Hydrotropic polymeric micelles for enhanced paclitaxel solubility: in vitro and in vivo characterization

Desosomes and desimicelles - a novel vesicular and micellar system for enhanced oral delivery of poorly soluble drug: Optimization of in vitro characteristics and in vivo performance

This study introduces two innovative nanocarrier systems to improve oral drug delivery. Desosomes and desimicelles combine Deep eutectic solvent (DES) with vesicular or micellar nanosystems, respectively. These novel nanosystems integrate the DES solubilization potency for administering drugs with low aqueous solubility and the vesicular and micellar systems to bypass physiological barriers and improve poor drug bioavailability. Lornoxicam (LRX) is a BCS class II anti-inflammatory with limited aqueous solubility and rapid clearance. Desosomes and desimicelles were prepared and successfully optimized. The optimization depended on particle size, zetapotential, entrapment efficiency, and solubility. The optimized desosomes (LRX-DES-V) and desimicelles (LRX-DES-M) were pictured by transmission electron microscope. Differential scanning calorimetry (DSC) and FTIR analysis indicated the successful inclusion of LRX inside each system. Invitro LRX release profiles revealed controlled release of LRX-DES-V and LRX-DES-M, with more sustained release by the later one. In-vivo study, inflammation was induced using a carrageenan rat model, and the anti-inflammatory effect of LRX-pure, marketed product, traditional niosomes, LRX-DES-V & LRX-DES-M were determined using inhibition %, serum inflammatory cytokines, and histopathology. After 4 h of induction, LRX-DES-M (68.05%) showed a significant inhibition compared to LRX-DES-V (63.57%). LRX-DES-M also showed a better reduction in COX2, PGE2, and TNF-α (1.25-fold, 1.24-fold, and 1.36-fold inhibition), respectively, compared to LRX-DES-V. We can conclude that LRX-DES-V and LRX-DES-M showed better effects than all other groups and that LRX-DES-M might be more effective than LRX-DES-V.

Self-assembled micelles loaded with itraconazole as anti-Acanthamoeba nano-formulation

Acanthamoeba castellanii are opportunistic pathogens known to cause infection of the central nervous system termed: granulomatous amoebic encephalitis, that mostly effects immunocompromised individuals, and a sight threatening keratitis, known as Acanthamoeba keratitis, which mostly affects contact lens wearers. The current treatment available is problematic, and is toxic. Herein, an amphiphilic star polymer with AB2 miktoarms [A = hydrophobic poly(ℇ-Caprolacton) and B = hydrophilic poly (ethylene glycol)] was synthesized by ring opening polymerization and CuI catalyzed azide-alkyne cycloaddition. Characterization by 1H and 13C NMR spectroscopy, size-exclusion chromatography and fluorescence spectroscopy was accomplished. The hydrophobic drug itraconazole (ITZ) was incorporated in self-assembled micellar structure of AB2 miktoarms through co-solvent evaporation. The properties of ITZ loaded (ITZ-PCL-PEG2) and blank micelles (PCL-PEG2) were investigated through zeta sizer, scanning electron microscopy and Fourier-transform infrared spectroscopy. Itraconazole alone (ITZ), polymer (DPB-PCL), empty polymeric micelles (PCL-PEG2) alone, and itraconazole loaded in polymeric micelles (ITZ-PCL-PEG2) were tested for anti-amoebic potential against Acanthamoeba, and the cytotoxicity on human cells were determined. The polymer was able to self-assemble in aqueous conditions and exhibited low value for critical micelle concentration (CMC) 0.05-0.06 µg/mL. The maximum entrapment efficiency of ITZ was 68%. Of note, ITZ, DPB, PCL-PEG2 and ITZ-PCL-PEG2 inhibited amoebae trophozoites by 37.34%, 36.30%, 35.77%, and 68.24%, respectively, as compared to controls. Moreover, ITZ-PCL-PEG2 revealed limited cytotoxicity against human keratinocyte cells. These results are indicative that ITZ-PCL-PEG2 micelle show significantly better anti-amoebic effects as compared to ITZ alone and thus should be investigated further in vivo to determine its clinical potential.

Preparation, Optimization and In Vitro Characterization of Fluticasoneloaded Mixed Micelles Based on Stearic Acid-g-chitosan as a Pulmonary Delivery System

PURPOSE

The primary objective of this study was to optimize formulation variables and investigate the in vitro characteristics of fluticasone propionate (FP)-loaded mixed polymeric micelles, which were composed of depolymerized chitosan-stearic acid copolymer (DC-SA) in combination with either tocopheryl polyethylene glycol succinate or dipalmitoylphosphatidylcholine for pulmonary drug delivery.

METHODS

A D-optimal design was employed for the optimization procedure, considering lipid/ polymer ratio, polymer concentration, drug/ polymer ratio, and lipid type as independent variables. Dependent variables included particle size, polydispersion index, zeta potential, drug encapsulation efficiency, and loading efficiency of the polymeric micelles. Additionally, the nebulization efficacy and cell viability of the optimal FP-loaded DC-SA micellar formulations were evaluated.

RESULTS

The mixed polymeric micelles were successfully prepared with properties falling within the desired ranges, resulting in four optimized formulations. The release of FP from the optimal systems exhibited a sustained release profile over 72 hours, with 70% of the drug still retained within the core of the micelles. The nebulization efficiency of these optimal formulations reached up to 63%, and the fine particle fraction (FPF) ranged from 41% to 48%. Cellular viability assays demonstrated that FP-loaded DC-SA polymeric micelles exhibited lower cytotoxicity than the free drug but were slightly more cytotoxic than empty mixed micelles.

CONCLUSION

In conclusion, this study suggests that DC-SA/ lipid mixed micelles have the potential to serve as effective carriers for nebulizing poorly soluble FP.

