU: 5.62-fold; PTX: 6.46-fold), achieving long circulation. PC-SLNs were used to treat lung cancer in a nude mouse xenograft tumor model and the tumor suppression rate reached 78.42%, while those of PTX and (CU + PTX) were 40.53% and 51.56%, respectively. As PC-SLNs can prevent P-glycoprotein efflux, reverse MDR and downregulate the NF-κB pathway. PC-SLNs are a potential antineoplastic agent that is more effective and less toxic in treating lung cancer.

Interface-Engineered Paclitaxel-Based Hollow Mesoporous Organosilica Nanoplatforms for Photothermal-Enhanced Chemotherapy of Tumor

Having benefited from the combination of different therapeutic modalities, functionalized nanoplatforms with synergistic strategies have aroused great interest in anticancer treatment. Herein, an engineered, a biodegradable hollow mesoporous organosilica nanoparticle (HMON)-based nanoplatform was fabricated for photothermal-enhanced chemotherapy of tumor. For the first time, we demonstrated that HMONs could serve as nanocarriers for co-delivering of both the paclitaxel and photothermal agent new indocyanine green (IR820), denoted as Paclitaxel/IR820@ HMONs-PEG. The as-prepared nanosystem exhibited a high paclitaxel-loading capacity of 28.4%, much higher than most paclitaxel-loaded nanoformulations. Furthermore, incorporating thioether bonds (S-S) into the HMONs' framework endowed them with GSH-responsive biodegradation behavior, leading to the controllable release of drugs under a tumor reducing microenvironment, and hindered the premature release of paclitaxel. Upon being irradiated with an NIR laser, the obtained co-delivery nanosystem exhibited great photothermal properties generated from IR820. The fabricated nanocomposites could significantly suppress tumor growth under NIR laser irradiation, as validated by in vitro and in vivo assessments. Combined with outstanding biocompatibility, the constructed nanosystem holds great potential in combinational antitumor therapy.

Transfersomes: a Revolutionary Nanosystem for Efficient Transdermal Drug Delivery

Transdermal delivery system has gained significance in drug delivery owing to its advantages over the conventional delivery systems. However, the barriers of stratum corneum along with skin irritation are its major limitations. Various physical and chemical techniques have been employed to alleviate these impediments. Among all these, transfersomes have shown potential for overcoming the associated limitations and successfully delivering therapeutic agents into systemic circulation. These amphipathic vesicles are composed of phospholipids and edge activators. Along with providing elasticity, edge activator also affects the vesicular size and entrapment efficiency of transfersomes. The mechanism behind the enhanced permeation of transfersomes through the skin involves their deformability and osmotic gradient across the application site. Permeation enhancers can further enhance their permeability. Biocompatibility; capacity for carrying hydrophilic, lipophilic as well as high molecular weight therapeutics; deformability; lesser toxicity; enhanced permeability; and scalability along with potential for surface modification, active targeting, and controlled release render them ideal designs for efficient drug delivery. The current review provides a brief account of the discovery, advantages, composition, synthesis, comparison with other cutaneous nano-drug delivery systems, applications, and recent developments in this area.

Development and Evaluations of Transdermally Delivered Luteolin Loaded Cationic Nanoemulsion: In Vitro and Ex Vivo Evaluations

