Cytotoxicity and permeability enhancement of Capmul®MCM in nanoemulsion formulation

Oral targeted drug delivery to post-gastrointestinal sites

As an essential branch of targeted drug delivery, oral targeted delivery is attracting growing attention in recent years. In addition to site-specific delivery for the treatment of locoregional diseases in the gastrointestinal tract (GIT), oral targeted delivery to remote sites beyond the GIT emerges as a cutting-edge research topic. This review aims to provide an overview of the fundamental concepts and most recent advances in this field. Owing to the physiological barriers existing in the GIT, carrier systems should be transported across the enteric epithelia to target remote sites. Recently, pioneer investigations have validated the transport of intact micro- or nanocarriers across gastrointestinal barriers and subsequently to various distal organs and tissues. The microfold (M) cell pathway is the leading mechanism underlying the oral absorption of particulates, but the contribution of the transcellular and paracellular pathways should not be neglected either. In addition to well-acknowledged physicochemical and biological factors, the formation of a protein corona may also influence the biological fate of carrier systems. Although in an early stage of conceptualization, oral targeted delivery to remote diseases has demonstrated promising potential for the treatment of inflammation, tumors, and diseases inflicting the lymphatic and mononuclear phagocytosis systems.

Amphotericin B loaded nanoemulsion: Optimization, characterization and in-vitro activity against L. donovani promastigotes

The present work aimed to develop and evaluate AmB-loaded nano-emulsion (AmB-NE) which will augment the solubility of AmB and lead to enhanced anti-leishmanial activity. The composition of AmB-NE was optimized by systematic screening followed by DoE-extreme vertices mixture design. The optimized NE revealed mean droplet size and PDI of 44.19 ± 5.5 nm, 0.265 ± 0.0723, respectively. The NE could efficiently encapsulate AmB with drug content and efficiency 83.509 ± 0.369% and 81.659 ± 0.013%, respectively. The presence of cholesterol and stearyl amine retarded the release (P < 0.0001) of AmB significantly compared to AmB suspension. The AmB-NE and pure AmB suspension demonstrated the IC50 of 0.06309 μg/mL and 0.3309 μg/mL against L.donovani promastigotes after 48 h incubation. The formulation was robust at all exaggerated stability conditions such as freeze-thaw and centrifugation. These findings indicate that AmB-NE is an attractive approach to treat visceral leishmaniasis with improved activity.

Medium-Chain Triacylglycerols (MCTs) and Their Fractions in Drug Delivery Systems : A Systematic Review

Medium-chain triacylglycerol (MCT) is a type of triacylglycerol that has six or seven to twelve carbon chains. It consists of three molecules of fatty acids attached to one molecule of glycerol. Drug delivery system (DDS) is defined as a formulation to distribute drugs into the human body. The unique properties of MCTs have garnered interest in using them as excipients in DDS. Even though there are many significant effects attributed to the use of MCTs, especially in modulating the rate of drug delivery in various DDS, they are all limited and intermittent. This warrants a detailed summary of the previous studies on the use of MCTs in various DDS. Therefore, this review focuses on presenting a systematic review of previous studies on the use of MCTs in the last six years and explores the types and effects of MCTs on DDS that employ various types of delivery routes. A systematic search through PubMed, Science Direct and Scopus was performed. Keywords like "medium-chain triglycerides", "medium-chain fatty acids", "medium-chain triglycerides and their fractions", "medium-chain fatty acids and their fractions", "MCTs", "MCFA", "in drug delivery", "in drug delivery system" and their combinations were used. The synonyms of the words were also used to extend the search. A total of 17 articles that met the inclusion criteria were identified. Findings from this review have identified the several MCTs and their fractions used in DDS that employed the oral/enteral, topical, transdermal, parenteral, and pulmonary routes of drug delivery. The review also highlights that the usage of MCTs in DDS results in a better transportation of drugs into the human body.

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.

