Microemulsions containing long-chain oil ethyl oleate improve the oral bioavailability of piroxicam by increasing drug solubility and lymphatic transportation simultaneously

Understanding lymphatic drug delivery through chylomicron blockade: A retrospective and prospective analysis

Scientists have developed and employed various models to investigate intestinal lymphatic uptake. One approach involves using specific blocking agents to influence the chylomicron-mediated lymphatic absorption of drugs. Currently utilized models include pluronic L-81, puromycin, vinca alkaloids, colchicine, and cycloheximide. This review offers a thorough analysis of the diverse models utilized, evaluating existing reports while delineating the gaps in current research. It also explores pharmacokinetic related aspects of intestinal lymphatic uptake pathway and its blockage through the discussed models. Pluronic L-81 has a reversible effect, minimal toxicity, and unique mode of action. Yet, it lacks clinical reports on chylomicron pathway blockage, likely due to low concentrations used. Puromycin and vinca alkaloids, though documented for toxicity, lack information on their application in drug intestinal lymphatic uptake. Other vinca alkaloids show promise in affecting triglyceride profiles and represent possible agents to test as blockers. Colchicine and cycloheximide, widely used in pharmaceutical development, have demonstrated efficacy, with cycloheximide preferred for lower toxicity. However, further investigation into effective and toxic doses of colchicine in humans is needed to understand its clinical impact. The review additionally followed the complete journey of oral lymphatic targeting drugs from intake to excretion, provided a pharmacokinetic equation considering the intestinal lymphatic pathway for assessing bioavailability. Moreover, the possible application of urinary data as a non-invasive way to measure the uptake of drugs through intestinal lymphatics was illustrated, and the likelihood of drug interactions when specific blockers are employed in human subjects was underscored.

Novel Microemulsion Containing Benzocaine and Fusidic Acid Simultaneously: Formulation, Characterization, and In Vitro Evaluation for Wound Healing

Modern drug carrier technologies, such as microemulsions with small droplet sizes and high surface areas, improve the ability of low water solubility active ingredients to permeate and localize. The goal of this study was to create microemulsion formulations for wound healing that contained both fusidic acid (FA), an antibacterial agent, and benzocaine (BNZ), a local anesthetic. Studies on characterization were carried out, including viscosity, droplet size, and zeta potential. The drug-loaded microemulsion had a stable structure with -3.014 ± 1.265 mV of zeta potential and 19.388 ± 0.480 nm of droplet size. In both in vitro release and ex vivo permeability studies, the microemulsion was compared with Fucidin cream and oily BNZ solution. According to the drug release studies, BNZ release from the microemulsion and the BNZ solution showed a similar profile (p > 0.05), while FA release from the microemulsion had a higher drug release compared to Fucidin cream (p < 0.001). The microemulsion presented lower drug permeation (p > 0.05) for both active ingredients, on the other hand, provided higher drug accumulation compared to the control preparations. Moreover, according to the results of in vitro wound healing activity, the microemulsion indicated a dose-dependent wound healing potential with the highest wound healing activity at the highest concentrations. To the best of our knowledge, this developed BNZ- and FA-loaded microemulsion would be a promising candidate to create new opportunities for wound healing thanks to present the active ingredients, which have low water solubility, in a single formulation and achieved higher accumulation than control preparations.

Preparation, in vitro and in vivo evaluation of a novel mitiglinide microemulsions

This study aimed to prepare an o/w mitiglinide microemulsion (MTGME) to improve the drug solubility and bioavailability. The formulation of o/w MTGME was optimized by the solubility study of drug, pseudo-ternary phase diagram and Box-Behnken design successively. MTGME was characterized by dynamic laser light scattering (DLS), zeta potential and transmission electron microscopy (TEM), moreover, the storage stability, pharmacodynamics and pharmacokinetics were investigated. The optimal prescription for MTGME consisted of Maisine 35-1 (oil), Cremophor EL (surfactant) and propylene glycol (PG, cosurfactant). MTGME with a spherical dimension of 58.1 ± 5.86 nm was stable when stored at 4 °C for 3 months. The blood glucose levers (BGL) of diabetic mice were uniformly and significantly decreased by intragastric (i.g.) administration of 1-4 mg/kg MTGME, in which BGL (i.g. 4 mg/kg MTGME) was reduced by 69% during 24 h. The pharmacokinetics study of MTGME (i.g., 20 mg/kg) in Wistar rats showed higher plasma drug concentration (Cmax, 2.9 folds), larger area under curve (AUC, 4.6 folds) and oral bioavailability than those of MTG suspensions. Generally, the MTGME (o/w) showed good effect on controlling hyperglycemia. Therefore, microemulsion can be used as an effective oral drug delivery system to improve the bioavailability of MTG.

