Oleanolic Acid Loaded PEGylated PLA and PLGA Nanoparticles with Enhanced Cytotoxic Activity against Cancer Cells

Hydrogel containing mPEG-PLGA nanoparticles for the vaginal delivery of saquinavir mesylate against HIV infection

Saquinavir mesylate (SQV) is a protease inhibitor commonly employed for the treatment of human immunodeficiency virus-1 infection. It is generally administered orally as tablets in combination with other antiviral drugs. Another promising route of administration can be represented by the vaginal one through topically applied formulations. This delivery can reduce the first-pass effect in the case of systemic drug adsorption or prevent HIV infection. We propose the formulation of a Carbopol® 974 (C974) hydrogel containing biodegradable mPEG-PL(L)GA nanoparticles (NPs) for the vaginal delivery of SQV, intended both as a prevention and a therapeutic strategy. mPEG-PL(L)GA NPs were incorporated into the C974 polymeric matrix, leading to a reduction of the hydrogel consistency dependent on NPs and C974 concentrations. Despite the moderate drug loading into NPs, the presence of the NPs had an impact on the in vitro release of the drug from the hydrogel at pH 5.5 using immersion cells. A higher amount of the drug was released, probably due to the effect of NPs in promoting the incorporation of the drug into the hydrogel at a high SQV dose. These findings can be useful for the development of topically applied hydrogels for SQV delivery, possibly having improved in vivo therapeutic outcomes.

The Equilibria of Triterpene Sapogenins-Phosphatidylcholine in Monolayers at the Air/Water Interface

Sapogenins are the non-sugar parts of saponins (aglycones), high-molecular-weight glycosides linked to one or more sugar side chains. This group of compounds presents many properties, e.g., the potent properties of reducing surface tension and foaming properties, as evidenced by the amphipathic nature of these substances. They are used in the cosmetics industry, the washing and detergent industry, and the food industry. In addition, they have many healing properties. They lower blood cholesterol but are also used to synthesize steroid drugs or hormones. As reported in the literature, saponins also show antitumor activity, leading to cell cycle inhibition and apoptosis of various neoplastic cells. In this study, the influence of two sapogenins: asiatic acid (AA) and oleanolic acid (OA), on the properties of monolayers made of phosphatidylcholine (DPPC) was investigated. The method used in these studies was the Langmuir method with Brewster angle microscopy. The interactions between the tested compounds in mixed monolayers were described. Using mathematical equations, we established that oleanolic acid and asiatic acid formed complexes with DPPC at 1:1 ratios, characterized by high stability constants. We derived the parameters characterizing the formed complexes and described the phase transitions that occur during the formation of pure and mixed monolayers.

Oleanolic Acid Complexation with Cyclodextrins Improves Its Cell Bio-Availability and Biological Activities for Cell Migration

Wound healing is a complex process to restore skin. Plant-derived bioactive compounds might be a source of substances for the treatment of wounds stalled in a non-resolving stage of wound healing. Oleanolic acid (OA), a pentacyclic triterpene, has shown favorable wound healing properties both in vitro and in vivo. Unfortunately, OA cannot be solubilized in aqueous media, and it needs to be helped by the use of dimethyl sulfoxide (DMSO). In this paper, we have shown that cyclodextrins (CDs) are a good alternative to DMSO as agents to deliver OA to cells, providing better features than DMSO. Cyclodextrins are natural macromolecules that show a unique tridimensional structure that can encapsulate a wide variety of hydrophobic compounds. We have studied the cyclodextrin-encapsulated form of OA with OA/DMSO, comparing their stability, biological properties for cell migration, and cell viability. In addition, detailed parameters related to cell migration and cytoskeletal reorganization have been measured and compared. Our results show that OA-encapsulateds compound exhibit several advantages when compared to non-encapsulated OA in terms of chemical stability, migration enhancement, and preservation of cell viability.

