Evaluation in vitro and in vivo of curcumin-loaded mPEG-PLA/TPGS mixed micelles for oral administration

The Bright Side of Curcumin: A Narrative Review of Its Therapeutic Potential in Cancer Management

Curcumin, a polyphenolic compound derived from Curcuma longa, exhibits significant therapeutic potential in cancer management. This review explores curcumin's mechanisms of action, the challenges related to its bioavailability, and its enhancement through modern technology and approaches. Curcumin demonstrates strong antioxidant and anti-inflammatory properties, contributing to its ability to neutralize free radicals and inhibit inflammatory mediators. Its anticancer effects are mediated by inducing apoptosis, inhibiting cell proliferation, and interfering with tumor growth pathways in various colon, pancreatic, and breast cancers. However, its clinical application is limited by its poor bioavailability due to its rapid metabolism and low absorption. Novel delivery systems, such as curcumin-loaded hydrogels and nanoparticles, have shown promise in improving curcumin bioavailability and therapeutic efficacy. Additionally, photodynamic therapy has emerged as a complementary approach, where light exposure enhances curcumin's anticancer effects by modulating molecular pathways crucial for tumor cell growth and survival. Studies highlight that combining low concentrations of curcumin with visible light irradiation significantly boosts its antitumor efficacy compared to curcumin alone. The interaction of curcumin with cytochromes or drug transporters may play a crucial role in altering the pharmacokinetics of conventional medications, which necessitates careful consideration in clinical settings. Future research should focus on optimizing delivery mechanisms and understanding curcumin's pharmacokinetics to fully harness its therapeutic potential in cancer treatment.

Self-Assembled Micelles Based on Ginsenoside Rg5 for the Targeted Treatment of PTX-Resistant Tumors

Paclitaxel (PTX) is one of the first-line drugs for prostate cancer (PC) treatment. However, the poor water solubility, inadequate specific targeting ability, multidrug resistance, and severe neurotoxicity are far from being fully resolved, despite diverse PTX formulations in the market, such as the gold-standard PTX albumin nanoparticle (Abraxane) and polymer micelles (Genexol-PM). Some studies attempting to solve the multiple problems of chemotherapy delivery fall into the trap of an extremely complicated formulation design and sacrifice druggability. To better address these issues, this study designed an efficient, toxicity-reduced paclitaxel-ginsenoside polymeric micelle (RPM). With the aid of the inherent amphiphilic molecular structure and pharmacological effects of ginsenoside Rg5, the prepared RPM enhances the water solubility and active targeting of PTX, inhibiting chemotherapy resistance in cancer cells. Moreover, the polymeric micelles demonstrated favorable anti-inflammatory and neuroprotective effects, providing ideas for the development of new clinical anti-PC preparations.

Naturally sourced amphiphilic peptides as paclitaxel vehicles for breast cancer treatment

The marketed paclitaxel (PTX) formulation Taxol relies on the application of Cremophor EL as a solubilizer. The major drawback of Taxol is its hypersensitivity reactions and a pretreatment of anti-allergic drugs is a necessity. Therefore, developing an efficient and safe delivery vehicle is a solution to increase PTX treatment outcomes with minimal adverse effects. In this work, we prepared the amphiphilic peptides (termed AmP) from soybean proteins using a facile two-step method. AmP could efficiently solubilize PTX by self-assembling into mixed micelles with D-α-tocopherol polyethylene glycol succinate (TPGS), a common pharmaceutical expedient (PTX@TPGS-AmP). The intravenously administrated PTX@TPGS-AmP exhibited a slow clearance (0.24 mL·(min·kg)-1) and an enhanced AUC (41.4 μg.h/mL), manifesting a 3.6-fold increase compared to Taxol. In a murine 4T1 tumor model, PTX@TPGS-AmP displayed a superior antitumor effect over Taxol. Importantly, safety assessment showed a high biocompatibility of AmP and an i.v. dose up to 2500 mg/kg led to no observable abnormalities in the mice. In summary, the AmP presents a new green and easily-prepared amphiphilic biomaterial, with promising potential as a pharmaceutical excipient for drug delivery.

Preparation, characterization, pharmacokinetics and ulcerative colitis treatment of hyperoside-loaded mixed micelles

At present, ulcerative colitis (UC) has become a global disease due to its high incidence. Hyperoside (HYP) is a naturally occurring flavonoid compound with many pharmacological effects. This study aimed to develop HYP-loaded mixed micelles (HYP-M) to improve oral bioavailability of HYP and to evaluate its therapeutic effect on UC. The prepared HYP-M exhibited stable physical and chemical properties, smaller particle size (PS) (21.48 ± 1.37 nm), good polydispersity index (PDI = 0.178 ± 0.013), negative Zeta potential (ZP) (- 20.00 ± 0.48 mV) and high entrapment rate (EE) (89.59 ± 2.03%). In vitro release and in vivo pharmacokinetic results showed that HYP-M significantly increased the releasing rate of HYP, wherein its oral bioavailability was 4.15 times higher than that of free HYP. In addition, HYP-M was more effective in the treatment of UC than free HYP. In conclusion, HYP-M could serve as a novel approach to improve bioavailability and increase anti-UC activity of HYP.

Enhanced fungicidal efficacy and improved interfacial properties with the co-delivery of prothioconazole and tebuconazole using polylactic acid microspheres

BACKGROUND

Prothioconazole (PTC) is one of the leading fungicide products worldwide. However, excessive use of PTC facilitates the development of resistance. Pesticide compounding technology plays an important role in reducing pesticide resistance. Microspherization technology for the construction of pesticide dual-loaded systems has recently provided a new direction for researching novel and efficient pesticide formulations. In this study, prothioconazole-tebuconazole@polylactic acid microspheres (PTC-TBA@PLA MS) were constructed by combining these two technologies.

