Tunable ciprofloxacin delivery through personalized electrospun patches for tympanic membrane perforations.

Approximately 740 million symptomatic patients are affected by otitis media every year. Being an inflammatory disease affecting the middle ear, it is one of the primary causes of tympanic membrane (TM) perforations, often resulting in impaired hearing abilities. Antibiotic therapy using broad-spectrum fluoroquinolones, such as ciprofloxacin (CIP), is frequently employed and considered the optimal route to treat otitis media. However, patients often get exposed to high dosages to compensate for the low drug concentration reaching the affected site. Therefore, this study aims to integrate tissue engineering with drug delivery strategies to create biomimetic scaffolds promoting TM regeneration while facilitating a localized release of CIP. Distinct electrospinning (ES) modalities were designed in this regard either by blending CIP into the polymer ES solution or by incorporating nanoparticles-based co-ES/electrospraying. The combination of these modalities was investigated as well. A broad range of release kinetic profiles was achieved from the fabricated scaffolds, thereby offering a wide spectrum of antibiotic concentrations that could serve patients with diverse therapeutic needs. Furthermore, the incorporation of CIP into the TM patches demonstrated a favorable influence on their resultant mechanical properties. Biological studies performed with human mesenchymal stromal cells confirmed the absence of any cytotoxic or anti-proliferative effects from the released antibiotic. Finally, antibacterial assays validated the efficacy of CIP-loaded scaffolds in suppressing bacterial infections, highlighting their promising relevance for TM applications.

Novel PLGA-based nanoformulation decreases doxorubicin-induced cardiotoxicity.

Nanotechnology has the potential to provide formulations of antitumor agents with increased selectivity towards cancer tissue thereby decreasing systemic toxicity. This in vivo study evaluated the potential of novel nanoformulation based on poly(lactic-co-glycolic acid) (PLGA) to reduce the cardiotoxic potential of doxorubicin (DOX). In vivo toxicity of PLGADOX was compared with clinically approved non-PEGylated, liposomal nanoformulation of DOX (LipoDOX) and conventional DOX form (ConvDOX). The study was performed using Wistar Han rats of both sexes that were treated intravenously for 28 days with 5 doses of tested substances at intervals of 5 days. Histopathological analyses of heart tissues showed the presence of myofiber necrosis, degeneration processes, myocytolysis, and hemorrhage after treatment with ConvDOX, whereas only myofiber degeneration and hemorrhage were present after the treatment with nanoformulations. All DOX formulations caused an increase in the troponin T with the greatest increase caused by convDOX. qPCR analyses revealed an increase in the expression of inflammatory markers IL-6 and IL-8 after ConvDOX and an increase in IL-8 expression after lipoDOX treatments. The mass spectra imaging (MSI) of heart tissue indicates numerous metabolic and lipidomic changes caused by ConvDOX, while less severe cardiac damages were found after treatment with nanoformulations. In the case of LipoDOX, autophagy and apoptosis were still detectable, whereas PLGADOX induced only detectable mitochondrial toxicity. Cardiotoxic effects were frequently sex-related with the greater risk of cardiotoxicity observed mostly in male rats.

A Straightforward Method to Produce Multi-Nanodrug Delivery Systems for Transdermal/Tympanic Patches Using Electrospinning and Electrospray.

