Molecular complexation of curcumin with pH sensitive cationic copolymer enhances the aqueous solubility, stability and bioavailability of curcumin

Nanotechnology-empowered therapeutics targeting neurodegenerative diseases

Neurodegenerative diseases are posing pressing health issues due to the high prevalence among aging populations in the 21st century. They are evidenced by the progressive loss of neuronal function, often associated with neuronal necrosis and many related devastating complications. Nevertheless, effective therapeutical strategies to treat neurodegenerative diseases remain a tremendous challenge due to the multisystemic nature and limited drug delivery to the central nervous system. As a result, there is a pressing need to develop effective alternative therapeutics to manage the progression of neurodegenerative diseases. By utilizing the functional reconstructive materials and technologies with specific targeting ability at the nanoscale level, nanotechnology-empowered medicines can transform the therapeutic paradigms of neurodegenerative diseases with minimal systemic side effects. This review outlines the current applications and progresses of the nanotechnology-enabled drug delivery systems to enhance the therapeutic efficacy in treating neurodegenerative diseases. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Advances in the development of amorphous solid dispersions: The role of polymeric carriers

Amorphous solid dispersion (ASD) is one of the most effective approaches for delivering poorly soluble drugs. In ASDs, polymeric materials serve as the carriers in which the drugs are dispersed at the molecular level. To prepare the solid dispersions, there are many polymers with various physicochemical and thermochemical characteristics available for use in ASD formulations. Polymer selection is of great importance because it influences the stability, solubility and dissolution rates, manufacturing process, and bioavailability of the ASD. This review article provides a comprehensive overview of ASDs from the perspectives of physicochemical characteristics of polymers, formulation designs and preparation methods. Furthermore, considerations of safety and regulatory requirements along with the studies recommended for characterizing and evaluating polymeric carriers are briefly discussed.

Fabrication of glycated yeast cell protein via Maillard reaction for delivery of curcumin: improved environmental stability, antioxidant activity, and bioaccessibility

BACKGROUND

The application of curcumin (CUR) in the food industry is limited by its instability, hydrophobicity and low bioavailability. Yeast cell protein (YCP) is a by-product of spent brewer's yeast, which has the potential to deliver bioactive substances. However, the environmental stresses such as pH, salt and heat treatment has restricted its application in the food industry. Maillard reaction as a non-enzymatic browning reaction can improve protein stability under environmental stress.

RESULTS

The CUR was successfully encapsulated into the hydrophobic core of YCP/glycated YCP (GYCP) and enhanced by hydrogen bonding, resulting in static fluorescence quenching of YCP/GYCP. The average diameter and dispersibility of GYPC-CUR nanocomplex were significantly improved after glucose glycation (121.40 nm versus 139.70 nm). Moreover, the encapsulation capacity of CUR was not influenced by glucose glycation. The oxidative stability and bioaccessibility of CUR in nanocomplexes were increased compared with free CUR, especially complexed with GYCP conjugates.

CONCLUSION

Steric hindrance provided by glucose conjugation improved the enviriomental stability, oxidative activity and bioaccessibility of CUR in nanocomplexes. Thus, glucose-glycated YCP has potential application as a delivery carrier for hydrophobic compounds in functional foods. © 2022 Society of Chemical Industry.

Curcumin in the treatment of liver cancer: From mechanisms of action to nanoformulations

Liver cancer is the sixth most prevalent cancer and ranks third in cancer-related death, after lung and colorectal cancer. Various natural products have been discovered as alternatives to conventional cancer therapy strategies, including radiotherapy, chemotherapy, and surgery. Curcumin (CUR) with antiinflammatory, antioxidant, and antitumor activities has been associated with therapeutic benefits against various cancers. It can regulate multiple signaling pathways, such as PI3K/Akt, Wnt/β-catenin, JAK/STAT, p53, MAPKs, and NF-ĸB, which are involved in cancer cell proliferation, metastasis, apoptosis, angiogenesis, and autophagy. Due to its rapid metabolism, poor oral bioavailability, and low solubility in water, CUR application in clinical practices is restricted. To overcome these limitations, nanotechnology-based delivery systems have been applied to use CUR nanoformulations with added benefits, such as reducing toxicity, improving cellular uptake, and targeting tumor sites. Besides the anticancer activities of CUR in combating various cancers, especially liver cancer, here we focused on the CUR nanoformulations, such as micelles, liposomes, polymeric, metal, and solid lipid nanoparticles, and others, in the treatment of liver cancer.

Development of Gastroretentive Carriers for Curcumin-Loaded Solid Dispersion Based on Expandable Starch/Chitosan Films

Curcumin, a polyphenolic extract from the rhizomes of turmeric, exhibits antioxidant, anti-inflammatory, and anticancer activities, which are beneficial for the treatment of gastric diseases. However, curcumin's therapeutic usefulness is restricted by its low aqueous solubility and short gastric residence time. In this study, curcumin-loaded solid dispersion (ratio 1:5) was prepared using Eudragit^® EPO (Cur EPO-SD), resulting in an approximately 12,000-fold increase in solubility to 6.38 mg/mL. Expandable films incorporating Cur EPO-SD were subsequently prepared by solvent casting using different types of starch (banana, corn, pregelatinized, and mung bean starch) in combination with chitosan. Films produced from banana, corn, pregelatinized and mung bean starch unfolded and expanded upon exposure to simulated gastric medium, resulting in sustained release of 80% of the curcumin content within 8 h, whereas films based on pregelatinized starch showed immediate release characteristics. Curcumin-loaded expandable films based on different types of starch exhibited similar cytotoxic effects toward AGS cells and more activity than unformulated curcumin. Furthermore, the films resulted in increased anti-inflammatory activity against RAW 264.7 macrophage cells compared with the NSAID, indomethacin. These findings demonstrate the potential of expandable curcumin-loaded films as gastroretentive dosage forms for the treatment of gastric diseases and to improve oral bioavailability.