Investigating the mechanism of Tongqiao Huoxue decotion in the treatment of allergic rhinitis based on network pharmacology and molecular docking: A review

Allergic rhinitis is prone to recurrence, and clinical treatments focus on control symptoms; however there is no radical cure. Our aim was to use network pharmacology and molecular docking to reveal the hub genes, biological functions, and signaling pathways of Tongqiao Huoxue decoction against allergic rhinitis. First, the chemical components and target genes of Tongqiao Huoxue decoction were obtained from the Traditional Chinese Medicine Systems Pharmacology database. Similarly, allergic rhinitis targets were screened using online Mendelian Inheritance In Man and GeneCards database. Then, all potential targets of Tongqiao Huoxue decoction in the treatment of allergic rhinitis were identified, the Venn diagram was portrayed using R software, and protein-protein interaction network was built using String. The hub genes were analyzed using enrichment analyses. Finally, molecular docking was used to verify the reliability of the key gene prediction. The core targets for Tongqiao Huoxue decoction to improve allergic rhinitis were AKT1, TP53, IL6, and so on. The enrichment analysis results showed that Tongqiao Huoxue decoction treatment in allergic rhinitis might be involved in the AGE-RAGE signaling pathway and fluid shear stress and atherosclerosis pathway. The molecular docking verification indicated that its ingredients bound well to the core targets of allergic rhinitis, and stigmasterol's docking ability with TNF (-12.73 kcal/mol) is particularly prominent. Based on these findings, it may be deduced that stigmasterol treated allergic rhinitis by acting on TNF targets. But, this conclusion needs to be confirmed by further in vitro and in vivo trials.

TPGS decorated NLC shift gefitinib from portal absorption into lymphatic delivery: Intracellular trafficking, biodistribution and bioavailability studies

Lymphatic drug delivery (LDD) is an attractive option for the prevention and treatment of cancer metastasis. This study aims to develop TPGS decorated nanostructure lipid carrier gefitinib loaded (TPGS-NLC-GEF). Biocompatibility and cytotoxicity were studied using erythrocytes and A549 cell lines. Furthermore, cellular uptake of the prepared TPGS-NLC was studied using 5-carboxyfluorescein (5-CF). Pharmacokinetic, biodistribution, and chylomicron-block flow studies were performed using male Wister Albino rats to investigate the influence of TPGS-NLC on plasma concentration-time profile, organ deposition, and LDD of GEF. The present results indicated that the prepared TPGS-NLC and TPGS-NLC-GEF formulation had a particle size range of 268 and 288 nm with a negative zeta-potential value of - 29.3 and - 26.5 mV, respectively. The in-vitro release showed burst drug release followed by sustained release. In addition, the biosafety in the term of the hemocompatibility study showed that the prepared formulation was safe at the therapeutic level. Additionally, an in-vitro cytotoxicity study showed that the TPGS-NLC was able to enhance the activity of GEF against the A549 cell line. The cellular uptake study showed the ability of TPGS-NLC to enhance 5-CF internalization by 12.6-fold compared to the 5-CF solution. Furthermore, the in-vivo study showed that TPGS-NLC was able to enhance GEF bioavailability (1.5-fold) through lymphatic system which was confirmed via the indirect chylomicron-block flow method. The tissue distribution study showed the ability of lipid nanoparticles to enhance lung drug deposition by 5.8-fold compared to a GEF suspension. This study concluded that GEF-NLC-GEF is an encouraging approach for the treatment of metastatic lung cancer through lymphatic delivery, enhanced bioavailability, and reduced systemic toxicity.