Targeting lung cancer cells with MUC1 aptamer-functionalized PLA-PEG nanocarriers

MUC1 aptamer-functionalized PLA-PEG nanocarriers at various w/w ratios (polymer to doxorubicin weight ratio) were prepared by a double emulsion method. Physiochemical properties, encapsulation efficiency (EE), loading content (LC) and in vitro release kinetics of DOX were assessed. Furthermore, cytotoxicity and antitumor activity of prepared PLA-PEG-Apt/DOX NPs at w/w ratio 10:1 were evaluated by MTT assay and flow cytometry against MUC1-overexpressing A-549 cell line. Targeted nanocarriers (PLA-PEG-Apt/DOX NPs at w/w ratio 10:1) induced higher apoptosis rate (36.3 ± 3.44%) for 24 h in MUC1 positive A-549 cancer cells in compare to non-targeted form (PLA-PEG/DOX NPs at w/w ratio 10:1, 11.37 ± 1.65%) and free DOX (4.35 ± 0.81%). In other word, the percentage of cell death in A-549 lung cancer cells treated with PLA-PEG-Apt/DOX NPs at w/w ratio 10:1 is 3.19 and 8.34 fold higher than in non-targeted form and Free DOX treated cancer cells, respectively. Therefore, PLA-PEG-Apt/DOX NPs might be considered a promising drug delivery system for targeted drug delivery towards MUC1-overexpressing tumors cells.

A nanosensitizer self-assembled from oleanolic acid and chlorin e6 for synergistic chemo/sono-photodynamic cancer therapy

BACKGROUND

Sono-photodynamic therapy (SPDT) which is the combination of photodynamic therapy (PDT) and sonodynamic therapy (SDT), could exert much better anti-cancer effects than monotherapy. The combination of chemotherapy and PDT or SDT has shown great potential for cancer treatment. However, the combination of SPDT and chemotherapy for cancer treatment is rarely explored.

PURPOSE

We utilized a natural hydrophobic anti-cancer drug oleanolic acid (OA) and a photosensitizer chlorin e6 (Ce6) through self-assembly technology to form a carrier-free nanosensitizer OC for combined chemotherapy and SPDT for cancer treatment. No studies involving using carrier-free nanomedicine for combined chemotherapy/SPDT have been reported yet.

STUDY DESIGN

After fully characterization of OC, the in vitro and in vivo anti-cancer activities of OC were investigated and the mechanisms of the synergistic therapeutic effects were studied.

METHODS

OC were synthesized through self-assembly technology and characterized by dynamic light scattering (DLS) and an atomic force microscope (AFM). Confocal microscope was used to investigate the intracellular uptake efficiency and the penetration ability of OC. The cell viability of PC9 and 4T1 cells treated with OC under laser and ultrasound (US) irradiation was determined by MTT assay. Furthermore, flow cytometry was performed to detect the reactive oxygen species (ROS) generation, loss of mitochondrial membrane potential (MMP), cell apoptosis and cell cycle arrest. Finally, the anti-tumor therapeutic efficacy of OC was investigated in orthotopic 4T1 breast tumor-bearing mouse model.

RESULTS

OC showed an average particle size of around 100 nm with excellent light stability. OC increased more than 23 times accumulation of Ce6 in cancer cells and had strong tumor penetration ability in three-dimensional (3D) multicellular tumor spheroids (MCTSs). Compared with other therapeutic options, OC showed obvious synergistic inhibitory effects under light and US irradiation in PC9 and 4T1 cells with a significant decrease in IC₅₀ values. Mechanism studies showed that OC could generate high ROS, induce MMP loss, and cause apoptosis and cell cycle arrest. In vivo studies also approved the synergistic therapeutic effects of OC in 4T1 mouse models.

CONCLUSION

Self-assembled carrier-free nanosensitizer OC could be a promising therapeutic agent for synergistic chemo/sono-photodynamic therapy for cancer treatment.