Unravelling the Therapeutic Potential of Nano-Delivered Functional Foods in Chronic Respiratory Diseases

Chronic inflammation of the respiratory tract is one of the most concerning public health issues, as it can lead to chronic respiratory diseases (CRDs), some of which are more detrimental than others. Chronic respiratory diseases include chronic obstructive pulmonary disease (COPD), asthma, lung cancer, and pulmonary fibrosis. The conventional drug therapies for the management and treatment of CRDs only address the symptoms and fail to reverse or recover the chronic-inflammation-mediated structural and functional damage of the respiratory tract. In addition, the low efficacy and adverse effects of these drugs have directed the attention of researchers towards nutraceuticals in search of potential treatment strategies that can not only ameliorate CRD symptoms but also can repair and reverse inflammatory damage. Hence, there is a growing interest toward investigating the medicinal benefits of nutraceuticals, such as rutin, curcumin, zerumbone, and others. Nutraceuticals carry many nutritional and therapeutic properties, including anti-inflammatory, antioxidant, anticancer, antidiabetic, and anti-obesity properties, and usually do not have as many adverse effects, as they are naturally sourced. Recently, the use of nanoparticles has also been increasingly studied for the nano drug delivery of these nutraceuticals. The discrete size of nanoparticles holds great potential for the level of permeability that can be achieved when transporting these nutraceutical compounds. This review is aimed to provide an understanding of the use of nutraceuticals in combination with nanoparticles against CRDs and their mechanisms involved in slowing down or reversing the progression of CRDs by inhibiting pro-inflammatory signaling pathways.

Niclosamide-loaded nanoparticles disrupt Candida biofilms and protect mice from mucosal candidiasis

Candida albicans biofilms are a complex multilayer community of cells that are resistant to almost all classes of antifungal drugs. The bottommost layers of biofilms experience nutrient limitation where C. albicans cells are required to respire. We previously reported that a protein Ndu1 is essential for Candida mitochondrial respiration; loss of NDU1 causes inability of C. albicans to grow on alternative carbon sources and triggers early biofilm detachment. Here, we screened a repurposed library of FDA-approved small molecule inhibitors to identify those that prevent NDU1-associated functions. We identified an antihelminthic drug, Niclosamide (NCL), which not only prevented growth on acetate, C. albicans hyphenation and early biofilm growth, but also completely disengaged fully grown biofilms of drug-resistant C. albicans and Candida auris from their growth surface. To overcome the suboptimal solubility and permeability of NCL that is well known to affect its in vivo efficacy, we developed NCL-encapsulated Eudragit EPO (an FDA-approved polymer) nanoparticles (NCL-EPO-NPs) with high niclosamide loading, which also provided long-term stability. The developed NCL-EPO-NPs completely penetrated mature biofilms and attained anti-biofilm activity at low microgram concentrations. NCL-EPO-NPs induced ROS activity in C. albicans and drastically reduced oxygen consumption rate in the fungus, similar to that seen in an NDU1 mutant. NCL-EPO-NPs also significantly abrogated mucocutaneous candidiasis by fluconazole-resistant strains of C. albicans, in mice models of oropharyngeal and vulvovaginal candidiasis. To our knowledge, this is the first study that targets biofilm detachment as a target to get rid of drug-resistant Candida biofilms and uses NPs of an FDA-approved nontoxic drug to improve biofilm penetrability and microbial killing.

Curcuminoid Co-Loading Platinum Heparin-Poloxamer P403 Nanogel Increasing Effectiveness in Antitumor Activity

Nanosized multi-drug delivery systems provide synergistic effects between drugs and bioactive compounds, resulting in increased overall efficiency and restricted side effects compared to conventional single-drug chemotherapy. In this study, we develop an amphiphilic heparin-poloxamer P403 (HP403) nanogel that could effectively co-load curcuminoid (Cur) and cisplatin hydrate (CisOH) (HP403@CisOH@Cur) via two loading mechanisms. The HP403 nanogels and HP403@CisOH@Cur nanogels were closely analyzed with 1H-NMR spectroscopy, FT-IR spectroscopy, TEM, and DLS, exhibiting high stability in spherical forms. In drug release profiles, accelerated behavior of Cur and CisOH at pH 5.5 compared with neutral pH was observed, suggesting effective delivery of the compounds in tumor sites. In vitro studies showed high antitumor activity of HP403@CisOH@Cur nanogels, while in vivo assays showed that the dual-drug platform prolonged the survival time of mice and prevented tail necrosis. In summary, HP403@CisOH@Cur offers an intriguing strategy to achieve the cisplatin and curcumin synergistic effect in a well-designed delivery platform that increases antitumor effectiveness and overcomes undesired consequences caused by cisplatin in breast cancer treatment.

Mechanistic Insight into the Effects of Curcumin on Neuroinflammation-Driven Chronic Pain

Chronic pain is a persistent and unremitting condition that has immense effects on patients' quality of life. Studies have shown that neuroinflammation is associated with the induction and progression of chronic pain. The activation of microglia and astrocytes is the major hallmark of spinal neuroinflammation leading to neuronal excitability in the projection neurons. Excessive activation of microglia and astrocytes is one of the major contributing factors to the exacerbation of pain. However, the current chronic pain treatments, mainly by targeting the neuronal cells, remain ineffective and unable to meet the patients' needs. Curcumin, a natural plant product found in the Curcuma genus, improves chronic pain by diminishing the release of inflammatory mediators from the spinal glia. This review details the role of curcumin in microglia and astrocytes both in vitro and in vivo and how it improves pain. We also describe the mechanism of curcumin by highlighting the major glia-mediated cascades in pain. Moreover, the role of curcumin on inflammasome and epigenetic regulation is discussed. Furthermore, we discuss the strategies used to improve the efficacy of curcumin. This review illustrates that curcumin modulating microglia and astrocytes could assure the treatment of chronic pain by suppressing spinal neuroinflammation.

In vitro and in vivo Study of a Novel Liposome-Mediated Dual Drug Delivery for Synergistic Lung Cancer Therapy via Oral Administration

Background

To establish the co-delivery liposomes of gefitinib (GFT) and curcumin (CUR) via oral administration with the goals of improving the synergistic effect and reducing acquired drug resistance.

Methods

We prepared liposomes (LPs) which can embed the anticancer compound GFT and CUR and investigated whether they could enhance the antitumor effects of anticancer drugs against MDR. The LPs system was characterized by transmission electron microscopy (TEM), particle size, encapsulation efficiency, cellular uptake and cell viability. In addition, the release characteristics and pharmacodynamics of the LPs were also studied in detail.

Results

The results showed that GFT/CUR LPs were characterized by small particle size of about 130 nm and negative zeta potential of about −22.2 mV, and the drug controlled to release slowly on a biphasic pattern. Compared with control groups, GFT/CUR LPs showed a higher cellular uptake and cell inhibition rates. Through pharmacodynamics analysis, we found that two compounds (GFT and CUR) were incorporated into one LPs carrier, which played a good role in synergistic effect.