RESULTS

The final PTC-TBA@PLA MS were selected by an orthogonal method, which were uniformly spherical with smooth surface. The resultant drug loading (DL) and average particle size of PTC-TBA@PLA MS were 31.34% and 22.3 μm, respectively. A PTC-TBA@PLA MS suspending agent (SC) with a high suspension rate of 94.3% was prepared according to the suspension rate, dumping ability and stability. Compared with a commercial SC, the PTC-TBA@PLA MS SC had a larger cumulative release and better interfacial properties. Biological experiments showed that PTC-TBA@PLA MS SC had an obviously improved bactericidal effect than the commercial SC.

CONCLUSION

The constructed PTC-TBA@PLA MS system detailed here is expected to reduce the risk of resistance and the frequency of pesticide use while enhancing fungal control. © 2023 Society of Chemical Industry.

In Vivo Efficacy of Curcumin and Curcumin Nanoparticle in Trypanosoma congolense, Broden 1904 (Kinetoplastea: Trypanosomatidae)-Infected Mice

Curcumin (CUR) is known for its wide folkloric effects on various infections; however, its solubility status has remained a hindrance to its bioavailability in the host. This study evaluated the comparative effects of CUR and CUR-nanoparticle in vitro on T. congolense, T. b. brucei, and T. evansi. Additionally, CUR and CUR-nanoparticle anti-Trypanosoma efficacy were assessed in vivo against T. congolense. All the CUR-nanoparticles were two folds more effective on the T. congolense as compared to CUR in vitro, with recorded efficacy of 3.67 ± 0.31; 7.61 ± 1.22; and 6.40 ± 3.07 μM, while the CUR-nanoparticles efficacy was 1.56 ± 0.50; 28.16 ± 9.43 and 13.12 ± 0.13 μM on T. congolense, T. b. brucei, and T. evansi, respectively. Both CUR and CUR-nanoparticles displayed moderate efficacy orally. The efficacy of CUR and CUR-nanoparticles in vivo was influenced by solubility, presence of food, and treatment period. CUR-treated mice were not cured of the infection; however, the survival rate of the orally treated mice was significantly prolonged as compared with intraperitoneal-treated mice. CUR-nanoparticles resulted in significant suppression of parasitemia even though relapsed was observed. In conclusion, CUR and CUR-nanoparticles possess moderate efficacy orally on the trypanosomes as compared to the intraperitoneal treatment.

Cationic Ester Prodrugs of Curcumin with N,N-dimethyl Amino Acid Promoieties Improved Poor Water Solubility and Intestinal Absorption

PURPOSE

Although curcumin (Cur) has powerful pharmacological effects, its use in medicine has not been established yet. The oral bioavailability (BA) of Cur is limited because of its poor water solubility. The purpose of this study was to confirm whether cationic N,N-dimethyl amino acid esters of Cur could act as prodrugs and improve its water solubility and oral bioavailability.

METHODS

Two N,N-dimethyl amino acid esters of Cur were synthesized. The hydrolysis profile of the esters was evaluated using rat and human microsomes. A pharmacokinetic study after oral administration of the Cur ester derivatives was performed in rats and compared to the administration of suspended or dissolved Cur formulation. The anti-inflammatory effects of the Cur derivatives were evaluated using macrophage RAW 264.7 stimulated with lipopolysaccharide.

RESULTS

Cur ester derivatives showed  > 200 mM water solubility. The derivatives were reconverted to the parent compound (Cur) after cleavage of the ester bonds by microsomal esterase, indicating that the compounds could act as Cur prodrugs. The Cur prodrugs enhanced the absolute oral bioavailability of Cur by a 9- and threefold increase of suspended and dissolved Cur administration, respectively, thereby improving intestinal absorption. Cur prodrugs strongly attenuated COX2, iNOS, and ERK phosphorylation.

CONCLUSIONS

The cationic N,N-dimethyl amino acid ester prodrugs of Cur improved the water solubility of Cur and enhanced oral bioavailability in rats. These Cur prodrugs may be good candidates for developing medicinal options previously unavailable due to the poor water solubility and oral BA of Cur.

Enhancing the bioaccessibility of vitamin D using mixed micelles - An in vitro study

Vitamin-D deficiency is a global issue and a food fortification strategy may reduce deficiency levels. Mixed micelles (MM) are crucial to vitamin-D absorption in vivo and may enhance vitamin-D food fortification. This study compared the ability of MM based delivery systems to oil-in-water emulsions to improve vitamin-D bioaccessibility in vitro. Vitamin-D loaded emulsions were formed with olive or coconut oil alone or with added l-α-phosphatidylcholine, as well as two MM based systems. Particle size throughout digestion, fatty acid release, and vitamin-D bioaccessibility were measured. After digestion, particles in the MM size range (∼6-10 nm) were observed for emulsions but not for MM based systems. The bioaccessibility of vitamin-D in olive and coconut emulsions was 75% and 78%, respectively, and ∼ 90% with added l-α-phosphatidylcholine. Bioaccessibility for the MM alone was 93% and 90% when mixed with a protein/lactose base. Overall, MM show good potential as a delivery system for vitamin-D in vitro.