Perivascular patch using biodegradable polymers: Investigation of mechanical and drug elution characteristics

Intimal hyperplasia (IH) is the primary cause for the vascular graft stenosis. Perivascular devices offer a potential treatment option to reduce the impact of intimal hyperplasia by providing mechanical support and local administration of therapeutic agents to control cellular overgrowth. In the present study, a perivascular patch primarily made up of biodegradable polymer, Poly L-Lactide, has been designed with adequate mechanical strength and ability for sustained drug elution of anti-proliferative drug (Paclitaxel). The elastic modulus of the polymeric film has been optimized by blending the base polymer with different grades of biocompatible polyethylene glycols. Using design of experiments, the optimized parameters were obtained as PLLA with 2.5% PEG-6000 and have shown 3.14 MPa elastic modulus. The film prepared based on optimum conditions has been employed for prolonged drug delivery (about four months) under simulated physiological conditions. The addition of drug release rate enhancer (polyvinyl pyrrolidone K90F) has improved the drug elution rate and ∼83% drug was released over entire study period. The molecular weight of the base biodegradable polymer was estimated by gel permeation chromatography (GPC) which remained unchanged during the drug release study duration. Evidences of Paclitaxel drug crystallization were found to contribute to the sustained drug elution. The SEM examination of the surface morphology post-incubation revealed micropores on the surface, contributing to the overall drug release rate. The study concluded that perivascular biodegradable films could be tailored for their mechanical properties, and sustained drug elution could also be formulated with reasonable choices of biodegradable polymer and biocompatible additives.

Paclitaxel-Loaded Lipid-Coated Magnetic Nanoparticles for Dual Chemo-Magnetic Hyperthermia Therapy of Melanoma

Melanoma is the most aggressive and metastasis-prone form of skin cancer. Conventional therapies include chemotherapeutic agents, either as small molecules or carried by FDA-approved nanostructures. However, systemic toxicity and side effects still remain as major drawbacks. With the advancement of nanomedicine, new delivery strategies emerge at a regular pace, aiming to overcome these challenges. Stimulus-responsive drug delivery systems might considerably reduce systemic toxicity and side-effects by limiting drug release to the affected area. Herein, we report the development of paclitaxel-loaded lipid-coated manganese ferrite magnetic nanoparticles (PTX-LMNP) as magnetosomes synthetic analogs, envisaging the combined chemo-magnetic hyperthermia treatment of melanoma. PTX-LMNP physicochemical properties were verified, including their shape, size, crystallinity, FTIR spectrum, magnetization profile, and temperature profile under magnetic hyperthermia (MHT). Their diffusion in porcine ear skin (a model for human skin) was investigated after intradermal administration via fluorescence microscopy. Cumulative PTX release kinetics under different temperatures, either preceded or not by MHT, were assessed. Intrinsic cytotoxicity against B16F10 cells was determined via neutral red uptake assay after 48 h of incubation (long-term assay), as well as B16F10 cells viability after 1 h of incubation (short-term assay), followed by MHT. PTX-LMNP-mediated MHT triggers PTX release, allowing its thermal-modulated local delivery to diseased sites, within short timeframes. Moreover, half-maximal PTX inhibitory concentration (IC50) could be significantly reduced relatively to free PTX (142,500×) and Taxol® (340×). Therefore, the dual chemo-MHT therapy mediated by intratumorally injected PTX-LMNP stands out as a promising alternative to efficiently deliver PTX to melanoma cells, consequently reducing systemic side effects commonly associated with conventional chemotherapies.

Synthesis of Carrier-Free Paclitaxel-Curcumin Nanoparticles: The Role of Curcuminoids

The systemic administration of paclitaxel (PTX)-based combinatorial therapies is significantly restricted due to the multidrug resistance. Curcumin (CUR) not only inhibits cancer-cell proliferation but also reverses the PTX resistance. However, achieving codelivery of these two drugs is a challenge due to their poor water solubility. Herein, we synthesized carrier-free PTX NPs by a facile nanoprecipitation method with the help of CUR and other curcuminoids present in turmeric extract. The prepared NPs demonstrated spherical morphologies with high conformational stability. Experimental studies showed that the presence of both bisdemethoxycurcumin and demethoxycurcumin is essential for the successful formation of spherical and monodisperse NPs. Computational studies revealed that the presence of the more sterically available curcuminoids BMC and DMC makes the self-assembly procedure more adaptable with a higher number of potential conformations that could give rise to more monodisperse PTX-CUR NPs. Compared with PTX alone, PTX-CUR NPs have shown comparable therapeutic efficiency in vitro and demonstrated a higher cellular internalization, highlighting their potential for in vivo applications. The successful formation of PTX-CUR NPs and the understanding of how multiple drugs behave at the molecular level also provide guidance for developing formulations for the synthesis of high-quality and effective carrier-free nanosystems for biomedical applications.

l-Amino Acid Based Phenol- and Catechol-Functionalized Poly(ester-urethane)s for Aromatic π-Interaction Driven Drug Stabilization and Their Enzyme-Responsive Delivery in Cancer Cells

Exploiting aromatic π-interaction for the stabilization of polyaromatic anticancer drugs at the core of the polymer nanoassemblies is an elegant approach for drug delivery in cancer research. To demonstrate this concept, here we report one of the first attempts on enzyme-responsive polymers from aryl-unit containing amino acid bioresources such as l-tyrosine and 3,4-dihydroxy-l-phenylalanine (l-DOPA). A silyl ether protection strategy was adopted to make melt polymerizable monomers, which were subjected to solvent free melt polycondensation to produce silyl-protected poly(ester-urethane)s. Postpolymerization deprotection yielded phenol- and catechol-functionalized poly(ester-urethane)s with appropriate amphiphilicity and produced 100 ± 10 nm size nanoparticles in an aqueous solution. The aromatic π-core in the nanoparticle turns out to be the main driving force for the successful encapsulation of anticancer drugs such as doxorubicin (DOX) and topotecan (TPT). The electron-rich catechol aromatic unit in l-DOPA was found to be unique in stabilizing the DOX and TPT, whereas its l-tyrosine counterpart was found to exhibit limited success. Aromatic π-interactions between l-DOPA and anticancer drug molecules were established by probing the fluorescence characteristics of the drug-polymer chain interactions. Lysosomal enzymatic biodegradation of the poly(ester-urethane) backbone disassembled the nanoparticles and released the loaded drugs at the cellular level. The nascent polymer was nontoxic in breast cancer (MCF7) and WT-MEF cell lines, whereas its DOX and TPT loaded nanoparticles showed remarkable cell growth inhibition. A LysoTracker-assisted confocal microscopic imaging study directly evidenced the polymer nanoparticles' biodegradation at the intracellular level. The present investigation gives an opportunity to design aromatic π-interaction driven drug stabilization in l-amino acid based polymer nanocarriers for drug delivery applications.

