Polymeric curcumin nanoparticles by a facile in situ method for macrophage targeted delivery

Polydispersity-mediated high efficacy of an in-situ aqueous nanosuspension of PPEF.3HCl in methicillin resistant Staphylococcus aureus sepsis model

Recently, World Health Organization declared antimicrobial resistance as the third greatest threat to human health. Absence of known cross-resistance, new class, new target, and a new mode of action are few major strategies being undertaken by researches to combat multidrug resistant pathogen. PPEF.3HCl, a bisbenzimidazole was developed as highly potent antibacterial agent against ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens, targeting topoisomerase IA. The present work encompasses a radical on-site generation of In-situ nanosuspension of PPEF.3HCl with enhanced efficacy against methicillin resistant S. aureus in septicemia model. We have generated instantaneously a PPEF.3HCl nanosuspension (IsPPEF.3HCl-NS) by mixing optimized monophasic PPEF.3HCl preconcentrate in propylene glycol into an aqueous medium comprising tween 80 as stabilizer. The IsPPEF.3HCl-NS showed precipitation efficiency of > 90 %, average particle size < 500 nm, retained upto 5 h, a negative zeta potential and bi/trimodal particle size distribution. Differential scanning calorimetry, X-ray diffraction confirmed partial amorphization and transmission electron microscopy revealed spherical particles. IsPPEF.3HCl-NS was non-hemolytic and exhibited good stability in serum. More significantly, it exhibited a ∼ 1.6-fold increase in macrophage uptake compared to free PPEF.3HCl in the RAW 264.7 macrophage cell line. Confocal microscopy revealed accumulation of IsPPEF.3HCl-NS within the lysosomal compartment and cell cytosol, proposing high efficacy. In terms of antimicrobial efficacy, IsPPEF.3HCl-NS outperforms free PPEF.3HCl against clinical methicillin sensitive and resistant S. aureus strains. In a pivotal experiment, IsPPEF.3HCl-NS exhibited over 83 % survival at 8 mg/kg.bw and an impressive reduction of ∼ 4-5 log-fold in bacterial load, primarily in the kidney, liver and spleen of septicemia mice. IsPPEF.3HCl-NS prepared by the In-situ approach, coupled with enhanced intramacrophage delivery and superior efficacy, positions IsPPEF.3HCl-NS as a pioneering and highly promising formulation in the battle against antimicrobial resistance.

Curcumin encapsulated in milk small extracellular vesicles as a nanotherapeutic alternative in experimental chronic liver disease

Curcumin is a natural molecule widely tested in preclinical and clinical studies due to its antioxidant and anti-inflammatory activity. Nevertheless, its high hydrophobicity and low bioavailability limit in vivo applications. To overcome curcumin´s drawbacks, small extracellular vesicles (sEVs) have emerged as potential drug delivery systems due to their non-immunogenicity, nanometric size and amphiphilic composition. This work presents curcumin cargo into milk sEV structure and further in vitro and in vivo evaluation as a therapeutic nanoplatform. The encapsulation of curcumin into sEV was performed by two methodologies under physiological conditions: a passive incorporation and active cargo employing saponin. Loaded sEVs (sEVCurPas and sEVCurAc) were fully characterized by physicochemical techniques, confirming that neither methodology affects the morphology or size of the nanoparticles (sEV: 113.3±5.1 nm, sEVCurPas: 127.0±4.5 nm and sEVCurAc: 98.5±3.6 nm). Through the active approach with saponin (sEVCurAc), a three-fold higher cargo was obtained (433.5 µg/mL) in comparison with the passive approach (129.1 µg/mL). These sEVCurAc were further evaluated in vitro by metabolic activity assay (MTT), confocal microscopy, and flow cytometry, showing a higher cytotoxic effect in the tumoral cells RAW264.7 and HepG2 than in primary hepatocytes, specially at high doses of sEVCurAc (4%, 15% and 30% of viability). In vivo evaluation in an experimental model of liver fibrosis confirmed sEVCurAc therapeutic effects, leading to a significant decrease of serum markers of liver damage (ALT) (557 U/L to 338 U/L with sEVCurAc therapy) and a tendency towards decreased liver fibrogenesis and extracellular matrix (ECM) deposition.