Baicalein Loaded Crown Ether-mPEG-PLGA Micelle Drug Delivery System for Increased Breast Cancer Treatment: Preparation, Characterization, In-Vitro and In-Vivo Evaluations

Due to low aqueous solubility and poor bioavailability of the flavone baicalein (BIC), a nano-micelle of delivery system was developed. Preparation of BIC-loaded crown ether-mPEG-PLGA micelle (BCPP-M) was performed via thin-film hydration method. Characterization of micellar excipients was accomplished with 1H NMR, while evaluation of the optimal BCPP-M formulation was appropriately carried out through zeta potential (ZP), size of particles (PS), efficiency of encapsulation (EE) and capacity of drug loading (DL). We evaluated BIC release In-Vitro and profile of In-Vivo pharmacokinetics. Evaluation of the anti-breast cancer property of BCPP-M using MCP-7 cells cytotoxicity and mice model was performed. Particles of BCPP-M were homogenously and spherically shaped with smaller average PS, coupled with higher EE and DL, good stability and polydispersity index (PDI). The accumulative release of BCPP-M was obviously higher than free-BIC. Significantly, oral biological availability of BCPP-M was improved comparable to free BIC. Besides, half maximum inhibitory concentration (IC50) of BCPP-M in MCP-7 cells was lower than free-BIC. Animal experiments also showed targeting, long circulation and antitumor potential of BCPP-M. Successful incorporation of BIC into long-acting and targeting micellar system could have enhanced solubility in aqueous media, oral In-Vivo availability and antitumor property of BIC.

Hyaluronic Acid Micelles for Promoting the Skin Permeation and Deposition of Curcumin

Background

The poor skin permeation and deposition of topical therapeutic drugs is a major issue in topical drug delivery, improving this issue is conducive to improving the topical therapeutic effect of drugs.

Methods

In this study, octadecylamine modified hyaluronic acid (OHA) copolymer was synthesized by amide reaction technique to prepare curcumin (CUR)-loaded micelles (CUR-M) for topical transdermal administration. CUR-M was successfully prepared by dialysis, and the formulation was evaluated for particle size, zeta potential, surface morphology, entrapment effciency (EE%), drug loading (DL), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and the in vitro drug release. Additionally, in vitro skin permeation and retention, in vivo topical analgesic and anti-inflammatory activity, and skin irritation were assessed.

Results

The mean drug loading (DL), drug entrapment efficiency (EE), hydrodynamic diameter and zeta potential of CUR-M were 8.26%, 90.86%, 165.64 nm and −26.85 mV, respectively. CUR-M was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), it was found that there was an interaction between CUR and OHA, and CUR existed in CUR-M in an amorphous form. CUR-M exhibited sustained release in 48 h and good stability at 4 °C for 21days. CUR-M could significantly increase the skin penetration and retention of CUR and had better analgesic and anti-inflammatory activities in vivo when compared with CUR solution. Hematoxylin-eosin staining results revealed that the transdermal penetration mechanism of CUR-M might be related to the hydration of stratum corneum by HA. In addition, CUR-M showed no skin irritation to mouse skin.

Conclusion

CUR-M might be a promising and safe drug delivery system for the treatment of topical diseases.

Hyperoside-loaded TPGs/mPEG-PDLLA self-assembled polymeric micelles: preparation, characterization and in vitro/in vivo evaluation

Hyperoside (Hyp) self-assembled polymeric micelles (Hyp-PMs) were purposely developed to enhance aqueous solubility, in vivo availability and anti-oxidative effect of Hyp. In preparing Hyp-PMs, we employed the thin film dispersion method with the micelles consisting of TPGs and mPEG2000-PDLLA3000. The particle size, polydispersity index and zeta potential of Hyp-PMs were 67.42 ± 1.44 nm, 0.229 ± 0.015 and -18.67 ± 0.576 mV, respectively, coupled with high encapsulation efficiency (EE)of 90.63 ± 1.45% and drug loading (DL) of 6.97 ± 1.56%. Furthermore, the value of critical micelle concentration (CMC) was quite low, which indicated good stability and improved self-assembly ability of Hyp-PMs. Also, trend of in vitro Hyp release from Hyp-PMs demonstrated enhanced solubility of Hyp. Similarly, in comparison with free Hyp, oral bioavailability of Hyp-PMs was improved (about 8 folds) whilst half-life of Hyp-PMs was extended (about 3 folds). In vitro anti-oxidative effect showed obvious strong scavenging DPPH capability of Hyp-PMs, which may be attributed to its smaller size and better solubility. Altogether, Hyp-PMs may serve as a possible strategy to potentially enhance aqueous solubility, bioavailability and anti-oxidative effect of Hyp, which may play a key role in Hyp application in the pharmaceutical industries.

Trends in advanced oral drug delivery system for curcumin: A systematic review

Although curcumin is globally recognized for its health benefits, its clinical application has been restricted by its poor aqueous solubility and stability. To overcome these limitations, nanocarrier-based drug delivery systems (NDS) are one of the most effective approaches being extensively explored over the last few decades to improve curcumin's physicochemical and pharmacological effects. Various NDS could provide productive platforms for addressing the formulation challenge of curcumin, but evidence of such systems has not been summarized. This study aimed to systematically review current evidence of lipid and polymer-based NDS for an oral delivery of curcumin focusing on in vivo models and clinical studies. Among the 48 included studies, 3 studies were randomized controlled clinical trials, while 45 studies were animal models. To date, only five curcumin NDS have been studied in healthy volunteers: γ-cyclodextrin, phytosome, liposome, microemulsion and solid dispersion, while most curcumin NDS have been studied in animal models. Most included studies found that NDS could increase oral bioavailability of curcumin as compared to free curcumin. In conclusion, this systematic review showed evidence of the positive effect of NDS for enhancement of oral bioavailability of curcumin. EXECUTIVE SUMMARY: Curcumin is globally recognized for its health benefits, but its clinical application has been limited by its poor aqueous solubility and stability, which causes poor absorption in the gastrointestinal tract (GI tract) via oral administration. Nanocarrier-based drug delivery systems (NDS) are considered as a productive platform to solve the formulation challenge of curcumin, but evidence of such systems has not been summarized. This study aimed to systematically review current evidence of lipid and polymer-based NDS for an oral delivery of curcumin focusing on in vivo models and clinical studies. Overall, most studies found that all studied NDS could increase the absorption of curcumin as compared to free curcumin. Curcumin was rapidly absorbed and exhibited a long residence time after oral administration of curcumin NDS. In summary, this systematic review showed positive impacts of NDS for enhancement of oral absorption of curcumin.