Arginine-Coated Nanoglobules for the Nasal Delivery of Insulin

Multiple daily injections via subcutaneous route are the primary modes of insulin delivery for patients with Diabetes Mellitus. While this process is invasive, painful and may cause patients to develop lipohypertrophy at injection site, the perception of fear surrounding this process causes patients to delay in initiation and remain persistent with insulin therapy over time. Moreover, poor glycemic control may often lead to acute complications, such as severe hypoglycemia and nocturnal hypoglycemia, especially in older patients with diabetes. To address the imperative need for a patient-convenient non-invasive insulin therapy, an insulin-loaded arginine-coated self-emulsifying nanoglobule system (INS-LANano) was developed for nasal delivery of insulin with a biodegradable cationic surfactant-Lauroyl Ethyl Arginate (LAE). Incorporation of LAE resulted in formation of positively charged nanoglobules with L-arginine oriented on the surface. LANano enabled binding of insulin molecules on the surface of nanoglobules via an electrostatic interaction between negatively charged α-helix and LAE molecules at physiological pH. INS-LANano showed a hydrodynamic diameter of 23.38 nm with a surface charge of +0.118 mV. The binding efficiency of insulin on LANano globules was confirmed by zeta potential, circular dichroism (CD) spectroscopy and centrifugal ultrafiltration studies. The attachment of insulin with permeation-enhancing nanoglobules demonstrated significantly higher in vitro permeability of insulin of 15.2% compared to insulin solution across human airway epithelial cell (Calu-3) monolayer. Upon intranasal administration of INS-LANano to diabetic rats at 2 IU/kg insulin dose, a rapid absorption of insulin with significantly higher Cmax of 14.3 mU/L and relative bioavailability (BA) of 23.3% was observed. Therefore, the INS-LANano formulation significant translational potential for intranasal delivery of insulin.

Brain-Targeted Intranasal Delivery of Zotepine Microemulsion: Pharmacokinetics and Pharmacodynamics

The purpose of our study was to improve the solubility, bioavailability, and efficacy of zotepine (ZTP) by brain-targeted intranasal delivery of microemulsion (ME) and its physicochemical properties, the pharmacokinetic and pharmacodynamic parameters were evaluated. The optimized ME formulations contain 10% w/w of oil (Capmul MCM C8, monoglycerides, and diglycerides of caprylic acid), 50% w/w of Smix (Labrasol and Transcutol HP, and 40% w/w of water resulting in a globule size of 124.6 ±3.52 nm with low polydispersity index (PDI) (0.212 ± 0.013) and 2.8-fold higher permeation coefficient through porcine nasal mucosa compared to pure drug. In vitro cell line studies on RPMI 2650, Beas-2B, and Neuro-2A revealed ZTP-ME as safe. ZTP-ME administered intranasally showed higher AUC0-t24 (18.63 ± 1.33 h x µg/g) in the brain by approximately 4.3-fold than oral ME (4.30 ± 0.92 h × µg/g) and 7.7-fold than intravenous drug solutions (2.40 ± 0.36 h × µg/g). In vivo anti-schizophrenic activity was conducted using catalepsy test scores, the formulation showed better efficacy via the intranasal route; furthermore, there was no inflammation or hemorrhage in the nasal cavity. The results concluded that the ZTP microemulsion as a safe and effective strategy could greatly enhance brain distribution by intranasal administration.

Oral delivery of therapeutic peptides and proteins: Technology landscape of lipid-based nanocarriers

The oral administration of therapeutic peptides and proteins is favoured from a patient and commercial point of view. In order to reach the systemic circulation after oral administration, these drugs have to overcome numerous barriers including the enzymatic, sulfhydryl, mucus and epithelial barrier. The development of oral formulations for therapeutic peptides and proteins is therefore necessary. Among the most promising formulation approaches are lipid-based nanocarriers such as oil-in-water nanoemulsions, self-emulsifying drug delivery systems (SEDDS), solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), liposomes and micelles. As the lipophilic character of therapeutic peptides and proteins can be tremendously increased such as by the formation of hydrophobic ion pairs (HIP) with hydrophobic counter ions, they can be incorporated in the lipophilic phase of these carriers. Since gastrointestinal (GI) peptidases as well as sulfhydryl compounds such as glutathione and dietary proteins are too hydrophilic to enter the lipophilic phase of these carriers, the incorporated therapeutic peptide or protein is protected towards enzymatic degradation as well as unintended thiol/disulfide exchange reactions. Stability of lipid-based nanocarriers towards lipases can be provided by the use to excipients that are not or just poorly degraded by these enzymes. Nanocarriers with a size <200 nm and a mucoinert surface such as PEG or zwitterionic surfaces exhibit high mucus permeating properties. Having reached the underlying absorption membrane, lipid-based nanocarriers enable paracellular and lymphatic drug uptake, induce endocytosis and transcytosis or simply fuse with the cell membrane releasing their payload into the systemic circulation. Numerous in vivo studies provide evidence for the potential of these delivery systems. Within this review we provide an overview about the different barriers for oral peptide and protein delivery, highlight the progress made on lipid-based nanocarriers in order to overcome them and discuss strengths and weaknesses of these delivery systems in comparison to other technologies.