Introduction: Luteolin (LUT) is natural flavonoid with multiple therapeutic potentials and is explored for transdermal delivery using a nanocarrier system. LUT loaded cationic nanoemulsions (CNE1–CNE9) using bergamot oil (BO) were developed, optimized, and characterized in terms of in vitro and ex vivo parameters for improved permeation. Materials and methods: The solubility study of LUT was carried out in selected excipients, namely BO, cremophor EL (CEL as surfactant), labrasol (LAB), and oleylamine (OA as cationic charge inducer). Formulations were characterized with globular size, polydispersity index (PDI), zeta potential, pH, and thermodynamic stability studies. The optimized formulation (CNE4) was selected for comparative investigations (% transmittance as %T, morphology, chemical compatibility, drug content, in vitro % drug release, ex vivo skin permeation, and drug deposition, DD) against ANE4 (anionic nanoemulsion for comparison) and drug suspension (DS). Results: Formulations such as CNE1–CNE9 and ANE4 (except CNE6 and CNE8) were found to be stable. The optimized CNE4 based on the lowest value of globular size (112 nm), minimum PDI (0.15), and optimum zeta potential (+26 mV) was selected for comparative assessment against ANE4 and DS. The %T values of CNE1–CNE9 were found to be ˃95% and CEL content slightly improved the %T value. The spherical CNE4 was compatible with excipients and showed % total drug content in the range of 97.9–99.7%. In vitro drug release values from CNE4 and ANE4 were significantly higher than DS. Moreover, permeation flux (138.82 ± 8.4 µg/cm²·h), enhancement ratio (8.23), and DD (10.98%) were remarkably higher than DS. Thus, ex vivo parameters were relatively high as compared to DS which may be attributed to nanonization, surfactant-mediated reversible changes in skin lipid matrix, and electrostatic interaction of nanoglobules with the cellular surface. Conclusion: Transdermal delivery of LUT can be a suitable alternative to oral drug delivery for augmented skin permeation and drug deposition.

Transdermal Delivery of Chemotherapeutics: Strategies, Requirements, and Opportunities

Chemotherapeutic drugs are primarily administered to cancer patients via oral or parenteral routes. The use of transdermal drug delivery could potentially be a better alternative to decrease the dose frequency and severity of adverse or toxic effects associated with oral or parenteral administration of chemotherapeutic drugs. The transdermal delivery of drugs has shown to be advantageous for the treatment of highly localized tumors in certain types of breast and skin cancers. In addition, the transdermal route can be used to deliver low-dose chemotherapeutics in a sustained manner. The transdermal route can also be utilized for vaccine design in cancer management, for example, vaccines against cervical cancer. However, the design of transdermal formulations may be challenging in terms of the conjugation chemistry of the molecules and the sustained and reproducible delivery of therapeutically efficacious doses. In this review, we discuss the nano-carrier systems, such as nanoparticles, liposomes, etc., used in recent literature to deliver chemotherapeutic agents. The advantages of transdermal route over oral and parenteral routes for popular chemotherapeutic drugs are summarized. Furthermore, we also discuss a possible in silico approach, Formulating for Efficacy™, to design transdermal formulations that would probably be economical, robust, and more efficacious.

Exploring potential formulation strategies for chemoprevention of breast cancer: a localized delivery perspective

This review focuses on the various formulation approaches that have been explored to achieve localized delivery in breast cancer. The rationale behind the necessity of localized drug delivery has been extensively reviewed. The review also emphasizes the various possible routes for achieving localized drug delivery. Particularly, different types of nanoplatforms like lipid-based drug carriers, polymeric particles, hydrogels, drug conjugates and other formulation strategies like microneedles and drug-eluting implants, which have been used to increase tumor retention and subsequently halt tumor progression, have been deliberated here. In addition, the significant challenges that may be encountered in the delivery of anticancer drugs and the aspects that require careful evaluation for effective localized delivery of chemotherapeutic agents have been discussed.

Optimization and efficacy study of synergistic vincristine coloaded liposomal doxorubicin against breast and lung cancer

Aim: To improve the efficacy of poly-ethylene glycol (PEG)ylated liposomes coloaded with doxorubicin and vincristine against triple-negative breast cancer (TNBC) and non-small-cell lung cancer (NSCLC). Methods: The combinatorial index of the drugs was established using the Chou-Talalay method in MDA-MB-231 and A549 cell lines. The most effective ratio was co-encapsulated in factorial design optimized nanoliposomes which were characterized for similarity to clinical standard and evaluated in vitro and in vivo for therapeutic efficacy. Results & conclusion: The formulation exhibited more than 95% co-encapsulation, a size of 95.74 ± 2.65 nm and zeta potential of -9.17 ± 1.19 mV while having no significant differences in physicochemical and biochemical characteristics as compared with the clinical standard. Efficacy evaluation studies showed significantly improved cytotoxicity and tumor regression compared with liposomal doxorubicin indicating improvement in efficacy against TNBC and NSCLC.