The delivery of drugs through the skin barrier at a predetermined rate is the aim of transdermal drug delivery systems (TDDSs). However, so far, TDDS has not fully attained its potential as an alternative to hypodermic injections and oral delivery. In this study, we presented a proof of concept of a dual drug-loaded patch made of nanoparticles (NPs) and ultrafine fibers fabricated by using one equipment, i.e., the electrospinning apparatus. Such NP/fiber systems can be useful to release drugs locally through the skin and the tympanic membrane. Briefly, dexamethasone (DEX)-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) fiber meshes were decorated with rhodamine (RHO)-loaded poly(lactic-co-glycolic acid) (PLGA) NPs, with RHO representing as a second drug model. By properly tuning the working parameters of electrospinning, DEX-loaded PHBHV fibers (i.e., by electrospinning mode) and RHO-loaded PLGA NPs (i.e., by electrospray mode) were successfully prepared and straightforwardly assembled to form a TDDS patch, which was characterized via Fourier transform infrared spectroscopy and dynamometry. The patch was then tested in vitro using human dermal fibroblasts (HDFs). The incorporation of DEX significantly reduced the fiber mesh stiffness. In vitro tests showed that HDFs were viable for 8 days in contact with drug-loaded samples, and significant signs of cytotoxicity were not highlighted. Finally, thanks to a beaded structure of the fibers, a controlled release of DEX from the electrospun patch was obtained over 4 weeks, which may accomplish the therapeutic objective of a local, sustained and prolonged anti-inflammatory action of a TDDS, as is requested in chronic inflammatory conditions, and other pathological conditions, such as in sudden sensorineural hearing loss treatment.

Higher Loading of Gold Nanoparticles in PAD Mesenchymal-like Stromal Cells Leads to a Decreased Exocytosis.

Cell therapy is an important new method in medicine and is being used for the treatment of an increasing number of diseases. The challenge here is the precise tracking of cells in the body and their visualization. One method to visualize cells more easily with current methods is their labeling with nanoparticles before injection. However, for a safe and sufficient cell labeling, the nanoparticles need to remain in the cell and not be exocytosed. Here, we test a glucose-PEG-coated gold nanoparticle for the use of such a cell labeling. To this end, we investigated the nanoparticle exocytosis behavior from PLX-PAD cells, a cell type currently in clinical trials as a potential therapeutic agent. We showed that the amount of exocytosed gold from the cells was influenced by the uptake time and loading amount. This observation will facilitate the safe labeling of cells with nanoparticles in the future and contribute to stem cell therapy research.

Imaging mass spectrometry differentiates the effects of doxorubicin formulations on non-targeted tissues.

Administration of cytotoxic agents like doxorubicin (DOX) is restrained by the effects on different non-targeted/non-cancerous tissues, which instigates the development of nano-enabled drug delivery systems, among others. In this study, imaging mass spectrometry (IMS) was selected to examine the effects of DOX nanoformulations on non-targeted tissues. Chemical alterations induced by liposomal (LPS) and poly (lactic-co-glycolic acid) (PLG) nanoformulations were assessed against the ones induced by the conventional (CNV) formulation. Kidney cryosections of the treated and control Wistar rats were used as a model of the non-targeted tissue and analyzed by MALDI TOF IMS in the 200-1000 Da m/z range. Principal component analysis (PCA) and Volcano plots of the average mass spectra demonstrated a large overlap between treatments. However, the Venn diagram of significant m/z values revealed a nanoformulation-specific fingerprint consisting of 59 m/z values, which set them apart from the CNV formulation characterized by the fingerprint of 22 significant m/z values. Fingerprint m/z values that were putatively annotated by metabolome database search were linked to apoptosis, cell migration and proliferation. In CNV and PLG cases, false discovery rate adjusted ANOVA showed no differences in the spatial distribution of fingerprint m/z values between the histological substructures like glomeruli and convoluted tubules indicating their tissue-nonselective effect. LPS caused the least significant changes in m/z values and some of the LPS-specific fingerprint m/z values were primarily distributed in the glomeruli. The IMS based procedure successfully differentiated the effects of DOX formulations on the model non-targeted tissue, thus indicating the importance of IMS in effective drug development.

Interaction of surfactant coated PLGA nanoparticles with in vitro human brain-like endothelial cells.

