<Emphasis Type="BoldItalic">In Vitro</Emphasis> and <Emphasis Type="BoldItalic">In Vivo</Emphasis> Modeling of Hydroxypropyl Methylcellulose (HPMC) Matrix Tablet Erosion Under Fasting and Postprandial Status

Purpose

To develop a model linking in vitro and in vivo erosion of extended release tablets under fasting and postprandial status.

Methods

A nonlinear mixed-effects model was developed from the in vitro erosion profiles of four hydroxypropyl methylcellulose (HPMC) matrix tablets studied under a range of experimental conditions. The model was used to predict in vivo erosion of the HPMC matrix tablets in different locations of the gastrointestinal tract, determined by magnetic marker monitoring. In each gastrointestinal segment the pH was set to physiological values and mechanical stress was estimated in USP2 apparatus rotation speed equivalent.

Results

Erosion was best described by a Michaelis–Menten type model. The maximal HPMC release rate (V_MAX) was affected by pH, mechanical stress, HPMC and calcium hydrogen phosphate content. The amount of HPMC left at which the release rate is half of V_MAX depended on pH and calcium hydrogen phosphate. Mechanical stress was estimated for stomach (39.5 rpm), proximal (93.3 rpm) and distal (31.1 rpm) small intestine and colon (9.99 rpm).

Conclusions

The in silico model accurately predicted the erosion profiles of HPMC matrix tablets under fasting and postprandial status and can be used to facilitate future development of extended release tablets.

     

Gentamicin-Loaded Polysaccharide Membranes for Prevention and Treatment of Post-operative Wound Infections in the Skeletal System

Purpose

To develop polysaccharide-based membranes that allow controlled and localized delivery of gentamicin for the treatment of post-operative bone infections.

Methods

Membranes made of gellan gum (GUM), sodium alginate (ALG), GUM and ALG crosslinked with calcium ions (GUM + Ca and ALG + Ca, respectively) as well as reference collagen (COL) were produced by freeze-drying. Mechanical properties, drug release, antimicrobial activity and cytocompatibility of the membranes were assessed.

Results

The most appropriate handling and mechanical properties (Young’s modulus, E = 92 ± 4 MPa and breaking force, F _MAX  = 2.6 ± 0.1 N) had GUM + Ca membrane. In contrast, COL membrane showed F _MAX  = 0.14 ± 0.02 N, E = 1.0 ± 0.3 MPa and was deemed to be unsuitable for antibiotic delivery. The pharmacokinetic data demonstrated a uniform and sustainable delivery of gentamicin from GUM + Ca (44.4 ± 1.3% within 3 weeks), while for COL, ALG and ALG + Ca membranes the most of the drug was released within 24 h (55.3 ± 1.9%, 52.5 ± 1.5% and 37.5 ± 1.8%, respectively). Antimicrobial activity against S. aureus and S. epidermidis was confirmed for all the membranes. GUM + Ca and COL membranes supported osteoblasts growth, whereas on ALG and ALG + Ca membranes cell growth was reduced.

Conclusions

GUM + Ca membrane holds promise for effective treatment of bone infections thanks to favorable pharmacokinetics, bactericidal activity, cytocompatibility and good mechanical properties.

     

Real-Time UV Imaging of Nicotine Release from Transdermal Patch

Purpose

This study was conducted to characterize UV imaging as a platform for performing in vitro release studies using Nicorette® nicotine patches as a model drug delivery system.

Methods

The rate of nicotine release from 2 mm diameter patch samples (Nicorette®) into 0.067 M phosphate buffer, pH 7.40, was studied by UV imaging (Actipix SDI300 dissolution imaging system) at 254 nm. The release rates were compared to those obtained using the paddle-over-disk method.

Results

Calibration curves were successfully established which allowed temporally and spatially resolved quantification of nicotine. Release profiles obtained from UV imaging were in qualitative agreement with results from the paddle-over-disk release method.