Herbal Drugs and Natural Products in the light of Nanotechnology and Nanomedicine for Developing Drug Formulations

Natural products and medicinal plants have played a vital role in providing healthcare and ensuring well-being for many civilizations since antiquity. It is estimated that around 50% of drugs in the market have a natural product origin especially medicinal plants and herbal drugs, animals, fungi, and marine organisms. Some of these biologically active constituents of extracts have low absorption and distribution which, as a result, lead to loss of bioavailability and efficacy and might hamper their applications in the clinic. To overcome these impediments for the formulation of herbal drugs, food supplements, and essential oils, several nanomedical approaches such as liposomes, microemulsions, polymeric nanoparticles, solid lipid nanoparticles (SLNs), liquid crystal systems (LC), and precursor systems for liquid crystals (PSLCs) have been proposed. Nanoparticles have been used to modify and ameliorate the pharmacokinetic and pharmacodynamic properties of different drugs, thus incorporating biotechnological systems may be useful to enhance the bioavailability and bioactivity of herbal drug formulations. Consequently, essential for any natural compounds is the extent of its absorption after being ingested and its ability to be distributed in various tissues or organs of the body. The present review article aims to give an overview of the recent advancements in developing herbal drug formulations based on nanoparticle technologies.

Development and Evaluation of Oleanolic Acid Dosage Forms and Its Derivatives

Oleanolic acid is a pentacyclic triterpenoid compound that exists widely in medicinal herbs and other plants. Because of the extensive pharmacological activity, oleanolic acid has attracted more and more attention. However, the structural characteristics of oleanolic acid prevent it from being directly made into new drugs, which limits the application of oleanolic acid. Through the application of modern preparation techniques and methods, different oleanolic acid dosage forms and derivatives have been designed and synthesized. These techniques can improve the water solubility and bioavailability of oleanolic acid and lay a foundation for the new drug development. In this review, the recent progress in understanding the oleanolic acid dosage forms and its derivatives are discussed. Furthermore, these products were evaluated comprehensively from the perspective of characterization and pharmacokinetics, and this work may provide ideas and references for the development of oleanolic acid preparations.

Synergism of cisplatin-oleanolic acid co-loaded hybrid nanoparticles on gastric carcinoma cells for enhanced apoptosis and reversed multidrug resistance

Combined administration of different drugs is a widely acknowledged approach for effective cancer therapy. However, the limited targeting, as well as inferior drug loading capacities of current drug delivery systems (DDS), are still the bottleneck for better performance in cancer treatment. Herein, we successfully developed a cancer cell membrane (CM) decorated calcium carbonate (CC) hybrid nanoparticles (HN) for the co-delivery of cisplatin (CDDP) and oleanolic acid (OA). The physicochemical property of HN/CDDP/OA was evaluated, which revealed that the as-prepared DDS was core-shell structured and well-dispersed nanoparticles with size around 100 nm. The HN/CDDP/OA showed high stability and biocompatibility with pH-responsive drug release. Moreover, the CM modification in HN also demonstrated highly elevated tumor-homing nature than bare CC. Finally, the feasibility of HN/CDDP/OA in the treatment of gastric cancer (MGC-803 cell line) was assessed. HN/CDDP/OA showed better performance than mono systems with enhanced apoptosis and capable of reversing multidrug resistance (MDR) of cancer cells.

In vivo biocompatibility and efficacy of dexamethasone-loaded PLGA-PEG-PLGA thermogel in an alkali-burn induced corneal neovascularization disease model

Challenges of ophthalmic drug delivery arise not only from the limited solubility of hydrophobic therapeutics, but also the restricted permeability and fast clearance of drugs due to the complex anatomy and physiology of eyes. Excellent biocompatibility of a thermosensitive polymer, PLGA-PEG-PLGA (1800-1500-1800, LA:GA ratio = 3:1), as an ophthalmic delivery system was demonstrated in our previous work. In this study, delivery of dexamethasone using this thermogel via a single subconjunctival injection for prolonged treatment was evaluated with corneal neovascularization using an alkali-burn diseased model in rat. Solubility of dexamethasone in the polymeric solution was increased by 5.2-fold and the resulting drug-loaded solution formed in situ rigid gel at body temperature. Prolonged in vitro release of dexamethasone from the gel structure was noted. Dexamethasone gel formulation was demonstrated to be more effective in reducing the burn stimulus and neovascularization in the rat diseased model. The findings suggest the PLGA-PEG-PLGA in situ gelling system can be applied for ophthalmic drug delivery to achieve sustained drug release and improved efficacy.