Treatment for CNS related diseases are limited by the difficulty of the drugs to cross the blood-brain barrier (BBB). The functionalization of polymeric nanoparticles (NPs) coated with the surfactants polysorbate 80 (PS80) and poloxamer 188 (P188), have shown promising results as drugs carriers are able to cross the BBB on animal models. In this study, poly(lactide-co-glycolide) (PLGA) NPs coated with PS80 and P188, labelled with a fluorescent dye were tested on human pre-clinical in vitro model to evaluate and compare their uptake profiles, mechanisms of transport and crossing over human brain-like endothelial cells (BLECs) mimicking the human BBB. In addition, these NPs were produced using a method facilitating their reproducible production at high scale, the MicroJet reactor® technology. Results showed that both formulations were biocompatible and able to be internalized within the BLECs in different uptake profiles depending on their coating: P188 NP showed higher internalization capacity than PS80 NP. Both NPs uptakes were ATP-dependent, following more than one endocytosis pathway with colocalization in the early endosomes, ending with a NPs release in the brain compartment. Thus, both surfactant-coated PLGA NPs are interesting formulations for delivery to the brain through the BBB, presenting different uptake profiles.

High-Throughput Method for the Simultaneous Determination of Doxorubicin Metabolites in Rat Urine after Treatment with Different Drug Nanoformulations.

Doxorubicin (DOX) is one of the most effective cytotoxic agents against malignant diseases. However, the clinical application of DOX is limited, due to dose-related toxicity. The development of DOX nanoformulations that significantly reduce its toxicity and affect the metabolic pathway of the drug requires improved methods for the quantitative determination of DOX metabolites with high specificity and sensitivity. This study aimed to develop a high-throughput method based on high-performance liquid chromatography with fluorescence detection (HPLC-FD) for the quantification of DOX and its metabolites in the urine of laboratory animals after treatment with different DOX nanoformulations. The developed method was validated by examining its specificity and selectivity, linearity, accuracy, precision, limit of detection, and limit of quantification. The DOX and its metabolites, doxorubicinol (DOXol) and doxorubicinone (DOXon), were successfully separated and quantified using idarubicin (IDA) as an internal standard (IS). The linearity was obtained over a concentration range of 0.05-1.6 µg/mL. The lowest limit of detection and limit of quantitation were obtained for DOXon at 5.0 ng/mL and 15.0 ng/mL, respectively. For each level of quality control (QC) samples, the inter- and intra-assay precision was less than 5%. The accuracy was in the range of 95.08-104.69%, indicating acceptable accuracy and precision of the developed method. The method was applied to the quantitative determination of DOX and its metabolites in the urine of rats treated by novel nanoformulated poly(lactic-co-glycolic acid) (DOX-PLGA), and compared with a commercially available DOX solution for injection (DOX-IN) and liposomal-DOX (DOX-MY).

A scale-up strategy for the synthesis of chitosan derivatives used in micellar nanomedicines.

Nanomedicines have been increasingly investigated and used by pharmaceutical industry due to their potential in solving various public health problems. However, standardizing and approving nanomedicines remains a significant challenge, as the translation from the laboratory to the market is still limited. These constraints are due to a lack of reproducibility and standardization of procedures, small batch sizes due to inability to scale-up, or the associated production costs as a result of the production methods chosen. In this work, two chitosan derivatives, methoxypolyethylene glycol-chitosan (mPEG-CS) and methoxypolyethylene glycol-chitosan-oleic acid (mPEG-CS-OA), produced at the lab scale were implemented in a pharmaceutical industry to achieve the scale-up production using cross flow filtration (CFF). The two copolymers were shown to be capable of retaining their physicochemical properties when produced in larger batch sizes, with reduced production time and increased yield. Also, both chitosan derivatives presented no in vitro cytotoxicity independent of the method of production. Furthermore, after scale-up, polymeric micelles produced from mPEG-CS-OA were tested for storage stability, demonstrating that micelles remained stable at - 20 °C for at least 6 months. This study demonstrated the feasibility of producing polymers and polymeric micelles closer to the bedside due to their suitability for GMP production.

Reliable release testing for nanoparticles with the NanoDis System, an innovative sample and separate technique.