Development and Efficacy Evaluation of a Novel Nano-Emulsion Adjuvant for a Foot-and-Mouth Disease Virus-like Particles Vaccine Based on Squalane

The successful development of foot-and-mouth disease virus-like particles (FMD-VLPs) has opened a new direction for researching a novel subunit vaccine for foot-and-mouth disease (FMD). Therefore, it is urgent to develop an adjuvant that is highly effective and safe to facilitate a better immune response to be pair with the FMD-VLP vaccine. In this research, we prepared a new nano-emulsion adjuvant based on squalane (SNA) containing CpG using the pseudo-ternary phase diagram method and the phase transformation method. The SNA consisted of Span85, Tween60, squalane, polyethene glycol-400 (PEG400) and CpG aqueous solution. The average particle diameter of the SNA was about 95 nm, and it exhibited good resistance to centrifugation, thermal stability, and biocompatibility. Then, SNA was emulsified as an adjuvant to prepare foot-and-mouth disease virus-like particles vaccine, BALB/c mice and guinea pigs were immunized, and we evaluated the immunization effect. The immunization results in mice showed that the SNA-VLPs vaccine significantly increased specific antibody levels in mice within 4 weeks, including higher levels of IgG1 and IgG2a. In addition, it increased the levels of IFN-γ and IL-1β in the immune serum of mice. Meanwhile, guinea pig-specific and neutralizing antibodies were considerably increased within 4 weeks when SNA was used as an adjuvant, thereby facilitating the proliferation of splenic lymphocytes. More importantly, in guinea pigs immunized with one dose of SNA-VLPs, challenged with FMDV 28 days after immunization, the protection rate can reach 83.3%, which is as high as in the ISA-206 control group. In conclusion, the novel squalane nano-emulsion adjuvant is an effective adjuvant for the FMD-VLPs vaccine, indicating a promising adjuvant for the future development of a novel FMD-VLPs vaccine.

Central Composite Design Implemented Azilsartan Medoxomil Loaded Nanoemulsion to Improve Its Aqueous Solubility and Intestinal Permeability: In Vitro and Ex Vivo Evaluation

The present research attempted to design and develop a nanoemulsion formulation of azilsartan medoxomil to improve its aqueous solubility and intestinal permeability. Based on the solubility profile, ethyl oleate, tween 80, and Transcutol P were selected as the oil phase, surfactant, and co-surfactant, respectively. Central composite design (CCD) suggested an optimized azilsartan medoxomil- nanoemulsion formulation (optimized AZL-NE formulation) with 1.25% oil, 15.73% Smix, and 90 s ultrasonication time; it was found to have the droplet size, percentage transmittance, and % cumulative drug release (%CDR) of 71.5 nm, 93.46 ± 1.13%, and 90.14 ± 0.94%, respectively. Furthermore, it exhibited a 0.141 polydispersity index, 34.05 mV zeta potential, a 1.413 ± 0.03 refractive index, 6.68 ± 0.22 pH, 28.17 ± 0.52 cps viscosity, and a 96.98 ± 0.94% percentage drug content. Transmission electron microscopy (TEM) assessed the nano-sized spherical shape, and a differential scanning calorimeter (DSC) assessed the solubilization of the drug in the optimized formulation. The %CDR was 1.71 times higher and the % cumulative drug permeation was 2.1 times higher for the optimized AZL-NE formulation than for the drug suspension through an intestinal segment of a rat, which was also supported by confocal laser scanning microscopy (CLSM) studies. Thus, the nanoemulsion formulation of azilsartan medoxomil ensured the enhancement of the drug availability in the body.

Development and characterization of monoterpene loaded microemulsions as novel scolicidal agents

Cystic echinococcosis (CE) is one of the most important zoonotic diseases. The primary treatment is surgery and chemical sterilization of the parasitic layers by injection of a scolicidal agent. Available scolicidals possess side effects, and may cause postoperative complications. Several studies reported the scolicidal properties of monoterpene phenols and alcohols such as carvacrol, thymol, and geraniol. The present study aimed to develop, characterize, and assess monoterpene loaded microemulsions as novel green scolicidals products. For this purpose, microemulsions composing 0.37%, 0.75%, and 1.5% of monoterpenoid(s), thymol, carvacrol, and geraniol, alone or in binary or ternary mixtures were formulated. Samples were analyzed by visual inspection, polarizing optical microscope, and dynamic light scattering (DLS). The stability of the samples was evaluated up to a 3-month storage. For the scolicidal bioassay, samples at different concentrations of 200, 100, 50, 25, and 10 μg/ml were added to wells containing 10⁴ viable protoscoleces and mortality rates were recorded at 2, 5, 10, and 20 min after exposure. Results of the present study showed that microemulsions formulated with 0.75% of pure carvacrol or the binary mixture of thymol and carvacrol at 0.375% are promising scolicidal agents.

