Surface modification of extracellular vesicles with polyoxazolines to enhance their plasma stability and tumor accumulation.

Extracellular vesicles (EVs) are future promising therapeutics, but their instability in vivo after administration remains an important barrier to their further development. Many groups evaluated EV surface modification strategies to add a targeting group with the aim of controlling EV biodistribution. Conversely, fewer groups focused on their stabilization to obtain "stealth" allogenic EVs. Modulating their stabilization and biodistribution is an essential prerequisite for their development as nano-therapeutics. Here, we explored polyoxazolines with lipid anchors association to the EV membrane (POxylation as an alternative to PEGylation) to stabilize EVs in plasma and control their biodistribution, while preserving their native properties. We found that this modification maintained and seemed to potentiate the immunomodulatory properties of EVs derived from mesenchymal stem/stromal cells (MSC). Using a radiolabeling protocol to track EVs at a therapeutically relevant concentration in vivo, we demonstrated that POxylation is a promising option to stabilize EVs in plasma because it increased EV half-life by 6 fold at 6 h post-injection. Moreover, EV accumulation in tumors was higher after POxylation than after PEGylation.

Tuning the Potency of Farnesol-Modified Polyethylenimine with Polyanionic Trans-Booster to Enhance DNA Delivery.

Low molecular weight polyethylenimine (PEI) based lipopolymers become an attractive strategy to construct nonviral therapeutic carriers with promising transfection efficiency and minimal toxicity. Herein, this paper presents the design and synthesis of novel farnesol (Far) conjugated PEI, namely PEI1.2k-SA-Far7. The polymers had quick DNA complexation, effective DNA unpacking (dissociation), and cellular uptake abilities when complexed with plasmid DNA. However, they were unable to provide robust transfection in culture, indicating inability of Far grafting to improve the transfection efficacy significantly. To overcome this limitation, the commercially available polyanionic Trans-Booster additive, which is capable of displaying electrostatic interaction with PEI1.2k-SA-Far7, has been used to enhance the uptake of pDNA polyplexes and transgene expression. pDNA condensation was successfully achieved in the presence of the Trans-Booster with more stable polyplexes, and in vitro transfection efficacy of the polyplexes was improved to be comparable to that obtained with an established reference reagent. The PEI1.2k-SA-Far7/pDNA/Trans-Booster ternary complex exhibited good compatibility with cells and minimal hemolysis activity. This work demonstrates the exemplary potency of using additives in polyplexes and the potential of resultant ternary complexes for effective pDNA delivery.

Biodistribution of Therapeutic Small Interfering RNAs Delivered with Lipid-Substituted Polyethylenimine-Based Delivery Systems.

Small interfering RNAs (siRNAs) have emerged as a powerful tool to manipulate gene expression in vitro. However, their potential therapeutic application encounters significant challenges, such as degradation in vivo, limited cellular uptake, and restricted biodistribution, among others. This study evaluates the siRNA delivery efficiency of three different lipid-substituted polyethylenimine (PEI)-based carriers, named Leu-Fect A-C, to different organs in vivo, including xenograft tumors, when injected into the bloodstream of mice. The siRNA analysis was undertaken by stem-loop RT-PCR, followed by qPCR or digital droplet PCR. Formulating siRNAs with a Leu-Fect series of carriers generated nanoparticles that effectively delivered the siRNAs into K652 and MV4-11 cells, both models of leukemia. The Leu-Fect carriers were able to successfully deliver BCR-Abl and FLT3 siRNAs into leukemia xenograft tumors in mice. All three carriers demonstrated significantly enhanced siRNA delivery into organs other than the liver, including the xenograft tumors. Preferential biodistribution of siRNAs was observed in the lungs and spleen. Among the delivery systems, Leu-Fect A exhibited the highest biodistribution into organs. In conclusion, lipid-substituted PEI-based delivery systems offer improvements in addressing pharmacokinetic challenges associated with siRNA-based therapies, thus opening avenues for their potential translation into clinical practice.