Preparation and performance of chlorfenapyr microcapsules with a degradable polylactide-based polyurethane wall material

To improve the utilization rate of chlorfenapyr and make the wall material of chlorfenapyr microcapsules easily degradable, polylactide diol, toluene diisocyanate and 1,4-butanediol were used to prepare a chlorfenapyr microcapsule suspension by interfacial polymerization. The product was characterized by the methods of optical microscopy, scanning electron microscopy and Fourier-transform infrared spectroscopy. The results indicated that the microcapsule particles were spherical, with an encapsulation efficiency of 84.20%. The diluted product had good wetting and spreading abilities on cabbage leaves. Compared with other commercial formulations, the slow-release effect of the microcapsule suspension was more obvious and the release mechanisms conform to Fickian diffusion, with the release rate controllable by adjusting the external pH conditions. Furthermore, the wall material of the microcapsules showed good degradation performance in a phosphate-buffered solution. Microencapsulation by this method significantly increased the validity period of chlorfenapyr and the wall material was also degraded easily.

Synthesis and characterization of lotus seed protein-based curcumin microcapsules with enhanced solubility, stability, and sustained release

BACKGROUND

Lotus seed protein (LSP) was extracted from lotus seed and used to encapsulate curcumin with or without complexing with pectin. The physicochemical properties of LSP-based microcapsules, including solubility, stability, and in vitro sustained release, were determined. The mechanism of interaction between curcumin, LSP, and pectin was revealed.

RESULTS

The encapsulation efficiency of curcumin was found to depend on LSP concentration and was highest (86.32%, w/w) at 50 mg mL^-1 . The curcumin in curcumin-LSP and curcumin-LSP-pectin powder particles achieved a solubility of 75.15% and 81.39%, respectively, which was a remarkable enhancement. The microencapsulation with LSP and LSP-pectin matrix showed a significant improvement in the antioxidant activity, photostability, thermostability, and storage stability of free curcumin. The microencapsulated curcumin showed sustained control release at the gastric stage and burst-type release in the subsequent intestinal stage, presenting cumulative release rates of 64.3% and 72.4% from curcumin-LSP and curcumin-LSP-pectin particles after gastrointestinal digestion. The LSP-pectin complex produced microcapsules with higher solubility, smaller particle size, enhanced physicochemical stability, and increased bioaccessibility. Fourier transform infrared, circular dichroism spectra, and differential scanning calorimetry data indicated that the encapsulated curcumin interacted with LSP and pectin mainly through hydrogen bonding, hydrophobic, and electrostatic interactions.

CONCLUSION

This work shows that LSP can be an alternative encapsulant for the delivery of hydrophobic nutraceuticals with enhanced solubility, stability, and sustained release. The results may contribute to the design of novel food-grade delivery systems based on LSP vehicles, thereby broadening the applications of LSP in the fields of functional food. © 2021 Society of Chemical Industry.

Antitumoral Activities of Curcumin and Recent Advances to ImProve Its Oral Bioavailability

Curcumin, a main bioactive component of the Curcuma longa L. rhizome, is a phenolic compound that exerts a wide range of beneficial effects, acting as an antimicrobial, antioxidant, anti-inflammatory and anticancer agent. This review summarizes recent data on curcumin's ability to interfere with the multiple cell signaling pathways involved in cell cycle regulation, apoptosis and the migration of several cancer cell types. However, although curcumin displays anticancer potential, its clinical application is limited by its low absorption, rapid metabolism and poor bioavailability. To overcome these limitations, several curcumin-based derivatives/analogues and different drug delivery approaches have been developed. Here, we also report the anticancer mechanisms and pharmacokinetic characteristics of some derivatives/analogues and the delivery systems used. These strategies, although encouraging, require additional in vivo studies to support curcumin clinical applications.

Development of Gelucire® 48/16 and TPGS Mixed Micelles and Its Pellet Formulation by Extrusion Spheronization Technique for Dissolution Rate Enhancement of Curcumin

The oral bioavailability of curcumin is limited, attributed to its low solubility or dissolution and poor absorption. Herein, the study describes formulation of curcumin-loaded mixed micelles of Gelucire® 48/16 and TPGS for its dissolution rate enhancement. Curcumin was dispersed in these molten lipidic surfactants which was then adsorbed on carrier and formulated as pellets by extrusion spheronization. Critical micelle concentration (CMC) of binary mixture of Gelucire® 48/16 and TPGS was lower than their individual CMC demonstrating the synergistic behavior of mixture. Thermodynamic parameters like partition coefficient and Gibbs free energy of solubilization indicated that mixed micelles were more efficient than micelles of its individual components in curcumin solubilization. Dynamic light scattering (DLS) suggested slight increase in micellar size of mixed micelles than its components suggesting curcumin loading in mixed micelles. Fourier transform infrared spectroscopy (FTIR) revealed that phenolic hydroxyl group interacts with lipids which contribute to its enhanced solubility. Furthermore, the differential scanning calorimetry (DSC) and X-ray diffraction (XRD) study indicated the conversion of crystalline curcumin into amorphous form. In the pellet formulation, Gelucire® 48/16 acted as a binder and eliminated the requirement of additional binder. Microcrystalline cellulose (MCC) forms wet mass and retards the release of curcumin from pellets. Increase in concentration of water-soluble diluent increased drug release. The optimized formulation released more than 90% drug and maintains supersaturation level of curcumin for 2 h. Thus, mixed micellar system was effective delivery system for curcumin while pellet formulation is an interesting formulation strategy consisting semi-solid lipids.

