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1.
Angew Chem Int Ed Engl ; 63(5): e202312823, 2024 Jan 25.
Article in English | MEDLINE | ID: mdl-38010646

ABSTRACT

Concerns over the sustainability and end-of-life properties of fossil-derived surfactants have driven interest in bio-based alternatives. Lignocellulosic biomass with its polar functional groups is an obvious feedstock for surfactant production but its use is limited by process complexity and low yield. Here, we present a simple two-step approach to prepare bio-based amphiphiles directly from hemicellulose and lignin at high yields (29 % w/w based on the total raw biomass and >80 % w/w of these two fractions). Acetal functionalization of xylan and lignin with fatty aldehydes during fractionation introduced hydrophobic segments and subsequent defunctionalization by hydrogenolysis of the xylose derivatives or acidic hydrolysis of the lignin derivatives produced amphiphiles. The resulting biodegradable xylose acetals and/or ethers, and lignin-based amphiphilic polymers both largely retained their original natural structures, but exhibited competitive or superior surface activity in water/oil systems compared to common bio-based surfactants.


Subject(s)
Lignin , Xylose , Lignin/chemistry , Biomass , Water , Surface-Active Agents , Hydrolysis
2.
AAPS J ; 25(4): 67, 2023 06 29.
Article in English | MEDLINE | ID: mdl-37386339

ABSTRACT

This study investigated the impact of gastro-intestinal fluid volume and bile salt (BS) concentration on the dissolution of carbamazepine (CBZ) immediate release (IR) 100 mg tablets and to integrate these in vitro biorelevant dissolution profiles into physiologically based pharmacokinetic modelling (PBPK) in pediatric and adult populations to determine the biopredictive dissolution profile. Dissolution profiles of CBZ IR tablets (100 mg) were generated in 50-900 mL biorelevant adult fasted state simulated gastric and intestinal fluid (Ad-FaSSGF and Ad-FaSSIF), also in three alternative compositions of biorelevant pediatric FaSSGF and FaSSIF medias at 200 mL. This study found that CBZ dissolution was poorly sensitive to changes in the composition of the biorelevant media, where dissimilar dissolution (F2 = 46.2) was only observed when the BS concentration was changed from 3000 to 89 µM (Ad-FaSSIF vs Ped-FaSSIF 50% 14 BS). PBPK modeling demonstrated the most predictive dissolution volume and media composition to forecast the PK was 500 mL of Ad-FaSSGF/Ad-FaSSIF media for adults and 200 mL Ped-FaSSGF/FaSSIF media for pediatrics. A virtual bioequivalence simulation was conducted by using Ad-FaSSGF and/or Ad-FaSSIF 500 mL or Ped-FaSSGF and/or Ped-FaSSIF 200 mL dissolution data for CBZ 100 mg (reference and generic test) IR product. The CBZ PBPK models showed bioequivalence of the product. This study demonstrates that the integration of biorelevant dissolution data can predict the PK profile of a poorly soluble drug in both populations. Further work using more pediatric drug products is needed to verify biorelevant dissolution data to predict the in vivo performance in pediatrics.


Subject(s)
Benzodiazepines , Drugs, Generic , Humans , Child , Adult , Solubility , Therapeutic Equivalency , Bile Acids and Salts , Carbamazepine
3.
Cryst Growth Des ; 23(3): 1668-1675, 2023 Mar 01.
Article in English | MEDLINE | ID: mdl-36879769

ABSTRACT

To explore the effect of chain length and conformation on the nucleation of peptides, the primary nucleation induction time of glycine homopeptides in pure water at different supersaturation levels under various temperatures has been determined. Nucleation data suggest that longer chains will prolong the induction time, especially for chains longer than three, where nucleation will occur over several days. In contrast, the nucleation rate increased with an increase in the supersaturation for all homopeptides. Induction time and nucleation difficulty increase at lower temperatures. However, for triglycine, the dihydrate form was produced with an unfolded peptide conformation (pPII) at low temperature. The interfacial energy and activation Gibbs energy of this dihydrate form are both lower than those at high temperature, while the induction time is longer, indicating the classical nucleation theory is not suitable to explain the nucleation phenomenon of triglycine dihydrate. Moreover, gelation and liquid-liquid separation of longer chain glycine homopeptides were observed, which was normally classified to nonclassical nucleation theory. This work provides insight into how the nucleation process evolves with increasing chain length and variable conformation, thereby offering a fundamental understanding of the critical peptide chain length for the classical nucleation theory and complex nucleation process for peptides.