Optimized lipopolymers with curcumin to enhance AZD5582 and GDC0152 activity and downregulate inhibitors of apoptosis proteins in glioblastoma multiforme.

Inhibition to glioblastoma multiforme (GBM) propagation is a critical challenge in clinical practice because binding of inhibitors of apoptosis proteins (IAPs) to caspase prevents cancer cells from death. In this study, folic acid (FA), lactoferrin (Lf) and rabies virus glycoprotein (RVG) were grafted on lipopolymers (LPs) composed of poly(ε-caprolactone) and Compritol 888 ATO to encapsulate AZD5582 (AZD), GDC0152 (GDC) and curcumin (CURC). The standard deviations of initial particle diameter and particle diameter after storage for 30 days were involved in LP composition optimization. The functionalized LPs were used to permeate the blood-brain barrier (BBB) and constrain IAP quantity in GBM cells. Experimental results revealed that an increase in Span 20 (emulsifier) concentration enlarged the size of LPs, and enhanced the entrapment and releasing efficiency of AZD, DGC and CURC. 1H nuclear magnetic resonance spectra showed that the hydrogen bonds between the LPs and drugs supported the sustained release of AZD, DGC and CURC from the LPs. The LPs modified with the three targeting biomolecules facilitated the penetration of AZD, GDC and CURC across the BBB, and could recognize U87MG cells and human brain cancer stem cells. Immunofluorescence staining, flow cytometry and western blot demonstrated that CURC-incorporated LPs enhanced AZD and GDC activity in suppressing cellular IAP 1 (cIAP1) and X-linked IAP (XIAP) levels, and raising caspase-3 level in GBM. Surface FA, Lf and RVG also promoted the ability of the drug-loaded LPs to avoid carcinoma growth. The current FA-, Lf- and RVG-crosslinked LPs carrying AZD, DGC and CURC can be promising in hindering IAP expressions for GBM management.

Evaluation of drug carrier hepatotoxicity using primary cell culture models.

This study aims to establish a primary rat hepatocyte culture model to evaluate dose-dependent hepatotoxic effects of drug carriers (lipopolymer nanoparticles; LPNs) temporal. Primary rat hepatocyte cell cultures were used to determine half-maximal Inhibition Concentrations (IC50) of the drug-carrier library. Drug-carrier library, at concentrations <50 µg/mL, is benign to primary rat hepatocytes as determined using albumin and urea secretions. Albumin, as a hepatic biomarker, exhibited a more sensitive and faster outcome, compared to urea, for the determination of the IC50 value of LPNs. Temporal measurements of hepatic biomarkers including urea and albumin, and rigorous physicochemical (hydrodynamic diameter, surface charge, etc.) characterization, should be combined to evaluate the hepatotoxicity of drug carrier libraries in screens.

Multiple gene knockdown strategies for investigating the properties of human leukemia stem cells and exploring new therapies.

The past two decades have witnessed significant strides in leukemia therapies through approval of therapeutic inhibitors targeting oncogene-driving dysregulated tyrosine kinase activities and key epigenetic and apoptosis regulators. Although these drugs have brought about complete remission in the majority of patients, many patients face relapse or have refractory disease. The main factor contributing to relapse is the presence of a small subpopulation of dormant drug-resistant leukemia cells that possess stem cell features (termed as leukemia stem cells or LSCs). Thus, overcoming drug resistance and targeting LSCs remain major challenges for curative treatment of human leukemia. Chronic myeloid leukemia (CML) is a good example, with rare, propagating LSCs and drug-resistant cells that cannot be eradicated by BCR-ABL-directed tyrosine kinase inhibitor (TKI) monotherapy and that are responsible for disease relapse/progression. Therefore, it is imperative to identify key players in regulating BCR-ABL1-dependent and independent drug-resistance mechanisms, and their key pathways, so that CML LSCs can be selectively targeted or sensitized to TKIs. Here, we describe several easily adaptable gene knockdown approaches in CD34+ CML stem/progenitor cells that can be used to investigate the biological properties of LSCs and molecular effects of genes of interest (GOI), which can be further explored as therapeutic modalities against LSCs in the context of human leukemia.