Conclusion

Visualization as well as quantification of nicotine concentration gradients was achieved by UV imaging in real time. UV imaging has the potential to become an important technology platform for conducting in vitro drug release studies.

     

Local,Controlled Delivery of Local Anesthetics <Emphasis Type="BoldItalic">In Vivo</Emphasis> from Polymer - Xerogel Composites

Purpose

Polymer-xerogel composite materials have been introduced to better optimize local anesthetics release kinetics for the pain management. In a previous study, it was shown that by adjusting various compositional and nano-structural properties of both inorganic xerogels and polymers, zero-order release kinetics over 7 days can be achieved in vitro. In this study, in vitro release properties are confirmed in vivo using a model that tests for actual functionality of the released local anesthetics.

Methods

Composite materials made with tyrosine-polyethylene glycol(PEG)-derived poly(ether carbonate) copolymers and silica-based sol–gel (xerogel) were synthesized. The in vivo release from the composite controlled release materials was demonstrated by local anesthetics delivery in a rat incisional pain model.

Results

The tactile allodynia resulting from incision was significantly attenuated in rats receiving drug-containing composites compared with the control and sham groups for the duration during which natural healing had not yet taken place. The concentration of drug (bupivacaine) in blood is dose dependent and maintained stable up to 120 h post-surgery, the longest time point measured.

Conclusions

These in vivo studies show that polymer-xerogel composite materials with controlled release properties represent a promising class of controlled release materials for pain management.

     

Pharmacokinetic/Pharmacodynamic Relationship of Gabapentin in a CFA-induced Inflammatory Hyperalgesia Rat Model

Purpose

Gabapentin displays non-linear drug disposition, which complicates dosing for optimal therapeutic effect. Thus, the current study was performed to elucidate the pharmacokinetic/pharmacodynamic (PKPD) relationship of gabapentin’s effect on mechanical hypersensitivity in a rat model of CFA-induced inflammatory hyperalgesia.

Methods

A semi-mechanistic population-based PKPD model was developed using nonlinear mixed-effects modelling, based on gabapentin plasma and brain extracellular fluid (ECF) time-concentration data and measurements of CFA-evoked mechanical hyperalgesia following administration of a range of gabapentin doses (oral and intravenous).

Results

The plasma/brain ECF concentration-time profiles of gabapentin were adequately described with a two-compartment plasma model with saturable intestinal absorption rate (K _m ?=?44.1 mg/kg, V _max ?=?41.9 mg/h?kg) and dose-dependent oral bioavailability linked to brain ECF concentration through a transit compartment. Brain ECF concentration was directly linked to a sigmoid E _max function describing reversal of hyperalgesia (EC _{50, plasma} ?=?16.7 μg/mL, EC _{50, brain} ?=?3.3 μg/mL).

Conclusions

The proposed semi-mechanistic population-based PKPD model provides further knowledge into the understanding of gabapentin’s non-linear pharmacokinetics and the link between plasma/brain disposition and anti-hyperalgesic effects. The model suggests that intestinal absorption is the primary source of non-linearity and that the investigated rat model provides reasonable predictions of clinically effective plasma concentrations for gabapentin.

     

Optimization,Biopharmaceutical Profile and Therapeutic Efficacy of Pioglitazone-loaded PLGA-PEG Nanospheres as a Novel Strategy for Ocular Inflammatory Disorders

Purpose

The main goal of this study was to encapsulate Pioglitazone (PGZ), in biodegradable polymeric nanoparticles as a new strategy for the treatment of ocular inflammatory processes.

Methods

To improve their biopharmaceutical profile for the treatment of ocular inflammatory disorders, nanospheres (NSs) of PGZ were formulated by factorial design with poly (lactic-co-glycolic acid) polyethylene glycol (PLGA-PEG). Interactions drug-polymer have been carried out by spectroscopic (X-ray spectroscopy, FTIR) and thermal methods (DSC). The PGZ-NSs were tested for their in vitro release profile, cytotoxicity, and ocular tolerance (HET-CAM® test); ex vivo corneal permeation, and in vivo inflammatory prevention and bioavailability.

