Multifunctional nanoemulsions for intraductal delivery as a new platform for local treatment of breast cancer

Thermosensitive Polymeric Nanoparticles for Drug Co-Encapsulation and Breast Cancer Treatment

Despite advances in breast cancer treatment, there remains a need for local management of noninvasive, low-grade ductal carcinoma in situ (DCIS). These focal lesions are well suited for local intraductal treatment. Intraductal administration supported target site drug retention, improved efficacy, and reduced systemic exposure. Here, we used a poly(N-isopropyl acrylamide, pNIPAM) nanoparticle delivery system loaded with cytotoxic piplartine and an MAPKAP Kinase 2 inhibitor (YARA) for this purpose. For tumor environment targeting, a collagen-binding peptide SILY (RRANAALKAGELYKSILYGSG-hydrazide) was attached to pNIPAM nanoparticles, and the nanoparticle diameter, zeta potential, drug loading, and release were assessed. The system was evaluated for cytotoxicity in a 2D cell culture and 3D spheroids. In vivo efficacy was evaluated using a chemical carcinogenesis model in female Sprague-Dawley rats. Nanoparticle delivery significantly reduced the IC50 of piplartine (4.9 times) compared to the drug in solution. The combination of piplartine and YARA in nanoparticles further reduced the piplartine IC50 (~15 times). Treatment with these nanoparticles decreased the in vivo tumor incidence (5.2 times). Notably, the concentration of piplartine in mammary glands treated with nanoparticles (35.3 ± 22.4 μg/mL) was substantially higher than in plasma (0.7 ± 0.05 μg/mL), demonstrating targeted drug retention. These results indicate that our nanocarrier system effectively reduced tumor development with low systemic exposure.

Nanostructured lipid carriers loaded into in situ gels for breast cancer local treatment

In this study, nanostructured lipid carriers (NLC) were developed and employed to obtain in situ thermosensitive formulations for the ductal administration and prolonged retention of drugs as a new strategy for breast cancer local treatment. NLC size was influenced by the type and concentration of the oil phase, surfactants, and drug incorporation, ranging from 221.6 to 467.5 nm. The type of liquid lipid influenced paclitaxel and 5-fluorouracil cytotoxicity, with tributyrin-containing NLC reducing IC50 values by 2.0-7.0-fold compared to tricaprylin NLC in MCF-7, T-47D and MDA-MB-231 cells. In spheroids, the NLCs reduced IC50 compared to either drug solution (3.2-6.2-fold). Although a significant reduction (1.26 points, p < 0.001) on the health index of Galleria mellonella larvae was observed 5 days after NLC administration, survival was not significantly reduced. To produce thermosensitive gels, the NLCs were incorporated in a poloxamer (11 %, w/w) dispersion, which gained viscosity (2-fold) at 37 °C. After 24 h, ∼53 % of paclitaxel and 83 % of 5-fluorouracil were released from the NLC; incorporation in the poloxamer gel further prolonged release. Intraductal administration of NLC-loaded gel increased the permanence of hydrophilic (2.2-3.0-fold) and lipophilic (2.1-2.3-fold) fluorescent markers in the mammary tissue compared to the NLC (as dispersion) and the markers solutions. In conclusion, these results contribute to improving our understanding of nanocarrier design with increased cytotoxicity and prolonged retention for the intraductal route. Tributyrin incorporation increased the cytotoxicity of paclitaxel and 5-fluorouracil in monolayer and spheroids, while NLC incorporation in thermosensitive gels prolonged tissue retention of both hydrophilic and hydrophobic compounds.

A review of FDA approved drugs and their formulations for the treatment of breast cancer

Breast cancer is one of the most diagnosed solid cancers globally. Extensive research has been going on for decades to meet the challenges of treating solid tumors with selective compounds. This article aims to summarize the therapeutic agents which are either being used or are currently under approval for use in the treatment or mitigation of breast cancer by the US FDA, to date. A structured search of bibliographic databases for previously published peer-reviewed research papers on registered molecules was explored and data was sorted in terms of various categories of drugs used in first line/adjuvant therapy for different stages of breast cancer. We included more than 300 peer-reviewed papers, including both research and reviews articles, in order to provide readers an useful comprehensive information. A list of 39 drugs are discussed along with their current status, dose protocols, mechanism of action, pharmacokinetics, possible side effects, and marketed formulations. Another interesting aspect of the article included focusing on novel formulations of these drugs which are currently in clinical trials or in the process of approval. This exhaustive review thus shall be a one-stop solution for researchers who are working in the areas of formulation development for these drugs.

Development and cytotoxicity evaluation of multiple nanoemulsions for oral co-delivery of 5-fluorouracil and short chain triglycerides for colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in the world, but current chemotherapy options are limited due to adverse effects and low oral bioavailability of drugs. In this study, we investigated the obtainment parameters and composition of new multiple nanoemulsions (MN) based on microemulsions for oral co-delivery of 5-fluorouracil (5FU) and short-chain triglycerides (SCT, either tributyrin or tripropionin). The area of microemulsion formation was increased from 14% to 38% when monocaprylin was mixed with tricaprylin as oil phase. Addition of SCT reduced this value to 24-26%. Using sodium alginate aqueous dispersion as internal aqueous phase (to avoid phase inversion) did not further affected the area but increased microemulsion viscosity by 1.5-fold. To obtain the MN, selected microemulsions were diluted in an external aqueous phase; droplet size was 500 nm and stability improved using polyoxyethylene (den Besten et al., 2013) oleyl ether at 1-2.5% as surfactant in the external phase and a dilution ratio of 1:1 (v/v). 5FU in vitro release could be better described by the Korsmeyer-Peppas model. No pronounced changes in droplet size were observed when selected MNs were incubated in buffers mimicking gastrointestinal fluids. The 5FU cytotoxicity in monolayer cell lines presenting various mutations was influenced by its incorporation in the nanocarrier, presence of SCT and cell mutation status. The MNs selected reduced the viability of tumor spheroids (employed as 3D tumor models) by 2.2-fold compared to 5FU solution and did not affect the survival of the G. mellonella, suggesting effectiveness and safety.