4.
Trials ; 23(1): 677, 2022 Aug 17.
Article in English | MEDLINE | ID: mdl-35978361

ABSTRACT

BACKGROUND: Approximately 75,000 people fracture a hip each year in the UK. This painful injury can be devastating-with a high associated mortality rate-and survivors likely to be more dependent and less mobile. Pain relief at the scene of injury is known to be inadequate. Intravenous morphine is usually given by paramedics, but opioids are less effective for dynamic pain and can cause serious side effects, including nausea, constipation, delirium and respiratory depression. These may delay surgery, require further treatment and worsen patient outcomes. We completed a feasibility study of paramedic-provided fascia iliaca compartment block (FICB), testing the intervention, trial methods and data collection. The study (RAPID) demonstrated that a full trial was feasible. In this subsequent study, we aim to test safety, clinical and cost-effectiveness of paramedic-provided FICB as pain relief to patients with suspected hip fracture in the prehospital environment. METHODS: We will conduct a pragmatic multi-centre individually randomised parallel-group trial, with a 1:1 allocation between usual care (control) and FICB (intervention). Hospital clinicians in five sites (paired ambulance services and receiving hospitals) in England and Wales will train 220 paramedics to administer FICB. The primary outcome is change in pain score from pre-randomisation to arrival at the emergency department. One thousand four hundred patients are required to find a clinically important difference between trial arms in the primary outcome (standardised statistical effect ~ 0.2; 90% power, 5% significance). We will use NHS Digital (England) and the SAIL (Secure Anonymised Information Linkage) databank (Wales) to follow up patient outcomes using routine anonymised linked data in an efficient study design, and questionnaires to capture patient-reported outcomes at 1 and 4 months. Secondary outcomes include mortality, length of hospital stay, job cycle time, prehospital medications including morphine, presence of hip fracture, satisfaction, mobility, and NHS costs. We will assess safety by monitoring serious adverse events (SAEs). DISCUSSION: The trial will help to determine whether paramedic administered FICB is a safe, clinically and cost-effective treatment for suspected hip fracture in the pre-hospital setting. Impact will be shown if and when clinical guidelines either recommend or reject the use of FICB in routine practice in this context. TRIAL REGISTRATION: ISRCTN15831813 . Registered on 22 September 2021.


Subject(s)
Analgesia , Hip Fractures , Nerve Block , Allied Health Personnel , Analgesia/methods , Cost-Benefit Analysis , Fascia , Hip Fractures/surgery , Humans , Morphine/adverse effects , Multicenter Studies as Topic , Nerve Block/adverse effects , Nerve Block/methods , Pain/drug therapy , Randomized Controlled Trials as Topic
5.
BMJ Open ; 12(6): e062971, 2022 06 09.
Article in English | MEDLINE | ID: mdl-35680254

ABSTRACT

INTRODUCTION: Adolescence is a challenging period for young people with type 1 diabetes, associated with worsening glycaemia and care disengagement. Educational interventions in this period tend to focus on diabetes-specific skills, with less emphasis on the psychosocial challenges associated with diabetes experienced by young people. To address this limitation, we codesigned with young people a psychosocially modelled programme of diabetes education, named 'Youth Empowerment Skills' (YES). The programme aims to facilitate a positive adaptation to life with diabetes and engagement with diabetes care through peer-based learning, immersive simulations and support from an outreach youth worker. Here, we present a protocol for a feasibility study of the YES programme. METHODS AND ANALYSIS: The study was designed following the Medical Research Council Complex Intervention Evaluation Framework to: test the feasibility (acceptance, implementability, recruitment and completion) of the YES programme; and estimate its efficacy in relation to metabolic and psychosocial outcomes. The study will take place in diabetes centres serving socioculturally diverse populations. We will conduct a feasibility randomised controlled trial (waiting-list design) with integrated process evaluation. Fifty young people with type 1 diabetes (aged 14-19 years) will be randomly allocated to either the YES intervention or a waiting-list control. Randomisation acceptability will be assessed with provision for a preference allocation. Outcomes will be evaluated at 6 months, at which point the waiting list participants will be exposed to the YES programme with further follow-up to 12 months. A simultaneous process evaluation will use a mixed-methods approach collecting qualitative and quantitative data. Study findings will be used to optimise the intervention components, outcome measures and recruitment methods to inform a subsequent definitive trial. ETHICS AND DISSEMINATION: The protocol has ethical approval from the UK Health Research Authority (approval IRAS project ID: 279877). Findings will be disseminated in multiple formats for lay and professional audiences. PROTOCOL DATE AND VERSION: 7 April 2021, V.1.1. TRIAL REGISTRATION NUMBER: NCT04670198.