Results

The optimized system showed a negative surface charge of ?13.9 mV, an average particle size (Z_av) of around 160 nm, a polydispersity index (PI) below 0.1, and a high encapsulation efficiency (EE) of around 92%. According to the DSC results, the drug was incorporated into the NSs polymeric matrix. The drug release was sustained for up to 14 h. PGZ-NSs up to 10 μg/ml exhibited no retinoblastoma cell toxicity. The ex vivo corneal and scleral permeation profiles of PGZ-NSs showed that retention and permeation through the sclera were higher than through the cornea. Ocular tolerance in vitro and in vivo demonstrated the non-irritant character of the formulation.

Conclusion

The in vivo anti-inflammatory efficacy of developed PGZ-NSs indicates this colloidal system could constitute a new approach to prevent ocular inflammation.

     

Formulation and Evaluation of Chitosan-Based Buccal Bioadhesive Films of Zolmitriptan

Purpose

Therapeutic efficacy of zolmitriptan in oral therapy is primarily limited by the biopharmaceutical issues. The objective of this study is to design and optimize chitosan-based buccal bioadhesive system for the effective delivery of zolmitriptan in the treatment of migraine.

Methods

Factorial design (3²) is constructed and conducted in a fully randomized manner to study all nine possible experimental runs. The films were prepared by solvent casting method by varying the content of chitosan (X₁) and polyvinyl alcohol (X₂). The effect of these two independent variables on swelling index (Y1), percent drug release in 15 min (Y2) and 5 h (Y3), and mucoadhesive strength (Y4) of prepared films was evaluated.

Results

The physical and chemical characteristics displayed by the prepared films (F1–F9) were found to be optimal. It was observed that the factor X₁ has positive and X₂ has negative effect on response Y1. In contrast, factor X₁ showed negative effects on drug release at both time intervals (15 min and 5 h) while X₂ displayed positive responses for these variables (Y2 and Y3). However, the mucoadhesion increased with an increase in factor X₁ and decreased when the factor X₂ was increased. Indeed, the desirable characteristics exhibited by the film F7 are ideal for buccal application. Greater flux (63.93?±?12.51 μg/cm²/h) demonstrated in ex vivo studies substantiated the potential of optimized film to effectively deliver zolmitriptan across the buccal membrane.

Conclusions

This study concludes that the chitosan-based buccal film (F7) could be used in both prophylaxis and acute treatment of migraine, although need to be proved in vivo.

     

Conjugated and Entrapped HPMA-PLA Nano-Polymeric Micelles Based Dual Delivery of First Line Anti TB Drugs: Improved and Safe Drug Delivery against Sensitive and Resistant <Emphasis Type="Italic">Mycobacterium Tuberculosis</Emphasis>

Purpose

First line antiTB drugs have several physical and toxic manifestations which limit their applications. RIF is a hydrophobic drug and has low water solubility and INH is hepatotoxic. The main objective of the study was to synthesize, characterize HPMA-PLA co-polymeric micelles for the effective dual delivery of INH and RIF.

Methods

HPMA-PLA co-polymer and HPMA-PLA-INH (HPI) conjugates were synthesized and characterized by FT-IR and ¹H–NMR spectroscopy. Later on RIF loaded HPMA-PLA-INH co-polymeric micelles (PMRI) were formulated and characterized for size, zeta potential and surface morphology (SEM, TEM) as well as critical micellar concentration. The safety was assessed through RBC’s interaction study. The prepared PMRI were evaluated through MABA assay against sensitive and resistant strains of M. Tuberculosis.