Preparation of polyacrylate/nanoemulsion composites and their adjuvant activity with OVA as the model antigen

A series of polyacrylate/nanoemulsion composites were prepared to form a new kind of nanoemulsion, their particle sizes and polydispersity indices were measured. The particle sizes of the polyacrylate/nanoemulsion composites are consistent with nanoemulsions used in the system. In addition, an ELISA-specific antigen-antibody binding method was used for physical adsorption experiments on ovalbumin. Results showed that the adsorption performance of the polyacrylate/nanoemulsion system is best when the particle size was 55 nm, and the nanoemulsion content was 20 wt%, 30 wt%, or 40 wt%. Meanwhile, in order to select the optimum experimental conditions, in vivo immunity experiments in mice were carried out to analyze the adjuvant properties of ovalbumin as a model antigen. Analysis of ovalbumin-specific IgG, IgG1, and IgG2a antibody titers showed the best results when the particle size of the polyacrylate/nanoemulsion composites is 55 nm, the polyacrylate content is 0.5 wt%, and the nanoemulsion contents is 20 wt%. Meanwhile, titer analysis also showed that the polyacrylate obviously enhanced the IgG2a titer in mice. Our polyacrylate/nanoemulsion composites can both stimulate humoral and cellular immunity and have an enhanced adjuvant effect on water-soluble protein antigens.

Quality by design (QbD)-based fabrication of atazanavir-loaded nanostructured lipid carriers for lymph targeting: bioavailability enhancement using chylomicron flow block model and toxicity studies

Atazanavir (ATV) is widely used as anti-HIV agent having poor aqueous solubility needs to modulate novel drug delivery system to enhance therapeutic efficiency and safety. The main objective of the present work was to fabricate ATV-loaded nanostructured lipid carriers (NLCs) employing quality by design (QbD) approach to address the challenges of bioavailability and their safety after oral administration. Herein, the main objective was to identify the influencing variables for the production of quality products. Considering this objective, quality target product profile (QTPP) was assigned and a systematic risk assessment study was performed to identify the critical material attributes (CMAs) and critical process parameter (CPP) having an influence on critical quality attributes (CQAs). Lipid concentrations, surfactant concentrations, and pressure of high-pressure homogenizer were identified as CMAs and CPP. ATV-NLCs were prepared by emulsification-high pressure homogenization method and further lyophilized to obtain solid-state NLCs. The effect of formulation variables (CMAs and CPP) on responses like particle size (Y₁), polydispersity index (Y₂), and zeta potential (Y₃) was observed by central composite rotatable design (CCRD). The data were statistically evaluated by ANOVA for confirmation of a significant level (p < 0.05). The optimal conditions of NLCs were obtained by generating design space and desirability value. The lyophilized ATV-NLCs were characterized by DSC, powder X-ray diffraction, and FT-IR analysis. The morphology of NLCs was revealed by TEM and FESEM. In vitro study suggested a sustained release pattern of drug (92.37 ± 1.03%) with a mechanism of Korsmeyer-Peppas model (r² = 0.925, and n = 0.63). In vivo evaluation in Wistar rats showed significantly higher (p < 0.001) plasma drug concentration of ATV-NLCs as compared to ATV-suspension using chylomicron flow block model. The relative bioavailability of ATV-NLCs was obtained to be 2.54 folds. Thus, a safe and promising drug targeting system was successfully developed to improve bioavailability and avoiding first-pass effect ensures to circumvent the acute-toxicity of liver.

Evaluation of the hypoglycemic effect of exendin-4's new oral self-nanoemulsifying system in rats