Intranasal delivery of insulin by self-emulsified nanoemulsion system: In vitro and in vivo studies

The main objective of this research was to develop a self-emulsified nanoemulsion (SEN) dosage form of insulin where insulin is loaded into the lipid phase of the nanoemulsion for enhanced absorption through intranasal delivery. When loaded into the lipid droplets (oil phase), insulin can be protected from enzymatic degradation, can penetrate through the mucus gel barrier in a comparatively effective manner and can be absorbed through transcellular permeation along with paracellular route. To incorporate lipophilicity to insulin molecule, Ins-SPC (Soy-L-α-phosphatidylcholine) complex was prepared by solid dispersion method to load insulin into the oil phase. The cytotoxicity of SPC and the developed nanoemulsions was tested on the human nasal epithelial cells in vitro. An optimized formulation with high loading of insulin and low in vitro cytotoxicity was developed and characterized. To predict the absorption of insulin through nasal mucosa in vivo by the nanoemulsion system, the insulin-loaded SEN along with controls was tested for the transport through human nasal epithelial cell monolayer in vitro. The insulin-loaded SEN significantly (p < 0.01) enhanced the permeation of insulin by three times as compared to the insulin solution. The in vivo absorption of insulin after intranasal delivery of the insulin-loaded SEN was evaluated in anesthetized rats. The results show that the C_max (maximum plasma concentration) and the bioavailability (relative to the subcutaneous delivery) of the insulin-loaded SEN was 255.9 µU/ml and 68 %, respectively, while the intranasal delivery of the insulin solution resulted in only 5.8 µU/ml of C_max and 5% of relative bioavailability. Intranasal delivery of 3.6 IU/kg insulin-loaded SEN decreased the plasma glucose level remarkably, achieving a maximum reduction of 70%, and the glucose reduction activity lasted for the whole experimental period of 4 h. Histological examination of the nasal mucosa showed no apparent signs of toxicity at the site of administration after single dose of the insulin-loaded SEN. These results demonstrate that the insulin-loaded SEN significantly enhanced insulin absorption through intranasal delivery, indicating that the developed nanoemulsion system offers a favorable approach for intranasal delivery of insulin.

Comparison of Cellular Monolayers and an Artificial Membrane as Absorptive Membranes in the in vitro Lipolysis-permeation Assay

Permeation across Caco-2 cells in lipolysis-permeation setups can predict the rank order of in vivo drug exposure obtained with lipid-based formulations (LBFs). However, Caco-2 cells require a long differentiation period and do not capture all characteristics of the human small intestine. We therefore evaluated two in vitro assays with artificial lecithin-in-dodecane (LiDo) membranes and MDCK cells as absorptive membranes in the lipolysis-permeation setup. Fenofibrate-loaded LBFs were used and the results from the two assays compared to literature plasma concentrations in landrace pigs administered orally with the same formulations. Aqueous drug concentrations, supersaturation, and precipitation were determined in the digestion chamber and drug permeation in the receiver chamber. Auxiliary in vitro parameters were assessed, such as permeation of the taurocholate, present in the simulated intestinal fluid used in the assay, and size of colloidal structures in the digestion medium over time. The LiDo membrane gave a similar drug distribution as the Caco-2 cells and accurately reproduced the equivalent rank-order of fenofibrate exposure in plasma. Permeation of fenofibrate across MDCK monolayers did not, however, reflect the in vivo exposure rankings. Taurocholate flux was negligible through either membrane. This process was therefore not considered to significantly affect the in vitro distribution of fenofibrate. We conclude that the artificial LiDo membrane is a promising tool for lipolysis-permeation assays to evaluate LBF performance.