Contributions of nanotechnology to the intraductal drug delivery for local treatment and prevention of breast cancer

Breast cancer is a major public health problem, affecting millions of people. It is a very heterogeneous disease, with localized and invasive forms, and treatment generally consists of a combination of surgery and radiotherapy followed by administration of estrogen receptor modulators or aromatase inhibitors. Given its heterogeneity, management strategies that take into consideration the type of disease and biological markers and can provide more personalized and local treatment are required. More recently, the intraductal administration (i.e., into the breast ducts) of drugs has attracted significant attention due to its ability of providing drug distribution through the ductal tree in a minimally invasive manner. Although promising, intraductal administration is not trivial, and difficulties in duct identification and cannulation are important challenges to the further development of this route. New drug delivery strategies such as nanostructured systems can help to achieve the full benefits of the route due to the possibility of prolonging tissue retention, improving targeting and selectivity, increasing cytotoxicity and reducing the frequency of administration. This review aims at discussing the potential benefits and challenges of intraductal administration, focusing on the design and use of nanocarriers as innovative and feasible strategies for local breast cancer therapy and prevention.

Lipid-core nanoparticles: Classification, preparation methods, routes of administration and recent advances in cancer treatment

Nanotechnological drug delivery platforms represent a new paradigm for cancer therapeutics as they improve the pharmacokinetic profile and distribution of chemotherapeutic agents over conventional formulations. Among nanoparticles, lipid-based nanoplatforms possessing a lipid core, that is, lipid-core nanoparticles (LCNPs), have gained increasing interest due to lipid properties such as high solubilizing potential, versatility, biocompatibility, and biodegradability. However, due to the wide spectrum of morphologies and types of LCNPs, there is a lack of consensus regarding their terminology and classification. According to the current state-of-the-art in this critical review, LCNPs are defined and classified based on the state of their lipidic components in liquid lipid nanoparticles (LLNs). These include lipid nanoemulsions (LNEs) and lipid nanocapsules (LNCs), solid lipid nanoparticles (SLNs) and nanostructured lipid nanocarriers (NLCs). In addition, we present a comprehensive and comparative description of the methods employed for their preparation, routes of administration and the fundamental role of physicochemical properties of LCNPs for efficient antitumoral drug-delivery application. Market available LCNPs, clinical trials and preclinical in vivo studies of promising LCNPs as potential treatments for different cancer pathologies are summarized.

Multilamellar ceramide core-structured microvehicles with substantial skin barrier function recovery

This study introduces a multilamellar ceramide core-structured microvehicle platform for substantial skin barrier function recovery. Our approach essentially focused on fabricating bacterial cellulose nanofiber (BCNF)-enveloped ceramide-rich lipid microparticles (CerMPs) by solidifying BCNF-armored oil-in-water Pickering emulsions. The oil drops consisted of Ceramide NP (a phytosphingosine backbone N-acylated with a saturated stearic acid) and fatty alcohols (FAs) with a designated stoichiometry. The thin BCNF shell layer completely blocked the growth of ceramide molecular crystals from the CerMPs for a long time. The CerMP cores displayed a multilamellar structure wherein the interlayer distance and lateral packing could be manipulated using FAs with different alkyl chain lengths. The CerMPs remarkably lowered the trans-epidermal water loss while restoring the structural integrity of the epidermis in damaged skin. The results obtained herein highlight that the CerMP system provides a practical methodology for developing various types of skin-friendly formulations that can strengthen the skin barrier function.

Monoolein-based nanodispersions for cutaneous co-delivery of methylene blue and metformin: Thermal and structural characterization and effects on the cutaneous barrier, skin penetration and cytotoxicity

This study evaluated the potential of monoolein (MO)-based nanodispersions to promote the cutaneous co-delivery of metformin (MET) and methylene blue (MB) for the treatment of non-melanoma skin cancer. MO-based nanodispersions were obtained using Kolliphor® P407 (KP) and/or sodium cholate (CH), and characterized concerning the structure, thermal stability, ability to disrupt the skin barrier, cutaneous permeation and retention of MB and MET. Additionally, the cytotoxic effect of MO nanodispersions-mediated combination therapy using MET and MB in A431 cells was evaluated. The nanodispersions exhibited nanometric size (<200 nm) and thermal and physical stability. Small angle X-ray scattering studies revealed multiple structures depending on composition. They were able to interact with stratum corneum lipid structure, increasing its fluidity. The effect of MO-nanodispersions on topical/transdermal delivery of MB and MET was composition-dependent. Nanodispersions with low MO content (5 %) and stabilized with KP and CH (0.05-0.10 %) were the most promising, enhancing the cutaneous delivery of MB and MET by 1.9 to 2.2-fold and 1.4 to 1.7-fold, respectively, compared to control. Cytotoxic studies revealed that the most promising MO nanodispersion-mediated combination therapy using MET and MB (1:1) reduced the IC₅₀ by 24-fold, compared to MB solution, and a further reduction (1.5-fold) was observed by MB photoactivation.

Novel targeted pH-responsive drug delivery systems based on PEGMA-modified bimetallic Prussian blue analogs for breast cancer chemotherapy

The development of novel nanoparticle-based drug delivery systems (nano-DDSs) with high loading capacity, low toxicity, precise targeting, and excellent biocompatibility remains urgent and important for the treatment of breast cancer (BC). Herein, novel BC-targeted nano-DDSs based on bimetallic Prussian blue analogs (PBA-DDSs) for intracellular doxorubicin (DOX) delivery and pH-responsive release were developed. Two kinds of bimetallic PBA, namely CuFe (copper-iron) PBA and CoFe (cobalt-iron) PBA, were synthesized by a coprecipitation method, followed by modification with polyethyleneglycol methacrylate (PEGMA) via surface-initiated atom transfer radical polymerization and immobilization with the AS1411 aptamer to obtain two kinds of novel BC-targeted nano-DDS. CuFePBA@PEGMA@AS1411 and CoFePBA@PEGMA@AS1411 showed high drug loading efficiency of 80% and 84%, respectively, for DOX, while 56.0% and 75.9% DOX release could be achieved under acidic pH conditions. In vitro cell viability and in vivo experiments proved the good biocompatibility of both PBA-DDSs. Cellular uptake and in vivo distribution suggested that both PBA-DDSs had efficient nucleolin-targeting capability, indicating the targeted delivery of DOX in tumor tissues. In vivo evaluation of anti-BC efficacy further confirmed that the obtained PBA-DDSs exhibited excellent therapeutic efficacy with limited side-effects. Therefore, the proposed novel PBA-DDSs can be used as secure and effective drug nano-DDSs for BC chemotherapy.