The objective of this study is to develop a new self-nanoemulsifying system containing exendin-4 with or without enzyme inhibitor chymostatin and to evaluate the effects of oral administration of exendin-4 and exendin-4/chymostatin loaded self nanoemulsifying system on plasma exendin-4, plasma insulin, blood glucose levels and to compare with the oral and subcutaneous administration of exendin-4 in non-diabetic and streptozotocin-induced type 2 diabetic rats. Exendin-4 and exendin-4/chymostatin loaded self-nanoemulsifying system containing ethyl oleate as the oil phase, Cremophor EL®/Labrasol® as the surfactants and propylene glycol as the co-solvent were prepared. The mean droplet size, polydispersity index, zeta potential and viscosity of exendin-4 loaded self-nanoemulsifying system were found as 24.28 ± 0.43 nm, 0.17 ± 0.01, -1.28 ± 3.61 mV, 79.60 ± 3.30 m.Pas, respectively. The mean droplet size, polydispersity index, zeta potential and viscosity of exendin-4/chymostatin loaded self-nanoemulsifying system were found as 20.25 ± 0.35 nm, 0.11 ± 0.02, -1.85 ± 2.49 mV, 100.02 ± 7.65 m.Pas, respectively according to our previous study. In the present study, we focused on long-term physical stability studies, pharmacokinetic studies and pharmacodynamic studies of prepared self-nanoemulsifying systems. According to the long- term physical stability data, exendin-4 and exendin-4/chymostatin loaded self-nanoemulsifying systems were found stable both at 5°C ± 3°C and at 25°C ± 60% RH for 12 months. Exendin-4 and exendin-4/chymostatin loaded self-nanoemulsifying systems increased AUC and C_max values in non-diabetic rats compared to the oral exendin-4 solution. In diabetic rats, exendin-4/chymostatin loaded self nanoemulsifying systems increased C_max values compared to the exendin-4 solution. Exendin-4/chymostatin loaded self-nanoemulsifying system decreased inter-subject variability compared to commercial Byetta®. At 30^th minute after administration of exendin-4 loaded self-nanoemulsifying system, exendin-4/chymostatin loaded self nanoemulsifying system and Byetta®, blood glucose levels decreased to 23%, 25%, 29%, respectively. It has been shown that pharmacodynamic response is close to Byetta® with exendin-4/chymostatin self-nanoemulsifying system oral administration. In conclusion, a self nanoemulsifying system was found to be a suitable carrier system, and the combination with enzyme inhibitor chymostatin is thought to be promising for oral delivery of exendin-4.

Lymphatic Transport of Drugs after Intestinal Absorption: Impact of Drug Formulation and Physicochemical Properties

PURPOSE

To provide a comprehensive and up-to-date overview focusing on the extent of lymphatic transport of drugs following intestinal absorption and to summarize available data on the impact of molecular weight, lipophilicity, formulation and prandial state.

METHODS

Literature was searched for in vivo studies quantifying extent of lymphatic transport of drugs after enteral dosing. Pharmacokinetic data were extracted and summarized. Influence of molecular weight, log P, formulation and prandial state was analyzed using relative bioavailability via lymph (F_RL) as the parameter for comparison. The methods and animal models used in the studies were also summarized.

RESULTS

Pharmacokinetic data on lymphatic transport were available for 103 drugs. Significantly higher F_RL [median (IQR)] was observed in advanced lipid based formulations [54.4% (52.0)] and oil solutions [38.9% (60.8)] compared to simple formulations [2.0% (27.1)], p < 0.0001 and p = 0.004, respectively. Advanced lipid based formulations also provided substantial F_RL in drugs with log P < 5, which was not observed in simple formulations and oil solutions. No relation was found between F_RL and molecular weight. There were 10 distinct methods used for in vivo testing of lymphatic transport after intestinal absorption so far.

CONCLUSION

Advanced lipid based formulations provide superior ability to increase lymphatic absorption in drugs of various molecular weights and in drugs with moderate to low lipophilicity.

Development and in vivo evaluation of baicalin-loaded W/O nanoemulsion for lymphatic absorption

Background: Lymphatic formations that effectively eradicate the virus in the lymphatic system will be therapeutically advantagous in hepatitis B virus (HBV) infection. Lipid-based formulation is often used to deliver drug via the lymphatic system. Baicalin nanoemulsion may be a promising drug delivery system for improved treatment of HBV infection. Objective: This study aimed to prepare, characterize, and evaluate a lipid-based nanoemulsion containing baicalin for lymphatic system absorption. Method: The presence of a nanoemulsion region was studied by pseudoternary phase diagrams. The physicochemical properties of a baicalin-loaded nanoemulsion were investigated. The oral bioavailability of the baicalin-loaded nanoemulsion was compared to that of a baicalin suspension. A chylomicron flow blocking model was used to examine the extent of lymphatic uptake. The lymph node distribution of baicalin was measured to investigate the lymphatic transport ability of the nanoemulsion compared to the suspension. Results: Compared to the baicalin suspension, the AUC_0-t and C_max values of the baicalin nanoemulsion were increased by 10.5-fold and 3.12-fold, respectively. Compared with the saline-treated rats that were orally administered the baicalin nanoemulsion, the AUC_0-t and C_max values of the nanoemulsion for the rats pretreated with cycloheximide were reduced from 23.076 ± 1.244 mg/L h to 9.236 ± 0.940 mg/L h and from 3.010 ± 0.119 mg/L to 1.567 ± 0.220 mg/L, respectively. In comparing baicalin in W/O nanoemulsion with suspension, the C_max value was found to be 11.5-fold higher in the lymph nodes of the rats treated with the nanoemulsion. Conclusion: The results indicated that a baicalin-loaded W/O nanoemulsion may be a promising drug delivery system for the treatment of chronic hepatitis B.