Lipid Nanoparticle Technology for Delivering Biologically Active Fatty Acids and Monoglycerides

There is enormous interest in utilizing biologically active fatty acids and monoglycerides to treat phospholipid membrane-related medical diseases, especially with the global health importance of membrane-enveloped viruses and bacteria. However, it is difficult to practically deliver lipophilic fatty acids and monoglycerides for therapeutic applications, which has led to the emergence of lipid nanoparticle platforms that support molecular encapsulation and functional presentation. Herein, we introduce various classes of lipid nanoparticle technology and critically examine the latest progress in utilizing lipid nanoparticles to deliver fatty acids and monoglycerides in order to treat medical diseases related to infectious pathogens, cancer, and inflammation. Particular emphasis is placed on understanding how nanoparticle structure is related to biological function in terms of mechanism, potency, selectivity, and targeting. We also discuss translational opportunities and regulatory needs for utilizing lipid nanoparticles to deliver fatty acids and monoglycerides, including unmet clinical opportunities.

The Effects of Solid and Liquid Lipids on the Physicochemical Properties of Nanostructured Lipid Carriers

The aim of this work was to identify from a review of current literature the effects of lipids used in the development of Nanostructured Lipid Carriers (NLCs) on the physicochemical properties of the resulting formulation. The size of the solid lipid, affected by the molecular weight and the complexity of the structure, tends to affect the particle size of the final formulation proportionally; the higher the molecular weight and the more complex the molecular structure, the bigger the particle size of the NLCs. However, there is no straight correlation between the size and the structure of the liquid lipid and the particle size. Moreover, there seems to be a correlation of the solid to liquid lipid ratio which affects the particle size; there has been a trend of increasing particle size when more solid lipid was used. Regarding the entrapment efficiency, it is highly affected by the drug and its interaction with the lipids, as its solubility in the lipids needs to be high so the drug can stay entrapped within the lipid core. There was no direct correlation between the type of lipid used or the ratio and the zeta potential, which affects the stability of the NLCs.

Enabling Oral Amphotericin B Delivery by Merging the Benefits of Prodrug Approach and Nanocarrier-Mediated Drug Delivery

Amphotericin B (AmB) is gold standard therapy for leishmaniasis and fungal infections. Considering the global disease burden, nearly 90% of cases occur in economically vulnerable countries, making the cost of AmB therapy a critical healthcare challenge in controlling disease burden. All currently marketed AmB products are administered through an intravenous (i.v.) route and involve high treatment costs. Designing an orally effective AmB formulation can substantially reduce the cost of therapy and improve patient compliance. However, it is a challenging task because of the distinctive physicochemical properties of AmB. Previously, we developed a lipid-based prodrug of AmB, AmB-oleyl conjugate (AmB-OA), which showcased remarkable stability in the gastrointestinal (GI) environment and improved intestinal permeation. Hereby, we have developed self-nanoemulsifiying drug delivery system (SNEDDS) of AmB-OA to further enhance the oral bioavailability of AmB and potentiate its therapeutic benefits. SNEDDS was developed by screening a wide range of oils, surfactants, and cosurfactants, and formulation composition was optimized using extreme vertices design. AmB-OA SNEDDS possessed the ability of quick self-nanoemulsification on dilution (droplet size ∼56 nm) along with remarkable stability in the GI environment. Accelerated stability (40 °C/75% relative humidity) studies and freeze-thaw cycling studies proved that the formulation was stable at tropical conditions as well as temperature cycling stress. Drug transport analysis in Caco-2 cells revealed a remarkable increase in drug transport for AmB-OA SNEDDS compared to AmB along with minimal cellular toxicities. AmB-OA SNEDDS showcased ∼8.9-fold higher AUC_Tot than AmB in in vivo pharmacokinetic study, proving the effectiveness of formulation to enhance oral bioavailability. In vivo toxicity analysis highlighted the ameliorated toxicity risk associated with SNEDDS formulation. Therefore, the AmB-OA SNEDDS formulation may provide a cost-friendly and effective strategy to resolve the oral AmB drug delivery challenge.