Delivery Systems for Birch-bark Triterpenoids and their Derivatives in Anticancer Research

Birch-bark triterpenoids and their semi-synthetic derivatives possess a wide range of biological activities including cytotoxic effects on various tumor cell lines. However, due to the low solubility and bioavailability, their medicinal applications are rather limited. The use of various nanotechnology-based drug delivery systems is a rapidly developing approach to the solubilization of insufficiently bioavailable pharmaceuticals. Herein, the drug delivery systems deemed to be applicable for birch-bark triterpenoid structures are reviewed. The aforementioned disadvantages of birch-bark triterpenoids and their semi-synthetic derivatives can be overcome through their incorporation into organic nanoparticles, which include various dendrimeric systems, as well as embedding the active compounds into polymer matrices or complexation with carbohydrate nanoparticles without covalent bonding. Some of the known triterpenoid delivery systems consist of nanoparticles featuring inorganic cores covered with carbohydrates or other polymers. Methods for delivering the title compounds through encapsulation and emulsification into lipophilic media are also suitable. Besides, the birch-bark triterpenoids can form self-assembling systems with increased bio-availability. Even more, the self-assembling systems are used as carriers for delivering other chemotherapeutic agents. Another advantage besides increased bioavailability and anticancer activity is the reduced overall systemic toxicity in most of the cases, when triterpenoids are delivered with any of the carriers.

Facile Dye-Initiated Polymerization of Lactide-Glycolide Generates Highly Fluorescent Poly(lactic-co-glycolic Acid) for Enhanced Characterization of Cellular Delivery

Poly(lactic-co-glycolic acid) (PLGA) is a versatile synthetic copolymer that is widely used in pharmaceutical applications. This is because it is well-tolerated in the body, and copolymers of varying physicochemical properties are readily available via ring-opening polymerization. However, native PLGA polymers are hard to track as drug delivery carriers when delivered to subcellular spaces, due to the absence of an easily accessible "handle" for fluorescent labeling. Here we show a one-step, scalable, solvent-free, synthetic route to fluorescent blue (2-aminoanthracene), green (5-aminofluorescein), and red (rhodamine-6G) PLGA, in which every polymer chain in the sample is fluorescently labeled. The utility of initiator-labeled PLGA was demonstrated through the preparation of nanoparticles, capable of therapeutic subcellular delivery to T-helper-precursor-1 (THP-1) macrophages, a model cell line for determining in vitro biocompatibility and particle uptake. Super resolution confocal fluorescence microscopy imaging showed that dye-initiated PLGA nanoparticles were internalized to punctate regions and retained bright fluorescence over at least 24 h. In comparison, PLGA nanoparticles with 5-aminofluorescein introduced by conventional nanoprecipitation/encapsulation showed diffuse and much lower fluorescence intensity in the same cells and over the same time periods. The utility of this approach for in vitro drug delivery experiments was demonstrated through the concurrent imaging of the fluorescent drug doxorubicin (λ_ex = 480 nm, λ_em = 590 nm) with carrier 5-aminofluorescein PLGA, also in THP-1 cells, in which the intracellular locations of the drug and the polymer could be clearly visualized. Finally, the dye-labeled particles were evaluated in an in vivo model, via delivery to the nematode Caenorhabditis elegans, with bright fluorescence again apparent in the internal tract after 3 h. The results presented in this manuscript highlight the ease of synthesis of highly fluorescent PLGA, which could be used to augment tracking of future therapeutics and accelerate in vitro and in vivo characterization of delivery systems prior to clinical translation.