Pluronic® triblock copolymer-based nanoformulations for cancer therapy: A 10-year overview

This paper provides a review of the literature on the use of Pluronic® triblock copolymers for drug encapsulation over the last 10 years. A special focus is given to the progress of drug delivery systems (e.g., micelles, liposomes, micro/nanoemulsions, hydrogels and nanogels, and polymersomes and niosomes); the beneficial aspects of Pluronic® triblock copolymers as biological response modifiers and as pharmaceutical additives, adjuvants, and stabilizers, are also discussed. The advantages and limitations encountered in developing site-specific targeting approaches based on Pluronic-based nanostructures in cancer treatment are highlighted, in addition to innovative examples for improving tumor cytotoxicity while reducing side effects.

Intraductal delivery of nanocarriers for ductal carcinoma in situ treatment: a strategy to enhance localized delivery

Ductal carcinoma in situ describes the most commonly occurring, noninvasive malignant breast disease, which could be the leading factor in invasive breast cancer. Despite remarkable advancements in treatment options, poor specificity, low bioavailability and dose-induced toxicity of chemotherapy are the main constraint. A unique characteristic of nanocarriers may overcome these problems. Moreover, the intraductal route of administration serves as an alternative approach. The direct nanodrug delivery into mammary ducts results in the accumulation of anticancer agents at targeted tissue for a prolonged period with high permeability, significantly decreasing the tumor size and improving the survival rate. This review focuses mainly on the intraductal delivery of nanocarriers in treating ductal carcinoma in situ, together with potential clinical translational research.

Emerging Roles of Ceramides in Breast Cancer Biology and Therapy

One of the classic hallmarks of cancer is the imbalance between elevated cell proliferation and reduced cell death. Ceramide, a bioactive sphingolipid that can regulate this balance, has long been implicated in cancer. While the effects of ceramide on cell death and therapeutic efficacy are well established, emerging evidence indicates that ceramide turnover to downstream sphingolipids, such as sphingomyelin, hexosylceramides, sphingosine-1-phosphate, and ceramide-1-phosphate, is equally important in driving pro-tumorigenic phenotypes, such as proliferation, survival, migration, stemness, and therapy resistance. The complex and dynamic sphingolipid network has been extensively studied in several cancers, including breast cancer, to find key sphingolipidomic alterations that can be exploited to develop new therapeutic strategies to improve patient outcomes. Here, we review how the current literature shapes our understanding of how ceramide synthesis and turnover are altered in breast cancer and how these changes offer potential strategies to improve breast cancer therapy.

A Lipid-Based In Situ-Forming Hexagonal Phase for Prolonged Retention and Drug Release in the Breast Tissue

In this study, the addition of monoolein to phosphatidylcholine (PC), tricaprylin, and propylene glycol (PG) mixtures was studied to produce fluid precursor formulations (FIPs) that could transform into hexagonal phase (resistant to aqueous dilution) in vitro and in vivo. The overall goal was to obtain FIPs that could incorporate chemopreventive drugs for subcutaneous administration in the mammary tissue to inhibit the development and/or recurrence of breast cancer. Increasing PG content reduced FIP viscosity up to ~ 2.5-fold, while increases in PC (over monoolein) increased the formation of emulsified systems. The hexagonal phase was observed at 20% of water and higher, with the minimum amount of water necessary for this formation increasing with PG content. The selected FIP formed a depot in vivo after ~ 24 h of administration; its structure was compatible with the hexagonal phase and it remained in the mammary tissue for at least 30 days, prolonging the permanence of a fluorescent probe. In vitro, the release of the synthetic retinoid fenretinide was slow, with ~ 9% of the drug released in 72 h. Consistent with this slow release, fenretinide IC₅₀ in breast cancer cells was ~ 100-fold higher in the selected FIP compared to its solution. The FIP reduced cell migration and presented higher cytotoxicity towards tumor compared to non-tumor cells. Given the limited number of options for pharmacological prevention of breast cancer development and recurrences, this formulation could potentially find applicability to reduce the frequency of administration and improve local concentrations of chemopreventive drugs.

Phosphatidylcholine-Based Nanoemulsions for Paclitaxel and a P-Glycoprotein Inhibitor Delivery and Breast Cancer Intraductal Treatment

In this study, incorporation of the cytotoxic agent paclitaxel and the P-glycoprotein inhibitor elacridar in hyaluronic acid (HA)-modified nanoemulsions was studied for intraductal delivery and breast cancer localized treatment. To improve cytotoxicity, we investigated the incorporation of perillyl alcohol or tributyrin as components of the nanoemulsion oil phase. The nanoemulsions presented size <180 nm and negative zeta potential. Both tributyrin and perillyl alcohol increased nanoemulsion cytotoxicity in MCF-7 cells, but not in MDA-MB-231. However, perillyl alcohol reduced nanoemulsion stability in the presence of the drugs. Concomitant incorporation of paclitaxel and elacridar in HA- and tributyrin-containing nanoemulsions (PE-NETri) increased cytotoxicity and reduced IC50 by 1.6 to 3-fold in MCF-7 and MDA-MB-231 cells compared to the nanoemulsion containing only paclitaxel (P-NE). This nanoemulsion also produced a 3.3-fold reduction in the viability of MDA-MB-231 spheroids. Elacridar incorporated in the nanoemulsion was capable of inhibiting P-glycoprotein in membranes. In vivo intraductal administration of the NE containing HA resulted in a three-fold higher retention of a fluorescent marker compared to a solution or nanoemulsion without HA, demonstrating the importance of HA. The nanoemulsion produced no histological changes in the mammary tissue. These results support the potential applicability of the nanoemulsion for local breast cancer management.

Hyaluronic acid nanoemulsions improve piplartine cytotoxicity in 2D and 3D breast cancer models and reduce tumor development after intraductal administration

Nanoemulsions modified with chitosan (NE-Q) or hyaluronic acid (NE-HA), developed for intraductal administration of piplartine (piperlongumine) and local breast cancer treatment, were evaluated for cytotoxic effects in vitro in 2D and 3D breast cancer models and in vivo in a chemically induced carcinogenesis model. Droplet size was lower than 100 nm, and zeta potential varied from +17.9 to -25.5 mV for NE-Q and NE-HA, respectively. Piplartine nanoencapsulation reduced its IC₅₀ up to 3.6-fold in T-47D and MCF-7 monolayers without differences between NE-Q and NE-HA, and up to 6.6-fold in cancer spheroids. Cytotoxicity improvement may result from a more efficient NE-mediated delivery, as suggested by stronger fluorescent staining of cells and spheroids. In 1-methyl-1-nitrosourea -induced breast cancer models, intraductal administration of piplartine-loaded NE-HA inhibited breast tumor development and histological alterations. These results support the potential applicability of piplartine-loaded NE-HA for intraductal treatment of breast cancer.