Transdermal Delivery Systems of Natural Products Applied to Skin Therapy and Care

Natural products are favored because of their non-toxicity, low irritants, and market reacceptance. We collected examples, according to ancient wisdom, of natural products to be applied in transdermal delivery. A transdermal delivery system, including different types of agents, such as ointments, patches, and gels, has long been used for skin concerns. In recent years, many novel transdermal applications, such as nanoemulsions, liposomes, lipid nanoparticles, and microneedles, have been reported. Nanosized drug delivery systems are widely applied in natural product deliveries. Nanosized materials notably enhance bioavailability and solubility, and are reported to improve the transdermal permeation of many substances compared with conventional topical formulations. Natural products have been made into nanosized biomaterials in order to enhance the penetration effect. Before introducing the novel transdermal applications of natural products, we present traditional methods within this article. The descriptions of novel transdermal applications are classified into three parts: liposomes, emulsions, and lipid nanoparticles. Each section describes cases that are related to promising natural product transdermal use. Finally, we summarize the outcomes of various studies on novel transdermal agents applied to skin treatments.

Novel Approach for Transdermal Delivery of Rifampicin to Induce Synergistic Antimycobacterial Effects Against Cutaneous and Systemic Tuberculosis Using a Cationic Nanoemulsion Gel

Purpose

This study demonstrated improved transdermal delivery of rifampicin-loaded cationic nanoemulsion gel to treat systemic and cutaneous tuberculosis using capmul, labrasol, and acconon, which exert anti-Mycobacterium activities. This approach enhanced drug permeation across the skin, increased therapeutic efficacy, and reduced dose-related side effects.

Methods

Design Expert^® was used to optimize formulations (S_mix ratio and capmul as independent factors), which were prepared using a slow spontaneous titration method. The optimized nanoemulsion was incorporated into carbopol gel to allow for topical application and comparative assessments. Nanoemulsions and gels were evaluated for size, size distribution, shape, zeta potential, percent spread, viscosity, in vitro hemolysis, in vitro release, and ex vivo skin permeation and deposition. A mechanistic evaluation was performed using scanning electron microscopy. Furthermore, in vivo pharmacokinetic and irritation studies were performed.

Results

The optimized cationic nanoemulsion (OCNE-1) was characterized by small particle size (≤100 nm), had optimal viscosity, percent spread, zeta potential, and percent drug release, and was hemocompatible. The OCNE-1T gel exhibited higher permeation flux (51.32 ± 0.5 µg/cm² hr), permeation coefficient (2.566 ± 0.08 cm/hr), drug deposition (994.404 µg/cm²), and enhancement ratio (7.16) than those of the OCNE-1 nanoemulsion or drug solution. Scanning electron microscopy was used to characterize the mechanism of enhanced permeation. An In vivo study showed that the C_max and area under the curve following transdermal application were 4.34- and 4.74-fold higher than those following oral administration.

Conclusion

Transdermal delivery of rifampicin could be a promising alternative to conventional approaches to treat systemic and local tuberculosis, and other bacterial infections.

Current development in the formulations of non-injection administration of paclitaxel

Paclitaxel (PTX) belongs to a class of taxane anti-tumor drug used for the clinic treatment of breast cancer, ovarian cancer, non-small-cell lung cancer, and so on. PTX has poor water solubility and oral bioavailability. It is generally administered via intravenous (i.v.) infusion. Traditional PTX injectable preparations contain Cremophor-EL and ethanol to improve its solubility, which would result in adverse reactions like severe hypersensitivity, neutropenia, etc. Adverse reactions can be reduced only by complicated pretreatment with glucocorticoid and antihistamines drugs and followed by PTX slow infusion for three hours, which has brought significant inconvenience to the patients. Though, a new-generation PTX formulation, Abraxane, free of Cremophor-EL and ethanol, is still being administrated by frequent i.v. infusions and extremely expensive. Therefore, non-injection administration of PTX is urgently needed to avoid the side effects as well as reduce inconvenience to the patients. Recently, a variety of non-injection drug delivery systems (DDSs) of PTX have been developed. This review aims to discuss the progress of non-injectable administration systems of PTX, including oral administration systems, vaginal administration systems, implantable DDSs, transdermal DDSs and intranasal administration for the future study and clinical applications.