Conclusion

Co-delivery of GFT and CUR has the potential to improve cancer treatment efficacy and overcome acquired resistance, especially towards GFT-resistant cells.

Review of Curcumin Physicochemical Targeting Delivery System

Curcumin (CUR), as a traditional Chinese medicine monomer extracted from the rhizomes of some plants in Ginkgo and Araceae, has shown a wide range of therapeutic and pharmacological activities such as anti-tumor, anti-inflammatory, anti-oxidation, anti-virus, anti-liver fibrosis, anti-atherosclerosis, and anti-Alzheimer’s disease. However, some issues significantly affect its biological activity, such as low aqueous solubility, physico-chemical instability, poor bioavailability, and low targeting efficacy. In order to further improve its curative effect, numerous efficient drug delivery systems have been carried out. Among them, physicochemical targeting preparations could improve the properties, targeting ability, and biological activity of CUR. Therefore, in this review, CUR carrier systems are discussed that are driven by physicochemical characteristics of the microenvironment (eg, pH variation of tumorous tissues), affected by external influences like magnetic fields and vehicles formulated with thermo-sensitive materials.

Nanotechnology to improve the Alzheimer's disease therapy with natural compounds

Alzheimer's disease (AD) is a form of dementia with high impact worldwide, accounting with more than 46 million cases. It is estimated that the number of patients will be four times higher in 2050. The initial symptoms of AD are almost imperceptible and typically involve lapses of memory in recent events. However, the available medicines still focus on controlling the symptoms and do not cure the disease. Regarding the advances in the discovery of new treatments for this devastating disease, natural compounds are gaining increasing relevance in the treatment of AD. Nevertheless, they present some limiting characteristics such as the low bioavailability and the low ability to cross the blood-brain barrier (BBB) that hinder the development of effective therapies. To overcome these issues, the delivery of natural products by targeting nanocarriers has aroused a great interest, improving the therapeutic activity of these molecules. In this article, a review of the research progress on drug delivery systems (DDS) to improve the therapeutic activity of natural compounds with neuroprotective effects for AD is presented. Graphical abstract.

Formulation and Nanotechnology-Based Approaches for Solubility and Bioavailability Enhancement of Zerumbone

About 40–70% of drug molecules in the clinical development pipeline suffer from one of either low aqueous solubility, poor absorption, or extremely low bioavailability. Approximately 75% of the world population relies on traditional therapies and therefore there has been a growing interest in the utilization of natural compounds. Zerumbone is one such natural compound, classified as a sesquiterpenoid that is extracted from the essential volatile oils of rhizomes from Zingiber zerumbet. It possesses strong antitumor, antioxidant, antimicrobial, and anti-inflammatory activity. However, despite promising preclinical studies demonstrating the therapeutic utility of zerumbone, its clinical development has been limited due to its low aqueous solubility, poor absorption, or associated low bioavailability. Multiple reviews demonstrating the pharmacological effects of zerumbone for various diseases have been published. However, to our knowledge, no review demonstrates the various formulation strategies developed to overcome the biopharmaceutical challenges of zerumbone. The purpose of this review is to provide a comprehensive perspective on zerumbone as a molecule for formulation development. A section related to pharmacokinetics, toxicity, and patents of zerumbone is included. This review provides the importance of developing novel formulations of zerumbone to overcome its biopharmaceutical challenges thereby advance its potential in the treatment of various diseases.

Nobiletin as a Molecule for Formulation Development: An Overview of Advanced Formulation and Nanotechnology-Based Strategies of Nobiletin

Approximately 40% of compounds in clinical drug development suffer from solubility and bioavailability challenges. Evidence from literature demonstrates the growing interest to utilize flavonoids as potential compounds owing to their widespread therapeutic utility in various ailments. Nobiletin (NOB), one such dietary polymethoxylated flavonoid found in citrus fruits, has multiple pharmacological effects such as antioxidant, anti-microbial, anti-cancer, and anti-inflammatory. It is useful in cancer, inflammatory bowel diseases, atherosclerosis, obesity, and Alzheimer's disease. Although preclinical studies demonstrate the therapeutic utility of NOB, it suffers from serious biopharmaceutical limitations such as low aqueous solubility (below 1 μg/ml), poor permeability across biological barriers, and low bioavailability. To overcome these biopharmaceutical challenges associated with NOB, the use of advanced formulations and nanotechnology-based strategies appears to be a promising approach to potentiate its therapeutic action. Multiple reviews cover the various therapeutic benefits of NOB in various diseases; however, there is an absence of a comprehensive review that focuses on the formulation development strategies of NOB. The purpose of this review is to provide a concise perspective on NOB as a candidate molecule for formulation development. The manuscript covers various aspects related to NOB, such as its chemistry, physicochemical properties, and pharmacological effects. This is also a thorough review of various formulation development strategies with advances made in the past years to improve the solubility, bioavailability, and therapeutic efficacy of NOB. The review also contains information related to toxicity and patents involving NOB and its formulation.

Developmental Strategies of Curcumin Solid Dispersions for Enhancing Bioavailability

BACKGROUND

Although curcumin has been demonstrated to be beneficial in treating various diseases, its low solubility, chemical stability and bioavailability limit its application, especially in cancer therapy.

METHODS

Solid dispersions have been utilized in the last few decades to improve the bioavailability and stability of curcumin.

RESULTS

However, there is a lack of summaries and classifications of the methods for preparing curcumin with this technology. The current review aims to overview the strategies used to develop solid dispersions containing curcumin for improving drug delivery. The classification of techniques for creating solid dispersions for curcumin was summarized, including systems for protecting curcumin degradation despite its chemical stability. The applications of advanced nanotechnologies in recent studies of solid dispersions were also discussed to explain the roles of nanoparticles in formulations.

CONCLUSION

This overview of recent developments in formulating solid dispersions for improving curcumin bioavailability will contribute to future studies of curcumin for clinical development.

Synthesis and Biological Evaluations of Monocarbonyl Curcumin Inspired Pyrazole Analogues as Potential Anti-Colon Cancer Agent

Purpose

The monocarbonyl analogs of curcumin (MCACs) have been widely studied for their promising antitumor activity. Pyrazole is a five-membered aromatic heterocyclic system with various bioactivities incorporated frequently in drugs. However, few of MCACs inspired pyrazole analogues were investigated. To search for more potent cytotoxic agents based on MCACs, a series of new 1,5-diaryl/heteroaryl-1,4-pentadien-3-ones inspired pyrazole moiety was synthesized and evaluated on their anti-colon cancer activities.