Heparin coated meta-organic framework co-delivering doxorubicin and quercetin for effective chemotherapy of lung carcinoma

Objective

To develop and evaluate a drug delivery system (DDS) capable of targeting cancer cells while at the same time delivering two chemotherapeutic agents to overcome multidrug resistance (MDR).

Methods

This study developed a DDS composed of heparin (HA)-coated meta-organic framework (MOF) nanoparticles (HM) designed to deliver doxorubicin (Dox) and quercetin (Que). A range of in vitro and in vivo studies were conducted to determine the characteristics of the HM/Dox/Que nanoparticles, their ability to produce cytotoxic effects in Dox-resistant A549/Dox cells and target and treat solid tumours in a mouse xenograft model of human lung carcinoma.

Results

This study demonstrated that the HM/Dox/Que nanoparticles reduced cell viability, increased apoptosis, arrested cells in the G0/G1 phase of the cell cycle and reversed MDR in A549/Dox cells in vitro when compared with mono-drug delivery. In a mouse xenograft model of human lung carcinoma, the HM/Dox/Que nanoparticles targeted the tumours and reduced tumour growth as determined by tumour volume.

Conclusion

The use of HM/Dox/Que nanoparticles might be a viable alternative to traditional chemotherapy of lung carcinoma.

Cancer Cell Membrane-Decorated Zeolitic-Imidazolate Frameworks Codelivering Cisplatin and Oleanolic Acid Induce Apoptosis and Reversed Multidrug Resistance on Bladder Carcinoma Cells

Combination therapy is emerging as a preferable approach in cancer therapy with minimized side effects and elevated performance. Nevertheless, the poor targeting and drug loading of currently available drug delivery systems (DDSs) are the main difficulties to realize preferable combination therapy of cancer. As a result, a cancer cell membrane-decorated zeolitic-imidazolate framework hybrid nanoparticle (HP) was successfully constructed in our study to codeliver cisplatin (DDP) and oleanolic acid (OLA). Our results showed positive results of the platform (HP/DDP/OLA) for the treatment of bladder cancer (SW780). In detail, HP/DDP/OLA could enhance apoptosis while reverse multidrug resistance in SW780 cells than free drugs alone or monodelivery systems, which might be a suitable DDS for codelivery of different drugs with great promise.

Oral delivery of paclitaxel by polymeric micelles: A comparison of different block length on uptake, permeability and oral bioavailability

Drug solubility and permeability are two major challenges affecting oral delivery, the most popular route of drug administration. Polymeric micelles is an emerging technology for overcoming the current oral drug delivery hurdles. Previous study primarily focused on developing new polymers or new micellar systems and a systematic investigation of the impact of the polymer block length on solubility and permeability enhancement; and their subsequent effect on oral bioavailability is lacking. Herein, by using paclitaxel, a poorly soluble P-glycoproteins (P-gp) substrate, as a model, we aim to assess and compare the drug-loaded micelles prepared with two different molecular weight of poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-b-PCL), with the ultimate goal of establishing a strong scientific rationale for proper design of formulations for oral drug delivery. PEG-b-PCL (750:570) (PEG₁₇-b-PCL₅) and PEG-b-PCL (5k:10k) (PEG₁₁₄-b-PCL₈₈) effectively enhanced the solubility of paclitaxel compared to the free drug. PEG-b-PCL (750:570) increased both P-gp and non P-gp substrate cellular uptake and increased the apparent permeability coefficient of a P-gp substrate. In vivo animal study showed that PEG-b-PCL micelles efficiently enhanced the oral bioavailability of paclitaxel. In addition to solubility enhancement, polymer choice also plays a pivotal role in determining the oral bioavailability improvement, probably via permeation enhancement. In conclusion, the knowledge gained in this study enables rational design of polymeric micelles to overcome the current challenges of oral drug delivery and it also provides a basis for future clinical translation of the technology.