Breast intraductal nanoformulations for treating ductal carcinoma in situ II: Dose de-escalation using a slow releasing/slow bioconverting prodrug strategy

Ductal carcinoma in situ (DCIS) represents approximately 20-25% of newly diagnosed breast cancers. DCIS is treated by surgery and possibly radiotherapy. Chemotherapy is only used as adjuvant or neoadjuvant therapy but not as primary therapy. The present study investigated the intraductal administration of Ciclopirox (CPX) formulated in nanosuspensions (NSs) or nanoparticles (NPs) to treat DCIS locally in a Fischer 344 rat model orthotopically implanted with 13762 Mat B III cells. Slow converting esterase responsive CPX prodrugs (CPDs) were successfully synthesized at high purity (> 95%) by directly acetylating the hydroxyl group or by appending a self-immolative linker between CPX and a phenolic ester. Direct esterification CPDs were not sufficiently stable so self-immolative CPDs were formulated in NSs and NPs. Prodrug release was evaluated from poly(lactic-co-glycolic acid) NPs, and CPD4 demonstrated the slowest release rate with the rank order of CPD2 (R = methyl) > CPD3 (R = t-butyl) > CPD4 (R = phenyl). Intraductally administered CPX NS, CPD4 NS, and an innovative mixture of CDP4 NS and NPs (at 1 mg CPX equivalent/duct) demonstrated significant (p < 0.05) in vivo anti-tumor efficacy compared with immediate release (IR) CPX NS and non-treated controls. CPX mammary persistence at 6 h and 48 h after CPD4 NS or NP administration was also greater than after the immediate release CPX NS. A strong correlation between CPX mammary persistence and efficacy is demonstrated. In conclusion, nanoformulations utilizing a slow releasing/slow bioconverting CPX prodrug delivery strategy resulted in significant dose de-escalation (~ five fold) while maintaining anti-tumor efficacy.

The other side to the use of active targeting ligands; the case of folic acid in the targeting of breast cancer

Due to its overexpression in cancer cells, the folate receptor (FR) is heavily exploited in the active targeting of nanoparticles (NPs). Its ligand, folic acid (FA) is as a consequence widely used as a NP targeting ligand. Although rather popular and successful in principle, recent data has shown that FA may result in breast cancer initiation and progression, which questions the suitability of FA as NP cancer targeting ligand. In this work, intravenous administration of free FA to healthy female mice resulted in breast tissue dysplasia, hyperplasia and in the increased expression of human epidermal growth factor receptor-2 (HER2), folate receptor (FR), cancer antigen 15-3 (CA15.3), vascular endothelial growth factor (VEGF), signal transducer and activator of transcription 3 (STAT3) and the pro-inflammatory cytokines, tumor necrosis factor alpha (TNFα), interleukin-6 (IL-6) and interleukin-1β. In addition to the reduction in IL2. To evaluate the suitability and safety of FA as NP targeting ligand in breast cancer, small (≈ 150 nm) and large (≈ 500 nm) chitosan NPs were formulated and decorated with two densities of FA. The success of active targeting by FA was confirmed in two breast cancer cell lines (MCF-7 and MDA-MB-231 cells) in comparison to HEK293 cells. FA modified NPs that demonstrated successful active targeting in-vitro were assessed in-vivo. Upon intravenous administration, large NPs modified with a high density of FA accumulated in the breast tissue and resulted in similar effects as those observed with free FA. These results therefore question the suitability of FA as a targeting ligand in breast cancer and shed light on the importance of considering the activity (other than targeting) of the ligands used in NP active targeting.

Nanoemulsions: Formulation, characterization, biological fate, and potential role against COVID-19 and other viral outbreaks

Viral diseases are emerging as global threats. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), that causes coronavirus disease (COVID-19), has severe global impacts. Safety, dosage, and potency of vaccines recently approved for emergency use against SARS-CoV-2 need further evaluation. There is still no effective treatment against COVID-19; therefore, safe, and effective vaccines or therapeutics against SARS-CoV-2 are urgently needed. Oil-in-water nanoemulsions (O/W NEs) are emerging as sophisticated, protective, and therapeutic platforms. Encapsulation capacity, which offers better drug pharmacokinetics, coupled with the tunable surfaces present NEs as promising tools for pharmaceutical applications. The challenges facing drug discovery, and the advancements of NEs in drug delivery demonstrate the potential of NEs against evolving diseases, like COVID-19. Here we summarize current COVID-19 knowledge and discuss the composition, stability, preparation, characterization, and biological fate of O/W NEs. We also provide insights into NE structural-functional properties that may contribute to therapeutic or preventative solutions against COVID-19.

Microemulsion for Prolonged Release of Fenretinide in the Mammary Tissue and Prevention of Breast Cancer Development

The need of pharmacological strategies to preclude breast cancer development motivated us to develop a non-aqueous microemulsion (ME) capable of forming a depot after administration in the mammary tissue and uptake of interstitial fluids for prolonged release of the retinoid fenretinide. The selected ME was composed of phosphatidylcholine/tricaprylin/propylene glycol (45:5:50, w/w/w) and presented a droplet diameter of 175.3 ± 8.9 nm. Upon water uptake, the ME transformed successively into a lamellar phase, gel, and a lamellar phase-containing emulsion in vitro as the water content increased and released 30% of fenretinide in vitro after 9 days. Consistent with the slow release, the ME formed a depot in cell cultures and increased fenretinide IC₅₀ values by 68.3- and 13.2-fold in MCF-7 and T-47D cells compared to a solution, respectively. At non-cytotoxic concentrations, the ME reduced T-47D cell migration by 75.9% and spheroid growth, resulting in ∼30% smaller structures. The depot formed in vivo prolonged a fluorochrome release for 30 days without producing any sings of local irritation. In a preclinical model of chemically induced carcinogenesis, ME administration every 3 weeks for 3 months significantly reduced (4.7-fold) the incidence of breast tumors and increased type II collagen expression, which might contribute to limit spreading. These promising results support the potential ME applicability as a preventive therapy of breast cancer.