Methods

Fifteen new compounds were synthesized and characterized by spectral datum, and then they were tested preliminarily by MTT assay for their cytotoxic activities against a panel of four human cancer cell lines, namely, gastric (SGC-7901), liver (HepG2), lung (A549), and colon (SW620) cancer cells. Compound 7h exhibited excellent selectivity and outstanding anti-proliferation activity against SW620 cells among these 15 compounds. Further, the mechanisms were investigated by transwell migration and invasion assay, clonogenic assay, cell apoptosis analysis, cell cycle analysis, Western blot analysis.

Results

The IC₅₀ value of 7h against SW620 cells was 12 nM, being more potent than curcumin (IC₅₀ = 9.36 μM), adriamysin (IC₅₀ = 3.28 μM) and oxaliplatin (IC₅₀ = 13.33 μM). Further assays showed that 7h inhibited SW620 cell migration, invasion and colony formation obviously, which was due to its ability to induce cell cycle arrest in the G2/M and S phases and apoptosis. Western blot assay revealed that 7h decreased the protein expression of ATM gene, which may primarily contribute to its anticancer activity against SW620 cells.

Conclusion

A new MCACs 7h was synthesized and found to exhibit excellent anti-proliferation activity against SW620 cells. Further studies indicated that 7h exerted its anticancer activity against SW620 cells probably via decreasing the ATM protein expression. The present study suggested that 7h was a promising candidate as an anti-colon cancer drug for future development.

Combination Therapy of Lung Cancer Using Layer-by-Layer Cisplatin Prodrug and Curcumin Co-Encapsulated Nanomedicine

Purpose

Lung cancer remains the leading cancer-associated deaths worldwide. Cisplatin (CDDP) was used in combination with curcumin (CUR) for the treatment of non-small cell lung cancer. The aim of this study was to prepare and characterize CDDP prodrug and CUR co-encapsulated layer-by-layer nanoparticles (CDDP-PLGA/CUR LBL NPs) to induce cooperative response, maximize the therapeutic effect, overcome drug resistance, and reduce adverse side effects.

Methods

CDDP prodrug (CDDP-PLGA) was synthesized. CDDP-PLGA/CUR LBL NPs were constructed and their physicochemical properties were investigated by particle-size analysis, zeta potential measurement, drug loading, drug entrapment efficiency, and in vitro drug release behavior. In vitro cytotoxicity against human lung adenocarcinoma cell line (A549 cells) was investigated, and in vivo anti-tumor efficiency of CDDP-PLGA/CUR LBL NPs was evaluated on mice bearing A549 cell xenografts.

Results

CDDP-PLGA/CUR LBL NPs have a size of 179.6 ± 6.7 nm, a zeta potential value of −29.9 ± 3.2 mV, high drug entrapment efficiency of 85.6 ± 3.9% (CDDP) and 82.1 ± 2.8% (CUR). The drug release of LBL NPs exhibited a sustained behavior, which made it an ideal vehicle for drug delivery. Furthermore, CDDP-PLGA/CUR LBL NPs could significantly enhance in vitro cytotoxicity and in vivo antitumor effect against A549 cells and lung cancer animal model compared to the single drug-loaded LBL NPs and free drug groups.

Conclusion

CDDP-PLGA/CUR LBL NPs were reported for the first time in the combination therapy of lung cancer. The results demonstrated that the CDDP-PLGA/CUR LBL NPs might be a novel promising system for the synergetic treatment of lung carcinoma.

Self-Microemulsifying Drug Delivery System for Improved Oral Delivery and Hypnotic Efficacy of Ferulic Acid

Purpose

Ferulic acid (FA) is a natural compound which is used to treat insomnia. However, its use is limited because of its poor oral bioavailability caused by extremely rapid elimination. The current study aimed to develop a self-microemulsifying drug delivery system (SMEDDS) to improve the oral delivery of FA and to enhance its hypnotic efficacy.

Methods

FA-SMEDDS was prepared, and its morphology and storage stability were characterized. The formulation was also subjected to pharmacokinetic and tissue distribution studies in rats. The hypnotic efficacy of FA-SMEDDS was evaluated in p-chlorophenylalanine-induced insomnia mice.

Results

FA-loaded SMEDDS exhibited a small droplet size (15.24 nm) and good stability. Oral administration of FA-SMEDDS yielded relative bioavailability of 185.96%. In the kidney, SMEDDS decreased the distribution percentage of FA from 76.1% to 59.4% and significantly reduced its metabolic conversion, indicating a reduction in renal elimination. Interestingly, FA-SMEDDS showed a higher distribution in the brain and enhanced serotonin levels in the brain, which extended the sleep time by 2-fold in insomnia mice.

Conclusion

This is the first study to show that FA-loaded SMEDDS decreased renal elimination, enhanced oral bioavailability, increased brain distribution, and improved hypnotic efficacy. Thus, we have demonstrated that SMEDDS is a promising carrier which can be employed to improve the oral delivery of FA and facilitate product development for the therapy of insomnia.

Curcumin Inhibits the Tumorigenesis of Breast Cancer by Blocking Tafazzin/Yes-Associated Protein Axis

Purpose

This study was aimed to explore the anti-tumor effect of curcumin on breast cancer (BC) and the underlying mechanism involving Tafazzin (TAZ)/Yes-associated protein (YAP) axis.

Methods

Different concentrations of curcumin (0, 10, 20 and 30 μM) were used to treat BC cells (MCF-7 and MDA-MB-231 cells). The viability, colony formation, apoptosis, migration, and invasion of BC cells were detected by MTT, colony formation, flow cytometry, wound-healing and transwell assay, respectively. The protein expression of TAZ and YAP (effectors of Hippo signaling pathway) was detected by Western blot. MDA-MB-231 cells were injected into mice to verify the anti-tumor effect of curcumin in vivo.