Results

Size, zeta and entrapment efficiency for RIF loaded HPMA-PLA-INH polymeric micelles (PMRI) was 87.64 ± 1.98 nm, ?19 ± 1.93 mV and 97.2 ± 1.56%, respectively. In vitro release followed controlled and sustained delivery pattern. Sustained release was also supported by release kinetics. Haemolytic toxicity of HPI and PMRI was 8.57 and 7.05% (p < 0.01, INH Vs PMRI; p < 0.0001, RIF Vs PMRI), respectively. MABA assay (cytotoxicity) based MIC values of PMRI formulation was observed as ≥0.0625 and ≥0.50 μg/mL (for sensitive and resistant strain). The microscopic analysis further confirmed that the delivery approach was effective than pure drugs.

Conclusions

RIF loaded and INH conjugated HPMA-PLA polymeric micelles (PMRI) were more effective against sensitive and resistant M tuberculosis. The developed approach can lead to improved patient compliance and reduced dosing in future, offering improved treatment of tuberculosis.

     

Co-Delivery of Ciprofloxacin and Colistin in Liposomal Formulations with Enhanced <Emphasis Type="BoldItalic">In Vitro</Emphasis> Antimicrobial Activities against Multidrug Resistant <Emphasis Type="BoldItalic">Pseudomonas aeruginosa</Emphasis>

Purpose

This study aims to develop liposomal formulations containing synergistic antibiotics of colistin and ciprofloxacin for the treatment of infections caused by multidrug-resistant Pseudomonas aeruginosa.

Methods

Colistin (Col) and ciprofloxacin (Cip) were co-encapsulated in anionic liposomes by ammonium sulfate gradient. Particle size, encapsulation efficiency, in vitro drug release and in vitro antibiotic activities were evaluated.

Results

The optimized liposomal formulation has uniform sizes of approximately 100 nm, with encapsulation efficiency of 67.0% (for colistin) and 85.2% (for ciprofloxacin). Incorporation of anionic lipid (DMPG) markedly increased encapsulation efficiency of colistin (from 5.4 to 67.0%); however, the encapsulation efficiency of ciprofloxacin was independent of DMPG ratio. Incorporation of colistin significantly accelerated the release of ciprofloxacin from the DMPG anionic liposomes. In vitro release of ciprofloxacin and colistin in the bovine serum for 2 h were above 70 and 50%. The cytotoxicity study using A549 cells showed the liposomal formulation is as non-toxic as the drug solutions. Liposomal formulations of combinations had enhanced in vitro antimicrobial activities against multidrug resistant P. aeruginosa than the monotherapies.

Conclusions

Liposomal formulations of two synergistic antibiotics was promising against multidrug resistant P. aeruginosa infections.

     

The Use of Magnetic Resonance Imaging for Non-Invasive Assessment of Venofer® Biodistribution in Rats

Purpose

The aim of this study was to determine the potential of magnetic resonance imaging to evaluate the biodistribution of exogenous iron within 24 h after one single injection of Venofer® (iron sucrose).

Methods

Venofer® was evaluated in vitro for its ability to generate contrast in MR images. Subsequently, iron disposition was assessed in rats with MRI, in vivo up to 3 h and post mortem at 24 h after injection of Venofer®, at doses of 10- and 40 mg/kg body weight (n?=?2?×?4), or saline (n?=?4).

Results

Within 10–20 min after injection of Venofer®, transverse relaxation rates (R₂) clearly increased, representative of a local increase in iron concentration, in liver, spleen and kidney, including the kidney medulla and cortex. In liver and spleen R₂ values remained elevated up to 3 h post injection, while the initial R₂ increase in the kidney was followed by gradual decrease towards baseline levels. Bone marrow and muscle tissue did not show significant increases in R₂ values. Whole-body post mortem MRI showed most prominent iron accumulation in the liver and spleen at 24 h post injection, which corroborated the in vivo results.