Folate targeted hybrid lipo-polymeric nanoplexes containing docetaxel and miRNA-34a for breast cancer treatment.

In spite of established evidence of the synergistic combination of hydrophobic anticancer molecule and microRNA for breast cancer treatment, their in vivo delivery has not been realized owing to their instability in the biological milieu and varied physicochemical properties. The present work reports folate targeted hybrid lipo-polymeric nanoplexes for co-delivering DTX and miR-34a. These nanoplexes exhibited a mean size of 129.3 nm with complexation efficiency at an 8:1 N/P ratio. The obtained nanoplexes demonstrated higher entrapment efficiency of DTX (94.8%) with a sustained release profile up to 85% till 48 h. Further, an improved transfection efficiency in MDA-MB-231 and 4T1 breast cancer cells was observed with uptake primarily through lipid-raft and clathrin-mediated endocytosis. Further, nanoplexes showed improved cytotoxicity (~3.5-5 folds), apoptosis (~1.6-2.0 folds), and change in expression of apoptotic genes (~4-7 folds) compared to the free treatment group in breast cancer cells. In vivo systemic administration of FA-functionalized DTX and FAM-siRNA-loaded nanoplexes showed an improved area under the curve (AUC) as well as circulation half-life compared to free DTX and naked FAM-labelled siRNA. Acute toxicity studies of the cationic polymer showed no toxicity at a dose equivalent to 10 mg/kg based on the hematological, biochemical, and histopathological examination.

Effect of pH on Isoliquiritigenin (ISL) fluorescence in lipo- polymeric system and metallic nanosystem.

Flavonoids have various medicinal properties such as anti-inflammatory, anti-oxidant, anti-cancer, antiviral. Yet, the fluorescent properties of flavonoids are less explored and termed as autofluorescence in general. This study investigates the fluorescence properties of Isoliquiritigenin (ISL) in various alkaline conditions. The maximum fluorescence emission was obtained at pH 12 on excitation wavelength of 440 nm. Theoretical and experimental investigation on the shift in UV-Vis absorbance spectra, upon the variation in pH, performed, indicated deprotonation as the cause. PEG-based stable liposome carrier, with an internal alkaline environment (LIP-ISL-NaOH) that aids in flavonoid fluorescence, was synthesized using a modified thin-film hydration method. The hydrodynamic size of the liposome synthesized was in the range of 50-70 nm. PEG, on the addition, found maintaining the alkaline environment in the internal chamber of the lipo-polymer system, helps the LIP-ISLNaOH nanosystem to exhibit fluorescence irrespective of the suspension pH. Further, reducing property of ISL was used for the synthesis of Au nanoclusters to achieve theranostic nature.

Lipopolymers and lipids from lung surfactants in association with N-acetyl-l-cysteine: Characterization and cytotoxicity.

In the present work, we obtained polymeric diacetylene liposomes that can associate N-Acetyl-l-Cysteine (NAC), a broad spectrum mucolytic. The reason for studying these formulations is that they could be applied in the future as NAC delivery systems, with a possible dose reduction but maintaining its effect. Liposomes used herein are obtained by a photopolymerization reaction, thus gaining stability and rigidity. Lipids belonging to lung surfactant were added in different ratios to the formulations in order to maximize its possible interaction with the lung tissue. Because of lipopolymer stability, the oral or nasal route could be appropriated. This formulation could efficiently transport NAC to exert its mucolytic activity and help in diseases such as cystic fibrosis, which has abnormal mucus production. Also, this type of treatment could be useful in other types of diseases, interacting with the mucus layer and making the lung tissue more permeable to other therapies. Formulations so obtained presented high levels of polymerization. Also, they present small hollow fibers structures with a high number of polymeric units. These types of arrangements could present advantages in the field of drug delivery, giving the possibility of a controlled release. Lipopolymers with lipids from lung surfactant associated with NAC are promising complexes in order to treat not only respiratory illnesses. The stability of the formulation would allow its inoculation through other routes such as the oral one, helping the reposition of NAC as an antioxidant drug. Finally, these formulations are non-toxic and easy to produce.