One of the critical quality attributes of nanoparticle formulations is drug release. Their release properties should therefore be well characterized with predictive and discriminative methods. However, there is presently still no standard method for the release testing of extended release nanoformulations. Dialysis techniques are widely used in the literature but suffer from severe drawbacks. Burst release of formulations can be masked by slow permeation kinetics of the free drug through the dialysis membrane, saturation in the membrane, and absence of agitation in the membrane. In this study, the release profile of poly(lactic co-glycolic) (PLGA) nanocapsules loaded with all-trans retinoic acid was characterized using an innovative sample and separate set-up, the NanoDis System, and compared to the release profile measured with a dialysis technique. The NanoDis System showed clear superiority over the dialysis method and was able to accurately characterize the burst release from the capsules and furthermore discriminate between different all-trans retinoic acid nanoparticle formulations.

Nano-in-Micro-Particles Consisting of PLGA Nanoparticles Embedded in Chitosan Microparticles via Spray-Drying Enhances Their Uptake in the Olfactory Mucosa.

Intranasal delivery has gained prominence since 1990, when the olfactory mucosa was recognized as the window to the brain and the central nervous system (CNS); this has enabled the direct site specific targeting of neurological diseases for the first time. Intranasal delivery is a promising route because general limitations, such as the blood-brain barrier (BBB) are circumvented. In the treatment of multiple sclerosis (MS) or Alzheimer's disease, for example, future treatment prospects include specialized particles as delivery vehicles. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles are well known as promising delivery systems, especially in the area of nose-to-brain (N2B) delivery. Chitosan is also broadly known as a functional additive due to its ability to open tight junctions. In this study, we produced PLGA nanoparticles of different sizes and revealed for the first time their size-time-dependent uptake mechanism into the lamina propria of porcine olfactory mucosa. The intracellular uptake was observed for 80 and 175 nm within only 5 min after application to the epithelium. After 15 min, even 520 nm particles were detected, associated with nuclei. Especially the presence of only 520 nm particles in neuronal fibers is remarkable, implying transcellular and intracellular transport via the olfactory or the trigeminal nerve to the brain and the CNS. Additionally, we developed successfully specialized Nano-in-Micro particles (NiMPs) for the first time via spray drying, consisting of PLGA nanoparticles embedded into chitosan microparticles, characterized by high encapsulation efficiencies up to 51%, reproducible and uniform size distribution, as well as smooth surface. Application of NiMPs accelerated the uptake compared to purely applied PLGA nanoparticles. NiMPs were spread over the whole transverse section of the olfactory mucosa within 15 min. Faster uptake is attributed to additional paracellular transport, which was examined via tight-junction-opening. Furthermore, a separate chitosan penetration gradient of ∼150 µm caused by dissociation from PLGA nanoparticles was observed within 15 min in the lamina propria, which was demonstrated to be proportional to an immunoreactivity gradient of CD14. Due to the beneficial properties of the utilized chitosan-derivative, regarding molecular weight (150-300 kDa), degree of deacetylation (80%), and particle size (0.1-10 µm) we concluded that M2-macrophages herein initiated an anti-inflammatory reaction, which seems to already take place within 15 min following chitosan particle application. In conclusion, we demonstrated the possibility for PLGA nanoparticles, as well as for chitosan NiMPs, to take all three prominent intranasal delivery pathways to the brain and the CNS; namely transcellular, intracellular via neuronal cells, and paracellular transport.

Screening of Surfactants for Improved Delivery of Antimicrobials and Poly-Lactic-co-Glycolic Acid Particles in Wound Tissue.

Topical wound management is often a challenge due to the poor penetration of antimicrobials in wound tissue and across the biofilm matrix where bacteria are embedded. Surfactants have been used for decades to improve the stability of formulations, increase drug solubility, and enhance penetration. In this study, we screened different detergents with respect to their cytotoxicity and their ability to improve the penetration of poly-lactic-co-glycolic acid (PLGA) particles in wound tissue. Among the tested surfactants, Kolliphor SLS and Tween 80 increased the penetration of PLGA particles and had a limited cytotoxicity. Then, these surfactants were used to formulate PLGA particles loaded with the poorly water-soluble antibiotic ciprofloxacin. The antimicrobial efficacy of the formulations was tested in a wound infection model based on human ex vivo skin. We found that even though PLGA particles had the same antimicrobial efficiency than the particle-free drug formulation, thanks to their solubilizing and anti-biofilm properties, the surfactants remarkably improved the antimicrobial activity of ciprofloxacin with respect to the drug formulation in water. We conclude that the use of Tween 80 in antimicrobial formulations might be a safe and efficient option to improve the topical antimicrobial management of chronic wound infections.