Women-specific routes of administration for drugs: A critical overview

The woman's body presents a number of unique anatomical features that can constitute valuable routes for the administration of drugs, either for local or systemic action. These are associated with genitalia (vaginal, endocervical, intrauterine, intrafallopian and intraovarian routes), changes occurring during pregnancy (extra-amniotic, intra-amniotic and intraplacental routes) and the female breast (breast intraductal route). While the vaginal administration of drug products is common, other routes have limited clinical application and are fairly unknown even for scientists involved in drug delivery science. Understanding the possibilities and limitations of women-specific routes is of key importance for the development of new preventative, diagnostic and therapeutic strategies that will ultimately contribute to the advancement of women's health. This article provides an overview on women-specific routes for the administration of drugs, focusing on aspects such as biological features pertaining to drug delivery, relevance in current clinical practice, available drug dosage forms/delivery systems and administration techniques, as well as recent trends in the field.

Topical transdermal chemoprevention of breast cancer: where will nanomedical approaches deliver us?

Despite the high incidence of breast cancer, there are few pharmacological prevention strategies for the high-risk population and those that are available have low adherence. Strategies that deliver drugs directly to the breasts may increase drug local concentrations, improving efficacy, safety and acceptance. The skin of the breast has been proposed as an administration route for local transdermal therapy, which may improve drug levels in the mammary tissue, due to both deep local penetration and percutaneous absorption. In this review, we discuss the application of nanotechnology-based strategies for the delivery of well established and new agents as well as drug repurposing using the topical transdermal route to improve the outcomes of preventive therapy for breast cancer.

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.

Nanostructured lipid carriers containing chitosan or sodium alginate for co-encapsulation of antioxidants and an antimicrobial agent for potential application in wound healing

The high incidence and costs of chronic wounds in the elderly have motivated the search for innovations to improve product performance and the healing process while reducing costs. In this study, bioadhesive nanostructured lipid carriers (NLC) were developed for the co-encapsulation of compounds with antioxidant (α-tocopherol and quercetin) and antimicrobial (tea tree oil) activity for management of wounds. The NLC was produced with shea butter and argan oil, and modified with sodium alginate or chitosan to confer bioadhesive properties. Spherical nanoparticles of ~307-330 nm and zeta potential varying from -21.2 to +11.8 mV were obtained. Thermal analysis demonstrated that the lipid matrix reduced tea tree oil thermal loss (~1.8-fold). Regardless of the type of polysaccharide employed, the NLCs promoted cutaneous localization of antioxidants in damaged (subjected to incision) skin, with a ~74 to 180-fold higher delivery into the skin compared to percutaneous delivery. This result is consistent with the similar bioadhesive properties of chitosan or sodium alginate-modified NLC. Nanoencapsulation of tea tree oil did not preclude its antimicrobial effects against susceptible and resistant strains of S. aureus and P. aeruginosa, while co-encapsulation of antioxidants increased the NLC-induced fibroblasts migration, supporting their potential usefulness for management of wounds.

Conventional Nanosized Drug Delivery Systems for Cancer Applications

Clinical responses and tolerability of conventional nanocarriers (NCs) are sometimes different from those expected in anticancer therapy. Thus, new smart drug delivery systems (DDSs) with stimuli-responsive properties and novel materials have been developed. Several clinical trials demonstrated that these DDSs have better clinical therapeutic efficacy in the treatment of many cancers than free drugs. Composition of DDSs and their surface properties increase the specific targeting of therapeutics versus cancer cells, without affecting healthy tissues, and thus limiting their toxicity versus unspecific tissues. Herein, an extensive revision of literature on NCs used as DDSs for cancer applications has been performed using the available bibliographic databases.

Development, characterisation, stability study and antileukemic evaluation of nanoemulsions containing Astrocaryum aculeatum extract

The objective of this work was to produce and characterise nanoemulsions containing tucumã extract and to evaluate the performance of the nanostructure and the free compound regarding antitumor activity, cytotoxicity, and oxidative metabolism in NB4/APL cells. The nanoemulsions showed adequate physicochemical characteristics (average size approx. 200 nm, polydispersity index less than 0.3, negative zeta potential and acid pH) maintained stable up to 90 days of storage in refrigeration condition. The nanoformulations did not present protein corona formation. Blank nanoemulsion treatments showed moderate toxicity. Furthermore, the nanoemulsion loaded with extract showed better antileukemic results than the free extract. However, nanoemulsions can be promising carriers of natural compounds, emphasising their biological properties and constituting alternatives in treating diseases.

Effect of nanoemulsion modification with chitosan and sodium alginate on the topical delivery and efficacy of the cytotoxic agent piplartine in 2D and 3D skin cancer models

Due to the limited options for topical management of skin cancer, this study aimed at developing and evaluating nanoemulsions (NE) for topical delivery of the cytotoxic agent piplartine (piperlongumine). NEs were modified with chitosan or sodium alginate, and the effects on the physicochemical properties, piplartine delivery and formulation efficacy were evaluated. The nanoemulsion droplets displayed similar size (96-112 nm), but opposite charge; the polysaccharides improved piplartine penetration into and across the skin (1.3-1.9-fold) in a similar manner, increasing the ratio "drug in the skin/receptor phase" by 1.4-1.5-fold compared to the plain NE and highlighting their relevance for cutaneous localization. Oleic acid addition to the chitosan-containing NE further increased drug penetration (~1.9-2.0-fold), as did increases in drug content from 0.5 to 1%. The cytotoxicity of piplartine was ~2.8-fold higher when the drug was incorporated in the chitosan-containing NE compared to its solution (IC50 = 14.6 μM) against melanoma cells. The effects of this nanocarrier on 3D melanoma tissues were concentration-related; at 1%, piplartine elicited marked epidermis destruction. These results support the potential applicability of the chitosan-modified nanoemulsion containing piplartine as a new strategy for local management of skin cancer.