siRNA-mediated BCR-ABL silencing in primary chronic myeloid leukemia cells using lipopolymers.

Despite development of effective tyrosine kinase inhibitors for treatment of chronic myeloid leukemia (CML), some patients do not effectively respond to the therapy and can display resistance in response to the drug therapy. To develop an alternative approach to CML therapy, we are exploring siRNA mediated silencing of the primary CML oncogene, BCR-ABL, by using non-viral (polymeric) delivery systems. In this study, a group of lipopolymers derived from low molecular PEIs substituted with linoleic acid (LA), α-linolenic acid (αLA) and cholesterol (Chol) was investigated for the first time for siRNA delivery to CML primary samples. The delivery efficiency in primary cells was equivalent to CML K562 cell line, and the lipopolymers gave effective internalization of siRNA depending on the nature of lipid substituent. The PEI-αLA (2.5 αLA/PEI), PEI-Chol (2.2 Chol/PEI), and PEI-LA (2.6 LA/PEI) lipopolymers used as BCR-ABL siRNA carriers (at 60 nM siRNA) reduced the BCR-ABL mRNA expression by 17% to 45%, and inhibited the formation of colonies by 24% to 41% in comparison with control siRNA in mononuclear cells. BCR-ABL siRNA treatment reduced the BCR-ABL mRNA expression by 50% in one of two CD34+ samples tested, and combination of BCR-ABL siRNA with imatinib (IM) treatment decreased the colony formation by 65% in one of two samples evaluated. The fact that no single polymer was universally effective in all patient samples may suggest patient-to-patient variability in terms of therapeutic responses to siRNA therapy. These results showed that a low dose of BCR-ABL siRNA could be used with lipopolymers to reduce BCR-ABL mRNA expression, CML cell survival and colony formation. This proof of principle study in CML primary cells can be applied to silencing of other therapeutic targets besides BCR-ABL and a study with larger patient samples is warranted for better identification of effective siRNA carriers.

Protection against Neurodegeneration in the Hippocampus Using Sialic Acid- and 5-HT-Moduline-Conjugated Lipopolymer Nanoparticles.

Significant involvement of oxidative stress in the brain can develop Alzheimer's disease (AD); however, a great number of clinical trials explains the limited success of antioxidant therapy in dealing with this neurodegenerative disease. Here, we established a lipopolymer system of poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) incorporated with phosphatidic acid (PA) and modified with sialic acid (SA) and 5-hydroxytryptamine-moduline (5HTM) to improve quercetin (QU) activity against oxidative stress induced by amyloid-ß (Aß) deposits. Morphological studies revealed a uniform exterior of QU-SA-5HTM-PA-PLGA NPs with a spherical structure and enhanced aggregation with inclusion of PA in the formulation. A better brain-targeted delivery of the lipopolymeric NPs was verified from the high blood-brain barrier (BBB) permeability of QU through strong interactions of surface SA and 5HTM with O-linked N-acetylglucosamine and 5-HT1B receptors, respectively. Immunofluorescence staining images also supported QU-SA-5HTM-PA-PLGA NPs to traverse the microvessels of AD rat brain. Western blot analysis showed that QU-loaded PA-PLGA NPs suppressed caspase-3 expression. The ability of the nanocarriers to recognize Aß fibrils was demonstrated from the reduced senile plaque formation and the attenuated acetylcholinesterase and malondialdehyde activity in the hippocampus. Hence, the medication of QU-SA-5HTM-PA-PLGA NPs can facilitate the BBB penetration and prevent Aß accumulation, lipid peroxidation, and neuronal apoptosis for the AD management.