Testing of aerosolized ciprofloxacin nanocarriers on cystic fibrosis airway cells infected with P. aeruginosa biofilms.

The major pathogen found in the lungs of adult cystic fibrosis (CF) patients is Pseudomonas aeruginosa, which builds antibiotic-resistant biofilms. Pulmonary delivery of antibiotics by inhalation has already been proved advantageous in the clinic, but the development of novel anti-infective aerosol medicines is complex and could benefit from adequate in vitro test systems. This work describes the first in vitro model of human bronchial epithelial cells cultivated at the air-liquid interface (ALI) and infected with P. aeruginosa biofilm and its application to demonstrate the safety and efficacy of aerosolized anti-infective nanocarriers. Such a model may facilitate the translation of novel therapeutic modalities into the clinic, reducing animal experiments and the associated problems of species differences. A preformed biofilm of P. aeruginosa PAO1 was transferred to filter-grown monolayers of the human CF cell line (CFBE41o-) at ALI and additionally supplemented with human tracheobronchial mucus. This experimental protocol provides an appropriate time window to deposit aerosolized ciprofloxacin-loaded nanocarriers at the ALI. When applied 1 h post-infection, the nanocarriers eradicated all planktonic bacteria and reduced the biofilm fraction of the pathogen by log 6, while CFBE41o- viability and barrier properties were maintained. The here described complex in vitro model approach may open new avenues for preclinical safety and efficacy testing of aerosol medicines against P. aeruginosa lung infection.

Microparticle formulations alter the toxicity of fenofibrate to the zebrafish Danio rerio embryo.

A wide variety of active pharmaceutical ingredients are released into the environment and pose a threat to aquatic organisms. Drug products using micro- and nanoparticle technology can lower these emissions into the environment by their increased bioavailability to the human patients. However, due to this enhanced efficacy, micro- and nanoscale drug delivery systems can potentially display an even higher toxicity, and thus also pose a risk to non-target organisms. Fenofibrate is a lipid-regulating agent and exhibits species-related hazards in fish. The ecotoxic effects of a fenofibrate formulation embedded into a hydroxypropyl methylcellulose microparticle matrix, as well as those of the excipients used in the formulation process, were evaluated. To compare the effects of fenofibrate without a formulation, fenofibrate was dispersed in diluted ISO water alone or dissolved in the solvent DMF and then added to diluted ISO water. The effects of these various treatments were assessed using the fish embryo toxicity test, acridine orange staining and gene expression analysis assessed by quantitative RT polymerase chain reaction. Exposure concentrations were assessed by chemical analysis. The effect threshold concentrations of fenofibrate microparticle precipitates were higher compared to the formulation. Fenofibrate dispersed in 20%-ISO-water displayed the lowest toxicity. For the fenofibrate formulation as well as for fenofibrate added as a DMF solution, greater ecotoxic effects were observed in the zebrafish embryos. The chemical analysis of the solutions revealed that more fenofibrate was present in the samples with the fenofibrate formulation as well as fenofibrate added as a DMF solution compared to fenofibrate dispersed in diluted ISO water. This could explain the higher ecotoxicity. The toxic effects on the zebrafish embryo thus suggested that the formulation as well as the solvent increased the bioavailability of fenofibrate.

Predicting the environmental emissions arising from conventional and nanotechnology-related pharmaceutical drug products.