Conclusions

MR imaging is a powerful imaging modality for non-invasive assessment of iron distribution in organs. It is recommended to use this whole-body imaging approach complementary to other techniques that allow quantification of iron disposition at a (sub)cellular level.

     

Sustained Release from Ionic-Gradient Liposomes Significantly Decreases ETIDOCAINE Cytotoxicity

Purpose

Etidocaine (EDC) is a long lasting local anesthetic, which alleged toxicity has restricted its clinical use. Liposomes can prolong the analgesia time and reduce the toxicity of local anesthetics. Ionic gradient liposomes (IGL) have been proposed to increase the upload and prolong the drug release, from liposomes.

Methods

First, a HPLC method for EDC quantification was validated. Then, large unilamellar vesicles composed of hydrogenated soy phosphatidylcholine:cholesterol with 250 mM (NH₄)₂SO₄ - inside gradient - were prepared for the encapsulation of 0.5% EDC. Dynamic light scattering, nanotracking analysis, transmission electron microscopy and electron paramagnetic resonance were used to characterize: nanoparticles size, polydispersity, zeta potential, concentration, morphology and membrane fluidity. Release kinetics and in vitro cytotoxicity tests were also performed.

Results

IGL_EDC showed average diameters of 172.3?±?2.6 nm, low PDI (0.12?±?0.01), mean particle concentration of 6.3?±?0.5?×?10¹²/mL and negative zeta values (?10.2?±?0.4 mV); parameters that remain stable during storage at 4°C. The formulation, with 40% encapsulation efficiency, induced the sustained release of EDC (ca. 24 h), while reducing its toxicity to human fibroblasts.

Conclusion

A novel formulation is proposed for etidocaine that promotes sustained release and reduces its cytotoxicity. IGL_EDC can come to be a tool to reintroduce etidocaine in clinical use.

     

Controlling Release of Integral Lipid Nanoparticles Based on Osmotic Pump Technology

Purpose

To achieve controlled release of integral nanoparticles by the osmotic pump strategy using nanostructured lipid carriers (NLCs) as model nanoparticles.

Methods

NLCs was prepared by a hot-homogenization method, transformed into powder by lyophilization, and formulated into osmotic pump tablets (OPTs). Release of integral NLCs was visualized by live imaging after labeling with a water-quenching fluorescent probe. Effects of formulation variables on in vitro release characteristics were evaluated by measuring the model drug fenofibrate. Pharmacokinetics were studied in beagle dogs using the core tablet and a micronized fenofibrate formulation as references.

Results

NLCs are released through the release orifices of the OPTs as integral nanoparticles. Near zero-order kinetics can be achieved by optimizing the influencing variables. After oral administration, decreased C _max and steady drug levels for as long as over 24 h are observed. NLC-OPTs show an oral bioavailability of the model drug fenofibrate similar to that of the core tablets, which is about 1.75 folds that of a fast-release formulation.

Conclusion

Controlled release of integral NLCs is achieved by the osmotic pump strategy.

     

Fabrication of 3-O-sn-Phosphatidyl-L-serine Anchored PLGA Nanoparticle Bearing Amphotericin B for Macrophage Targeting

Purpose

To fabricate, characterize and evaluate 3-O-sn-Phosphatidyl-L-serine (PhoS) anchored PLGA nanoparticles for macrophage targeted therapeutic intervention of VL.

Materials and Methods

PLGA-AmpB NPs were prepared by well-established nanoprecipitation method and decorated with Phos by thin film hydration method. Physico-chemical characterization of the formulation was done by Zetasizer nano ZS and atomic force microscopy.

Results

The optimized formulation (particle size, 157.3?±?4.64 nm; zeta potential, ? 42.51?±?2.11 mV; encapsulation efficiency, ～98%) showed initial rapid release up to 8 h followed by sustained release until 72 h. PhoS generated ‘eat-me’ signal driven augmented macrophage uptake, significant increase in in-vitro (with ～82% parasite inhibition) and in-vivo antileishmanial activity with preferential accumulation in macrophage rich organs liver and spleen were found. Excellent hemo-compatibility justified safety profile of developed formulation in comparison to commercial formulations.