Sodium cholate-enhanced polymeric micelle system for tumor-targeting delivery of paclitaxel

PURPOSE

Polymeric micelles are attractive nanocarriers for tumor-targeted delivery of paclitaxel (PTX). High antitumor efficacy and low toxicity require that PTX mainly accumulated in tumors with little drug exposure to normal tissues. However, many PTX-loaded micelle formulations suffer from low stability, fast drug release, and lack of tumor-targeting capability in the circulation. To overcome these challenges, we developed a micellar formulation that consists of sodium cholate (NaC) and monomethoxy poly (ethylene glycol)-block-poly (d,l-lactide) (mPEG-PDLLA).

METHODS

PTX-loaded NaC-mPEG-PDLLA micelles (PTX-CMs) and PTX-loaded mPEG-PDLLA micelles (PTX-Ms) were formulated, and their characteristics, particle size, surface morphology, release behavior in vitro, pharmacokinetics and in vivo biodistributions were researched. In vitro and in vivo tumor inhibition effects were systematically investigated. Furthermore, the hemolysis and acute toxicity of PTX-CMs were also evaluated.

RESULTS

The size of PTX-CMs was 53.61±0.75 nm and the ζ-potential was -19.73±0.68 mV. PTX was released much slower from PTX-CMs than PTX-Ms in vitro. Compared with PTX-Ms, the cellular uptake of PTX-CMs was significantly reduced in macrophages and significantly increased in human cancer cells, and therefore, PTX-CMs showed strong growth inhibitory effects on human cancer cells. In vivo, the plasma AUC0-t of PTX-CMs was 1.8-fold higher than that of PTX-Ms, and 5.2-fold higher than that of Taxol. The biodistribution study indicated that more PTX-CMs were accumulated in tumor than PTX-Ms and Taxol. Furthermore, the significant antitumor efficacy of PTX-CMs was observed in mice bearing BEL-7402 hepatocellular carcinoma and A549 lung carcinoma. Results from drug safety assessment studies including acute toxicity and hemolysis test revealed that the PTX-CMs were safe for in vivo applications.

CONCLUSION

These results strongly revealed that NaC-mPEG-PDLLA micelles can tumor-target delivery of PTX and enhance drug penetration in tumor, suggesting that NaC-mPEG-PDLLA micelles are promising nanocarrier systems for anticancer drugs delivery.

Elastic liposomes as novel carriers: recent advances in drug delivery

Elastic liposomes (EL) are some of the most versatile deformable vesicular carriers that comprise physiologically biocompatible lipids and surfactants for the delivery of numerous challenging molecules and have marked advantages over other colloidal systems. They have been investigated for a wide range of applications in pharmaceutical technology through topical, transdermal, nasal, and oral routes for efficient and effective drug delivery. Increased drug encapsulation efficiency, enhanced drug permeation and penetration into or across the skin, and ultradeformability have led to widespread interest in ELs to modulate drug release, permeation, and drug action more efficiently than conventional drug-release vehicles. This review provides insights into the versatile role that ELs play in the delivery of numerous drugs and biomolecules by improving drug release, permeation, and penetration across the skin as well as stability. Furthermore, it provides future directions that should ensure the widespread use of ELs across all medical fields.