Vitamin E succinate with multiple functions: A versatile agent in nanomedicine-based cancer therapy and its delivery strategies

Vitamin E succinate (VES), a succinic acid ester of vitamin E, is one of the most effective anticancer compounds of the vitamin E family. VES can inhibit tumor growth by multiple pathways mainly involve tumor proliferation inhibition, apoptosis induction, and metastasis prevention. More importantly, the mitochondrial targeting and damaging property of VES endows it with great potential in exhibiting synergetic effect with conventional chemotherapeutic drugs and overcoming multidrug resistance (MDR). Given the lipophilicity of VES that hinders its bioavailability and therapeutic activity, nanotechnology with multiple advantages has been widely explored to deliver VES and opened up new avenues for its in vivo application. This review aims to introduce the anticancer mechanisms of VES and summarize its delivery strategies using nano-drug delivery systems. Specifically, VES-based combination therapy for synergetic anticancer effect, MDR-reversal, and oral chemotherapy improvement are highlighted. Finally, the challenges and perspectives are discussed.

Exploring the potential of functional polymer-lipid hybrid nanoparticles for enhanced oral delivery of paclitaxel

Most biopharmaceutics classification system (BCS) class IV drugs, with poor solubility and inferior permeability, are also substrates of P-glycoprotein (P-gp) and cytochrome P450 (CYP450), leading to their low oral bioavailability. The objective of this study is to explore the potential of using functional polymer-lipid hybrid nanoparticles (PLHNs) to enhance the oral absorption of BCS IV drugs. In this paper, taking paclitaxel (PTX) as a drug model, PTX-loaded PLHNs were prepared by a self-assembly method. Chitosan was selected to modify the PLHN to enhance its mucoadhesion and stability. Three P-gp inhibitors (D-α-tocopherol polyethylene glycol 1000 succinate, pluronic P123 and Solutol^Ⓡ HS15) were incorporated into selected PLHNs, and a CYP450 inhibitor (the extract of VBRB, BC0) was utilized to jointly promote the drug absorption. Properties of all the PLHNs were characterized systemically, including particle size, zeta potential, encapsulation efficiency, morphology, stability, in vitro drug release, mucoadhesion, in situ intestinal permeability and in vivo systemic exposure. It was found mucoadhesion of the CS-modified PLHNs was the strongest among all the formulations tested, with absolute bioavailability 21.95%. P-gp and CYP450 inhibitors incorporation further improved the oral bioavailability of PTX to 42.60%, 8-fold increase compared with that of PTX itself (4.75%). Taken together, our study might shed light on constructing multifunctional PLHNs based on drug delivery barriers for better oral absorption, especially for BCS IV drugs.

Mixed micelles for enhanced oral bioavailability and hypolipidemic effect of liquiritin: preparation, in vitro and in vivo evaluation

OBJECTIVES

Liquiritin, as one of the main flavonoids in Glycyrrhiza, exhibits extensive pharmacological effects, such as the anti-oxidant, anti-inflammatory, anti-tumor and so on. Herein, the aqueous solubility and oral bioavailability of liquiritin was purposely enhanced via the preparation of the mixed micelles.

METHODS

The liquiritin-loaded micelles (LLM) were fabricated via thin-film dispersion method. The optimal LLM formulation was evaluated through physical properties including particle size (PS), encapsulation efficiency (EE) and drug loading (DL). In vitro accumulate release as well as in vivo pharmacokinetics were also evaluated. Moreover, the hypolipidemic activity of LLM was observed in the hyperlipidemia mice model.

RESULTS

The LLM exhibited a homogenous spherical shape with small mean PS, good stability and high encapsulation efficiency. The accumulate release rates in vitro of the LLM were obviously higher than free liquiritin. The oral bioavailability of the formulation was heightened by 3.98 times in comparison with the free liquiritin. More importantly, LLM increased the hypolipidemic and effect of alleviating lipid metabolism disorder in hepatocytes of liquiritin in hyperlipidemia mice model.

CONCLUSIONS

Collectively, the improved solubility of liquiritin in water coupled with its enhanced oral bioavailability and concomitant hypolipidemic activity could be attributed to the incorporation of the drug into the mixed micelles.