Today, environmental pollution with pharmaceutical drugs and their metabolites poses a major threat to the aquatic ecosystems. Active substances such as fenofibrate, are processed to pharmaceutical drug formulations before they are degraded by the human body and released into the wastewater. Compared to the conventional product Lipidil® 200, the pharmaceutical product Lipidil 145 One® and Ecocaps take advantage of nanotechnology to improve uptake and bioavailability of the drug in humans. In the present approach, a combination of in vitro drug release studies and physiologically-based biopharmaceutics modeling was applied to calculate the emission of three formulations of fenofibrate (Lipidil® 200, Lipidil 145 One®, Ecocaps) into the environment. Special attention was paid to the metabolized and non-metabolized fractions and their individual toxicity, as well as to the emission of nanomaterials. The fish embryo toxicity test revealed a lower aquatic toxicity for the metabolite fenofibric acid and therefore an improved toxicity profile. When using the microparticle formulation Lipidil® 200, an amount of 126 mg of non-metabolized fenofibrate was emitted to the environment. Less than 0.05% of the particles were in the lower nanosize range. For the nanotechnology-related product Lipidil 145 One®, the total drug emission was reduced by 27.5% with a nanomaterial fraction of approximately 0.5%. In comparison, the formulation prototype Ecocaps reduced the emission of fenofibrate by 42.5% without any nanomaterials entering the environment. In a streamlined life cycle assessment, the lowered dose in combination with a lowered drug-to-metabolite ratio observed for Ecocaps led to a reduction of the full life cycle impacts of fenofibrate with a reduction of 18% reduction in the global warming potential, 61% in ecotoxicity, and 15% in human toxicity. The integrated environmental assessment framework highlights the outstanding potential of advanced modeling technologies to determine environmental impacts of pharmaceuticals during early drug development using preclinical in vitro data.

Key for crossing the BBB with nanoparticles: the rational design.

Central nervous system diseases are a heavy burden on society and health care systems. Hence, the delivery of drugs to the brain has gained more and more interest. The brain is protected by the blood-brain barrier (BBB), a selective barrier formed by the endothelial cells of the cerebral microvessels, which at the same time acts as a bottleneck for drug delivery by preventing the vast majority of drugs to reach the brain. To overcome this obstacle, drugs can be loaded inside nanoparticles that can carry the drug through the BBB. However, not all particles are able to cross the BBB and a multitude of factors needs to be taken into account when developing a carrier system for this purpose. Depending on the chosen pathway to cross the BBB, nanoparticle material, size and surface properties such as functionalization and charge should be tailored to fit the specific route of BBB crossing.

The solid progress of nanomedicine.

This commentary article conveys the views of the board of the Nanomedicine and Nanoscale Delivery Focus Group of the Controlled Release Society regarding the decision of the United States National Cancer Institute (NCI) in halting funding for the Centers of Cancer Nanotechnology Excellence (CCNEs), and the subsequent editorial articles that broadened this discussion. Graphical abstract.

Evaluation of potential environmental toxicity of polymeric nanomaterials and surfactants.

Nanomaterials have gained huge importance in various fields including nanomedicine. Nanoformulations of drugs and nanocarriers are used to increase pharmaceutical potency. However, it was seen that polymeric nanomaterials can cause negative effects. Thus, it is essential to identify nanomaterials with the least adverse effects on aquatic organisms. To determine the toxicity of polymeric nanomaterials, we investigated the effects of poly(lactic-co-glycolid) acid (PLGA), Eudragit® E 100 and hydroxylpropyl methylcellulose phthalate (HPMCP) on zebrafish embryos using the fish embryo toxicity test (FET). Furthermore, we studied Cremophor® RH40, Cremophor® A25, Pluronic® F127 and Pluronic® F68 applied in the generation of nanoformulations to identify the surfactant with minimal toxic impact. The order of ecotoxicty was HPMCP < PLGA < Eudragit® E100 and Pluronic® F68 < Pluronic® F127 < Cremophor® RH40 < Cremophor® A25. In summary, HPMCP and Pluronic® F68 displayed the least toxic impact, thus suggesting adequate environmental compatibility for the generation of nanomedicines.

Development, standardization and testing of a bacterial wound infection model based on ex vivo human skin.