Conclusion

The developed PhoS-PLGA-AmpB NPs have improved efficacy, and necessary stability which promisingly put itself as a better alternative to available commercial formulations for optimized treatment of VL.

     

Drug Interaction Between Clopidogrel and Ranitidine or Omeprazole in Stable Coronary Artery Disease: A Double-Blind,Double Dummy,Randomized Study

Background

Proton-pump inhibitors (PPIs) are often prescribed to patients receiving dual antiplatelet therapy (DAPT). However, this class of medication, especially omeprazole, has been associated with a reduction in clopidogrel efficacy, leading many clinicians to substitute omeprazole with ranitidine.

Objectives

Our objective was to compare the antiplatelet effect of clopidogrel before and after the addition of omeprazole or ranitidine.

Methods

We measured platelet aggregability at baseline and after 1 week of clopidogrel 75 mg daily. Subjects were then randomized in a double-blinded, double-dummy fashion to omeprazole 20 mg twice daily (bid) or ranitidine 150 mg bid. We repeated aggregability tests after 1 additional week, using VerifyNow P2Y12? (Accumetrics; San Diego, CA, USA), depicting aggregability as percent inhibition of platelet aggregation (IPA).

Results

We enrolled 41 patients in the omeprazole group and 44 in the ranitidine group. IPA was significantly decreased after the addition of omeprazole to clopidogrel (from 26.3 ± 32.9 to 17.4 ± 33.1 %; p = 0.025), with no statistical significant changes observed in the ranitidine group (from 32.6 ± 28.9 to 30.1 ± 31.3 %; p = 0.310). The comparison of IPA in both groups at the end of the follow-up showed a trend toward significance (p = 0.07, 95 % confidence interval [CI] ?1.19 to 26.59); after excluding homozygous patients for 2C19*2 genotype, the comparison of IPA between the groups reached statistical significance (32.7 ± 30.8 vs. 17.7 ± 33.4 %, respectively, for ranitidine and omeprazole groups; p = 0.04).

Conclusions

Unlike omeprazole, ranitidine did not influence platelet aggregability response to clopidogrel.

Clinical Trial Registration

NCT01896557.

     

Evaluations of the Effect of Sodium Metabisulphite on the Stability and Dissolution Rates of Various Model Drugs from the Extended Release Polyethylene Oxide Matrices

Purpose

This study examines the effect of sodium metabisulphite (SMB) as an antioxidant on the stability and release of various model drugs, namely, propranolol HCl, theophylline and zonisamide from the polyethylene oxide (PEO) tablets. The antioxidant was used to minimise degradation and instability of the manufactured tablets when stored at 40 °C (55 ± 5% RH) over 8 weeks.

Method

Multiple batches of tablets weighing 240 mg (50% w/w) with a ratio of 1:1 drug/polymer and 1% (w/w) sodium metabisulphite containing different model drugs and various molecular weights of PEO 750 and 303 were produced.

Results

The results indicated that the use of sodium metabisulphite marginally assisted in reducing drug release and degradation via oxidation in propranolol HCl tablets containing both PEO 750 and 303. In the case of poorly and semi-soluble drugs (zonisamide and theophylline), the formulations with both PEO showed entirely superimposable phenomenon and different release profiles compared to control samples (matrices without SMB). DSC study demonstrated the modifications of the polymer due to degradation and observed the effect of SMB on the thermal degradation of the PEO matrices.

Conclusion

The use of antioxidant has assisted in retaining the stability of the manufactured tablets with different model drugs especially those with the highly soluble drug that are susceptible to rapid degradation. This has been reflected by an extended release profile of various drugs used at various stages of the storage time up to 8 weeks.