Results

Curcumin (20 and 30 μM) inhibited the proliferation, migration and invasion, and promoted the apoptosis of MCF-7 and MDA-MB-231 cells. Curcumin decreased the protein expression of TAZ and YAP in MCF-7 and MDA-MB-231 cells. Overexpression of YAP reversed the anti-tumor effect of curcumin on MDA-MB-231 cells. In addition, curcumin (100, 200 and 300 mg/kg/d) inhibited the growth of tumor xenografts in mice, and down-regulated the protein expression of TAZ and YAP in tumor xenografts. However, curcumin at a concentration of 300 mg/kg/d slowed the increasing of body weight in mice.

Conclusion

Curcumin inhibited the tumorigenesis of BC by blocking TAZ/YAP axis.

Co-Delivery of Curcumin and Paclitaxel by "Core-Shell" Targeting Amphiphilic Copolymer to Reverse Resistance in the Treatment of Ovarian Cancer

Background

Ovarian cancer is a common malignancy in the female reproductive system with a high mortality rate. The most important reason is multidrug resistance (MDR) of cancer chemotherapy. To reduce side effects, reverse resistance and improve efficacy for the treatment of ovarian cancer, a “core-shell” polymeric nanoparticle-mediated curcumin and paclitaxel co-delivery platform was designed.

Methods

Nuclear magnetic resonance confirmed the successful grafting of polyethylenimine (PEI) and stearic acid (SA) (PEI-SA), which is designed as a mother core for transport carrier. Then, PEI-SA was modified with hyaluronic acid (HA) and physicochemical properties were examined. To understand the regulatory mechanism of resistance and measure the anti-tumor efficacy of the treatments, cytotoxicity assay, cellular uptake, P-glycoprotein (P-gp) expression and migration experiment of ovarian cancer cells were performed. In addition, adverse reactions of nanoformulation to the reproductive system were examined.

Results

HA-modified drug-loaded PEI-SA had a narrow size of about 189 nm in diameters, and the particle size was suitable for endocytosis. The nanocarrier could target specifically to CD44 receptor on the ovarian cancer cell membrane. Co-delivery of curcumin and paclitaxel by the nanocarriers exerts synergistic anti-ovarian cancer effects on chemosensitive human ovarian cancer cells (SKOV3) and multi-drug resistant variant (SKOV3-TR30) in vitro, and it also shows a good anti-tumor effect in ovarian tumor-bearing nude mice. The mechanism of reversing drug resistance may be that the nanoparticles inhibit the efflux of P-gp, inhibit the migration of tumor cells, and curcumin synergistically reverses the resistance of PTX to increase antitumor activity. It is worth noting that the treatment did not cause significant toxicity to the uterus and ovaries with the observation of macroscopic and microscopic.

Conclusion

This special structure of targeting nanoparticles co-delivery with the curcumin and paclitaxel can increase the anti-tumor efficacy without increasing the adverse reactions as a promising strategy for therapy ovarian cancer.

Comparative Effect Of Curcumin Versus Liposomal Curcumin On Systemic Pro-Inflammatory Cytokines Profile, MCP-1 And RANTES In Experimental Diabetes Mellitus

Purpose

Anti-inflammatory proprieties of curcumin were proved to be useful in various diseases, including diabetes mellitus. The aim of this study was to assess the anti-inflammatory comparative effect of curcumin solution with liposomal curcumin formula, regarding the improvement of serum levels of TNF-α (tumor necrosis factor-alpha), IL-6 (interleukin), IL-1α, IL-1β, MCP-1 (monocyte chemoattractant protein-1) and RANTES in experimental diabetes, induced by streptozotocin (STZ), in rats.

Materials and methods

Six groups of 7 rats were investigated regarding the effect of i.p. (intraperitoneal) administration of two concentrations of curcumin solution (CC1 and CC2) and two concentrations of liposomal curcumin (LCC1 and LCC2): group 1 – control group with i.p. administration of 1 mL saline solution, group 2 – i.p. STZ administration (60mg/kg bw, bw=body weight), group 3 – STZ+CC1 administration, group 4 – STZ+CC2 administration, group 5 – STZ+ LCC1 administration and group 6 – STZ+ LCC2 administration. The concentrations of curcumin formulas were 1 mg/0.1 kg bw for CC1 and LCC1 and 2 mg/0.1 kg bw for CC2 and LCC2, respectively. Serum levels of C-peptide (as an indicator of pancreatic function) and TNF-α, IL-6, IL-1α, IL-1β, MCP-1, and RANTES (as biomarkers for systemic inflammation) were assessed for each group.

Results

The plasma level of C-peptide showed significant improvements when LCC was administrated, with better results for LCC2 when compared to LCC1 (P<0.003). LCC2 pretreatment proved to be more efficient in reducing the level of TNF-α (P<0.003) and RANTES (P<0.003) than CC2 pretreatment. Upon comparing LCC2 with LCC1 formulas, the differences were significant for TNF-α (P=0.004), IL-1β (P=0.022), and RANTES (P=0.003) levels.

Conclusion

Liposomal curcumin in a dose of 2 mg/0.1 kg bw proved to have an optimum therapeutic effect as a pretreatment in DM induced by STZ. This result can constitute a base for clinical studies for curcumin efficiency as adjuvant therapy in type 1 DM.

Analysis of toxicity and anticancer activity of micelles of sodium alginate-curcumin

Background

Curcumin is a natural polyphenol with anti-inflammatory, chemopreventive and anticancer activity. However, its high hydrophobicity and poor bioavailability limit its medical application. The development of nanocarriers for curcumin delivery is an attractive approach to overcome its low bioavailability and fast metabolism in the liver. We synthesized a blood compatible alginate-curcumin conjugate, AA-Cur, which formed colloidally stable micelles of approximately 200 nm and, as previously shown, exerted strong cytotoxicity against mouse cancer cell lines. Here we analyze in vivo toxicity and antitumor activity of AA-Cur in two different mouse tumor models.

Method

Potential toxicity of intravenously injected AA-Cur was evaluated by: i) analyses of blood parameters (morphology and biochemistry), ii) histology, iii) DNA integrity (comet assay), and iv) cytokine profiling (flow cytometry). Antitumor activity of AA-Cur was evaluated by measuring the growth of subcutaneously inoculated colon MC38-CEA- or orthotopically injected breast 4T1 tumor cells in control mice vs mice treated with AA-Cur.

Results

Injections of four doses of AA-Cur did not reveal any toxicity of the conjugate, thus indicating the safety of its use. AA-Cur elicited moderate anti-tumor activity toward colon MC38-CEA or breast 4T1 carcinomas.