Transportan in nanocarriers improves skin localization and antitumor activity of paclitaxel

In this study, the ability of nanocarriers containing protein transduction domains (PTDs) of various classes to improve cutaneous paclitaxel delivery and efficacy in skin tumor models was evaluated. Microemulsions (MEs) were prepared by mixing a surfactant blend (polyoxyethylene 10 oleoyl ether, ethanol and propylene glycol), monocaprylin, and water. The PTD transportan (ME-T), penetratin (ME-P), or TAT (ME-TAT) was added at a concentration of 1 mM to the plain ME. All MEs displayed nanometric size (32.3–40.7 nm) and slight positive zeta potential (+4.1 mV to +6.8 mV). Skin penetration of paclitaxel from the MEs was assessed for 1–12 hours using porcine skin and Franz diffusion cells. Among the PTD-containing formulations, paclitaxel skin (stratum corneum + epidermis and dermis) penetration at 12 hours was maximized with ME-T, whereas ME-TAT provided the lowest penetration (1.6-fold less). This is consistent with the stronger ability of ME-T to increase transepidermal water loss (2.4-fold compared to water) and tissue permeability. The influence of PTD addition on the ME irritation potential was assessed by measuring interleukin-1α expression and viability of bioengineered skin equivalents. A 1.5- to 1.8-fold increase in interleukin-1α expression was induced by ME-T compared to the other formulations, but this effect was less pronounced (5.8-fold) than that mediated by the moderate irritant Triton. Because ME-T maximized paclitaxel cutaneous localization while being safer than Triton, its efficacy was assessed against basal cell carcinoma cells and a bioengineered three-dimensional melanoma model. Paclitaxel-containing ME-T reduced cells and tissue viability by twofold compared to drug solutions, suggesting the potential clinical usefulness of the formulation for the treatment of cutaneous tumors.

Vitamin E TPGS based nanogel for the skin targeting of high molecular weight anti-fungal drug: development and in vitro and in vivo assessment

Enhanced skin permeation and deposition potential of nanogel containing Vitamin E TPGS.

Recent expansions in an emergent novel drug delivery technology: Emulgel

Emulgel is an emerging topical drug delivery system to which if more effort is paid towards its formulation & development with more number of topically effective drugs it will prove a boon for derma care & cosmetology. Emulgels are either emulsion of oil in water or water in oil type, which is gelled by mixing it with gelling agent. Incorporation of emulsion into gel increases its stability & makes it a dual control release system. Due to lack of excess oily bases & insoluble excipients, it shows better drug release as compared to other topical drug delivery system. Presence of gel phase makes it a non greasy & favors good patient compliance. These reviews give knowledge about Emulgel including its properties, advantages, formulation considerations, and its recent advances in research field. All factors such as selection of gelling agent, oil agent, emulsifiers influencing the stability and efficacy of Emulgel are discussed. All justifications are described in accordance with the research work carried out by various scientists. These brief reviews on formulation method have been included. Current research works that carried out on Emulgel are also discussed and highlighted the wide utility of Emulgel in topical drug delivery system. After the vast study, it can be concluded that the Emulgels appear better & effective drug delivery system as compared to other topical drug delivery system. The comprehensive analysis of rheological and release properties will provide an insight into the potential usage of Emulgel formulation as drug delivery system.

Skin permeation behavior of elastic liposomes: role of formulation ingredients

INTRODUCTION

With the incorporation of edge activators into the lipid bilayer structure, elasticity properties are given to liposomes. Regardless of the debate over the precise permeation mechanism of elastic liposomes, these vesicles have been proven to enhance drug permeation into or through skin in most cases.

AREAS COVERED

This article provides an overview of the formulation ingredients of elastic liposomes and their relationship with skin permeation behavior. The ingredients are divided into two categories of basic and optional ingredients. The effect of stability on permeation behavior of the vesicles is highlighted.

EXPERT OPINION

More attention should be paid to the stability of elastic liposomes. The different stability properties of the elastic liposomes following administration can induce different skin permeation behaviors of the vesicles. It is necessary to select the optimum composition of the elastic liposomes in order to control the stability and permeation behavior of the vesicles into or through the skin. Moreover, for the development of elastic liposomes, particular attention should also be paid to the drug leakage from the vesicles during long-term storage. The application of optional ingredients to improve the stability and/or elasticity of the elastic liposomes is becoming a new trend.