Development and mechanistic study of a microemulsion containing vitamin E TPGS for the enhancement of oral absorption of celecoxib

Purpose: The purpose of this study was to develop a microemulsion containing D-α-tocopheryl polyethylene glycol 1000 succinate (vitamin E TPGS) as a biodegradable surfactant to increase the oral absorption of celecoxib. Methods: This study investigated the intestinal absorption enhancement mechanism of this microemulsion by measuring transepithelial electrical resistance (TEER) values. This study also evaluated microemulsion particle-intestine interactions in terms of release and attachment processes using confocal laser scanning microscopy (CLSM). Results: The prepared microemulsion particles had a size of <300 nm with a neutral surface charge. The celecoxib-loaded microemulsion release kinetic was classified as the zero-order model. This vitamin E TPGS-based microemulsion significantly increased the in vitro intestinal absorption of celecoxib compared to celecoxib solution. The CLSM study suggested that microemulsion particles with entrapped drugs might attach to the intestinal epithelium before releasing the entrapped drug into tissues. The TEER value of the intestinal tissues treated with the celecoxib-loaded microemulsion was significantly decreased compared to the value before treatment, indicating an increase in drug transport via the paracellular pathway. The evaluation of intestinal tissue cytotoxicity using lactate dehydrogenase cytotoxicity assay suggested that the prepared celecoxib-loaded microemulsion was safe for oral route administration. Conclusions: The prepared celecoxib loaded microemulsion could increase the intestinal absorption of celecoxib compared to celecoxib solution. The intestinal absorption enhancement mechanism of this microemulsion resulted from the increase of the drug transport via the paracellular pathway.

A novel microemulsion-based isotonic perfusate modulated by Ringer's solution for improved microdialysis recovery of liposoluble substances

Background

Microdialysis is promising technique for dynamic microbiochemical sampling from tissues. However, the application of typical aqueous perfusates to liposoluble substances is limited. In this study, a novel microemulsion (ME)-based isotonic perfusate (RS-ME) was prepared to improve the recovery of liposoluble components using microdialysis probes.

Results

Based on pseudo-ternary phase diagrams and comparisons of the ME area, Kolliphor^® EL and Transcutol^® P were selected as the surfactant and co-surfactant, respectively, with a weight ratio (Km) of 2:1 and ethyl oleate as the oil phase. The ME was mixed with Ringer’s solution at a 1:6 ratio (v/v) to obtain the isotonic RS-ME. The droplet size distribution of the ME in RS-ME was 78.3 ± 9.2 nm, with a zeta potential of − 3.5 ± 0.3 mV. By microdialysis perfusion, RS-ME achieved higher recovery rates of the poorly water-soluble compounds evodiamine (EVO) and ruthenium (RUT), i.e., 58.36 ± 0.57% and 49.40 ± 0.57%, respectively, than those of 20% (v/v) PEG 400 Ringer's solution (RS-PEG) and 10% (v/v) ethanol Ringer’s solution (RS-EtOH). In vivo microdialysis experiments confirmed that RS-ME captured EVO and RUT molecules around the dialysis membrane more efficiently and exhibited less spreading than RS-PEG and RS-EtOH.

Conclusions

Owing to the nanosized droplets formed by lipid components in the RS-ME and the limited dispersion out of the dialysis membrane, we obtained good biocompatibility and reliable dialysis results, without affecting the tissue microenvironment. As a novel perfusate, RS-ME provides an easy and reliable approach to the microdialysis sampling of fat-soluble components.