Conclusion

The tested conjugate of alginate and curcumin, AA-Cur, is non-toxic and safe, but exhibits limited anticancer activity.

Intermolecular Interactions between Drugs and Aminoalkyl Methacrylate Copolymer in Solution to Enhance the Concentration of Poorly Water-Soluble Drugs

An aminoalkyl methacrylate copolymer, Eudragit^® E (EUD-E), has gained tremendous attention as a solid dispersion carrier because it efficiently stabilizes drugs in the amorphous state. Furthermore, EUD-E remarkably enhances drug dissolution in water. This review focuses on the interaction between drugs and EUD-E in solution, which contributes to the enhancement of drug concentration. Studies examining interactions between acidic drugs and EUD-E in organic solvents have revealed that the interaction occurs predominantly by electrostatic interaction, including hydrogen bonding and dipolar interactions. Other studies on interactions in aqueous solution found evidence for strong electrostatic interactions between acidic drugs and EUD-E in ion exchange experiments. ¹H-NMR studies using high-resolution magic-angle spinning, nuclear Overhauser effect spectroscopy, diffusion, and relaxation time measurements successfully identified the interaction site and strength in aqueous solution. Hydrophobic and ionic interactions occurred between drugs and EUD-E. The conformation of EUD-E, which was affected by the ionic strength and pH of the aqueous media, also influenced the interaction. The knowledge discussed in this review will be helpful in designing solid dispersion formulations with EUD-E, which will efficiently enhance drug concentration and subsequent absorption into the body.

Methacrylate-Copolymer Eudragit EPO as a Solubility-Enabling Excipient for Anionic Drugs: Investigation of Drug Solubility, Intestinal Permeability, and Their Interplay

The purpose of this work was to investigate the use of the dimethylaminoethyl methacrylate-copolymer Eudragit EPO (EPO) in oral solubility-enabling formulations for anionic lipophilic drugs, aiming to guide optional formulation design and maximize oral bioavailability. We have studied the solubility, the permeability, and their interplay, using the low-solubility nonsteroidal anti-inflammatory drug mefenamic acid as a model drug. Then, we studied the biorelevant solubility enhancement of mefenamic acid from EPO-based formulations throughout the gastrointestinal tract (GIT), using the pH-dilution dissolution method. EPO allowed a profound and linear solubility increase of mefenamic acid, from 10 μg/mL without EPO to 9.41 mg/mL in the presence of 7.5% EPO (∼940-fold; 37 °C); however, a concomitant decrease of the drug permeability was obtained, both in vitro and in vivo in rats, indicating a solubility-permeability trade-off. In the absence of an excipient, the unstirred water layer (UWL) adjacent to the GI membrane was found to hinder the permeability of the drug, accounting for this UWL effect and revealing that the true membrane permeability allowed good prediction of the solubility-permeability trade-off as a function of EPO level using a direct relationship between the increased solubility afforded by a given EPO level and the consequent decreased permeability. Biorelevant dissolution studies revealed that EPO levels of 0.05 and 0.1% were insufficient to dissolve mefenamic acid dose during the entire dissolution time course, whereas 0.5 and 1% EPO allowed complete solubility with no drug precipitation. In conclusion, EPO may serve as a potent solubility-enabling excipient for BCS class II/IV acidic drugs; however, it should be used carefully. It is prudent to use the minimal EPO amounts just sufficient to dissolve the drug dose throughout the GIT and not more than that. Excess amounts of EPO provide no solubility gain and cause further permeability loss, jeopardizing the overall success of the formulation. This work may help the formulator to hit the optimal solubility-permeability balance, maximizing the oral bioavailability afforded by the formulation.

Determination and pharmacokinetic study of isothiouronium-modified pyrimidine-substituted curcumin analog (1G), a novel antitumor agent, in rat plasma by liquid chromatography-tandem mass spectrometry

1G, a novel derivative of curcumin, exhibits promising anticancer activities in various cancer cell lines. To support its further pharmacological studies, a liquid chromatography-tandem mass spectrometry method was developed and validated in accordance with FDA's Guidance. After extraction by protein precipitation, analytes were separated by a 4.5 min gradient elution (water/0.1% formic acid and methanol) on a reverse-phase C₁₈ column at 40 °C. The multiple reaction monitoring mode was used for quantification on a triple quadrupole mass spectrometer with positive ionization. The assay was linear over the concentration range of 5-1000 ng/mL with a correlation coefficient (r) greater than 0.99. Values of intra- and inter-day precision and accuracy were satisfactory, i.e. <10.1% for precision and within ± 14.5% for accuracy. No obvious matrix effect was observed. Recovery of the analyte was higher than 95.3%. 1G was stable during the whole analytic process. The validated method was successfully applied to the pharmacokinetic study of 1G after intravenous and intraperitoneal administration in rats. Favorable pharmacokinetic profiles were demonstrated, including good abdominal absorption (F = 62.58%), moderate clearance and high extravascular distribution. Results indicated that as a novel antitumor agent, 1G exhibited acceptable pharmacokinetic properties for further in vivo pharmacologic evaluation.

Co-Delivery of Eugenol and Dacarbazine by Hyaluronic Acid-Coated Liposomes for Targeted Inhibition of Survivin in Treatment of Resistant Metastatic Melanoma

While melanoma remains a challenge for oncologists, possibilities are being continuously explored to fight resistant metastatic melanoma more effectively. Eugenol is reported to inhibit survivin protein in breast cancer cells. Survivin is also overexpressed by melanoma cells, and is known to impart resistance to them against chemotherapy-induced apoptosis. To be able to fight resistant melanoma, we formulated hyaluronic acid (HA)-coated liposomes loaded with an effective combination of anti-melanoma agents (Dacarbazine and Eugenol), using a solvent injection method. Quality-by-Design (QbD) was applied to optimize and obtain a final formulation with the desired quality attributes, and within an acceptable size range. The optimized formulation was then subjected to performance analysis in cell lines. Coated-Dacarbazine Eugenol Liposomes were found to possess 95.08% cytotoxicity at a dacarbazine concentration of 0.5 µg/mL, while Dacarbazine Solution showed only 10.20% cytotoxicity at the same concentration. The number of late apoptotic cells was also found to be much higher (45.16% vs. 8.43%). Furthermore, migration assay and proliferation study also revealed significantly higher inhibition of cell migration and proliferation by Coated-Dacarbazine Eugenol Liposomes, signifying its potential against metastasis. Thus, surface-functionalized dacarbazine- and eugenol-loaded liposomes hold great promise against resistant and aggressive metastatic melanoma, with much less unwanted cytotoxicity and reduced doses of the chemotherapeutic agent.