Protein transduction domain-containing microemulsions as cutaneous delivery systems for an anticancer agent

In this study, we developed cationic microemulsions containing a protein transduction domain (penetratin) for optimizing paclitaxel localization within the skin. Microemulsions were prepared by mixing a surfactant blend (BRIJ:ethanol:propylene glycol 2:1:1, w/w/w) with monocaprylin (oil phase) at 1.3:1 ratio, and adding water at 30% (ME-30), 43% (ME-43), and 50% (ME-50). Electrical conductivity and viscosity measurements indicated that ME-30 is most likely a bicontinuous system, whereas ME-43 and ME-50 are water continuous. Their irritation potential, studied in bioengineered skin equivalents, decreased as aqueous content increased. Because ME-50 was not stable in the presence of paclitaxel (0.5%), ME-43 was selected for penetratin incorporation (0.4%). The microemulsion containing penetratin (ME-P) displayed zeta potential of +5.2 mV, and promoted a 1.8-fold increase in paclitaxel cutaneous (but not transdermal) delivery compared with the plain ME-43, whereas the enhancement promoted by another cationic microemulsion containing phytosphingosine was 1.3-fold. Compared with myvacet oil, ME-P promoted a larger increase on transepidermal water loss (twofold) than the plain or the phytosphingosine-containing microemulsions (1.5-fold), suggesting that penetratin addition increases the barrier-disrupting and penetration-enhancing effects of microemulsions. The ratio Δcutaneous/Δtransdermal delivery promoted by ME-P was the highest among the formulations, suggesting its potential for drug localization within cutaneous tumor lesions.

Lamellar liquid crystalline phases for cutaneous delivery of Paclitaxel: impact of the monoglyceride

PURPOSE

To develop liquid crystalline phases with monoglycerides, and assess whether the monoglyceride type favors cutaneous over transdermal paclitaxel delivery.

METHODS

BRIJ-based lamellar phases were prepared with 0.5% paclitaxel and 20% of either monocaprylin (LP-MC), monomyristolein (LP-MM) or monoolein (LP-MO). Skin electrical resistance, drug release and cutaneous delivery in vitro and in vivo were assessed. Viability of skin equivalents and release of IL-1α were assessed as indexes of irritation potential.

RESULTS

An inverse relationship between monoglyceride acyl chain length and amount of paclitaxel delivered was observed. Although the largest paclitaxel amounts were delivered by LP-MC, all formulations delivered higher levels of drug in the skin (56-64-fold) than across the tissue. The superiority of LP-MC seems related to a stronger decrease in skin resistance (as an index of permeability), and not to increased drug release. LP-MC displayed similar penetration-enhancing ability in vivo, and a much lower irritation potential than Triton-X100 (a moderate irritant), leading to 3-fold higher skin equivalent viability and release of 60-fold less IL-1α.

CONCLUSIONS

Even though LP-MC delivered the largest amounts of paclitaxel, all formulations provided similar cutaneous/transdermal delivery ratios, suggesting that changing the monoglyceride acyl chain length did not affect the balance between cutaneous and transdermal delivery.

Ethogel topical formulation for increasing the local bioavailability of 5-fluorouracil: a mechanistic study