Galactosamine-modified PEG-PLA/TPGS micelles for the oral delivery of curcumin

In this study, galactosamine-modified poly(ethylene glycol)-poly(lactide) (Gal-PEG-PLA) polymers were synthesized and Gal-PEG-PLA/D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) micelles named as GPP micelles were designed to promote the oral absorption of a hydrophobic drug, curcumin (CUR). CUR-loaded Gal-PEG-PLA/TPGS micelles (CUR@GPP micelles) were fabricated using the thin-film dispersion method. CUR@GPP micelles had a size of about 100 nm, a near-neutral zeta potential, drug loading (DL) of 14.6%, and sustained release properties. GPP micelles with high Gal density (GPP3 micelles) were superior in facilitating uptake in epithelial cells and improving intestinal permeation. In situ intestinal absorption studies suggested that the jejunum and ileum were the best absorption segments in the intestinal tract. Additionally, biodistribution results revealed that GPP3 micelles could be remarkably taken up by the jejunum and ileum. Pharmacokinetics revealed that the maximum plasma concentration (C_max) and the area under the plasma concentration-time curve from 0 to 24 h (AUC_0-24) for CUR@GPP3 micelles were both significantly increased, and that the relative bioavailability of CUR@GPP3 micelles to CUR-loaded mPEG-PLA/TPGS micelles (CUR@PP micelles) was 258.8%. Furthermore, CUR-loaded micelles could reduce damage to the liver and intestinal tissues. This study highlights the importance of Gal content in the design of targeting nanocarrier Gal-modified micelles, which have broad prospects for oral delivery of hydrophobic drugs. Therefore, they could serve as a promising candidate for targeted delivery to the liver.

Antiviral effect of phytochemicals from medicinal plants: Applications and drug delivery strategies

Viral infections affect three to five million patients annually. While commonly used antivirals often show limited efficacy and serious adverse effects, herbal extracts have been in use for medicinal purposes since ancient times and are known for their antiviral properties and more tolerable side effects. Thus, naturally based pharmacotherapy may be a proper alternative for treating viral diseases. With that in mind, various pharmaceutical formulations and delivery systems including micelles, nanoparticles, nanosuspensions, solid dispersions, microspheres and crystals, self-nanoemulsifying and self-microemulsifying drug delivery systems (SNEDDS and SMEDDS) have been developed and used for antiviral delivery of natural products. These diverse technologies offer effective and reliable delivery of medicinal phytochemicals. Given the challenges and possibilities of antiviral treatment, this review provides the verified data on the medicinal plants and related herbal substances with antiviral activity, as well as applied strategies for the delivery of these plant extracts and biologically active phytochemicals. Graphical Abstract.

Nanoformulations to Enhance the Bioavailability and Physiological Functions of Polyphenols

Polyphenols are micronutrients that are widely present in human daily diets. Numerous studies have demonstrated their potential as antioxidants and anti-inflammatory agents, and for cancer prevention, heart protection and the treatment of neurodegenerative diseases. However, due to their vulnerability to environmental conditions and low bioavailability, their application in the food and medical fields is greatly limited. Nanoformulations, as excellent drug delivery systems, can overcome these limitations and maximize the pharmacological effects of polyphenols. In this review, we summarize the biological activities of polyphenols, together with systems for their delivery, including phospholipid complexes, lipid-based nanoparticles, protein-based nanoparticles, niosomes, polymers, micelles, emulsions and metal nanoparticles. The application of polyphenol nanoparticles in food and medicine is also discussed. Although loading into nanoparticles solves the main limitation to application of polyphenolic compounds, there are some concerns about their toxicological safety after entry into the human body. It is therefore necessary to conduct toxicity studies and residue analysis on the carrier.

A composite nanocarrier to inhibit precipitation of the weakly basic drug in the gastrointestinal tract

For weakly basic drugs, the sharp decrease of drug solubility and the following drug precipitation after drugs transferring from the gastric fluid to the intestinal fluid in the gastrointestinal (GI) tract is a main reason for the poor oral bioavailability of drugs. Here, an anticoagulant dabigatran etexilate (DE) was used as a model drug, and a composite nanocarrier system of DE was developed to improve the drug dissolution by decreasing the drug leakage in the stomach and inhibiting the drug precipitation in the intestinal tract. With the encapsulation of drugs in nanocarriers, the precipitation percentage of DE in composite nanocarriers was 22.25 ± 3.88% in simulated intestinal fluid, which was far below that of the commercial formulation. Moreover, the relative bioavailability of DE-loaded composite nanocarriers (456.58%) was greatly enhanced and the peak of its activated partial thromboplastin time was also significantly prolonged (p < .01) compared with the commercial formulation, indicating that the anticoagulant effect of DE was effectively improved. Therefore, the designed composite nanocarrier system of DE presents great potentials in improving the therapeutic efficiency and expanding the clinical applications of poorly water-soluble weakly basic drugs.

Development of TPGS/F127/F68 mixed polymeric micelles: Enhanced oral bioavailability and hepatoprotection of syringic acid against carbon tetrachloride-induced hepatotoxicity

Syringic acid (SA), a natural polyphenol found in fruits and vegetables, is claimed to show notable hepatoprotection. Nevertheless, low solubility and bioavailability hamper the application of SA. This study aimed to investigate the potential of TPGS/F127/F68 mixed polymeric micelles as a sustained and liver-targeting nanocarrier for SA. Herein, the prepared SA-loaded TPGS/F127/F68 mixed polymeric micelles (SA-TPGS-Ms) were spherically-shaped and homogeneously-distributed nanoparticles with high entrapment efficiency (94.67 ± 2.05%) and sustained release. Besides, in-vitro cell culture studies revealed that SA-TPGS-Ms substantially promoted cellular uptake with excellent biocompatibility. After oral administration, SA-TPGS-Ms demonstrated an increased bioavailability (2.3-fold) and delayed in-vivo elimination compared with the free SA. Furthermore, the alleviation of oxidative stress and amelioration of hepatic injury in CCl₄-induced hepatotoxicity mice further demonstrated the excellent hepatoprotection of SA-TPGS-Ms. Collectively, SA-TPGS-Ms could be a promising nanocarrier for the utilization of SA in functional foods, with enhanced bioavailability and hepatoprotection.