Subject(s)
Diabetes Mellitus, Type 1 , Adolescent , Blood Glucose , Diabetes Mellitus, Type 1/therapy , Feasibility Studies , Health Education , Humans , Randomized Controlled Trials as Topic
6.
Nat Chem ; 14(9): 976-984, 2022 09.
Article in English | MEDLINE | ID: mdl-35739426

ABSTRACT

The development of sustainable plastics from abundant renewable feedstocks has been limited by the complexity and efficiency of their production, as well as their lack of competitive material properties. Here we demonstrate the direct transformation of the hemicellulosic fraction of non-edible biomass into a tricyclic diester plastic precursor at 83% yield (95% from commercial xylose) during integrated plant fractionation with glyoxylic acid. Melt polycondensation of the resulting diester with a range of aliphatic diols led to amorphous polyesters (Mn = 30-60 kDa) with high glass transition temperatures (72-100 °C), tough mechanical properties (ultimate tensile strengths of 63-77 MPa, tensile moduli of 2,000-2,500 MPa and elongations at break of 50-80%) and strong gas barriers (oxygen transmission rates (100 µm) of 11-24 cc m-2 day-1 bar-1 and water vapour transmission rates (100 µm) of 25-36 g m-2 day-1) that could be processed by injection moulding, thermoforming, twin-screw extrusion and three-dimensional printing. Although standardized biodegradation studies still need to be performed, the inherently degradable nature of these materials facilitated their chemical recycling via methanolysis at 64 °C, and eventual depolymerization in room-temperature water.


Subject(s)
Polyesters , Sugars , Lignin , Plastics
7.
Nanomaterials (Basel) ; 10(9)2020 Sep 15.
Article in English | MEDLINE | ID: mdl-32942556

ABSTRACT

Extracellular vesicles (EVs) are emerging as promising nanoscale therapeutics due to their intrinsic role as mediators of intercellular communication, regulating tissue development and homeostasis. The low immunogenicity and natural cell-targeting capabilities of EVs has led to extensive research investigating their potential as novel acellular tools for tissue regeneration or for the diagnosis of pathological conditions. However, the clinical use of EVs has been hindered by issues with yield and heterogeneity. From the modification of parental cells and naturally-derived vesicles to the development of artificial biomimetic nanoparticles or the functionalisation of biomaterials, a multitude of techniques have been employed to augment EVs therapeutic efficacy. This review will explore various engineering strategies that could promote EVs scalability and therapeutic effectiveness beyond their native utility. Herein, we highlight the current state-of-the-art EV-engineering techniques with discussion of opportunities and obstacles for each. This is synthesised into a guide for selecting a suitable strategy to maximise the potential efficacy of EVs as nanoscale therapeutics.

8.
Colloids Surf B Biointerfaces ; 190: 110902, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32143010

ABSTRACT

Topical administration of corticosteroids is the cornerstone treatment of anterior uveitis, but poor corneal penetration and retention cause hindrance in their therapeutic utility. The conventional eye drops are less valuable in conditions where inflammation reaches deeper regions of the eye. Therefore, there is a clear need for an effective drug delivery system, which can increase corticosteroid penetration after topical application. To address this, cationic nanostructured lipid carriers of the drug triamcinolone acetonide (cTA-NLC) were prepared. The cTA-NLC were prepared by a hot microemulsion method and evaluated for drug release, permeation, cell uptake, cytotoxicity, anti-inflammatory activity and ocular irritancy. The cTA-NLC are nanometric in size (< 200 nm), with a zeta potential of about +35 mv and % drug EE of 88 %. The nanocarriers exhibited slow and sustained release of around 84 % in 24 h and transcorneal drug permeation of 51 % in 8 h. The nanocarriers exhibited no cytotoxicity (% cell viability of>90 %). The cell uptake study showed that nanocarriers could retain inside the cells for 24 h. The developed formulation could significantly reduce the TNF-α level in LPS induced inflamed cells. The studies indicated that cTA-NLC could be a promising option for the topical treatment of uveitis.