5-Fluorouracil (5-FU) is an anticancer drug and is considered a gold standard for the treatment of skin cancer. At present, topical chemotherapy with 5-FU is associated with the limitations of poor skin permeation, retention at target site, and skin irritation potential. In the present study, an attempt has been made to develop an ethosome-based topical gel formulation (ethogel) for skin targeting of 5-FU. The ethosomal formulation was prepared using the classical dispersion method, and loading of 5% w/w of the drug was optimized to the commercial strength of marketed 5-FU cream. Carbopol 934P was used as a gel former in 0.5, 0.75, 1.0, and 1.5% w/w concentration for preparation of ethosome-based ethogel formulation. The ethogel formulation was characterized for viscosity, spreadability, extrudability, and pH. Viscosity of the developed ethogel and that of the marketed formulation was found to be 3070±14.7 and 2870±14.4 cP, respectively. An in-vitro skin permeation and deposition study was carried out across rat skin using the marketed cream and 5-FU drug solution as controls. The amount of drug deposition was found to increase 5.9- and 9.4-fold on treatment with ethogel in comparison with the marketed cream and drug solution, respectively. The result of antitumor activity evaluated using a Cytoselect 96-well cell transformation assay revealed a large reduction in tumor density with treatment with the 5-FU ethogel formulation in comparison with the marketed formulation. A significant reduction in the skin irritation potential of 5-FU ethogel formulation was also found in comparison with that of the marketed formulation as measured by the Draize test. The results of the present study demonstrated ethogel as a better alternative for increasing the local bioavailability of 5-FU in comparison to the marketed formulation.

Effects of silymarin and formulation on the oral bioavailability of paclitaxel in rats

The aims of the present study were to investigate the effects of silymarin, an inhibitor of the P-glycoprotein efflux pump, on oral bioavailability of paclitaxel in rats, and to compare pharmacokinetic parameters of paclitaxel between a commercial formulation of paclitaxel (Taxol®) and a paclitaxel microemulsion. Oral bioavailability of paclitaxel in a Taxol® formulation was enhanced in the combination with silymarin (10 and 20mg/kg). In particular, the mean maximum plasma concentration (C(max)) and the mean area under the plasma concentration-time curve (AUC(0-)(t)) of paclitaxel in the Taxol® formulation were significantly increased 3-fold and 5-fold compared with control, respectively, following oral co-administration with 10mg/kg of silymarin (p<0.01). When the paclitaxel microemulsion was co-administered with silymarin (20mg/kg) orally, it caused a maximum increase in the absolute bioavailability of paclitaxel (19%). In addition, the relative bioavailability of the paclitaxel microemulsion was 184% as compared to Taxol® after oral dosing, whereas the mean time required to reach C(max) (T(max)) of paclitaxel was decreased in the microemulsion formulation compared with Taxol®, suggesting faster absorption. Based on these results, we conclude that oral bioavailability of paclitaxel is significantly improved by co-administration with silymarin, an inhibitor of the P-gp efflux pump and by microemulsion formulation.

Evaluation of biosafety and intracellular uptake of Cremophor EL free paclitaxel elastic liposomal formulation

The present study examines the acute, sub-acute toxicity, and cytotoxicity of paclitaxel elastic liposomal formulation in comparison to a marketed Cremophor EL (polyoxyethylated castor oil):ethanol (1:1, v/v) based formulation. In the previous study, Cremophor EL free paclitaxel elastic liposomal formulation was developed and characterized. Cytotoxicity of formulation was evaluated by MTT assay using A549 cell lines. Percentage intracellular uptake of paclitaxel elastic liposomal and marketed formulation was determined using a fluorescence activating cell sorting assay (FACS) and fluorescence microscopy techniques. Single and repeated dose toxicity measurement showed no mortality, hematological, biochemical, or histopathological changes up to a dose of 120 mg/kg for paclitaxel elastic liposomal formulation, in comparison the marketed formulation showed toxicity at a dose of 40 mg/kg. Maximum tolerated dose (MTD) for paclitaxel elastic liposomal and marketed formulation was found to be 160 mg/kg and 40 mg/kg, respectively. Results of FACS analysis showed a 94.6 ± 2.5% intracellular uptake of fluorescence marker acridine orange (AO) loaded in elastic liposomes; in comparison the AO solution showed only a 19.8 ± 1.1% uptake. Paclitaxel elastic liposomal formulation seems to be a better alternative for safe and effective delivery of paclitaxel. This study proves the safety and higher intracellular uptake of paclitaxel elastic liposomal formulation.