Long-circulating zein-polysulfobetaine conjugate-based nanocarriers for enhancing the stability and pharmacokinetics of curcumin

Though curcumin has potential treatment value for most chronic diseases, it exerts little potency in the clinic because of its low aqueous solubility, high chemical instability and poor pharmacokinetics. To enhance its potency, we developed a zein-based micelle as a nanocarrier to encapsulate curcumin. Herein, superhydrophilic zwitterionic polymers, poly(sulfobetaine methacrylate) (PSBMA), were conjugated to zein to obtain an amphiphilic zein-PSBMA conjugate. These conjugates could self-assemble into micelles composed of antifouling PSBMA shells and zein cores. The results from the cytokine secretion assay showed that the micelles induced a low level of macrophage activation. Moreover, the results from the in vivo fluorescence imaging experiment confirmed their long-circulating property, exceeding 72 h in mice. In comparison with native curcumin, micelle-encapsulated curcumin had a 230-fold increase in stability in vitro, and its half-life was 22-fold longer, according to a pharmacokinetic study on mice. Overall, this work presents a zein-PSBMA micelle with a long circulation time as a useful nanocarrier for effective curcumin delivery.

Polymeric micelles loading with ursolic acid enhancing anti-tumor effect on hepatocellular carcinoma

Ursolic acid (UA) is widely found in many dietary plants, which has been proved to be effective in cancer therapy. But unfortunately its hydrophobic property limits its clinical application. Polymer micelles (PMs) are constructed from amphiphilic block copolymers that tend to self-assemble and form the unique core-shell structure consisting of a hydrophilic corona outside and a hydrophobic inner core. PMs could entrap the hydrophobic substance into its hydrophobic inner core for solubilizing these poorly water-soluble drugs and it is widely applied as a novel nano-sized drug delivery system. This study aimed to develop the drug delivery system of UA-loaded polymer micelles (UA-PMs) to overcome the disadvantages of UA in clinical application thus enhancing antitumor effect on hepatocellular carcinoma. UA-PMs was prepared and characterized for the physicochemical properties. It was investigated the cell-growth inhibition effect of UA-PMs against the human hepatocellular carcinoma cell line HepG2 and human normal liver cell line L-02. UA-PMs was evaluated about the in vivo toxicity and the antitumor activity. We took a diblock copolymer of methoxy poly (ethylene glycol)-poly(L-lactic acid) (mPEG-PLA) as carrier material to prepare UA-PMs by the thin-film dispersion method. MTT assay and wound-healing assay were investigated to assess the inhibition effect of UA-PMs against HepG2 cells on cell-growth and cell-migration. Further, we chose KM mice for the acute toxicity experiment and assessed the antitumor effect of UA-PMs on the H22 tumor xenograft. UA-PMs could markedly inhibit the proliferation and migration of HepG2 cells. In vivo study showed that UA-PMs could significantly inhibit the growth of H22 xenograft and prolong the survival time of tumor-bearing mice. It demonstrated that UA-PMs possess great potential in liver cancer therapy and may enlarge the application of UA in clinical therapy.

Preparation, In Vivo and In Vitro Release of Polyethylene Glycol Monomethyl Ether-Polymandelic Acid Microspheres Loaded Panax Notoginseng Saponins

In order to enrich the types of Panax notoginseng saponins (PNS) sustained-release preparations and provide a new research idea for the research and development of traditional Chinese medicine sustained-release formulations, a series of Panax notoginseng saponins microspheres was prepared by a double emulsion method using a series of degradable amphiphilic macromolecule materials polyethylene glycol monomethyl ether-polymandelic acid (mPEG-PMA) as carrier. The structure and molecular weight of the series of mPEG-PMA were determined by nuclear magnetic resonance spectroscopy (1 HNMR) and gel chromatography (GPC). The results of the appearance, particle size, drug loading and encapsulation efficiency of the drug-loaded microspheres show that the mPEG10000-PMA (1:9) material is more suitable as a carrier for loading the total saponins of Panax notoginseng. The particle size was 2.51 ± 0.21 μm, the drug loading and encapsulation efficiency were 8.54 ± 0.16% and 47.25 ± 1.64%, respectively. The drug-loaded microspheres were used for in vitro release and degradation experiments to investigate the degradation and sustained release behaviour of the drug-loaded microspheres. The biocompatibility of the microspheres was studied by haemolytic, anticoagulant and cytotoxicity experiments. The pharmacological activity of the microspheres was studied by anti-inflammatory and anti-tumour experiments. The results showed that the drug-loaded microspheres could be released stably for about 12 days and degraded within 60 days. At the same time, the microspheres had good biocompatibility, anti-inflammatory and anti-tumour activities.

Preparation of ginsenoside compound-K mixed micelles with improved retention and antitumor efficacy

Introduction

Ginsenoside compound K (CK) has effects on cell-cycle regulation, tumor growth inhibition, and apoptosis induction. However, it has limited applications in clinical settings because of its low solubility and poor absorption.

Methods

To overcome these limitations, we aimed to develop a mixed micellar system composed of phosphatidylcholine (PC) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine polyethylene glycol 2000 (DSPE PEG 2000; DP). CK encapsulated in PC/DP mixed micelles had enhanced solubility, permeability, and retention effects.

Results

Compared to free CK, the CK PC/DP micellar system exhibited improved anticancer effects in vitro, including cell-cycle arrest, apoptosis, and anti-invasion in human lung carcinoma A549 cells. The significant proapoptotic effect was reflected by increased chromosomal condensation, annexin V/propidium iodide staining, and related protein expression. In vitro cellular uptake and optical mouse imaging in vivo suggested that the improved antitumor effect was caused primarily by enhanced uptake and tumor targeting. Furthermore, an in vivo antitumor efficacy study indicated that the CK mixed micelles significantly inhibited tumor growth, thereby decreasing tumor volume at the end of the experiment as compared with that in the control mice. Histological analysis confirmed the antitumor effect with low toxicity.