Cerium oxide nanoparticles elicit antitumourigenic effect in experimental breast cancer induced by N-methyl-N-nitrosourea and benzo(a)pyrene in female Wistar rats

The use of cerium oxide nanoparticles [CeO₂ NPs] in the biomedical field has continued to gain prominence due to its potent antioxidant property. This study was designed to assess the antitumorigenic effect of CeO₂ NPs in rats administered N-methyl-N-nitrosourea [NMU] and benzo(a)pyrene (BaP). Twenty four female Wistar rats were equally assigned into four groups and treated with normal saline (control), [NMU + BaP], [NMU + BaP+CeO₂ NPs], and [NMU + BaP + vincristine]. Animals were pretreated with NMU and BaP three times (age 7, 10, and 13 weeks). Thereafter, vincristine and CeO₂ NPs were administered twice and three times per week, respectively, for 13 weeks. Results showed that the administration of NMU and BaP increased serum nitric oxide [NO] and myeloperoxidase [MPO] by 220% and 132%, respectively, whereas the activities of aspartate and alanine aminotransferases and level of total bilirubin remained unchanged. Furthermore, mammary inflammatory [NO and MPO] and oxidative stress (LPO) markers were increased by 37%, 19%, and 24%, respectively. Mammary superoxide dismutase, catalase, reduced glutathione, and glutathione-S-transferase were significantly decreased in [NMU + BaP]-administered rats by 165%, 146%, 35%, and 36%, respectively. Immunohistochemistry showed downregulation of Bax, p53, and caspase-3, while histology revealed the presence of malignant epithelial cells with pyknotic nuclei and high nucleocytoplasm in [NMU + BaP]-administered rats. Treatment with CeO₂ NPs attenuated oxidative stress, apoptosis, and inflammation and restored the cytoarchitecture of the tissue. Overall, CeO₂ NPs show an antitumourigenic effect in experimental breast cancer by targeting pathways linked to inflammation and apoptosis.

Melatonin loaded lecithin-chitosan nanoparticles improved the wound healing in diabetic rats

Wound healing in diabetic patients remains a worldwide problem that can cause amputations and even lead to death. This work aimed to produce lecithin-chitosan nanoparticles loaded with melatonin (MEL-NP) incorporated in a topical formulation to be evaluated for healing in the in vivo animal model for diabetes. To produce nanoparticles, an ethanolic solution containing soybean lecithin and melatonin was added dropwise to an aqueous solution of chitosan under sonication. The nanoparticles were physicochemical characterized and evaluated in vivo for toxicity using the Galleria mellonella model and its potential for wound healing in diabetic rats. The MEL-NPs presented a particle size of 160 nm and a zeta potential of 25 mV. The melatonin entrapment efficiency was 27%. Our results indicated that treatment with MEL-NP improved wound healing demonstrated by wound closure earlier than the other treatments evaluated. A desired therapeutic effect was achieved by MEL-NP in the induction of fibroblast and angiogenic proliferation. In addition, it was accompanied by an expressive collagen deposition. Considering the observed data, the MEL-NP developed could be used as a proof of concept to develop a promising strategy for the healing of diabetic wound.

Bioresponsive nanostructured systems for sustained naltrexone release and treatment of alcohol use disorder: Development and biological evaluation

In this study, microemulsions capable of transforming into nanostructured hexagonal phase gels in vivo upon uptake of biological fluids for naltrexone prolonged release were investigated as a strategy for management of alcohol use disorder (AUD). Microemulsions were prepared using monoolein, tricaprylin, water and propylene glycol; after preliminary characterization, one formulation was selected, which contained 55% of monoolein-tricaprylin (M-55). This microemulsion displayed size below 200 nm and Newtonian rheological behavior. Liquid crystalline gels formed in vitro upon 8 h of contact with water following a second order kinetics. After 120 h, <50% of naltrexone was released in vitro independently on drug loading (5 or 10%). In vivo, gels formed within 24 h of M-55 subcutaneous administration, and persisted locally for over 30 days providing slow release of the fluorescent marker Alexa fluor compared to a solution. Using the conditioned place preference paradigm, a test used to measure drug's rewarding effects, a single dose of M-55 containing 5% naltrexone reduced the time spent in the ethanol-paired compartment by 1.8-fold compared to saline; this effect was similar to that obtained with daily naltrexone injections, demonstrating the formulation efficacy and its ability to reduce dosing frequency. A more robust effect was observed following administration of M-55 containing 10% of naltrexone, which was compatible with aversion. These results support M-55 as a platform for sustained release of drugs that can be further explored for management of AUD to reduce dosing frequency and aid treatment adherence.

The Arachis hypogaea Essential Oil Nanoemulsion as an Efficient Safe Apoptosis Inducer in Human Lung Cancer Cells (A549)

Nanoemulsions have improved therapeutic efficiency. In this regard, due to the Arachis hypogaea components such as flavonoids, we planned to produce Arachis hypogaea oil nanoemulsion (AHO-NE) in order to evaluate its anticancer impacts on A549 lung cancer cells.  The AHO-NE was formulated by ultrasonication, characterized, and used in treating A549 cells. Then, we evaluated Caspase-3 gene expression, flow cytometry results, and MTT assay on A549 cells to check its anticancer impacts. The 50.3 nm AHO-NE significantly reduced the of A549 cells' viability comparing with HFF normal cells. The increasing SubG1 peaks and Cas3 overexpression indicate the AHO-NE apoptotic impact on A549 cells. We found its antioxidant activity (ABTS IC₅₀ = 270.42 μg/ml and DPPH IC₅₀ = 208.51 μg/ml). In conclusion, AHO-NE has the potential to be used as an exclusive cell-dependent anticancer compound in A549 lung cancer cells.

Intraductal Therapy in Breast Cancer: Current Status and Future Prospective

With our improved understanding of the biological behavior of breast cancer, minimally invasive intervention is urgently needed for personalized treatment of early disease. Intraductal therapy is one such minimally invasive approach. With the help of appropriate tools, technologies using the intraductal means of entering the ducts may be used both to diagnose and treat lesions in the mammary duct system with less trauma and at the same time avoid systemic toxicity. Traditional agents such as those targeting pathways, endocrine therapy, immunotherapy, or gene therapy can be used alone or combined with other new technologies, such as nanomaterials, through the intraductal route. Additionally, relevant mammary tumor models in rodents which reflect changes in the tumor microenvironment will help deepen our understanding of their biological behavior and heterogeneity. This article reviews the current status and future prospects of intraductal therapy in breast cancer, with emphasis on ductal carcinoma in situ.

Breast intraductal nanoformulations for treating ductal carcinoma in situ I: Exploring metal-ion complexation to slow ciclopirox release, enhance mammary persistence and efficacy

INTRODUCTION

Ductal Carcinoma In Situ (DCIS) represents a significant fraction (~20-25%) of all newly diagnosed breast cancer cases and, if left untreated, a significant fraction of patients will progress to invasive disease. Surgery is the only treatment option. Ciclopirox (CPX), an FDA-approved antifungal drug, has exhibited promising antitumor activity by down-regulating the expression of vital antiapoptotic cellular proteins and inhibiting the genetic expression of several oncogenic pathways. In this study, the feasibility of using nanoscale delivery systems to control release and prolong mammary tissue persistence of a lipophilic metal complex of CPX and Zinc (CPXZn) after intraductal administration was investigated.