Impact of bile salts and a medium chain fatty acid on the physical properties of self-emulsifying drug delivery systems

The aim of this study was the evaluation of the influence of bile salts and fatty acids, important components of intestinal fluids, on physical characteristics of self-emulsifying drug delivery systems (SEDDS) such as size, polydispersity (PDI), zeta potential (Zp), turbidity (T%), cloud point temperature (CPT) and drug release. At this purpose, nonionic (ni-SEDDS) and cationic (c-SEDDS) were emulsified in aqueous media containing increasing concentrations of bile salts (BS) and decanoate (Dec). Zp of ni-SEDDS and c-SEDDS became highly negative at 15 mM BS and Dec. Size of ni-SEDDS decreased of 112 nm and of 76 nm at 15 mM BS and Dec, respectively. Size of c-SEDDS decreased of 53 nm at 15 mM BS, but it was not affected by 15 mM Dec. PDI and T% of ni- and c-SEDDS were lowered as well. CPT of ni-SEDDS increased from 70 °C to 97 °C and 84 °C at 15 mM BS and Dec. CPT of c-SEDDS decreased from above 100 °C to 80 °C and to 85 °C at 1.5 mM BS and at 5 mM Dec, respectively. Generally, BS had a more pronounced effect on SEDDS Zp, size, PDI, T %, and CPT than Dec. The release of the model drug quinine was accelerated by BS and Dec. As BS and fatty acids affect the physical characteristics and drug release behavior of SEDDS, their impact should be addressed during the development process.

In Vitro Evaluation of Self-Nano-Emulsifying Drug Delivery Systems (SNEDDS) Containing Room Temperature Ionic Liquids (RTILs) for the Oral Delivery of Amphotericin B

Amphotericin B (AmpB), one of the most commonly used agents in the treatment of severe fungal infections and life-threatening parasitic diseases such as visceral Leishmaniasis, has a negligible oral bioavailability, primarily due to a low solubility and permeability. To develop an oral formulation, medium chain triglycerides and nonionic surfactants in a self-nano-emulsifying drug delivery system (SNEDDS) containing AmpB were combined with room temperature ionic liquids (RTILs) of imidazolium. The presence of ionic liquids significantly enhanced the solubility of AmpB, exhibited a low toxicity and increased the transport of AmpB across Caco-2 cell monolayers. The combination of RTILs with a lipid formulation might be a promising strategy to improve the oral bioavailability of AmpB.

Protection of Protein Drugs by Self-Emulsified Nanoemulsion Against Proteolysis

The present study aimed to develop a self-emulsified nanoemulsion for salmon calcitonin (sCT) for non-invasive delivery. Hydrophobic ion pairing method was used to form hydrophobic complex of sCT with 4 counter ions (oleate, deoxycholate, docusate and tripolyphosphate). The partition coefficient and dissociation of the complexes in water of various pH were investigated. The complex-loaded nanoemulsions were characterized for droplet size, leakage of sCT from the droplets, and protection of sCT from enzymatic degradation. The results show that all the counter ions could form complexes with sCT with a complexation efficiency about 95% at pH 8.0. The complexes significantly increased the partition coefficient of sCT. The dissociation of the complexes in water was pH-dependent. At pH 6.8 and 7.4, the dissociation was negligible. At pH 1.0, the dissociation was 71%, 8%, 37% and 50% for sCT-polyphosphate, sCT-docusate, sCT-oleate and sCT-deoxycholate, respectively. The developed nanoemulsions had a size in the range of 27-62 nm. The leakage of sCT from the nanodroplets into the aqueous phase depended on the lipophilicity of the counter ions: 60%, 56%, and 24% leakage for sCT-docusate, sCT-oleate and sCT-deoxycholate, respectively. The nanoemulsion protected sCT from enzyme degradation when loaded inside the droplets, but not the leaked sCT.