Subject(s)
Anti-Inflammatory Agents/pharmacology , Biological Products/pharmacology , Lipids/chemistry , Nanoparticles/chemistry , Triamcinolone Acetonide/pharmacology , Uveitis/drug therapy , Animals , Anti-Inflammatory Agents/chemistry , Biological Products/chemistry , Cations/chemistry , Cell Survival/drug effects , Cells, Cultured , Chickens , Dose-Response Relationship, Drug , Drug Liberation , Humans , Particle Size , Structure-Activity Relationship , Surface Properties , Triamcinolone Acetonide/chemistry , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Uveitis/pathology
9.
J Biocommun ; 44(1): e3, 2020.
Article in English | MEDLINE | ID: mdl-36406015

ABSTRACT

Medical photography can be both challenging and rewarding, particularly when faced with less than ideal situations and under pressure of time, environment, and clinicians' expectations. Clinical photographs are a scientific record, therefore, should be accurately focused, exposed and framed. They should fulfil the brief and illustrate the subject effectively. I will describe a photography technique that has been invaluable in the documentation and diagnosis of a rare clinical condition, (multicystic peritoneal mesothelioma) and in informing fellow clinicians of the visual appearance of disease.

10.
J Obstet Gynaecol Can ; 40(11): 1401-1408, 2018 11.
Article in English | MEDLINE | ID: mdl-30477637

ABSTRACT

OBJECTIVE: This study seeks to identify barriers to colposcopy examination faced by patients living in Northern BC to improve outcomes for women at risk of developing cervical cancer. METHODS: A retrospective chart review (n = 309) was conducted in the four colposcopy clinics in Northern BC to collect information regarding patients who were referred for colposcopy after abnormal cytology. Demographic factors associated with non-attendance were identified as barriers to accessing care. Aggregate data from the Cervical Cancer Screening Program (n = 4265) were used to calculate wait times by health region across BC. RESULTS: The odds of having missed an appointment was highest for women who were pregnant (OR 4.0) or attending site D vs. site A (OR 6.0); however, only clinic location remained significant in a multivariable model. Wait times were longer for women who had ever missed appointments, and varied among the sites, with site A and D having significantly longer wait times than the remaining sites. The Northern Health Authority had the longest overall median colposcopy wait time for high-grade cytology in the province at 41 days longer than the provincial average of 62 days. CONCLUSION: The Northern Health Authority faces unique challenges associated with geography and patient population that are associated with longer wait times for colposcopy when compared with other health authorities in the province.


Subject(s)
Colposcopy/statistics & numerical data , Early Detection of Cancer/statistics & numerical data , Health Services Accessibility/statistics & numerical data , Healthcare Disparities/statistics & numerical data , Uterine Cervical Dysplasia/diagnosis , Adult , British Columbia/epidemiology , Female , Humans , Middle Aged , Retrospective Studies , Rural Health Services , Young Adult
11.
J Control Release ; 235: 24-33, 2016 08 10.
Article in English | MEDLINE | ID: mdl-27180635

ABSTRACT

Lipid nanocapsules (LNCs) are semi-rigid spherical capsules with a triglyceride core that present a promising formulation option for the pulmonary delivery of drugs with poor aqueous solubility. Whilst the biodistribution of LNCs of different size has been studied following intravenous administration, the fate of LNCs following pulmonary delivery has not been reported. We investigated quantitatively whether lung inflammation affects the clearance of 50nm lipid nanocapsules, or is exacerbated by their pulmonary administration. Studies were conducted in mice with lipopolysaccharide-induced lung inflammation compared to healthy controls. Particle deposition and nanocapsule clearance kinetics were measured by single photon emission computed tomography/computed tomography (SPECT/CT) imaging over 48 h. A significantly lower lung dose of (111)In-LNC50 was achieved in the lipopolysaccharide (LPS)-treated animals compared with healthy controls (p<0.001). When normalised to the delivered lung dose, the clearance kinetics of (111)In-LNC50 from the lungs fit a first order model with an elimination half-life of 10.5±0.9h (R(2)=0.995) and 10.6±0.3h (R(2)=1.000) for healthy and inflamed lungs respectively (n=3). In contrast, (111)In-diethylene triamine pentaacetic acid (DTPA), a small hydrophilic molecule, was cleared rapidly from the lungs with the majority of the dose absorbed within 20min of administration. Biodistribution to lungs, stomach-intestine, liver, trachea-throat and blood at the end of the imaging period was unaltered by lung inflammation. This study demonstrated that lung clearance and whole body distribution of lipid nanocapsules were unaffected by the presence of acute lung inflammation.