Current research on wound infections is primarily conducted on animal models, which limits direct transferability of these studies to humans. Some of these limitations can be overcome by using-otherwise discarded-skin from cosmetic surgeries. Superficial wounds are induced in fresh ex vivo skin, followed by intradermal injection of Pseudomonas aeruginosa under the wound. Subsequently, the infected skin is incubated for 20 hours at 37°C and the CFU/wound are determined. Within 20 hours, the bacteria count increased from 107 to 109 bacteria per wound, while microscopy revealed a dense bacterial community in the collagen network of the upper wound layers as well as numerous bacteria scattered in the dermis. At the same time, IL-1alpha and IL-1beta amounts increased in all infected wounds, while-due to bacteria-induced cell lysis-the IL-6 and IL-8 concentrations rose only in the uninfected samples. High-dosage ciprofloxacin treatment resulted in a decisive decrease in bacteria, but consistently failed to eradicate all bacteria. The main benefits of the ex vivo wound model are the use of healthy human skin, a quantifiable bacterial infection, a measureable donor-dependent immune response and a good repeatability of the results. These properties turn the ex vivo wound model into a valuable tool to examine the mechanisms of host-pathogen interactions and to test antimicrobial agents.

Ciprofloxacin-loaded PLGA nanoparticles against cystic fibrosis P. aeruginosa lung infections.

Current pulmonary treatments against Pseudomonas aeruginosa infections in cystic fibrosis (CF) lung suffer from deactivation of the drug and immobilization in thick and viscous biofilm/mucus blend, along with the general antibiotic resistance. Administration of nanoparticles (NPs) with high antibiotic load capable of penetrating the tight mesh of biofilm/mucus can be an advent to overcome the treatment bottlenecks. Biodegradable and biocompatible polymer nanoparticles efficiently loaded with ciprofloxacin complex offer a solution for emerging treatment strategies. NPs were prepared under controlled conditions by utilizing MicroJet Reactor (MJR) to yield a particle size of 190.4±28.6nm with 0.089 PDI. Encapsulation efficiency of the drug was 79% resulting in a loading of 14%. Release was determined to be controlled and medium-independent in PBS, PBS+0.2% Tween 80 and simulated lung fluid. Cytotoxicity assays with Calu-3 cells and CF bronchial epithelial cells (CFBE41o-) indicated that complex-loaded PLGA NPs were non-toxic at concentrations ≫ MICcipro against lab strains of the bacteria. Antibacterial activity tests revealed enhanced activity when applied as nanoparticles. NPs' colloidal stability in mucus was proven. Notably, a decrease in mucus turbidity was observed upon incubation with NPs. Herewith, ciprofloxacin complex-loaded PLGA NPs are introduced as promising pulmonary nano drug delivery systems against P.aeruginosa infections in CF lung.

Influence of different stabilizers on the encapsulation of desmopressin acetate into PLGA nanoparticles.

To address targeting and bioavailability issues of peptidic drugs like desmopressin, the encapsulation into nanoparticles (NP) has become standard in pharmaceutics. This study investigated the encapsulation of desmopressin into PLGA NP by the use of pharmaceutically common stabilizers as a precursor to future, optional targeting and bioavailability experiments. Polymer dry weights were measured by freeze drying and thermo gravimetric analysis (TGA). Particle sizes (ranging between 105 and 130nm, PDI<0.1) and zeta potentials (-35 to -45mV) were analyzed with Dynamic Light Scattering (DLS) and Laser-Doppler-Anemometry (LDA) respectively. Highest loading efficiencies, quantified by RP-HPLC, were achieved with Pluronic F-68 as stabilizer of the inner aqueous phase (1.16±0.07µg desmopressin/mg PLGA) and were significantly higher than coating approaches and approaches without stabilizer (0.74±0.01µg/mg). Optimized nanoformulations are thus in competition with the concentration of commercial non-nanoparticulate desmopressin products. Stability of desmopressin after the process was evaluated by HPLC peak purity analysis (diode array detector) and by mass spectrometry. Desmopressin was shown to remain intact during the whole process; however, despite these very good results the encapsulation efficiency turned out to be a bottle neck and makes the system a challenge for potential applications.