Effect of PEGylation on assembly morphology and cellular uptake of poly ethyleneimine-cholesterol conjugates for delivery of sorafenib tosylate in hepatocellular carcinoma.

Introduction: Sorafenib (SFB) is an FDA-approved chemotherapeutic agent with a high partition coefficient (log P = 4.34) for monotherapy of hepatocellular carcinoma (HCC). The oral bioavailability is low and variable, so it was aimed to study the application of the polymeric nanoassembly of cholesterol conjugates of branched polyethyleneimine (PEI) for micellar solubilization of SFB and to investigate the impact of the polymer PEGylation on the physicochemical and cellular characteristics of the lipopolymeric dispersions. Methods: Successful synthesis of cholesterol-PEI lipopolymers, either native or PEGylated, was confirmed by FTIR, 1H-NMR, pyrene assay methods. The nanoassemblies were also characterized in terms of morphology, particle size distribution and zeta-potential by TEM and dynamic light scattering (DLS). The SFB loading was optimized using general factorial design. Finally, the effect of particle characteristics on cellular uptake and specific cytotoxicity was investigated by flow cytometry and MTT assay in HepG2 cells. Results: Transmission electron microscopy (TEM) showed that PEGylation of the lipopolymers reduces the size and changes the morphology of the nanoassembly from rod-like to spherical shape. However, PEGylation of the lipopolymer increased critical micelle concentration (CMC) and reduced the drug loading. Moreover, the particle shape changes from large rods to small spheres promoted the cellular uptake and SFB-related cytotoxicity. Conclusion: The combinatory effects of enhanced cellular uptake and reduced general cytotoxicity can present PEGylated PEI-cholesterol conjugates as a potential carrier for delivery of poorly soluble chemotherapeutic agents such as SFB in HCC that certainly requires further investigations in vitro and in vivo.

Effective cellular internalization, cell cycle arrest and improved pharmacokinetics of Tamoxifen by cholesterol based lipopolymeric nanoparticles.

The present study aims at the development of cholesterol based lipopolymeric nanoparticles for improved entrapment, better cell penetration and improved pharmacokinetics of Tamoxifen (TMX). Self-assembling cholesterol grafted lipopolymer, mPEG-b-(CB-{g-chol}-co-LA) was synthesized from poly(ethyleneglycol)-block-2-methyl-2-carboxyl-propylenecarboxylic acid-co-poly (l-lactide) [mPEG-b-(CB-{g-COOH}-co-LA)] copolymer followed by carbodiimide coupling for attaching cholesterol. Lipopolymeric nanoparticles were prepared using o/w solvent evaporation technique, which were subsequently characterized to determine its particle size, entrapment efficiency, release pattern and compared with mPEG-PLA nanoparticles. Further, in order to assess the in vitro efficacy, cytotoxicity studies, uptake, apoptosis assay and cell cycle analysis were performed in breast cancer cell lines (MCF-7 and 4T1). Finally, the pharmacokinetic profile of TMX loaded mPEG-b-(CB-{g-chol}-co-LA) lipopolymeric nanoparticles was also performed. TMX loaded lipopolymeric nanoparticles of particle size 151.25 ±â€¯3.74 (PDI 0.123) and entrapment efficiency of 73.62 ±â€¯3.08% were formulated. The haemolytic index, protein binding and in vitro drug release of the optimized nanoparticles were found to be comparable to that of the TMX loaded mPEG-PLA nanoparticles. Lipopolymeric nanoparticles demonstrated improved IC50 values in breast cancer cells (22.2 µM in 4T1; 18.8 µM in MCF-7) than free TMX (27.6 µM and 23.5 µM respectively) and higher uptake efficiency. At IC50 values, TMX loaded lipopolymeric nanoparticles induced apoptosis and cell cycle arrest (G0/G1 phase) to similar extent as that of free drug. Pharmacokinetic studies indicated ∼2.5-fold increase in the half-life (t1/2) (p < 0.001) and ∼2.7-fold (p < 0.001) increase in the mean residence time (MRT) of TMX following incorporation into lipopolymeric nanoparticles. Thus, mPEG-b-(CB-{g-chol}-co-LA) lipopolymeric nanoparticles offer a more promising approach for delivery of Tamoxifen in breast cancer by improving drug internalization and prolonging the mean residence time of the drug indicating possibility of dose reduction and hence bypassing the adverse effects of TMX therapy.