Hydrotropic Hydrogels Prepared from Polyglycerol Dendrimers: Enhanced Solubilization and Release of Paclitaxel

Polyglycerol dendrimers (PGD) exhibit unique properties such as drug delivery, drug solubilization, bioimaging, and diagnostics. In this study, PGD hydrogels were prepared and evaluated as devices for controlled drug release with good solubilization properties. The PGD hydrogels were prepared by crosslinking using ethylene glycol diglycidylether (EGDGE). The concentrations of EGDGE and PGDs were varied. The hydrogels were swellable in ethanol for loading paclitaxel (PTX). The amount of PTX in the hydrogels increased with the swelling ratio, which is proportional to EGDGE/OH ratio, meaning that heterogeneous crosslinking of PGD made high dense region of PGD molecules in the matrix. The hydrogels remained transparent after loading PTX and standing in water for one day, indicating that PTX was dispersed in the hydrogels without any crystallization in water. The results of FTIR imaging of the PTX-loaded PGD hydrogels revealed good dispersion of PTX in the hydrogel matrix. Sixty percent of the loaded PTX was released in a sink condition within 90 min, suggesting that the solubilized PTX would be useful for controlled release without any precipitation. Polyglycerol dendrimer hydrogels are expected to be applicable for rapid release of poorly water-soluble drugs, e.g., for oral administration.

A comparative evaluation of anti-tumor activity following oral and intravenous delivery of doxorubicin in a xenograft model of breast tumor

Purpose

Natural materials have been extensively studied for oral drug delivery due to their biodegradability and other unique properties. In the current research, we fabricated sodium caseinate nanomicelles (NaCNs) using casein as a natural polymer to develop a controlled-release oral delivery system that would improve the therapeutic potential of doxorubicin (DOX) and reduce its toxicity.

Methods

DOX-loaded NaCNs were synthesized and thoroughly characterized, then subjected to in vivo anti-tumor evaluation and bio-distribution analysis in a 4T1-induced breast cancer model.

Results

Our findings indicated that the tumor would shrink by eight-fold in the group orally treated with DOX-NaCNs when compared to free DOX. The tumor accumulated drug 1.27-fold more from the orally administered DOX-NaCNs compared to the intravenously administered DOX-NaCNs, 6.8-fold more compared to free DOX, and 8.34-times more compared to orally administered free DOX. In comparison, the orally administered DOX-NaCNs lead to a significant reduction in tumor size (5.66 ± 4.36 mm3) compared to intravenously administered DOX-NaCNs (10.29 ± 4.86 mm3) on day 17 of the experiment. NaCNs were well tolerated at a single dose of 2000 mg/kg in an acute oral toxicity study.

Conclusion

The enhanced anti-tumor effects of oral DOX-NaCNs might be related to the controlled release of DOX from the delivery system when compared to free DOX and the intravenous formulation of DOX-NaCNs. Moreover, NaCNs is recognized as a safe and non-toxic delivery system with excellent bio-distribution profile and high anti-tumor effects that has a potential for oral chemotherapy.

Overview of nanoparticulate strategies for solubility enhancement of poorly soluble drugs

Poor aqueous solubility and poor bioavailability are major issues with many pharmaceutical industries. By some estimation, 70-90% drug candidates in development stage while up-to 40% of the marketed products are poorly soluble which leads to low bioavailability, reduced therapeutic effects and dosage escalation. That's why solubility is an important factor to consider during design and manufacturing of the pharmaceutical products. To-date, various strategies have been explored to tackle the issue of poor solubility. This review article focuses the updated overview of commonly used macro and nano drug delivery systems and techniques such as micronization, solid dispersion (SD), supercritical fluid (SCF), hydrotropy, co-solvency, micellar solubilization, cryogenic technique, inclusion complex formation-based techniques, nanosuspension, solid lipid nanoparticles, and nanogels/nanomatrices explored for solubility enhancement of poorly soluble drugs. Among various techniques, nanomatrices were found a promising and impeccable strategy for solubility enhancement of poorly soluble drugs. This article also describes the mechanism of action of each technique used in solubilization enhancement.

Efavirenz Loaded Mixed Polymeric Micelles: Formulation, Optimization, and In Vitro Characterization

Efavirenz (EFZ) is a biopharmaceutics classification system (BCS) Class-II, first-line antiretroviral (ARV) drug. However, its utility through the oral route is restricted by its poor solubility. The objective of this study was to formulate EFZ-loaded binary-mixed micelles as a potential carrier for oral administration of EFZ. Rubingh's regular solution theory was used to determine the interaction behavior of the two components (Cremophor RH 40 and Phospholipon 80H) and of the mixed micelles and synergistic behavior was confirmed. The mixed miceller system was formulated using solvent evaporation method and a 3² factorial design was used for the optimization of selected independent variables. Miceller systems were further characterized in terms of morphology, particle size, zeta potential, percent entrapment efficiency, and drug loading. Fourier transform infrared and differential scanning calorimetry measurements confirmed the entrapment of EFZ in the micelles. The optimized formulation presented desirable qualities viz., nanometric size (17.27 ± 0.079), high entrapment efficiency, and good colloidal stability. The prepared optimized micelles can be potential carriers for EFZ in ARV therapies.

Amphiphilic diblock copolymers of poly(glycidol) with biodegradable polyester/polycarbonate. organocatalytic one-pot ROP and self-assembling property

Poly(glycidol)-based block copolymers with excellent micelle formation properties were prepared via organocatalytic one-pot ROP.