Preparation, Characterization, and In vitro Evaluation of Curcumin- and Resveratrol-Loaded Solid Lipid Nanoparticles

Curcumin and resveratrol are natural compounds with significant anticancer activity; however, their bioavailability is limited due to poor solubility. This study aimed to overcome the solubility problem by means of solid lipid nanoparticles (SLN). 2-Hydroxypropyl β-cyclodextrin (HPβCD) was selected from a range of polymers based on miscibility and molecular interactions. SLNs were obtained by probe sonication and freeze-drying curcumin-resveratrol with/without HPβCD incorporated in gelucire 50/13. SLNs were characterized by dynamic light scattering (DLS), zeta potential, powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and physical stability. The in vitro release of drugs from the SLNs was performed by the direct dispersion method and analyzed using a validated UV-visible method. In vitro efficacy was tested using a colorectal cancer cell line. Curcumin-resveratrol-gelucire 50/13-HPβCD (CRG-CD) and curcumin-resveratrol-gelucire 50/13(CRG) SLNs showed a particle size from 100 to 150 nm and were not in the crystalline state per PXRD results. MDSC results complimented PXRD results by the absence of melting endotherm of curcumin; TGA showed no weight loss, confirming the absence of organic solvent residual, and the shape of the SLNs was confirmed as spherical by SEM. CRG SLNs were stable for 21 days with respect to particle size and zeta potential. MTT assay indicated better IC₅₀ value for CRG as compared to CRG-CD. Hence, novel SLNs of curcumin and resveratrol incorporated in gelucire 50/13 and HPβCD were prepared and characterized to improve their bioavailability and anticancer activity.

Novel self-nanomicellizing solid dispersion based on rebaudioside A: a potential nanoplatform for oral delivery of curcumin

Purpose

Rebaudioside A (RA) has nanocarrier characteristics that allow it to self-assemble into micelles in aqueous solutions. The purpose of this study was to determine if a self-nanomicellizing solid dispersion based on RA could be utilized as an oral nano-drug delivery system.

Materials and methods

Curcumin (Cur) served as a model hydrophobic drug, and a Cur-loaded self-nanomicellizing solid dispersion based on RA (RA-Cur) was formulated. The properties of RA-Cur in the solid state and in aqueous solution were characterized. The antioxidant activity and mechanism of RA-Cur endocytosis were also investigated. The pharmacokinetics, biodistribution in the intestinal tract, and anti-inflammation properties were also evaluated in vivo.

Results

RA-Cur could be easily fabricated, and it self-assembled into ultrasmall micelles (particle size ~4 nm) in a homogeneous distribution state (polydispersity index <0.2) when dissolved in water. Cur was readily encapsulated into RA micelles and this improved its water solubility (to 14.34±1.66 mg/mL), as well as its in vitro release and membrane permeability. The antioxidant activities of Cur in RA-Cur were also significantly improved. Biodistribution in the intestinal tract confirmed a significant enhancement of Cur absorption in the duodenum, jejunum, and ileum by encapsulation in RA-Cur, and the absorption of RA-Cur was governed by mixed transcytosis mechanisms. Pharmacokinetic tests of RA-Cur in rats revealed a dramatic 19.06-fold enhancement of oral bioavailability when compared to free Cur. More importantly, oral administration of RA-Cur could efficiently ameliorate ulcerative colitis in a mouse model induced by dextran sodium sulfate.

Conclusion

Self-nanomicellizing solid dispersions based on RA have great potential as novel oral nano-drug delivery systems for hydrophobic drugs such as Cur.

Effect of Piperine on Skin Permeation of Curcumin from a Bacterially Derived Cellulose-Composite Double-Layer Membrane for Transdermal Curcumin Delivery

Curcumin is a naturally occurring substance with various pharmacological activities. It has not been developed as a drug because of its low bioavailability due to its low solubility and absorption. Piperine is a natural enhancer that is popularly used to increase the absorption of curcumin in oral applications; however, it has not been applied for transdermal curcumin delivery. This study aims to develop a transdermal curcumin delivery system using piperine as a skin permeation enhancer in the form of composite double-layer membrane; the upper layer consisted of curcumin and the lower layer consisted of piperine. The amount of curcumin was fixed, but the amount of piperine varied at three levels from 1.96% to 7.41%. The composite membrane had moderate mechanical strength (15⁻22 MPa) with a good swelling degree (~435%). From an in vitro skin permeation study, piperine had the effect to increase the permeation of curcumin. The permeation rate was related to the amount of piperine. The composite membrane containing piperine at 7.41% could increase the permeation rate of curcumin by about 1.89 times compared with non-piperine contained membrane. Bacterially-derived cellulose containing curcumin and piperine may have the potential for transdermal curcumin delivery in order to improve curcumin's bioavailability.

Curcumin: pharmaceutical solids as a platform to improve solubility and bioavailability

The remarkable improvements in the pharmacokinetics and high bioavailability of curcumin polymorphs, amorphous, cocrystals, eutectics, and coamorphous solids are discussed. The importance of pharmaceutical solids in the advanced formulation development of herbal and bioactive molecule curcumin is presented.

Pathogen-mimicking vaccine delivery system designed with a bioactive polymer (inulin acetate) for robust humoral and cellular immune responses

New and improved vaccines are needed against challenging diseases such as malaria, tuberculosis, Ebola, influenza, AIDS, and cancer. The majority of existing vaccine adjuvants lack the ability to significantly stimulate the cellular immune response, which is required to prevent the aforementioned diseases. This study designed a novel particulate based pathogen-mimicking vaccine delivery system (PMVDS) to target antigen-presenting-cells (APCs) such as dendritic cells. The uniqueness of PMVDS is that the polymer used to prepare the delivery system, Inulin Acetate (InAc), activates the innate immune system. InAc was synthesized from the plant polysaccharide, inulin. PMVDS provided improved and persistent antigen delivery to APCs as an efficient vaccine delivery system, and simultaneously, activated Toll-Like Receptor-4 (TLR-4) on APCs to release chemokine's/cytokines as an immune-adjuvant. Through this dual mechanism, PMVDS robustly stimulated both the humoral (>32 times of IgG1 levels vs alum) and the cell-mediated immune responses against the encapsulated antigen (ovalbumin) in mice. More importantly, PMVDS stimulated both cytotoxic T cells and natural killer cells of cell-mediated immunity to provide tumor (B16-ova-Melanoma) protection in around 40% of vaccinated mice and significantly delayed tumor progression in rest of the mice. PMVDS is a unique bio-active vaccine delivery technology with broader applications for vaccines against cancer and several intracellular pathogens, where both humoral and cellular immune responses are desired.