Reconstitution of the membrane protein OmpF into biomimetic block copolymer-phospholipid hybrid membranes.

Structure and function of many transmembrane proteins are affected by their environment. In this respect, reconstitution of a membrane protein into a biomimetic polymer membrane can alter its function. To overcome this problem we used membranes formed by poly(1,4-isoprene-block-ethylene oxide) block copolymers blended with 1,2-diphytanoyl-sn-glycero-3-phosphocholine. By reconstituting the outer membrane protein OmpF from Escherichia coli into these membranes, we demonstrate functionality of this protein in biomimetic lipopolymer membranes, independent of the molecular weight of the block copolymers. At low voltages, the channel conductance of OmpF in 1 M KCl was around 2.3 nS. In line with these experiments, integration of OmpF was also revealed by impedance spectroscopy. Our results indicate that blending synthetic polymer membranes with phospholipids allows for the reconstitution of transmembrane proteins under preservation of protein function, independent of the membrane thickness.

Targeting CXCR4/SDF-1 axis by lipopolymer complexes of siRNA in acute myeloid leukemia.

In spite of high complete remission rates in Acute Myeloid Leukemia (AML), little progress has been made in the long-term survival of relapsing AML patients, urging for the development of novel therapies. The CXCR4/SDF-1 axis is a potential therapeutic target in AML to reduce the enhanced survival and proliferation of leukemic cells, with current drug development efforts focusing on antagonists and blocking antibodies. The RNAi technology mediated by siRNA is a promising alternative; however, further development of clinically relevant siRNA carriers is needed since siRNA on its own is an incompetent silencing agent. Here, we report on lipid-substituted polymeric carriers for siRNA delivery to AML cells, specifically targeting CXCR4. Our results demonstrate an effective suppression of CXCR4 protein with the polymeric siRNA delivery in AML THP-1 cells. The suppression of CXCR4 as well as its ligand, SDF-1 (CXCL12), decreased THP-1 cell numbers due to reduced cell proliferation. The reduced proliferation was also observed in the presence of human bone marrow stromal cells (hBMSC), suggesting that our approach would be effective in the protective bone marrow microenvironment. The combination of CXCR4 silencing and cytarabine treatment resulted in more effective cytotoxicity when the cells were co-incubated with hBMSC. We observed a decrease in the toxicity of the lipopolymer/siRNA complexes when THP-1 cells were treated in the presence of hBMSC but this effect did not negatively affect CXCR4 silencing. In addition, siRNA delivery to mononuclear cells derived from AML patients led to significant CXCR4 silencing in 2 out of 5 samples, providing a proof-of-concept for clinical translation. We conclude that decreasing CXCR4 expression via lipopolymer/siRNA complexes is a promising option for AML therapy and could provide an effective alternative to current CXCR4 inhibition strategies.

Interfacial behavior of PEGylated lipids and their effect on the stability of squalenoyl-drug nanoassemblies.