Carrier-free nanodrugs for safe and effective cancer treatment

Clinical applications of many anti-cancer drugs are restricted due to their hydrophobic nature, requiring use of harmful organic solvents for administration, and poor selectivity and pharmacokinetics resulting in off-target toxicity and inefficient therapies. A wide variety of carrier-based nanoparticles have been developed to tackle these issues, but such strategies often fail to encapsulate drug efficiently and require significant amounts of inorganic and/or organic nanocarriers which may cause toxicity problems in the long term. Preparation of nano-formulations for the delivery of water insoluble drugs without using carriers is thus desired, requiring elegantly designed strategies for products with high quality, stability and performance. These strategies include simple self-assembly or involving chemical modifications via coupling drugs together or conjugating them with various functional molecules such as lipids, carbohydrates and photosensitizers. During nanodrugs synthesis, insertion of redox-responsive linkers and tumor targeting ligands endows them with additional characteristics like on-target delivery, and conjugation with immunotherapeutic reagents enhances immune response alongside therapeutic efficacy. This review aims to summarize the methods of making carrier-free nanodrugs from hydrophobic drug molecules, evaluating their performance, and discussing the advantages, challenges, and future development of these strategies.

Multifunctional periodontal membrane for treatment and regeneration purposes

Periodontitis is a chronic inflammatory disease that causes gum tissue degeneration and alveolar bone and tooth loss. The aim of this study is to develop a multifunctional matrix for the treatment of periodontitis and enhancement of regeneration of the periodontal tissue. The matrix was prepared from vitamin E containing hydrogel made of alginate and gelatin, and doxycycline HCl containing methoxy poly(ethylene glycol)-block-polycaprolactone micelles. Methoxy poly(ethylene glycol)-block-polycaprolactone was synthesized with ring-opening polymerization technique and characterized by proton nuclear magnetic resonance (1H NMR), Fourier-transform infrared spectroscopy, differential scanning calorimetry, and gel permeation chromatography. Micelles were characterized by measuring zeta potential, hydrodynamic diameter, drug encapsulation efficiency, drug loading capacity, and in vitro drug-release kinetics. Micelles were obtained with an average size of 164 nm and drug loading amount of 5.8%. The activity of doxycycline HCl–loaded micelles and vitamin E containing hydrogels was determined against Escherichia coli ( E. coli) and Staphylococcus aureus ( S. aureus) with disk diffusion method. Bio-efficacy of micelle-loaded alginate–gelatin hydrogels were tested in vitro using L929 fibroblasts and dental pulp stem cells. Doxycycline HCl–loaded micelles and vitamin E containing hydrogels showed a sustained release and exhibited inhibition zone against E. coli and S. aureus. Hydrogels with vitamin E and doxycycline HCl–loaded micelles promoted osteogenic differentiation of dental pulp stem cells. Results suggest that alginate–gelatin hydrogels containing doxycycline HCl–loaded micelles and vitamin E can be good candidates for the treatment of periodontitis and tissue regeneration.

Encapsulation for Cancer Therapy

The current rapid advancement of numerous nanotechnology tools is being employed in treatment of many terminal diseases such as cancer. Nanocapsules (NCs) containing an anti-cancer drug offer a very promising alternative to conventional treatments, mostly due to their targeted delivery and precise action, and thereby they can be used in distinct applications: as biosensors or in medical imaging, allowing for cancer detection as well as agents/carriers in targeted drug delivery. The possibility of using different systems-inorganic nanoparticles, dendrimers, proteins, polymeric micelles, liposomes, carbon nanotubes (CNTs), quantum dots (QDs), biopolymeric nanoparticles and their combinations-offers multiple benefits to early cancer detection as well as controlled drug delivery to specific locations. This review focused on the key and recent progress in the encapsulation of anticancer drugs that include methods of preparation, drug loading and drug release mechanism on the presented nanosystems. Furthermore, the future directions in applications of various nanoparticles are highlighted.

Micro and nanoscale technologies in oral drug delivery

Oral administration is a pillar of the pharmaceutical industry and yet it remains challenging to administer hydrophilic therapeutics by the oral route. Smart and controlled oral drug delivery could bypass the physiological barriers that limit the oral delivery of these therapeutics. Micro- and nanoscale technologies, with an unprecedented ability to create, control, and measure micro- or nanoenvironments, have found tremendous applications in biology and medicine. In particular, significant advances have been made in using these technologies for oral drug delivery. In this review, we briefly describe biological barriers to oral drug delivery and micro and nanoscale fabrication technologies. Micro and nanoscale drug carriers fabricated using these technologies, including bioadhesives, microparticles, micropatches, and nanoparticles, are described. Other applications of micro and nanoscale technologies are discussed, including fabrication of devices and tissue engineering models to precisely control or assess oral drug delivery in vivo and in vitro, respectively. Strategies to advance translation of micro and nanotechnologies into clinical trials for oral drug delivery are mentioned. Finally, challenges and future prospects on further integration of micro and nanoscale technologies with oral drug delivery systems are highlighted.

Bioavailability Enhancement of Poorly Soluble Drugs: The Holy Grail in Pharma Industry

Background:

Bioavailability, one of the prime pharmacokinetic properties of a drug, is defined as the fraction of an administered dose of unchanged drug that reaches the systemic circulation and is used to describe the systemic availability of a drug. Bioavailability assessment is imperative in order to demonstrate whether the drug attains the desirable systemic exposure for effective therapy. In recent years, bioavailability has become the subject of importance in drug discovery and development studies.

Methods:

A systematic literature review in the field of bioavailability and the approaches towards its enhancement have been comprehensively done, purely focusing upon recent papers. The data mining was performed using databases like PubMed, Science Direct and general Google searches and the collected data was exhaustively studied and summarized in a generalized manner.

Results:

The main prospect of this review was to generate a comprehensive one-stop summary of the numerous available approaches and their pharmaceutical applications in improving the stability concerns, physicochemical and mechanical properties of the poorly water-soluble drugs which directly or indirectly augment their bioavailability.

Conclusion:

The use of novel methods, including but not limited to, nano-based formulations, bio-enhancers, solid dispersions, lipid-and polymer-based formulations which provide a wide range of applications not only increases the solubility and permeability of the poorly bioavailable drugs but also improves their stability, and targeting efficacy. Although, these methods have drastically changed the pharmaceutical industry demand for the newer potential methods with better outcomes in the field of pharmaceutical science to formulate various dosage forms with adequate systemic availability and improved patient compliance, further research is required.