Subject(s)
Lipids/administration & dosage , Lipids/pharmacokinetics , Lung/metabolism , Nanocapsules/administration & dosage , Pneumonia/metabolism , Administration, Inhalation , Animals , Bronchoalveolar Lavage Fluid/cytology , Cell Count , Half-Life , Kinetics , Lipopolysaccharides , Lung/drug effects , Lung/pathology , Male , Mice, Inbred BALB C , Pneumonia/chemically induced , Pneumonia/pathology , Tissue Distribution
12.
Curr Top Med Chem ; 15(22): 2254-66, 2015.
Article in English | MEDLINE | ID: mdl-26043738

ABSTRACT

With a number of formulations currently in clinical trials, the interest in polymer micelles as drug carriers in unlikely to subside. Historically, linear diblock copolymers have been used as the building blocks for micelle preparation. Yet, recent advances in polymer chemistry have meant that a wider variety of polymer architectures and compositions have become available and been trialed for pharmaceutical applications. This mini-review aims to provide an overview of recent, exciting developments in triblock, graft and hyperbranched polymer chemistries that may change the way polymeric micelles drug formulations are prepared.


Subject(s)
Drug Carriers/chemistry , Drug Delivery Systems/methods , Micelles , Polymers/chemistry , Antineoplastic Agents/administration & dosage , Chemistry, Pharmaceutical , Humans
13.
Biomacromolecules ; 16(3): 733-42, 2015 Mar 09.
Article in English | MEDLINE | ID: mdl-25590257

ABSTRACT

Conjugated polymer nanoparticles are being developed for a variety of diagnostic and theranostic applications. The conjugated polymer, F8BT, a polyfluorene derivative, was used as a model system to examine the biological behavior of conjugated polymer nanoparticle formulations stabilized with ionic (sodium dodecyl sulfate; F8BT-SDS; ∼207 nm; -31 mV) and nonionic (pegylated 12-hydroxystearate; F8BT-PEG; ∼175 nm; -5 mV) surfactants, and compared with polystyrene nanoparticles of a similar size (PS200; ∼217 nm; -40 mV). F8BT nanoparticles were as hydrophobic as PS200 (hydrophobic interaction chromatography index value: 0.96) and showed evidence of protein corona formation after incubation with serum-containing medium; however, unlike polystyrene, F8BT nanoparticles did not enrich specific proteins onto the nanoparticle surface. J774A.1 macrophage cells internalized approximately ∼20% and ∼60% of the F8BT-SDS and PS200 delivered dose (calculated by the ISDD model) in serum-supplemented and serum-free conditions, respectively, while cell association of F8BT-PEG was minimal (<5% of the delivered dose). F8BT-PEG, however, was more cytotoxic (IC50 4.5 µg cm(-2)) than F8BT-SDS or PS200. The study results highlight that F8BT surface chemistry influences the composition of the protein corona, while the properties of the conjugated polymer nanoparticle surfactant stabilizer used determine particle internalization and biocompatibility profile.


Subject(s)
Benzothiazoles/chemistry , Coated Materials, Biocompatible/chemistry , Fluorenes/chemistry , Fluorescent Dyes/chemistry , Nanoparticles/chemistry , Phagocytes/physiology , Polymers/chemistry , Surface-Active Agents/chemistry , Adsorption , Animals , Blood Proteins/chemistry , Cell Line , Cell Survival , Coated Materials, Biocompatible/toxicity , Hydrophobic and Hydrophilic Interactions , Inhibitory Concentration 50 , Materials Testing , Mice, Inbred BALB C , Nanoparticles/toxicity , Particle Size , Phagocytes/drug effects , Phagocytosis , Polyethylene Glycols/chemistry , Protein Binding , Sodium Dodecyl Sulfate/chemistry , Surface Properties
14.
Nanotoxicology ; 9(1): 106-15, 2015 Feb.
Article in English | MEDLINE | ID: mdl-24621376