Squalenoyl-gemcitabine (Sq-Gem) and squalenoyl-dideoxycytidine (Sq-ddC) are amphiphilic prodrugs that self-assemble in water to form nanoassemblies (NAs) with well-defined structures and size. However, like other drug nanocarriers, these nanoassemblies are rapidly cleared from the blood stream by the reticulo-endothelial system. By adding squalenoyl-PEG (Sq-PEG) or cholesterol-PEG (Chol-PEG) to the squalenoyl prodrugs, composite nanoassemblies (CNAs) were formed, with different sizes and structures. The effect of the PEG-lipids on the formation and stability of these nanoassemblies was assessed by transmission electron microscopy, quasi-elastic light scattering and surface tension measurements in various conditions. The results revealed different stabilities with time for Sq-ddC and Sq-Gem nanoassemblies in aqueous medium, the latter being much less stable than the former. They also demonstrated that the presence of Sq-PEG or Chol-PEG in composite Sq-ddC nanoassemblies contributed to their rapid destabilization. The analysis of the adsorption kinetics of Sq-PEG into a prodrug monolayer below and above its critical aggregation concentration allowed getting a better insight into prodrug-lipopolymer molecular interactions, and their consequences on the formation of composite prodrug nanoassemblies.

Cyclen-based lipidic oligomers as potential gene delivery vehicles.

A series of cyclen-based linear oligomers bearing hydrophobic long chains (lipopolymers Cy-LC, where Cy and LC represent cyclen-based linear backbone and hydrophobic long chain substituents, respectively) were designed and synthesized. The effects of type and degree of substitution (DS) of hydrophobic long chains on the transfection efficiency were systematically studied. The nitrogen atoms with relatively strong basicity on the cyclen ensure their good DNA binding ability, which was confirmed by gel retardation and ethidium bromide exclusion assays. Lipopolyplexes could be formed as nanoparticles with suitable sizes and zeta potentials for gene transfection. In vitro gene delivery experiments revealed that the linoleic acid (LIN) substituted material Cy-LIN has better transfection efficiency than 25 kDa polyethylenimine in the absence or in the presence of serum. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and hemolysis assays showed low cytotoxicity and good biocompatibility of the lipopolyplexes. Fluorescent labeled DNA was used to study the cellular uptake and intracellular distribution of transfected DNA. Flow cytometry results suggested that a long chain is necessary for efficient cellular uptake, and images from confocal laser scanning microscopy showed that after 4h transfection, most of the fluorescent labeled DNA accumulated in the perinuclear region, which was required for efficient gene expression. Moreover, it was also found that the DS of the hydrophobic moiety can adjust the balance between DNA binding ability and dissociation of polyplexes, significantly affecting the transfection efficiency.

Dry powder cationic lipopolymeric nanomicelle inhalation for targeted delivery of antitubercular drug to alveolar macrophage.

Excipients having self-assembling properties are less explored in the field of dry powder inhalation (DPI) technology. An amphiphilic lipopolymer system was developed using stearic acid (SA) and branched polyethyleneimine (BPEI) (1800 Dalton), at different proportions by covalent conjugation. A molecular dynamic (MD) simulation tool was employed for predicting the carrier behavior in a polar in vivo condition. The structural characterization was carried out using nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared (FTIR) spectroscopy. The physical nature of the lipopolymer was analyzed by differential scanning calorimetry. Determination of zeta potential and diameter of the micelles showed existence of cationic particles in the nano size range when a lower number of primary amino groups of BPEI was grafted with SA. The rifampicin (RIF)-loaded lipopolymer was also formulated further into spray-dried microparticles. Powder X-ray diffraction (PXRD) studies revealed that the RIF API (active pharmaceutical ingredient) exists as molecular dispersion in spray-dried microparticles. Topological analysis of the spray-dried nanomicelle was carried out using scanning electron microscopy (SEM). A large population of the drug-carrying particles were found to be under the inhalable size range (fine particle fraction 67.88% ± 3%). In vitro drug release kinetics from spray-dried nanomicelles were carried out at lung fluid pH.