Novel propyl karaya gum nanogels for bosentan: In vitro and in vivo drug delivery performance

The amphiphilic propyl Karaya gum (KG) with a degree of propyl group substitution of 3.24 was synthesized to design self-assembled nanogels as carriers for bosentan monohydrate, a poorly soluble antihypertensive drug. The drug was physically hosted into the hydrophobic core of the micellar nanogels by solvent evaporation method. TEM images revealed spherical shape and core-shell morphology of the nanogels. Depending upon polymer: drug weight ratio, the drug entrapment efficiency of >85% was attained. The carriers had hydrodynamic diameter in the range of 230-305 nm with narrow size distribution. The zeta potential of -23.0 to -24.9 mV and low critical association concentration (CAC) of 8.32 mg/l provided evidence that the colloidal nanogel system was physically stable. Thermodynamics of the propyl KG system in water favored spontaneous self-assembly of propyl KG. FTIR, thermal and x-ray analyses suggested that the drug was compatible in the hydrophobic confines of the nanogels. The micellar nanogels liberated their contents in simulated gastrointestinal condition in a pH-dependent manner over a period of 10 h. Peppas-Sahlin modeling of in vitro drug release data suggested that the polymer relaxation/swelling mechanism dominated the drug release process. Pre-clinical testing of the mucoadhesive nanogel formulations exhibited that the system could monitor the anti-hypertensive activity for a prolonged period. Overall, this propyl KG micellar nanogel system had a great potential and splendid outlook to serve as novel oral controlled release carriers for poorly soluble drugs with outstanding pharmacodynamics.

Thermodynamic insights and molecular environments into catanionic surfactant systems: Influence of chain length and molar ratio

HYPOTHESIS

Imidazolium-based Ionic liquids as new generation cationic surfactants can provide designable alkyl chain length. In the catanionic surfactant systems, the alkyl chain lengths and molar ratios can greatly influence the interactions such as electrostatic and hydrophobic interaction. The variation in these interactions has a significant effect on the molecular environments of the self-assembly structure, and this process is always accompanied by the transition of aggregates and release or consumption of heat. Hence, it is of interest to study the relationship between intermolecular interactions, molecular environments, self-assembly structure and the change in energy of system in the catanionic surfactant mixed systems.

EXPERIMENTS

The enthalpy change ΔH of titrations the imidazolium-based into SDS micelle solution was studied to characterize the heat by using isothermal titration calorimetry (ITC) during the transitions of the aggregate structures. The corresponding self-assembly structure was monitored via cryogenic transmission electron microscopy (cryo-TEM). Employing proton magnetic resonance (¹H NMR), we focus on the interactions between imidazolium-based ILs and SDS based on the variations in the molecular environments of aggregates.

FINDINGS

Of these imidazolium-based ionic liquids/SDS system, the 1-octyl-3-methylimidazolium ([OMIM]Cl)/SDS system shows several features such as intense energy absorption and releasing processes, which indicate the formation of high entanglement wormlike micelles and vesicles. This is related to the formation of self-adjusting state between the SDS and [OMIM]Cl molecules due to the balance between the electrostatic interaction and hydrophobic interaction. Varying the alkyl chain length appears to cause significant differences to the molecular environments. From the molecular environments, three different models about the polarity of the catanionic surfactant molecules are used to explain the balance of the intermolecular interactions.

Paclitaxel/hydroxypropyl-β-cyclodextrin complex-loaded liposomes for overcoming multidrug resistance in cancer chemotherapy

Multidrug resistance (MDR) is the largest obstacle to the success of chemotherapy. The development of innovative strategies and safe sensitizers is required to overcome MDR. Paclitaxel (PTX) is a widely used chemotherapeutic drug, the application of which has been learn to understand MDR. However, the application and use are severely restricted because of this MDR. Cyclodextrins (CDs) of many carriers, additionally have shown anti-cancer capability in MDR cancer cells. In this study, novel paclitaxel/hydroxypropyl-β-cyclodextrin complex-loaded liposomes (PTXCDL) have been developed in an attempt to overcome MDR in a PTX-resistant human lung adenocarcinoma (A549/T) cell line. The in vitro application of PTXCDL exhibited pH-sensitive PTX release, potent cytotoxicity, and enhanced intracellular accumulation. In comparison to in vivo, PTXCDL also show a stronger inhibition of tumor growth. In comparison, these findings suggest that the PTXCDL provide a novel strategy for effective therapy of resistant cancers by overcoming the drug resistance.

Strategic use of nanotechnology in drug targeting and its consequences on human health: A focused review

Since the development of first lipid-based nanocarrier system, about 15% of the present pharmaceutical market uses nanomedicines to achieve medical benefits. Nanotechnology is an advanced area to meliorate the delivery of compounds for improved medical diagnosis and curing disease. Nanomedicines are gaining significant interest due to the ultra small size and large surface area to mass ratio. In this review, we discuss the potential of nanotechnology in delivering of active moieties for the disease therapy including their toxicity evidences. This communication will help the formulation scientists in understanding and exploring the new aspects of nanotechnology in the field of nanomedicine.

pH-Responsive Polyion Complex Vesicle with Polyphosphobetaine Shells

When a bioactive molecule is taken into cells by endocytosis, it is sometimes unable to escape from the lysosomes, resulting in inefficient drug release. We prepared pH-responsive polyion complex (PIC) vesicles that collapse under acidic conditions such as those inside a lysosome. Furthermore, under acidic conditions, cationic polymer was released from the PIC vesicles to break the lysosome membranes. Diblock copolymers (P₂₀M₁₆₇ and P₂₀A₁₉₀) consisting of water-soluble zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) block and cationic or anionic blocks were synthesized via reversible addition-fragmentation chain transfer (RAFT) radical polymerization. Poly(3-(methacrylamidopropyl) trimethylammonium chloride) (PMAPTAC) and poly(sodium 6-acrylamidohexanoate) (PAaH) were used as the cationic and anionic blocks, respectively. The pendant hexanoate groups in the PAaH block are ionized in basic water and in phosphate buffered saline (PBS), while the hexanoate groups are protonated in acidic water. In basic water, PIC vesicles were formed from a charge neutralized mixture of oppositely charged diblock copolymers. At the interface of PIC vesicle and water exists biocompatible PMPC shells. Under acidic conditions, the PIC vesicles collapsed, because the charge balance shifted due to protonation of the PAaH block. After collapse of the PIC vesicles, P₂₀A₁₉₀ formed micelles composed of protonated PAaH core and PMPC shells, while P₂₀M₁₆₇ was released as unimers. PIC vesicles can encapsulate hydrophilic nonionic guest molecules into their hollow core. Under acidic conditions, the PIC vesicles can release the guest molecules and P₂₀M₁₆₇. The cationic P₂₀M₁₆₇ can break the lysosome membrane to efficiently release the guest molecules from the lysosomes to the cytoplasm.