Polymeric nanoparticles developed by vitamin E-modified aliphatic polycarbonate polymer to promote oral absorption of oleanolic acid

Oleanolic acid (OA) exhibited good pharmacological activities in the clinical treatment of hypoglycemia, immune regulation, acute jaundice and chronic toxic hepatitis. However, the oral delivery of OA is greatly limited by its inferior water solubility and poor intestinal mucosa permeability. Herein, we developed a novel polymeric nanoparticle (NP) delivery system based on vitamin E modified aliphatic polycarbonate (mPEG-PCC-VE) to facilitate oral absorption of OA. OA encapsulated mPEG-PCC-VE NPs (OA/mPEG-PCC-VE NPs) showed uniform particle size of about 170 nm with high drug loading capability (8.9%). Furthermore, the polymeric mPEG-PCC-VE NPs, with good colloidal stability and pH-sensitive drug release characteristics, significantly enhanced the in vitro dissolution of OA in the alkaline medium. The in situ single pass intestinal perfusion (SPIP) studies performed on rats demonstrated that the OA/mPEG-PCC-VE NPs showed significantly improved permeability in the whole intestinal tract when compared to OA solution, especially for duodenum and colon. As a result, the in vivo pharmacokinetics study indicated that the bioavailability of OA/mPEG-PCC-VE NPs showed 1.5-fold higher than commercially available OA tablets. These results suggest that mPEG-PCC-VE NPs are a promising platform to facilitate the oral delivery of OA.

Oleanolic Acid Alters Multiple Cell Signaling Pathways: Implication in Cancer Prevention and Therapy

Nowadays, much attention has been paid to diet and dietary supplements as a cost-effective therapeutic strategy for prevention and treatment of a myriad of chronic and degenerative diseases. Rapidly accumulating scientific evidence achieved through high-throughput technologies has greatly expanded the understanding about the multifaceted nature of cancer. Increasingly, it is being realized that deregulation of spatio-temporally controlled intracellular signaling cascades plays a contributory role in the onset and progression of cancer. Therefore, targeting regulators of oncogenic signaling cascades is essential to prevent and treat cancer. A plethora of preclinical and epidemiological evidences showed promising role of phytochemicals against several types of cancer. Oleanolic acid, a common pentacyclic triterpenoid, is mainly found in olive oil, as well as several plant species. It is a potent inhibitor of cellular inflammatory process and a well-known inducer of phase 2 xenobiotic biotransformation enzymes. Main molecular mechanisms underlying anticancer effects of oleanolic acid are mediated by caspases, 5' adenosine monophosphate-activated protein kinase, extracellular signal-regulated kinase 1/2, matrix metalloproteinases, pro-apoptotic Bax and bid, phosphatidylinositide 3-kinase/Akt1/mechanistic target of rapamycin, reactive oxygen species/apoptosis signal-regulating kinase 1/p38 mitogen-activated protein kinase, nuclear factor-κB, cluster of differentiation 1, CKD4, s6k, signal transducer and activator of transcription 3, as well as aforementioned signaling pathways . In this work, we critically review the scientific literature on the molecular targets of oleanolic acid implicated in the prevention and treatment of several types of cancer. We also discuss chemical aspects, natural sources, bioavailability, and safety of this bioactive phytochemical.

Study of a novel disintegrable oleanolic acid-polyvinylpolypyrrolidone solid dispersion

Novel solid dispersions of oleanolic acid-polyvinylpolypyrrolidone (OLA-PVPP SDs) were designed and prepared to improve the apparent solubility of drug, as well as to improve the stability, fluidity and compressibility of SDs. Disintegrable OLA-PVPP SDs were then evaluated both in vitro and in vivo. DSC, XRD, IR and SEM analysis proved the formation of OLA-PVPP SD and its amorphous state. The results of fluidity study, moisture absorption test and stability test showed that OLA-PVPP SD with good fluidity and qualified stability was successfully obtained. Meanwhile excellent dissolution rate was achieved for in vitro studies; dissolution test showed that ∼50-75% of OLA was dissolved from SDs within the first 10 min, which is about 10-15 times of free OLA. In vivo study indicated that the formation of solid dispersion could largely improve the absorption of OLA, resulting in a much shorter T_max (p < .05) and higher C_max (p < .01) than those of free drug. The AUC_0→∞ of OLA-PVPP SDs (1:6) were 155.4 ± 37.24 h·ng/mL compared to the 103.11 ± 26.69 h·ng/mL and 94.92 ± 13.05 h·ng/mL of OLA-PVPP physical mixture (1:6) and free OLA, respectively. These proved PVPP could be a promising carrier of solid dispersions and was industrially feasible alternative carrier in the manufacture of solid dispersions.