METHODS

CPX and CPX-Zn nanosuspensions (NSs) were prepared using an evaporative nanoprecipitation-ultra-sonication method. Flash nanoprecipitation was used to prepare PLGA nanoparticles (NPs) loaded with CPXZn. Our established orthotopic DCIS rat model was used to evaluate efficacy. Briefly, two days after 13762 Mat B III cell intraductal inoculation, rats were divided into treatment groups and a single intraductal injection of CPX NS, CPX-Zn NS or CPX-Zn NPs was administered. In the first study arm, the efficacy of CPX NS (1, 3, 5 mg/duct) was evaluated. In the second arm, the in vivo efficacy of CPX NS, CPX-Zn NS and CPX-Zn loaded NPs was evaluated and compared at equivalent CPX doses. The mammary persistence of CPX from CPX NS, CPX-Zn NS, and CPX-Zn PLGA NPs was also assessed.

RESULTS

CPX-Zn complex was successfully synthesized and characterized by several spectral analyses. CPX release was slowed from the CPX-Zn NS and further slowed by incorporating CPX-Zn into PLGA NPs as compared to the CPX NS with release half times following the order: CPX NS < CPX-Zn NS << CPX-Zn NP. Intraductal CPX NS administration was dose and time dependent in suppressing tumor initiation suggesting prolonged mammary exposure may improve efficacy. In the second arm, mammary tissue persistence of CPX followed the rank order CPX NS < CPX-Zn NS << CPX-Zn NP at 6 h and 48 h post-administration. Prolonged mammary CPX exposure was highly correlated to improved efficacy. Prolonged CPX tissue persistence, attributed to slower release from the zinc complex and the PLGA NPs, resulted in a 5-fold dose reduction compared to the CPX NS.

CONCLUSIONS

The current results demonstrate that slowing drug release in the mammary duct after intraductal administration overcomes the rapid ductal clearance of CPX, prolongs mammary tissue persistence, improves efficacy against DCIS lesions in vivo, and requires 5-fold less CPX to achieve equivalent efficacy. The studies also provide a strategic path forward for developing a locally administered drug delivery system for treating DCIS, for which no primary chemotherapy option is available.

Citrus aurantium L. bloom essential oil nanoemulsion: Synthesis, characterization, cytotoxicity, and its potential health impacts on mice

This research was performed to synthesize the Citrus aurantium L. bloom essential oil nanoemulsion (CABE-NE) and investigate its cytotoxic and apoptotic impacts on human lung (A549 cells), and further, the effects of CABE-NE on mice health parameters was determined. The obtained results demonstrated that C. aurantium bloom contained 1.2 ± 0.16% of essential oil with linalyl acetate, limonene, and α-terpineol as major compounds. The CABE-NE possessed particle size of 76.9 ± 6.11 nm, PDI of 0.19, and zeta potential of -43.5 mV. The CABE-NE indicated the cytotoxicity against A549 cells with the IC₅₀ value of 152 µg/ml. The CABE-NE induced the overexpression of Cas-3 and triggered the apoptotic cells death. The mice gavaged daily with CABE-NE at the concentrations of 10 and 20 mg/kg body weight for 30 days did not show any remarkable histopathological alteration in the liver and kidney while exhibited enhancement in the jejunum morpho-structural architecture and hepatic antioxidant redox potential. PRACTICAL APPLICATIONS: According to the results, the produced CABE-NE drug delivery system could be considered as a promising alternative to prevent lung cancer progression and it provides a new way to enhance the therapeutic value of the plant phytochemicals.

Development, skin targeting and antifungal efficacy of topical lipid nanoparticles containing itraconazole

Considering the increased incidence of sporotrichosis and other fungal infections in rural and urban areas, and the limitations and adverse effects of oral itraconazole therapy, we studied nanostructured lipid carriers (NLC) as topical delivery systems to increase itraconazole localization in skin lesions and associate efficacy with reduced systemic exposure. Unloaded and itraconazole-loaded NLC showed nanometric size (~216-340 nm), negative zeta potential (~ -17 mV), and high entrapment efficiency (~97%). NLC treatment decreased transepidermal water loss, an index of cutaneous barrier function, in intact skin and in tissues damaged with a linear incision (to mimic lesions) by 23-36%, and reduced drug transdermal delivery by ~2-fold, demonstrating its ability to localize itraconazole within the skin. The unloaded and itraconazole-loaded NLC were considered safe, as indicated by scores of 0.5 and 0.6 in HET-CAM models, respectively, and lack of toxicity (measured by survival and health index) on the Galleria mellonella larvae. The values obtained for minimum inhibitory concentration and minimum fungicidal concentration on Sporothrix brasiliensis yeasts were 0.25 and 32 μg/mL, respectively. The drug in solution displayed similar values, indicating that encapsulation does not hinder itraconazole antifungal effect. NLC treatment improved the survival rate and health index of G. mellonella larvae infected with S. brasiliensis yeasts and C. albicans, demonstrating antifungal efficacy. Taken together, itraconazole encapsulation in NLC represents a viable strategy to optimize cutaneous localization without compromising its efficacy against fungal infections.

Nanocarriers Provide Sustained Antifungal Activity for Amphotericin B and Miltefosine in the Topical Treatment of Murine Vaginal Candidiasis

Topical drug administration is frequently used for the treatment of vaginal candidiasis; however, most formulations using this route do not provide prolonged drug release. Our aim was to evaluate the antifungal efficacy of amphotericin B (AMB) and miltefosine (MFS) incorporated in nanocarriers for sustained drug release, in a murine model of vaginal candidiasis. AMB and MFS were incorporated in different topical formulations, namely: conventional vaginal cream (daily dose for 6 days; MFS-CR and AMB-CR groups), microemulsion that transforms into a liquid crystalline gel in situ (single dose, or in three doses, every 48 h; AMB-ME and MFS-ME groups) and alginate nanoparticles (single dose; MFS-AN group). Formulations were administered intravaginally in BALB/c female mice 24 h post-infection by Candida albicans yeasts. On the 7th day post-infection the animals were euthanized for mycological and histological analyses. Formulation persistence in the vaginal canal was assessed for 7 days by in vivo imaging, using nanocarriers labeled with Alexa-Fluor 647. AMB-ME(3×), MFS-ME(3×), and MFS-AN(1×) formulations were able to control fungal infection at comparable levels to those vaginal cream formulations. Notably, a single dose of MFS-AN was sufficient to reduce the fungal burden as effectively as MFS-ME(3×) and MFS-CR(6×). In vivo imaging showed that nanocarriers allowed prolonged antifungal activity by intravaginal administration reducing drug administration frequency. Therefore, AMB and MFS incorporated into a microemulsion and MFS encapsulated in alginate nanoparticles could be effective therapeutic alternatives for vaginal candidiasis, likely due to the sustained antifungal activity provided by these nanocarriers.