     

Biodegradable Nanoparticles Improve Oral Bioavailability of Amphotericin B and Show Reduced Nephrotoxicity Compared to Intravenous Fungizone®

Purpose

Amphotericin B (AMB), an effective antifungal and antileishmanial agent associated with low oral bioavailability (0.3%) and severe nephrotoxicity, was entrapped into poly(lactide-co-glycolide) (PLGA) nanoparticles to improve the oral bioavailability and to minimize the adverse effects associated with it.

Materials and Methods

The AMB-nanoparticles (AMB-NP) were prepared by nanoprecipitation method employing Vitamin E-TPGS as a stabilizer. In vitro release was carried out using membrane dialysis method. The in vitro hemolytic activity of AMB-NP was evaluated by incubation with red blood cells (RBCs). The acute nephrotoxicity profile and oral bioavailability of AMB-NP were evaluated in rats.

Results

The prepared AMB-NP formulation contained monodispersed particles in the size range of 165.6?±?2.9 nm with 34.5?±?2.1% entrapment at 10% w/w initial drug loading. AMB-NP formulation showed biphasic drug release, an initial rapid release followed by a sustained release. The AMB-NP formulation exerted lower hemolysis and nephrotoxicity as compared to Fungizone®. The relative oral bioavailability of the AMB-NP was found to be ～800% as compared to Fungizone®.

Conclusion

Together, these results offer a possibility of treating systemic fungal infection and leishmaniasis with oral AMB-NP, which could revolutionize the infectious disease treatment modalities.

     

Triple Drug Combination of Zidovudine,Efavirenz and Lamivudine Loaded Lactoferrin Nanoparticles: an Effective Nano First-Line Regimen for HIV Therapy

Purpose

To enhance efficacy, bioavailability and reduce toxicity of first-line highly active anti-retroviral regimen, zidovudine?+?efavirenz?+?lamivudine loaded lactoferrin nanoparticles were prepared (FLART-NP) and characterized for physicochemical properties, bioactivity and pharmacokinetic profile.

Methods

Nanoparticles were prepared using sol-oil protocol and characterized using different sources such as FE-SEM, AFM, NanoSight, and FT-IR. In-vitro and in-vivo studies have been done to access the encapsulation-efficiency, cellular localization, release kinetics, safety analysis, biodistribution and pharmacokinetics.

Results

FLART-NP with a mean diameter of 67 nm (FE-SEM) and an encapsulation efficiency of >58% for each drug were prepared. In-vitro studies suggest that FLART-NP deliver the maximum of its payload at pH5 with a minimum burst release throughout the study period with negligible toxicity to the erythrocytes plus improved in-vitro anti-HIV activity. FLART-NP has improved the in-vivo pharmacokinetics (PK) profiles over the free drugs; an average of >4fold increase in AUC and AUMC, 30% increase in the C_max, >2fold in the half-life of each drug. Biodistribution data suggest that FLART-NP has improved the bioavailability of all drugs with less tissue-related inflammation as suggested with histopathological evaluation

Conclusions

The triple-drug loaded nanoparticles have various advantages against soluble (free) drug combination in terms of enhanced bioavailability, improved PK profile and diminished drug-associated toxicity.

     

A Tunable,Biodegradable, Thin-Film Polymer Device as a Long-Acting Implant Delivering Tenofovir Alafenamide Fumarate for HIV Pre-exposure Prophylaxis

Purpose

The effectiveness of Tenofovir based HIV pre-exposure prophylaxis (PrEP) is proven, but hinges on correct and consistent use. User compliance and therapeutic effectiveness can be improved by long acting drug delivery systems. Here we describe a thin-film polymer device (TFPD) as a biodegradable subcutaneous implant for PrEP.

Methods

A thin-film polycaprolactone (PCL) membrane controls drug release from a reservoir. To achieve membrane controlled release, TAF requires a formulation excipient such as PEG300 to increase the dissolution rate and reservoir solubility. Short-term In vitro release studies are used to develop an empirical design model, which is applied to the production of in vitro prototype devices demonstrating up to 90-days of linear release and TAF chemical stability.