Ethyl oleate food-grade O/W emulsions loaded with apigenin: Insights to their formulation characteristics and physico-chemical stability

Apigenin has attracted a great interest in the food industry due to the wide range of its biological activities including antioxidant and anti-inflammatory. The encapsulation of apigenin in oil-in-water (O/W) emulsions could overcome its low solubility and lead to the development of new functional food products. The aim of this study is to formulate food-grade O/W submicron emulsions loaded with apigenin using high-pressure homogenization. Supersaturated solutions of 0.1 wt% apigenin in ethyl oleate were heated at 100 °C for 30, 60, or 120 min and the supernant after centrifugation were used as to-be-dispersed phases. An aqueous solution containing 1 wt% tween 20 was used as the continuous phase. We examined the effect of heating process of the ethyl oleate prior to emulsification and the homogenization-pressure (60-150 MPa) on the physico-chemical characteristics of the O/W emulsions immediately after formulation and during storage. Submicron O/W emulsions were formulated and the lowest average droplet diameter (d_av) was 169 ± 2.082 nm with a polydispersity index (PDI) of 0.06 ± 0.002. After 30 days of storage at 4 °C, the O/W emulsion formulated remained physically stable with little change in their d_av and PDI values. The preheat treatment of ethyl oleate, affected the initial loaded apigenin concentration but hardly affected the physico-chemical stability of O/W emulsions. However, HPLC analysis demonstrated that the emulsification pressure was a relevant parameter affecting apigenin retention during the storage of O/W emulsions. Apigenin degradation in ethyl oleate O/W emulsions followed zero order kinetics and about 91.5-93.5% of apigenin could be retained in O/W emulsions after 30 days of storage.

Oral Bioavailability and Lymphatic Transport of Pueraria Flavone-Loaded Self-Emulsifying Drug-Delivery Systems Containing Sodium Taurocholate in Rats

We developed self-microemulsifying drug-delivery systems (SMEDDS), including bile salts, to improve the oral bioavailability of pueraria flavones (PFs). The physical properties of the SMEDDS using Cremophor RH 40, and bile salts as mixed surfactants at weight ratios of 10:0⁻0:10 were determined. The particle sizes of PFs-SMEDDS_NR containing sodium taurocholate (NaTC) and Cremophor RH 40, and PFs-SMEDDS_R containing Cremophor RH 40 were measured upon dilution with deionized water and other aqueous media. Dilution volume presented no remarkable effects on particle size, whereas dilution media slightly influenced particle size. PFs-SMEDDS_NR and PFs-SMEDDS_R provided similar release rates in pH-1.2 hydrochloride solution. However, the release rate of PFs-SMEDDS_NR was faster than that of PFs-SMEDDS_R in pH-6.8 phosphate buffer containing 20 mM NaTC and 500 U/mL porcine pancreas lipase. The pharmacokinetics and bioavailability were measured in rats. The oral bioavailability of PFs-SMEDDS_NR was 2.57- and 2.28-fold that of a suspension of PFs (PFs-suspension) before and after the blockade of the lymphatic transport route by cycloheximide, respectively. These results suggested PFs-SMEDDS_NR could significantly improve the oral relative absorption of PFs via the lymphatic uptake pathway. SMEDDS containing NaTC may provide an effective approach for enhancing the oral bioavailability of PFs.

Preparation and Pharmacokinetics Evaluation of Solid Self-Microemulsifying Drug Delivery System (S-SMEDDS) of Osthole

The study was performed aiming to enhance the solubility and oral bioavailability of poorly water-soluble drug osthole by formulating solid self-microemulsifying drug delivery system (S-SMEDDS) via spherical crystallization technique. Firstly, the liquid self-microemulsifying drug delivery system (L-SMEDDS) of osthole was formulated with castor oil, Cremophor RH40, and 1,2-propylene glycol after screening various lipids and emulsifiers. The type and amount of polymeric materials, good solvents, bridging agents, and poor solvents in S-SMEDDS formulations were further determined by single-factor study. The optimal formulation contained 1:2 of ethyl cellulose (EC) and Eudragit S100, which served as matrix forming and enteric coating polymers respectively. Anhydrous ethanol and dichloromethane with a ratio of 5:3 are required to perform as good solvent and bridging agent, respectively, with the addition of 0.08% SDS aqueous solution as poor solvent. The optimized osthole S-SMEDDS had a high yield (83.91 ± 3.31%) and encapsulation efficiency (78.39 ± 2.25%). Secondly, osthole L-SMEDDS was solidified to osthole S-SMEDDS with no significant changes in terms of morphology, particle size, and zeta potential. In vitro release study demonstrated a sustained release of the drug from osthole S-SMEDDS. Moreover, in vivo pharmacokinetic study showed that the T_max and mean residence time (MRT_(0-t)) of osthole were significantly prolonged and further confirmed that osthole S-SMEDDS exhibited sustained release effect in rabbits. Comparing with osthole aqueous suspension and L-SMEDDS, osthole S-SMEDDS increased bioavailability by 205 and 152%, respectively. The results suggested that S-SMEDDS was an effective oral solid dosage form, which can improve the solubility and oral bioavailability of poorly water-soluble drug osthole.