Evaluation of Cytotoxicity of Self-Emulsifying Formulations Containing Long-Chain Lipids Using Caco-2 Cell Model: Superior Safety Profile Compared to Medium-Chain Lipids

Medium-chain (MC) and long-chain (LC) lipids are used for development of self-emulsifying drug delivery systems (SEDDS). MC lipids are often preferred because of their ability to form stable microemulsions with relatively high drug solubilization capacity. On the other hand, LC lipids could be more biocompatible as most endogenous and dietary lipids are LC glycerides. They also maintain high drug solubilization capacity after digestion. The present study was undertaken to determine the cytotoxicity of LC lipids and their formulations on Caco-2 cells of 1-day, 5-day, and 21-day maturity. The results were compared with the cytotoxicity profiles of MC lipids reported previously from our laboratory. The cell viability and cell membrane integrity were, respectively, determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and the lactate dehydrogenase assay. The cytotoxicity was partially due to lipid surfactant-induced membrane rupture, and it was influenced by cell maturity and formulation composition. The lipid-surfactant combinations showed greater tolerance than surfactants alone, and LC-SEDDS were well-tolerated at almost 10-fold higher concentration than corresponding MC-SEDDS. Furthermore, the cytotoxicity of digestion end products of both LC and MC triglycerides in the presence of 3 mM sodium taurocholate was compared on 21-day Caco-2 cultures by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The LC lipid formulations showed better tolerance than MC lipid formulations after digestion. Thus, although MC and LC lipids are well-tolerated at doses normally administered to humans, LC lipids show much better safety than MC lipids in a cell-culture model.

Role of Omega-3 Fatty Acids and Butter Oil in Targeting Delivery of Donepezil Hydrochloride Microemulsion to Brain via the Intranasal Route: a Comparative Study

In order to investigate the possible role of butter oil (BO) and omega-3 fatty acids-rich fish oil (O3FO) in the delivery of donepezil hydrochloride microemulsion (DH-ME) to the brain via intranasal route, the present study was conducted. DH:BO and DH:O3FO binary mixtures (9:1 to 1:9) were prepared by simple physical mixing and subjected to in vitro diffusion study. Ratios of DH:BO and DH:O3FO, which showed the highest diffusion, were selected for further development of microemulsion (ME). Globule sizes of DH-BO-ME and DH-O3FO-ME were found to be 87.66 ± 5.23 nm and 88.59 ± 8.23 nm, respectively. Nasal histopathological study and in vitro cytotoxicity study revealed the safety of the formulation. Higher percentage of nasal diffusion was found with DH-BO-ME (71.22 ± 1.21%) and DH-O3FO-ME (62.16 ± 1.23%) in comparison to DH-ME (59.69 ± 1.74%) and DH solution (55.01 ± 1.19%), which was further supported by in vitro cell permeability study. After intranasal administration, %bioavailability of drug in the rat brain (Sprague-Dawley rats)(on the basis of DH-ME IV) was higher with DH-BO-ME (313.59 ± 12.98%) and DH-O3FO-ME (361.73 ± 15.15%) in comparison to DH-ME (168.62 ± 6.60%) and DH solution (8.960 ± 0.23%). The results of ex vivo diffusion study and in vivo pharmacokinetic study suggested that BO and O3FO helped in enhancing the nasal permeability and the brain uptake of drug when administered intranasally.

Clove oil nanoemulsion showed potent inhibitory effect against Candida spp

Increasing resistance to current fungicides is a clinical problem that leads to the need for new treatment strategies. Clove oil (CO) has already been described as having antifungal action. However, it should not be applied directly to the skin as it may be irritating. One option for CO delivery and suitable topical application would be nanoemulsions (NEs). NEs have advantages such as decreased irritant effects and lower dose use. The purpose of this work was the development of NEs containing CO and in vitro evaluation against Candida albicans and Candida glabrata. The NEs were produced by an ultrasonic processor with different proportions of CO and Pluronic^® F-127. In order to determine the best composition and ultrasound amplitude, an experimental design was performed. For the evaluation, droplet size and polydispersity index (PdI) were used. After the stability study, in vitro activity against C. albicans and C. glabrata was evaluated. NEs selected for the stability study, with diameter <40 nm and PdI <0.2, remained stable for 420 d. Activity against Candida spp. was improved when the CO was nanoemulsified, for it possibly leads to a better interaction between the active and the microorganisms, mainly in C. albicans.