Results

The size and shape of the TFPD are tunable, achieving release rates ranging from 0.5 to 4.4 mg/day in devices no larger than a contraceptive implant. Based on published data for oral TAF, subcutaneous constant-rate release for HIV PrEP is estimated at <2.8 mg/day. Prototype devices demonstrated linear release at 1.2 mg/day for up to 90 days and at 2.2 mg/day for up to 60 days.

Conclusions

We present a biodegradable TFPD for subcutaneous delivery of TAF for HIV PrEP. The size, shape and release rate of the device are tunable over a >8-fold range.

     

Biodegradable Polymersomes as Nanocarriers for Doxorubicin Hydrochloride: Enhanced Cytotoxicity in MCF-7/ADR Cells and Prolonged Blood Circulation

Purpose

DOX is one of the most potent anticancer drugs. But its short half-life and the occurrence of multi-drug resistance (MDR) markedly limit its clinical application. To solve these problems, we develop DOX loaded polymersomes (DOX polymersomes).

Methods

An methoxy poly(ethylene glycol)-b-poly(epsilon-caprolactone) (mPEG-b-PCL) copolymer was synthesized and used to prepare DOX polymersomes. The pharmaceutical properties of DOX polymersomes were characterized. The in vitro release profile of DOX from polymersomes was investigated. The in vitro cytotoxicity and cell uptake studies were performed on MCF-7 and MCF-7/ADR cells. The in vivo pharmacokinetic profiles were investigated on Sprague–Dawley rats.

Results

DOX polymersomes had a nano-scale particle size of about 60 nm with a hydrophobic membrane about 10 nm in thickness. Release of DOX from the polymersomes took place in a sustained manner. Cell experiments showed DOX polymersomes enhanced the cytotoxicity and the intracellular accumulation of DOX in MCF-7/ADR cells, compared with free DOX. In vivo pharmacokinetic study showed the DOX polymersomes increased the bioavailability and prolonged the circulation time in rats.

Conclusions

The entrapment of DOX in biodegradable polymersomes could enhance cytotoxicity in MCF-7/ADR cells and improve its in vivo pharmacokinetic profile.

     

Regulation of the Human Fc-Neonatal Receptor alpha-Chain Gene <Emphasis Type="BoldItalic">FCGRT</Emphasis> by MicroRNA-3181

Purpose

FCGRT encodes the alpha-chain component of the neonatal Fc receptor (FcRn). FcRn is critical for the trafficking of endogenous and exogenous IgG molecules and albumin in various tissues. Few regulators of FcRn expression have been identified. We investigated the epigenetic regulation of FcRn by two microRNAs (hsa-miR-3181 and hsa-miR-3136-3p) acting on FCGRT.

Methods

The binding of candidate microRNAs to the 3′-untranslated region of FCGRT was evaluated using luciferase reporter constructs in CHO cells. The effect of microRNAs on FCGRT mRNA and FcRn protein expression was evaluated using specific microRNA mimics and inhibitor transfections in A549, HEK293 and HepG2 cells.

Results

Hsa-miR-3181 mimic reduced luciferase reporter activity by 70.1% (10 nM, P <?0.0001). In A549, HEK293 and HepG2 cells, hsa-miR-3181 decreased FCGRT mRNA expression (48.6%, 51.3% and 43.5% respectively, 25 nM, P <?0.05). The hsa-miR-3181 mimic decreased the expression of FcRn protein by 40% after 48 h (25 nM, P <?0.001). The mature form of hsa-miR-3181 was detected in samples of human liver.

Conclusions

These data suggest that hsa-miR-3181 is an epigenetic regulator of FCGRT expression. The identification of this regulator of FCGRT may provide insights into a potential determinant of interindividual variability in FcRn expression.