ABSTRACT

Inhaled nanomaterials present a challenge to traditional methods and understanding of respiratory toxicology. In this study, a non-targeted metabolomics approach was used to investigate relationships between nanoparticle hydrophobicity, inflammatory outcomes and the metabolic fingerprint in bronchoalveolar fluid. Measures of acute lung toxicity were assessed following single-dose intratracheal administration of nanoparticles with varying surface hydrophobicity (i.e. pegylated lipid nanocapsules, polyvinyl acetate nanoparticles and polystyrene beads; listed in order of increasing hydrophobicity). Broncho-alveolar lavage (BAL) fluid was collected from mice exposed to nanoparticles at a surface area dose of 220 cm(2) and metabolite fingerprints were acquired via ultra pressure liquid chromatography-mass spectrometry-based metabolomics. Particles with high surface hydrophobicity were pro-inflammatory. Multivariate analysis of the resultant small molecule fingerprints revealed clear discrimination between the vehicle control and polystyrene beads (p < 0.05), as well as between nanoparticles of different surface hydrophobicity (p < 0.0001). Further investigation of the metabolic fingerprints revealed that adenosine monophosphate (AMP) concentration in BAL correlated with neutrophilia (p < 0.01), CXCL1 levels (p < 0.05) and nanoparticle surface hydrophobicity (p < 0.001). Our results suggest that extracellular AMP is an intermediary metabolite involved in adenine nucleotide-regulated neutrophilic inflammation as well as tissue damage, and could potentially be used to monitor nanoparticle-induced responses in the lung following pulmonary administration.


Subject(s)
Adenosine Monophosphate/metabolism , Bronchoalveolar Lavage Fluid/chemistry , Nanoparticles/toxicity , Pneumonia/chemically induced , Pneumonia/metabolism , Adenosine Monophosphate/analysis , Animals , Hydrophobic and Hydrophilic Interactions , Male , Mice , Mice, Inbred BALB C , Polystyrenes/toxicity , Surface Properties
15.
Nanomedicine ; 11(2): 369-77, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25267700

ABSTRACT

Gemcitabine is currently the standard therapy for pancreatic cancer. However, growing concerns over gemcitabine resistance mean that new combinatory therapies are required to prevent loss of efficacy with prolonged treatment. Here, we suggest that this could be achieved through co-administration of RNA interference agents targeting the ubiquitin ligase ITCH. Stable anti-ITCH siRNA and shRNA dendriplexes with a desirable safety profile were prepared using generation 3 poly(propylenimine) dendrimers (DAB-Am16). The complexes were efficiently taken up by human pancreatic cancer cells and produced a 40-60% decrease in ITCH RNA and protein expression in vitro (si/shRNA) and in a xenograft model of pancreatic cancer (shRNA). When co-administered with gemcitabine (100 mg/kg/week) at a subtherapeutic dose, treatment with ITCH-shRNA (3x 50 mg/week) was able to fully suppress tumour growth for 17 days, suggesting that downregulation of ITCH mediated by DAB-Am16/shRNA sensitizes pancreatic cancer to gemcitabine in an efficient and specific manner. FROM THE CLINICAL EDITOR: Gemcitabine delivery to pancreatic cancer often results in the common problem of drug resistance. This team overcame the problem through co-administration of siRNA and shRNA dendriplexes targeting the ubiquitin ligase ITCH.


Subject(s)
Cell Proliferation/drug effects , Deoxycytidine/analogs & derivatives , Pancreatic Neoplasms/drug therapy , Repressor Proteins/antagonists & inhibitors , Ubiquitin-Protein Ligases/antagonists & inhibitors , Apoptosis/drug effects , Cell Line, Tumor , Deoxycytidine/administration & dosage , Deoxycytidine/chemistry , Drug Resistance, Neoplasm/drug effects , Gene Expression Regulation, Neoplastic/drug effects , Humans , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/pathology , Polypropylenes/administration & dosage , Polypropylenes/chemistry , RNA Interference , Repressor Proteins/biosynthesis , Ubiquitin-Protein Ligases/biosynthesis , Gemcitabine
16.
J Control Release ; 183: 94-104, 2014 Jun 10.
Article in English | MEDLINE | ID: mdl-24657808