Facile Strategy Enabling Both High Loading and High Release Amounts of the Water-Insoluble Drug Clofazimine Using Mesoporous Silica Nanoparticles

The use of nanocarriers to deliver poorly soluble drugs to the sites of diseases is an attractive and general method, and mesoporous silica nanoparticles (MSNs) are increasingly being used as carriers. However, both loading a large amount of drugs into the pores and still being able to release the drug is a challenge. In this paper, we demonstrate a general strategy based on a companion molecule that chaperones the drug into the pores and also aids it in escaping. A common related strategy is to use a miscible co-solvent dimethyl sulfoxide (DMSO), but although loading may be efficient in DMSO, this co-solvent frequently diffuses into an aqueous environment, leaving the drug behind. We demonstrate the method by using acetophenone (AP), an FDA-approved food additive as the chaperone for clofazimine (CFZ), a water-insoluble antibiotic used to treat leprosy and multidrug-resistant tuberculosis. AP enables a high amount of CFZ cargo into the MSNs and also carries CFZ cargo out from the MSNs effectively when they are in an aqueous biorelevant environment. The amount of loading and the CFZ release efficiency from MSNs were optimized; 4.5 times more CFZ was loaded in MSNs with AP than that with DMSO and 2300 times more CFZ was released than that without the assistance of the AP. In vitro treatment of macrophages infected by Mycobacterium tuberculosis with the optimized CFZ-loaded MSNs killed the bacteria in the cells in a dose-dependent manner. These studies demonstrate a highly efficient method for loading nanoparticles with water-insoluble drug molecules and the efficacy of the nanoparticles in delivering drugs into eukaryotic cells in aqueous media.

Enhanced biopharmaceutical effects of tranilast on experimental colitis model with use of self-micellizing solid dispersion technology

The present study aimed to clarify the applicability of a self-micellizing solid dispersion of tranilast (SMSD/TL) to the treatment of inflammatory bowel diseases (IBD) using an experimental colitis model. SMSD/TL with several loading amounts ranging from 10 to 50% was prepared using a wet-milling system. The physicochemical properties of SMSD/TL were evaluated in terms of the dissolution behavior, morphology, and particle size distribution. Animal studies were conducted to evaluate oral bioavailability in rats and anti-inflammatory effects in a rat model of chemically induced colitis. SMSD/TL with drug loading of 15% (SMSD/TL15) showed enhanced dissolution behavior at pH 1.2, compared with other tested other formulations. After the dispersion of SMSD/TL15 in deionized water, fine micelles formed with an average diameter of 137 nm. SMSD/TL15 (10 mg-TL/kg) exhibited about 147- and 34-fold greater value for C_max and the area under the curve of plasma concentration vs. time than crystalline TL, respectively. Although the anti-inflammatory effect on the colitis model was very limited in the crystalline TL (2 mg/kg) group, inflammatory events, such as myeloperoxidase activity and thickening of the submucosa in colon tissues, were significantly suppressed in the SMSD/TL15 (2 mg-TL/kg) group. Based on these findings, SMSD/TL might be a more efficacious dosage option for improved IBD treatment.

Synthetic low-density lipoprotein (sLDL) selectively delivers paclitaxel to tumor with low systemic toxicity

Low density lipoprotein (LDL), which is a principal carrier for the delivery of cholesterol, has been used as a great candidate for the delivery of drugs to tumor based on the great requirements for cholesterol of many cancer cells. Mimicking the structure and composition of LDL, we designed a synthetic low-density lipoprotein (sLDL) to encapsulate paclitaxel-alpha linolenic acid (PALA) for tumor therapy. The PALA loaded sLDL (PALA-sLDL) and PALA-loaded microemulsion (PALA-ME, without the binding domain for LDLR) displayed uniform sizes with high drug loading efficiency (> 90%). In vitro studies demonstrated PALA-sLDL exhibited enhanced cellular uptake capacity and better cytotoxicity to LDLR over-expressed U87 MG cells as compared to PALA-ME. The uptake mechanisms of PALA-sLDL were involved in a receptor mediated endocytosis and macropinocytosis. Furthermore, the in vivo biodistribution and tumor growth inhibition studies of PALA-sLDL were investigated in xenograft U87 MG tumor-bearing mice. The results showed that PALA-sLDL exhibited higher tumor accumulation than PALA-ME and superior tumor inhibition efficiency (72.1%) compared to Taxol^® (51.2%) and PALA-ME (58.8%) but with lower toxicity. These studies suggested that sLDL is potential to be used as a valuable carrier for the selective delivery of anticancer drugs to tumor with low systemic toxicity.

RNA Loading on Nano-Structured Hyperbranched β-Cyclodextrin

BACKGROUND

β-Cyclodextrin functionalized hyper-branched polyglycerol (HBCD: β-CD-g-PG), a biocompatible polymer, has recently been proposed for delivery of poorly water soluble compounds.

METHODS

The present study examines the interaction of HBCD with RNA, utilizing a constant concentration of RNA and different HBCD/RNA ratios of 1/16 to 1/1, at physiological condition in an aqueous solution. Circular Dichroism (CD), UV-visible, FTIR spectroscopic methods, zeta potential and Dynamic Light Scattering (DLS) were used to analyze the particle formation, particle charge, particle size, aggregation, RNA conformation, binding constant and mode, and the effect of polymer complexation on RNA stability.

RESULTS

The results indicate that the interaction of RNA with HBCD leads to the formation of a linear dendritic supramolecule biopolymer with an overall binding constant of K_HBCD/RNA= 1.25 × 10³.

CONCLUSION

The small sized synthesized polymer can be considered as an appropriate system for preventing RNA aggregation and protecting the gene by host-guest interaction.

A new difluoromethoxyl-containing acrylate monomer for PEG-b-PDFMOEA amphiphilic diblock copolymers

This article reports the first synthesis of a well-defined difluoromethoxyl-containing polyacrylate via ATRP.