Conclusion

The PC/DP micellar system was an effective drug delivery system for CK in tumor therapy.

Mixed micellar system stabilized with saponins for oral delivery of vitamin K

Poorly soluble vitamin K cannot be absorbed by patients suffering from cholestasis due to extremely low level of bile salts in the intestine. A formulation of vitamin K including glycocholic acid (i.e. Konakion® MM), does not increase bioavailability because it is unstable due to protonation of glycocholic acid at gastric pH. To develop a stable formulation, saponins were introduced as neutral surfactants to (partly) replace glycocholic acid. Experimental design was made to investigate the effect of the composition on particle size at neutral pH and upon acidification at pH 1.5. Two formulations that were within the optimized composition window were loaded with vitamin K and those showed superior stability at low pH as compared to Konakion® MM: sizes were between 43 and 46 nm at pH 7.3 and between 46 and 58 nm after 1 h incubation at pH 1.5, respectively, but large aggregates were formed at pH 1.5 in presence of Konakion® MM. Micelles were cytocompatible with Caco-2 cells at concentration of surfactants (saponins and glycocholic acid) up to 0.15 mg/ml. Uptake of vitamin K by Caco-2 cells was 4.2-4.9 nmol/mg protein for saponins-containing formulations and 7.1 nmol/mg protein for Konakion® MM. This, together with the superior stability at low pH, makes saponins-containing mixed micelles promising oral formulations for vitamin K.

Development of Chitosan-Based pH-Sensitive Polymeric Micelles Containing Curcumin for Colon-Targeted Drug Delivery

pH-sensitive N-naphthyl-N,O-succinyl chitosan (NSCS) and N-octyl-N,O-succinyl chitosan (OSCS) polymeric micelles carriers have been developed to incorporate curcumin (CUR) for colon-targeted drug delivery. The physical entrapment methods (dialysis, co-solvent evaporation, dropping, and O/W emulsion) were applied. The CUR-loaded micelles prepared by the dialysis method presented the highest loading capacity. Increasing initial amount of CUR from 5 to 40 wt% to polymer resulted in the increase in loading capacity of the polymeric micelles. Among the hydrophobic cores, there were no significant differences in the loading capacity of CUR-loaded micelles. The particle sizes of all CUR-loaded micelles were in the range of 120-338 nm. The morphology of the micelles changed after being contacted with medium with different pH values, confirming the pH-responsive properties of the micelles. The release characteristics of curcumin from all CUR-loaded micelles were pH-dependent. The percent cumulative release of curcumin from all CUR-loaded micelles in simulated gastric fluid (SGF) was limited to about 20%. However, the release amount was significantly increased after contacted with simulated intestinal fluid (SIF) (50-55%) and simulated colonic fluid (SCF) (60-70%). The released amount in SIF and SCF was significantly greater than the release of CUR from CUR powder. CUR-loaded NSCS exhibited the highest anti-cancer activity against HT-29 colorectal cancer cells. The stability studies indicated that all CUR-loaded micelles were stable for at least 90 days. Therefore, the colon targeted, pH-sensitive NSCS micelles may have potential to be a prospective candidate for curcumin delivery to the colon.

Preparation and in vitro and in vivo evaluation of quercetin-loaded mixed micelles for oral delivery

Quercetin (QT) is a plant polyphenol with various pharmacological properties. However, the low water solubility limits its therapeutic efficacy. In the present study, QT-loaded sodium taurocholate-Pluronic P123 (QT-loaded ST/P123) mixed micelles were developed and characterized, and the effect of the formulation on improving the water solubility of QT was investigated. QT-loaded ST/P123 mixed micelles were prepared by thin film hydration-direct dissolution and optimized by uniform design. The optimal formulation possessed high drug loading (12.6%) and entrapment efficiency (95.9%) in small (16.20 nm) spherically-shaped micelles. A low critical micelle concentration indicated that the micelles were stable, and they showed a sustained release pattern, as determined in vitro in simulated gastric fluid and intestinal fluid. Pharmacokinetic evaluation showed the Cmax and AUC0–24 were 1.8-fold and 1.6-fold higher than the QT suspension. The present results indicate that QT-loaded ST/P123 micelles are potential candidates to improve the solubility and oral bioavailability of QT.

Recent Advances in the Application of Vitamin E TPGS for Drug Delivery

D-ɑ-tocopheryl polyethylene glycol succinate (Vitamin E TPGS or TPGS) has been approved by FDA as a safe adjuvant and widely used in drug delivery systems. The biological and physicochemical properties of TPGS provide multiple advantages for its applications in drug delivery like high biocompatibility, enhancement of drug solubility, improvement of drug permeation and selective antitumor activity. Notably, TPGS can inhibit the activity of ATP dependent P-glycoprotein and act as a potent excipient for overcoming multi-drug resistance (MDR) in tumor. In this review, we aim to discuss the recent advances of TPGS in drug delivery including TPGS based prodrugs, nitric oxide donor and polymers, and unmodified TPGS based formulations. These potential applications are focused on enhancing delivery efficiency as well as the therapeutic effect of agents, especially on overcoming MDR of tumors. It also demonstrates that the clinical translation of TPGS based nanomedicines is still faced with many challenges, which requires more detailed study on TPGS properties and based delivery system in the future.