Sinomenine-loaded microcapsules fabricated by phase reversion emulsification-drying in liquid method: An evaluation of process parameters, characterization, and released properties

Sinomenine is a natural alkaloid with important biological activities (e.g. anti-cancer, anti-inflammatory, and anti-allergic). However, the unstability and short half-life absolutely limited its application to foods. Microencapsulation technology can offer a way to solve these issues. In this study, polylactic acid microcapsules loading sinomenine hydrochloride were fabricated by phase inversion emulsification-drying in liquid technique. The results showed that microcapsules had nice spherical shape, uniform particle size, and free flowing. The encapsulation efficiency was 89.2% and drug loading was 8.9% under the optimal conditions. In vitro release assays demonstrated that release of sinomenine from microcapsules was sustained and slow. Moreover, it was found that the sinomenine release fitted Fickian diffusion mechanism. The results of cytotoxicity study showed that sinomenine-loaded microcapsules were biocompatible. Sinomenine-loaded microcapsules could inhibit the growth of MDA-MB-231 cells using methyl thiazolyl tetrazolium assay. In summary, polylactide microcapsules exhibit excellent properties for sinomenine that can be used in drug or food industry.

Enhancing biopharmaceutical performance of an anticancer drug by long chain PUFA based self-nanoemulsifying lipidic nanomicellar systems

The aim of this study was to develop polyunsaturated fatty acid (PUFA) long chain glyceride (LCG) enriched self-nanoemulsifying lipidic nanomicelles systems (SNELS) for augmenting lymphatic uptake and enhancing oral bioavailability of docetaxel and compare its biopharmaceutical performance with a medium-chain fatty acid glyceride (MCG) SNELS. Equilibrium solubility and pseudo ternary phase studies facilitated the selection of suitable LCG and MCG. The critical material attributes (CMAs) and critical process parameters (CPPs) were earmarked using Placket-Burman Design (PBD) and Fractional Factorial Design (FFD) for LCG- and MCG-SNELS respectively, and nano micelles were subsequently optimized using I- and D-optimal designs. Desirability function unearthed the optimized SNELS with T_emul <5min, D_nm <100nm, Rel_15min >85% and Perm_45min >75%. The SNELS demonstrated efficient biocompatibility and energy dependent cellular uptake, reduced P-gp efflux and increased permeability using bi-directional Caco-2 model. Optimal PUFA enriched LCG-SNELS exhibited distinctly superior permeability and absorption parameters during ex vivo permeation, in situ single pass intestinal perfusion, lymphatic uptake and in vivo pharmacokinetic studies over MCG-SNELS.

Development of a novel microemulsion for oral absorption enhancement of all-trans retinoic acid

This study was aimed to develop a novel microemulsion that contained oleth-5 as a surfactant to enhance the oral absorption of all-trans retinoic acid (ATRA). The prepared microemulsion was evaluated for its particle size, shape, zeta potential, in vitro release, in vitro intestinal absorption, intestinal membrane cytotoxicity and stability. The obtained microemulsion was spherical in shape with a particle size of <200 nm and a negative surface charge. The in vitro release of the ATRA-loaded microemulsion was best fit with the zero-order model. This microemulsion significantly improved the intestinal absorption of ATRA. Confocal laser scanning microscopy analysis using a fluorescent dye-loaded microemulsion also confirmed the intestinal absorption result. The intestinal membrane cytotoxicity of the ATRA-loaded microemulsion did not differ from an edible oil (fish oil). Stability testing showed that the ATRA-loaded microemulsion was more stable at 25°C than 40°C.

Preparation of Pickering emulsions with short, medium and long chain triacylglycerols stabilized by starch nanocrystals and their in vitro digestion properties

In vitrodigestion fate of food-grade Pickering emulsions stabilized by starch nanocrystals were varied by incorporating short, medium and long chain triacylglycerols.