Dehydroascorbic Acid and pGPMA Dual Modified pH-Sensitive Polymeric Micelles for Target Treatment of Liver Cancer

In clinical therapy, the poor prognosis of hepatocellular carcinoma (HCC) is mainly attributed to the failure of chemotherapeutical agents to accumulate in tumor as well as lack of potency of tumor penetration. In this work, we developed actively tumor-targeting micelles with pH-sensitive linker as a novel nanocarrier for HCC therapy. These micelles comprised biodegradable poly(ethylene glycol)-poly(aspartate) polymers, in which paclitaxel can be covalently conjugated to pAsp via an acid-labile acetal bond to form pH-responsive structures. In vitro drug release studies showed that these structures were stable in physiological condition, whereas collapsed once internalized into cells due to the mildly acidic environment in endo/lysosomes, resulting in facilitated intracellular paclitaxel release. In addition, dehydroascorbic acid and guanidinopropyl methacrylamide polymers were decorated on the surface of micelles to achieve specific tumor accumulation and tumor penetration. Cellular uptake and in vivo imaging studies proved that these micelles had remarkable targeting property toward hepatocarcinoma cells and tumor. Enhanced anti-HCC efficacy of the micelles was also confirmed both in vitro and in vivo. Therefore, this micellar system may be a potential platform of chemotherapeutics delivery for HCC therapy.

Nanomanufacturing through microfluidic-assisted nanoprecipitation: Advanced analytics and structure-activity relationships

We have employed microfluidics (cross-shaped chip) for the preparation of drug-loaded poly(lactic acid-co-glycolic acid) (PLGA) nanoparticles. The polymer precipitates from an acetone solution upon its controlled laminar mixing (flow focusing) with an aqueous solution of a surfactant, allowing for an operator-independent, up-scalable and reproducible preparative process of nanoformulations. Firstly, using PEGylated surfactants we have compared batch and microfluidic processes, and showed the superior reproducibility of the latter and its strong dependency on the acetone/water ratio (flow rate ratio). We have then focused on the issue of purification from free surfactant, and employed advanced characterization techniques such as flow-through dynamic light scattering as the in-line quality control technique, and field flow fractionation (FFF) with dynamic and static light scattering detection, which allowed the detection of surfactant micelles in mixture with nanoparticles (hardly possible with stand-alone dynamic light scattering). Finally, we have shown that the choice of polymer and surfactant affects the release behaviour of a model drug (paclitaxel), with high molecular weight PLGA (RG756) and low molecular weight surfactant (tocopheryl poly(ethylene glycol) 1000 succinate, TPGS) apparently showing higher burst and accelerated release.

Intermolecular Interactions between Coencapsulated Drugs Inhibit Drug Crystallization and Enhance Colloidal Stability of Polymeric Micelles

Novel "pairs" of drugs possessing pharmacological synergies could be encapsulated into polymeric micelles and exert superb therapeutic effects in vivo upon intravenous administration, with the prerequisite that the micelles remain stable. NADP(H) quinone oxidoreductase 1 (NQO1) inhibitors, such as β-lapachone (LPC) and tanshinone IIA (THA), are structurally and pharmacologically similar molecules that are poorly water-soluble, crystallize extremely fast, and demonstrate synergistic anticancer effect when used together with paclitaxel (PTX). However, when coencapsulated with PTX in poly(ethylene glycol)-b-poly(d,l-lactic acid) (PEG-PLA) micelles, only PTX/LPC but not the PTX/THA pair yields satisfactory colloidal stability. To reveal the molecular mechanism contributing to the colloidal stability of the coencapsulated micelles, we investigated the molecular interactions of PTX/LPC and PTX/THA, through both experimental methods (crystallization kinetics, ¹³C NMR) and molecular dynamic simulation. We observed that PTX was capable of inhibiting LPC but not THA crystallization both in an aqueous environment and in the solid state, which could be attributed to the strong hetero-intermolecular interactions (π-π, H-bonding) between LPC and PTX, which disrupted the homo-intermolecular interactions between LPC molecules and thus formed a favorable miscible binary system. In comparison, the lack of a strong PTX/THA interaction left the strong THA/THA stacking interaction undisturbed and the fast THA crystallization tendency unrestrained. We conclude that the intermolecular interactions, i.e., the "pharmaceutical synergy", between the coencapsulated drugs critically control the colloidal stability of polymeric micelles and, therefore, should be evaluated when coencapsulated drug delivery systems are designed for optimal therapeutic benefits.

Efficient Codelivery of Paclitaxel and Curcumin by Novel Bottlebrush Copolymer-based Micelles

The novel self-assembling bottlebrush polyethylene glycol-polynorbornene-thiocresol block copolymers (PEG-PNB-TC) were synthesized by the ring opening metathesis polymerization (ROMP), followed by functionalization of the polymer backbone via the thio-bromo "click" postpolymerization strategy. The PEG-PNB-TC copolymers could easily self-assemble into the nanoscale core-shell polymeric micelles. The hydrophobic anticancer drugs, such as paclitaxel (PTX), could be loaded into their hydrophobic core to form a stable drug-loaded micelle with a superior drug loading capacity of up to ∼35% (w/w). The sustained drug release behavior of the PEG-PNB-TC micelles was observed under a simulated "sink condition". Compared with commercial PTX formulation (Taxol), the PTX-loaded PEG-PNB-TC micelles showed the enhanced in vitro cellular uptake and comparable cytotoxicity in the drug-sensitive cancer cells, while the copolymers were much safer than Cremophor EL, the surfactant used in Taxol. Furthermore, curcumin (CUR), a natural chemotherapy drug sensitizer, was successfully coloaded with PTX into the PEG-PNB-TC micelles. High drug loading capacity of the PEG-PNB-TC micelles allowed for easy adjustment of drug doses and the ratio of the coloaded drugs. The combination of PTX and CUR showed synergistic anticancer effect in both the drug mixture and drug coloaded micelles at high CUR/PTX ratio, while low CRU/PTX ratio only exhibited additive effects. The combinatorial effects remarkably circumvented the PTX resistance in the multidrug resistant (MDR) cancer cells. Due to the easy polymerization and functionalization, excellent self-assembly capability, high drug loading capability, and great stability, the PEG-PNB-TC copolymers might be a promising nanomaterial for delivery of the hydrophobic anticancer drugs, especially for combination drug therapy.