ABSTRACT

To date, the role of nanoparticle surface hydrophobicity has not been investigated quantitatively in relation to pulmonary biocompatibility. A panel of nanoparticles spanning three different biomaterial types, pegylated lipid nanocapsules, polyvinyl acetate (PVAc) and polystyrene nanoparticles, were characterized for size, surface charge, and stability in biofluids. Surface hydrophobicity of five nanoparticles (50-150nm) was quantified using hydrophobic interaction chromatography (HIC) and classified using a purpose-developed hydrophobicity scale: the HIC index, range from 0.00 (hydrophilic) to 1.00 (hydrophobic). This enabled the relationship between the nanomaterial HIC index value and acute lung inflammation after pulmonary administration to mice to be investigated. The nanomaterials with low HIC index values (between 0.50 and 0.64) elicited little or no inflammation at low (22cm(2)) or high (220cm(2)) nanoparticle surface area doses per animal, whereas equivalent surface area doses of the two nanoparticles with high HIC index values (0.88-0.96) induced neutrophil infiltration, elevation of pro-inflammatory cytokines and adverse histopathology findings. In summary, a HIC index is reported that provides a versatile, discriminatory, and widely available measure of nanoparticle surface hydrophobicity. The avoidance of high (HIC index>~0.8) surface hydrophobicity appears to be important for the design of safe nanomedicines for inhalation therapy.


Subject(s)
Biocompatible Materials/chemistry , Chromatography, Liquid/methods , Drug Carriers/chemistry , Lung/drug effects , Nanoparticles/chemistry , Administration, Inhalation , Animals , Apoptosis/drug effects , Biocompatible Materials/toxicity , Bronchoalveolar Lavage Fluid/chemistry , Bronchoalveolar Lavage Fluid/cytology , Bronchoalveolar Lavage Fluid/immunology , Cell Line , Cytokines/immunology , Drug Carriers/toxicity , Hydrophobic and Hydrophilic Interactions , Lipids/chemistry , Lipids/toxicity , Lung/immunology , Lung/pathology , Male , Mice, Inbred BALB C , Nanoparticles/toxicity , Particle Size , Pneumonia/chemically induced , Pneumonia/immunology , Pneumonia/pathology , Polystyrenes/toxicity , Polyvinyls/toxicity , Surface Properties
17.
Eur J Pharm Biopharm ; 76(2): 147-58, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20600891

ABSTRACT

In the case of chronic therapies, the oral route is often the preferred route for drug administration given its acceptability and convenience. However, various factors which limit drug absorption through the gastro-intestinal (GI) mucosa contribute to restricting the bioavailability of the drug, that is, the actual amount which reaches the bloodstream. Among these factors, poor drug permeability through the GI mucosa and/or low aqueous solubility are of central importance. Polymeric micelles, which form upon self-assembly of amphiphilic macromolecules, can act as vehicles for the oral delivery of these drugs. This manuscript summarizes the literature in relation to the design of these micellar systems and their characterization with respect to drug loading and retention properties as well as the ability to withstand dissociation and drug discharge upon oral administration. Also, the role of certain polymers in improving drug absorption through the GI mucosa, either by increasing membrane permeability to the drug and/or carrier or by inhibiting drug efflux transporters in the GI mucosa, is discussed. Finally, this review reports other drug delivery strategies such as using bioadhesive polymers which may lengthen residence time in the GI tract and promote drug permeation, or rendering the polymeric micelles pH-sensitive in order to ensure drug release from the carrier at its site of absorption.


Subject(s)
Drug Carriers/chemistry , Drug Delivery Systems , Polymers/chemistry , Animals , Biological Availability , Humans , Hydrogen-Ion Concentration , Intestinal Absorption , Intestinal Mucosa/metabolism , Micelles , Pharmaceutical Preparations/administration & dosage , Pharmaceutical Preparations/metabolism , Solubility
18.
J Control Release ; 132(3): 208-15, 2008 Dec 18.
Article in English | MEDLINE | ID: mdl-18571266

ABSTRACT

Star-shaped (4- to 8-arms) and linear poly(glycidyl methacrylate)s were synthesized by atom transfer radical polymerization as precursors of poly(glycerol methacrylate)s (PG(OH)MAs). The water-soluble PG(OH)MA backbones were modified through the esterification of pendant hydroxyl functions with acyl chlorides (12 to 18 carbons). Alkyated PG(OH)MAs were shown to self-assemble into reverse micelles (RMs) in organic solvents and/or oil. The resulting nanosized aggregates (20-60 nm) were able to reversibly extract anionic dyes from water and solubilise them in an organic phase. Furthermore, the encapsulation of vasopressin, a model peptide, in RMs significantly improved its solubility in an oily vehicle. This observation led to the development of water-free peptide formulations. In vitro release studies showed that the entrapped peptide slowly diffused out of an oily RM solution (<15% in 7 days). The release rate could be significantly increased upon emulsification of the oleaginous phase. In vivo, the subcutaneous administration of loaded RMs to rats significantly prolonged the pharmacological effect of vasopressin (>48 h vs. 8-10 h for an aqueous solution). These results highlight the ability of RMs to act as solubilizers for hydrophilic solutes in organic media, a property that may be exploited for applications in organic chemistry and pharmaceutical technology.