Intraductal Drug Delivery to the Breast: Effect of Particle Size and Formulation on Breast Duct and Lymph Node Retention

Drug delivery by direct intraductal administration can achieve high local drug concentration in the breast and minimize systemic levels. However, the clinical application of this approach for breast cancer treatment is limited by the rapid clearance of the drug from the ducts. With the goal of developing strategies to prolong drug retention in the breast, this study was focused on understanding the influence of particle size and formulation on breast duct and lymph node retention. Fluorescent-labeled polystyrene (PS) particles ranging in size from 100 to 1000 nm were used to study the influence of particle size. Polylactic acid-co-glycolic acid (PLGA) was used to develop and test formulations for intraductal delivery. Cy 5.5, a near-IR dye, was encapsulated in PLGA microparticles, nanoparticles, and the in situ gel to study the biodistribution in rats using an in vivo imager. PS microparticles (1 μm) showed longer retention in the duct compared to 100 and 500 nm nanoparticles. The ductal retention half-life was 5-fold higher for PS microparticles compared to the nanoparticles. On the other hand, the free dye was cleared from the breast within 6 h. PLGA nanoparticles sustained the release of Cy 5.5 for >4 days. Microparticles and gel showed a much slower release than nanoparticles. PLGA in situ gel and microparticles were retained in the breast for up to 4 days, while the nanoparticles were retained in the breast for 2 days. PLGA nanoparticles and microparticles drained to the axillary lymph node and were retained for up to 24 and 48 h, respectively, while the in situ gel and the free dye did not show any detectable fluorescence in the lymph nodes. Taken together, the results demonstrate the feasibility of prolonged retention in the breast duct and lymph node by optimal formulation design. The findings can serve as a framework to design formulations for localized treatment of breast cancer.

Optimization of composition and obtainment parameters of biocompatible nanoemulsions intended for intraductal administration of piplartine (piperlongumine) and mammary tissue targeting

As a new strategy for treatment of ductal carcinoma in situ, biocompatible and bioadhesive nanoemulsions for intraductal administration of the cytotoxic agent piplartine (piperlongumine) were optimized in this study. To confer bioadhesive properties, the nanoemulsion was modified with chitosan or hyaluronic acid. Tricaprylin was selected as the nanoemulsion non-polar phase due to its ability to dissolve larger drug amounts compared to isopropyl myristate and monocaprylin. Use of phosphatidylcholine as sole surfactant did not result in a homogeneous nanoemulsion, while its association with polysorbate 80 and glycerol (in a surfactant blend) led to the formation of nanoemulsions with droplet size of 76.5 ± 1.2 nm. Heating the aqueous phase to 50 °C enabled sonication time reduction from 20 to 10 min. Inclusion of either chitosan or hyaluronic acid resulted in nanoemulsions with similar in vitro bioadhesive potential, and comparable ability to prolong mammary tissue retention (to 120 h) in vivo without causing undesirable histological alterations. Piplartine was stable in both nanoemulsions for 60 days; however, the size of loaded NE-HA was maintained at a similar range for longer periods of time, suggesting that this nanoemulsion may be a stronger candidate for intraductal delivery.

Producing the sour cherry pit oil nanoemulsion and evaluation of its anti-cancer effects on both breast cancer murine model and MCF-7 cell line

Aims: The sour cherry pit oil (SCPO) displays the potent anti-inflammatory, and antioxidant activities. In the present study, we have produced the SCPO nanoemulsion (SCPO-NE) to evaluate their anticancer impacts on breast cancer comparing with its un-processed oil. Methods: We employed an ultrasonication method to formulate the stable SCPO-NE. Their size, stability, and morphology were measured. Then, their cytotoxic impacts and apoptotic activity were checked on MCF7 breast cancer cells and compared with the normal Human foreskin fibroblasts (HFF). Finally, their anti-tumour effect was studied on murine breast cancer model (inoculated with TUBO cancer cells). Results: The results indicated the 36.5 nm stable SCPO-NE significantly decreased the MCF7 cells viability comparing with normal HFF cells, and reduced the tumour size in the murine model. Conclusion: We suggest that SCPO-NEs are able to efficiently inhibit breast cancer progression in both MCF7 cells and murine breast cancer model through apoptotic death induction.

Current Applications of Nanoemulsions in Cancer Therapeutics

Nanoemulsions are pharmaceutical formulations composed of particles within a nanometer range. They possess the capacity to encapsulate drugs that are poorly water soluble due to their hydrophobic core nature. Additionally, they are also composed of safe gradient excipients, which makes them a stable and safe option to deliver drugs. Cancer therapy has been an issue for several decades. Drugs developed to treat this disease are not always successful or end up failing, mainly due to low solubility, multidrug resistance (MDR), and unspecific toxicity. Nanoemulsions might be the solution to achieve efficient and safe tumor treatment. These formulations not only solve water-solubility problems but also provide specific targeting to cancer cells and might even be designed to overcome MDR. Nanoemulsions can be modified using ligands of different natures to target components present in tumor cells surface or to escape MDR mechanisms. Multifunctional nanoemulsions are being studied by a wide variety of researchers in different research areas mainly for the treatment of different types of cancer. All of these studies demonstrate that nanoemulsions are efficiently taken by the tumoral cells, reduce tumor growth, eliminate toxicity to healthy cells, and decrease migration of cancer cells to other organs.

Nanoemulsions in drug delivery: formulation to medical application

Nanoscale oil-in-water emulsions (NEs), heterogeneous systems of two immiscible liquids stabilized by emulsifiers or surfactants, show great potential in medical applications because of their attractive characteristics for drug delivery. NEs have been explored as therapeutic carriers for hydrophobic compounds via various routes of administration. NEs provide opportunities to improve drug delivery via alternative administration routes. However, deep understanding of the NE manufacturing and functionalization fundamentals, and how they relate to the choice of administration route and pharmacological profile is still needed to ease the clinical translation of NEs. Here, we review the diversity of medical applications for NEs and how that governs their formulation, route of administration, and the emergence of increasing sophistication in NE design for specific application.