Tri-block co-polymer nanocarriers for enhancement of oral delivery of felodipine: preparation, in vitro characterization and ex vivo permeation

This study aimed to prepare, optimize and characterize novel felodipine-loaded polymeric nanomicelles, using a pluronic mixture of F127 and P123. Thin-film hydration method was adopted for the preparation of different polymeric nanomicelles (T1-T12) according to a 4¹.3¹ full factorial design. Factors studied were: Pluronic®:drug ratio (P:D ratio) (10, 20, 30 and 40 w/w) and percent of hydrophilic polymer (F127%) (33.33%, 50% and 66.67% w/w). Optimization criteria were to maximize transmittance percent (T%) and entrapment efficiency percent (EE%) and to minimize particle size (PS) and polydispersity index (PDI). The optimized formulation was further characterized by DSC, FTIR and ¹H NMR studies. It was also subjected to stability testing and ex vivo permeation using rabbit intestines. Spherical nanomicelles of particle size ranging from 26.18 to 87.54 nm were successfully obtained. The optimized formulation was found to be the already prepared formulation T12 (P:D ratio of 40 and 66.67% F127) with suitable T% and EE% of 95.12% and 91.75%, respectively. DSC, FTIR and ¹H NMR studies revealed felodipine (FLD) incorporation within T12 nanomicelles. T12 enhanced the ex vivo intestinal permeation of FLD when compared to a drug suspension and showed good stability. Therefore, pluronic nanomicelles could be promising for improved oral delivery of FLD.

Molecularly targeted co-delivery of a histone deacetylase inhibitor and paclitaxel by lipid-protein hybrid nanoparticles for synergistic combinational chemotherapy

In this study, a transferrin-anchored albumin nanoplatform with PEGylated lipid bilayers (Tf-L-APVN) was developed for the targeted co-delivery of paclitaxel and vorinostat in solid tumors. Tf-L-APVN exhibited a sequential and controlled release profile of paclitaxel and vorinostat, with an accelerated release pattern at acidic pH. At cellular levels, Tf-L-APVN significantly enhanced the synergistic effects of paclitaxel and vorinostat on the proliferation of MCF-7, MDA-MB-231, and HepG2 cancer cells. Vorinostat could significantly enhance the cytotoxic potential of paclitaxel, induce marked cell apoptosis, alter cell cycle patterns, and inhibit the migratory capacity of cancer cells. In addition, Tf-L-APVN showed prolonged circulation in the blood and maintained an effective ratio of 1:1 (for paclitaxel and vorinostat) throughout the study period. In HepG2 tumor-bearing mice, Tf-L-APVN displayed excellent antitumor efficacy and the combination of paclitaxel and vorinostat significantly inhibited the tumor growth. Taken together, dual drug-loaded Tf receptor-targeted nanomedicine holds great potential in chemotherapy of solid tumors.

Hydrotropic polymer-based paclitaxel-loaded self-assembled nanoparticles: preparation and biological evaluation

Hydrotropic polymer-based paclitaxel-loaded self-assembled nanoparticles: preparation and biological evaluation.

Biocompatible hyperbranched polyglycerol modified β-cyclodextrin derivatives for docetaxel delivery

The development of biocompatible vector for hydrophobic drug delivery remains a longstanding issue in cancer therapy. We design and synthesis a drug delivery system based on HPG modified β-CD (β-CD-HPG) by conjugating HPG branches onto β-CD core and its structure was confirmed by NMR, FTIR, GPC and solubility. In vitro biocompatibility tests showed that HPG modification significantly improved red blood cells morphology alteration and hemolysis cause by β-CD and β-CD-HPG displayed cell safety apparently in a wide range of 0.01-1mg/mL. An anti-cancer drug, docetaxel, was effectively encapsulated into β-CD-HPG which was confirmed by DSC analysis. This copolymer could form nanoparticles with small size (<200nm) and exhibited better DTX loading capacity and controlled release kinetics without initial burst release behavior compared with β-CD. Furthermore, antitumor assay in vitro show that β-CD-HPG/DTX effectively inhibited proliferation of human breast adenocarcinoma cells. Therefore, β-CD-HPG/DTX exhibit great potential for cancer chemotherapy.

Click modified amphiphilic graft copolymeric micelles of poly(styrene-alt-maleic anhydride) for combinatorial delivery of doxorubicin and plk-1 siRNA in cancer therapy

The anti-apoptotic defense mechanism of cancer cells poses a major hurdle which makes chemotherapy less effective. Combinatorial delivery of drugs and siRNAs targeting anti-apoptotic proteins is a vital means for improving therapeutic effects. The present study aims at designing a suitable carrier which can effectively co-deliver doxorubicin and plk1 siRNA to tumor cells. Low molecular weight poly(styrene-alt-maleic anhydride) was chemically modified via a click reaction to obtain a cationic amphiphilic polymer for the co-delivery of therapeutic agents. Short glycol chains were utilized as linker molecules for grafting which in turn imparted a stealth nature and minimized plasma protein adsorption to the polymeric surface. Isonicotinic acid was grafted to the polymer due to its ability to penetrate the endolysosomal membrane and arginine-lysine conjugates were embedded for complexing siRNA. The polymer was able to self-assemble in to smooth, spherical micellar structures with a CMC of ∼3 μg mL^-1. The particle size of the micelles was ∼14-30 nm as depicted using TEM and FESEM. Atomic force microscopic analysis showed an average height of ∼12 nm for the polymeric micelles. An optimum doxorubicin loading of ∼9% w/w was achieved with the micelles using a dialysis method. Effective complexation of siRNA occurred above a polymer/siRNA weight ratio of 10 without any significant change in the particle size. Doxorubicin and fluorescent labeled siRNA loaded micelles exhibited excellent co-localization within the cytoplasm of MCF-7 cells. The synergistic effect of the active agents in inhibiting tumor cell proliferation was depicted using an MTT assay and visualized using calcein/propidium iodide staining of the treated cells. Co-administration of doxorubicin and plk1 siRNA in EAT tumor bearing Swiss albino mice using the cationic micelles significantly enhanced the antitumor efficacy.