Subject(s)
Antidiuretic Agents/administration & dosage , Micelles , Nanoparticles , Polymethacrylic Acids/chemical synthesis , Surface-Active Agents/chemical synthesis , Technology, Pharmaceutical , Vasopressins/administration & dosage , Administration, Oral , Animals , Antidiuretic Agents/chemistry , Chemistry, Pharmaceutical , Diffusion , Drug Compounding , Injections, Subcutaneous , Kinetics , Male , Molecular Structure , Oils/chemistry , Rats , Rats, Sprague-Dawley , Solubility , Solvents/chemistry , Technology, Pharmaceutical/methods , Urination/drug effects , Vasopressins/chemistry
19.
Blood ; 110(4): 1123-31, 2007 Aug 15.
Article in English | MEDLINE | ID: mdl-17468341

ABSTRACT

We present the results of a multicenter clinical trial using Epstein-Barr virus (EBV)-specific cytotoxic T lymphocytes (CTLs) generated from EBV-seropositive blood donors to treat patients with EBV-positive posttransplantation lymphoproliferative disease (PTLD) on the basis of the best HLA match and specific in vitro cytotoxicity. Thirty-three PTLD patients who had failed on conventional therapy were enrolled. No adverse effects of CTL infusions were observed and the response rate (complete or partial) in 33 patients was 64% at 5 weeks and 52% at 6 months. Fourteen patients achieved a complete remission, 3 showed a partial response, and 16 had no response at 6 months (5 died before completing treatment). At 5 weeks, there was a significant trend toward better responses with higher numbers of CD4(+) cells in infused CTL lines (P = .001) that were maintained at 6 months (P = .001). Patients receiving CTLs with closer HLA matching responded better at 6 months (P = .048). Female patients responded better than male patients, but the differences were not statistically significant. Our results show that allogeneic CTLs are a safe and rapid therapy for PTLD, bypassing the need to grow CTLs for individual patients. The response rate in this poor prognosis patient group is encouraging.


Subject(s)
Epstein-Barr Virus Infections/therapy , Herpesvirus 4, Human/immunology , Lymphoproliferative Disorders/therapy , T-Lymphocytes, Cytotoxic/transplantation , Adolescent , Adult , Aged , Antibodies, Viral/blood , Case-Control Studies , Child , Child, Preschool , Epstein-Barr Virus Infections/virology , Female , HLA Antigens/immunology , Humans , Immunotherapy , Immunotherapy, Adoptive , Infant , Lymphoproliferative Disorders/virology , Male , Middle Aged , Organ Transplantation , Polymerase Chain Reaction , Transplantation Immunology , Transplantation, Homologous
20.
J Am Chem Soc ; 128(45): 14599-605, 2006 Nov 15.
Article in English | MEDLINE | ID: mdl-17090044

ABSTRACT

Reverse polymeric micelles are obtained following the association of polymeric amphiphiles in apolar media. To this date, reports of pharmaceutical applications for such micelles have been scarce, mainly because these systems have been studied in solvents that are not suitable for medical use. Here, alkylated star-shaped poly(glycerol methacrylate) polymers have been proposed in the design of oil-soluble reverse polymeric micelles. Micellar behavior was studied in various apolar solvents, including ethyl oleate, a pharmaceutically acceptable vehicle. The polymers were shown to assemble into spherical nanostructures (<40 nm) as determined by cryogenic transmission electron microscopy and atomic force microscopy studies. Interestingly, the reverse micelles were able to encapsulate various peptides/proteins (vasopressin, myoglobin, and albumin) in substantial amounts and facilitate their solubilization in oil. The nature of both the polymer used in micelle formation and the guest molecules was found to influence the ability of the micelle to interact with hydrophilic compounds.


Subject(s)
Nanostructures , Magnetic Resonance Spectroscopy , Microscopy, Atomic Force , Microscopy, Electron, Transmission
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