Curcumin-loaded polysaccharide nanoparticles: Optimization and anticariogenic activity against Streptococcus mutans

Curcumin was loaded into different polysaccharide nanoparticles chitosan, alginate and starch, using the desolvation method. Curcumin-loaded nanoparticles exhibited enhanced solubility in aqueous solutions comparing with free curcumin. Effects of formulation parameters such as curcumin concentration and different volumes of ethanolic solution were affected the particle size and loading efficiency. Under optimum conditions, curcumin-loaded chitosan, starch and alginate nanoparticles with mean particles sizes of 66.3, 61.1 and 78.8nm, and maximum loading efficiencies of 11.9%, 14.3% and 13.35% were achieved, respectively. Additionally, the minimum inhibitory concentration for chitosan, starch and alginate nanoparticles against the microorganism, Streptococcus mutans, were 0.114, 0.204 and 0.204mg/mL, respectively. Curcumin was observed to release from nanoparticles under physiological pH over a period of 96h. The effect of curcumin-loaded nanoparticles on S. mutans biofilms was assessed on dental models. According to the results, curcumin-loaded chitosan nanoparticles hold promises for being used in dental decay fighting products.

Curcumin Nanotechnologies and Its Anticancer Activity

Cancer is one of the leading causes of death worldwide. Curcumin is a well-established anticancer agent in vitro but its efficacy is yet to be proven in clinical trials. Poor bioavailability of curcumin is the principal reason behind the lack of efficiency of curcumin in clinical trials. Many studies prove that the bioavailability of curcumin can be improved by administering it through nanoparticle drug carriers. This review focuses on the efforts made in the field of nanotechnology to improve the bioavailability of curcumin. Nanotechnologies of curcumin come in various shapes and sizes. The simplest curcumin nanoparticle that increased the bioavailability of curcumin is the curcumin-metal complex. On the other hand, we have intricate thermoresponsive nanoparticles that can release curcumin upon stimulation (analogous to a remote control). Future research required for developing potent curcumin nanoparticles is also discussed.

Discovery of inulin acetate as a novel immune-active polymer and vaccine adjuvant: synthesis, material characterization, and biological evaluation as a toll-like receptor-4 agonist

Vaccine adjuvants are an essential part of modern vaccine design, especially against intracellular pathogens such as M. tuberculosis, malarial parasite, HIV, influenza virus and Ebola. The present work offers a unique approach to designing novel vaccine adjuvants by identifying polymers that mimic "pathogen associated molecular patterns" (PAMPS) and engineering an immune-active particulate vaccine delivery system that uses the polymer. By using this strategy, we report the discovery of the first plant polymer based toll-like receptor-4 (TLR-4) agonist, inulin acetate (InAc). InAc was synthesised from the plant polysaccharide inulin. Inulin acetate as a polymer and particles prepared using InAc were characterised using various physicochemical techniques. The TLR-4 agonistic activity of InAc was established in multiple immune, microglial, dendritic, peripheral blood mononuclear (human and swine) and genetically modified epithelial cells (HEK293) that exclusively express TLR-4 on their surface. InAc activated all the above-mentioned cells to release proliferative cytokines; however, InAc failed to activate when the were cells either pre-incubated with a TLR-4 specific antagonist or isolated from mice deficient in adapter proteins involved in TLR signalling (Mal/MyD88). Antigen encapsulated microparticles prepared with TLR-4 agonist InAc mimicked pathogens to offer improved antigen delivery to dendritic cells compared to soluble antigen (47 times) or antigen encapsulated poly(lactic-co-glycolic acid) (PLGA) particles (1.57 times). In conclusion, InAc represents a novel polymer-based modern vaccine adjuvant targeting specific signalling pathways of the innate immune system, which could be formulated into a platform vaccine delivery system against cancer and viral diseases.

Spices for Prevention and Treatment of Cancers

Spices have been widely used as food flavorings and folk medicines for thousands of years. Numerous studies have documented the antioxidant, anti-inflammatory and immunomodulatory effects of spices, which might be related to prevention and treatment of several cancers, including lung, liver, breast, stomach, colorectum, cervix, and prostate cancers. Several spices are potential sources for prevention and treatment of cancers, such as Curcuma longa (tumeric), Nigella sativa (black cumin), Zingiber officinale (ginger), Allium sativum (garlic), Crocus sativus (saffron), Piper nigrum (black pepper) and Capsicum annum (chili pepper), which contained several important bioactive compounds, such as curcumin, thymoquinone, piperine and capsaicin. The main mechanisms of action include inducing apoptosis, inhibiting proliferation, migration and invasion of tumors, and sensitizing tumors to radiotherapy and chemotherapy. This review summarized recent studies on some spices for prevention and treatment of cancers, and special attention was paid to bioactive components and mechanisms of action.

Bioavailability of curcumin and curcumin glucuronide in the central nervous system of mice after oral delivery of nano-curcumin

Curcumin is a bioactive molecule extracted from Turmeric roots that has been recognized to possess a wide variety of important biological activities. Despite its great pharmacological activities, curcumin is highly hydrophobic, which results in poor bioavailability. We have formulated this hydrophobic compound into stable polymeric nanoparticles (nano-curcumin) to enhance its oral absorption. Pharmacokinetic analysis after oral delivery of nano-curcumin in mice demonstrated approximately 20-fold reduction in dose requirement when compared to unformulated curcumin to achieve comparable plasma and central nervous system (CNS) tissue concentrations. This investigation corroborated our previous study of curcumin functionality of attenuating opioid tolerance and dependence, which shows equivalent efficacy of low-dose (20mg/kg) nano-curcumin and high-dose (400mg/kg) pure curcumin in mice. Furthermore, the highly selective and validated liquid chromatography-mass spectrometry (LC-MS) method was developed to quantify curcumin glucuronide, the major metabolite of curcumin. The results suggest that the presence of curcumin in the CNS is essential for prevention and reversal of opioid tolerance and dependence.