Surface Modified Multifunctional and Stimuli Responsive Nanoparticles for Drug Targeting: Current Status and Uses

Nanocarriers, due to their unique features, are of increased interest among researchers working with pharmaceutical formulations. Polymeric nanoparticles and nanocapsules, involving non-toxic biodegradable polymers, liposomes, solid lipid nanoparticles, and inorganic-organic nanomaterials, are among the most used carriers for drugs for a broad spectrum of targeted diseases. In fact, oral, injectable, transdermal-dermal and ocular formulations mainly consist of the aforementioned nanomaterials demonstrating promising characteristics such as long circulation, specific targeting, high drug loading capacity, enhanced intracellular penetration, and so on. Over the last decade, huge advances in the development of novel, safer and less toxic nanocarriers with amended properties have been made. In addition, multifunctional nanocarriers combining chemical substances, vitamins and peptides via coupling chemistry, inorganic particles coated by biocompatible materials seem to play a key role considering that functionalization can enhance characteristics such as biocompatibility, targetability, environmental friendliness, and intracellular penetration while also have limited side effects. This review aims to summarize the "state of the art" of drug delivery carriers in nanosize, paying attention to their surface functionalization with ligands and other small or polymeric compounds so as to upgrade active and passive targeting, different release patterns as well as cell targeting and stimuli responsibility. Lastly, future aspects and potential uses of nanoparticulated drug systems are outlined.

Micellar delivery of dasatinib for the inhibition of pathologic cellular processes of the retinal pigment epithelium

The objective of this study was to fabricate dasatinib-loaded nanoparticles and evaluate their efficacy in inhibiting cellular processes of the retinal pigment epithelium (RPE) related to proliferative vitreoretinopathy (PVR), for which there are no approved pharmacological approaches. We successfully encapsulated dasatinib, a poorly soluble multi-targeted tyrosine kinase inhibitor which has great potential for the treatment of PVR, into nanoparticles prepared from micellation of PEG-b-PCL. The size of the nanomicelles was approximately 55nm with a narrow distribution. They increased the solubility of dasatinib by 475× and provided a sustained drug release. ARPE-19, an immortal RPE cell line, was used to assess the in vitro efficacy of micellar dasatinib because the RPE is believed to play a key role in the pathogenesis of PVR. Three cell-based assays, namely, proliferation, adhesion and migration, which represent three important PVR-related cellular changes of the RPE, were conducted and the cytotoxicity of micelles was also evaluated. Both blank and dasatinib-loaded micelles were non-cytotoxic towards ARPE-19 cells. Micellar dasatinib significantly inhibited cell proliferation, adhesion and migration compared to the free drug; this might be attributable to enhanced solubility. PEG-b-PCL micelles were taken up into the ARPE-19 cells by an energy-dependent clatharin and caveolae-mediated endocytosis. Our results indicated that cellular uptake and the anti-proliferation effect of drugloaded micelles were linearly correlated. Drug loading appears to be a critical parameter for cellular uptake which in turn impacts the in vitro bioactivities of polymeric micelles. Our results clearly demonstrated that dasatinib-encapsulated micelles offer considerable promise in the management of PVR.

Barrigenol triterpenes from the husks of Xanthoceras sorbifolia Bunge and their antitumor activities

New barrigenol derivatives from the husks Xanthoceras sorbifolia Bunge and their anti-tumor activities.