Macrophage targeted polymeric curcumin nanoparticles limit intracellular survival of Mycobacterium tuberculosis through induction of autophagy and augment anti-TB activity of isoniazid in RAW 264.7 macrophages

Rapid emergence of antibiotic resistance in tuberculosis has left us with limited resources to treat and manage multi drug resistant (MDR) cases of tuberculosis, prompting the development of novel therapeutics. Mycobacterium tuberculosis (MTB) perturbs the host protective pathways for its survival, therefore host directed therapeutic (HDT) interventions offer an attractive alternative strategy. Curcumin (CMN), the principle curcuminoid from Curcuma longa is known to have anti-TB activity against MDR strains of MTB in macrophages. We discovered that treatment of CMN induced autophagy in uninfected and MTB infected macrophages which was evident by conversion of LC3-I to LC3-II and degradation of p62. Inhibition of autophagy by a pharmacological inhibitor 3-MA resulted in significant inhibition of intracellular killing activity of CMN, suggesting the involvement of autophagy in intracellular clearance of MTB. Moreover, annexin v-FITC/PI staining data suggested induction of apoptosis in uninfected and MTB infected macrophages post CMN treatment. This finding was further corroborated by up-regulated expression of pro-apoptotic proteins, Bax, cleaved caspase-3 and PARP and diminished expression of anti-apoptotic protein Bcl-2 as evaluated by immunoblotting. Using GFP-MTB H37Rv and Lysotracker Red staining we demonstrated co-localization of GFP-MTB H37Rv containing phagosome to lysosome after CMN treatment, indicating enhanced phagosome lysosome fusion. Due to poor bioavailability of CMN, its clinical use is limited, therefore to overcome this issue, CMN was encapsulated in Poly(lactic-co-glycolic) acid (PLGA) shell, resulting in polymeric CMN nano particles (ISCurNP). Flow cytometric evaluation suggested >99% uptake of ISCurNP after 3h of treatment. In BALB/c mice, oral dose of ISCurNP resulted in 6.7-fold increase in the bioavailability compared to free CMN. Moreover, ISCurNP treatment resulted in significant decrease in the intracellular survival of MTB H37Rv through induction of autophagy. Adjunct action of ISCurNP and CMN in combination with isoniazid (INH) revealed >99% decrease in intracellular survival of MTB in macrophage as compared to ISCurNP, CMN or INH alone. In conclusion, our findings suggest the role of ISCurNP as novel host directed formulation to combat both sensitive and MDR strains of MTB by induction of autophagy.

Facile engineering of resveratrol nanoparticles loaded with 20(S)-protopanaxadiol for the treatment of periodontitis by regulating the macrophage phenotype

Periodontitis is an inflammatory disease, mainly caused by the formation of a subgingival plaque biofilm. In recent years, growing attention has been paid to immunotherapy in the treatment of periodontitis, and the importance of communal intervention associated with macrophage polarization was emphasized. Herein, resveratrol (RES) and 20(S)-protopanaxadiol (PPD) were successfully self-assembled into RES@PPD nanoparticles (NPs) by the phenolic resin reaction. RES@PPD NPs have good stability and biocompatibility. The combined application of PPD and RES enhances the anti-inflammatory and antioxidant properties of nanocomposites, remarkably reduces the level of reactive oxygen species, and finally realizes the coordinated regulation of host immunity in periodontitis. The detailed mechanism is as follows: RES@PPD NPs inhibit M1 polarization of macrophages, promote M2 polarization by scavenging ROS, and then inhibit the NF-κB signalling pathway to regulate host immunity. In the animal model of periodontitis, RES@PPD NPs can remarkably decrease the level of pro-inflammatory cytokines, up-regulate the anti-inflammatory cytokines, and exhibit a profound therapeutic effect on local inflammation. Therefore, RES@PPD NPs are effective in antioxidation and anti-inflammation, thus providing a promising candidate drug for the treatment of periodontitis.

Polymeric Nanoparticles for Delivery of Natural Bioactive Agents: Recent Advances and Challenges

In the last few decades, several natural bioactive agents have been widely utilized in the treatment and prevention of many diseases owing to their unique and versatile therapeutic effects, including antioxidant, anti-inflammatory, anticancer, and neuroprotective action. However, their poor aqueous solubility, poor bioavailability, low GIT stability, extensive metabolism as well as short duration of action are the most shortfalls hampering their biomedical/pharmaceutical applications. Different drug delivery platforms have developed in this regard, and a captivating tool of this has been the fabrication of nanocarriers. In particular, polymeric nanoparticles were reported to offer proficient delivery of various natural bioactive agents with good entrapment potential and stability, an efficiently controlled release, improved bioavailability, and fascinating therapeutic efficacy. In addition, surface decoration and polymer functionalization have opened the door to improving the characteristics of polymeric nanoparticles and alleviating the reported toxicity. Herein, a review of the state of knowledge on polymeric nanoparticles loaded with natural bioactive agents is presented. The review focuses on frequently used polymeric materials and their corresponding methods of fabrication, the needs of such systems for natural bioactive agents, polymeric nanoparticles loaded with natural bioactive agents in the literature, and the potential role of polymer functionalization, hybrid systems, and stimuli-responsive systems in overcoming most of the system drawbacks. This exploration may offer a thorough idea of viewing the polymeric nanoparticles as a potential candidate for the delivery of natural bioactive agents as well as the challenges and the combating tools used to overcome any hurdles.

Facile Technology for Extemporaneous Preparation of Long-Acting Injectable Microparticulate Suspensions at the Patient Side

In this study, we present an innovative and facile in situ approach for extemporaneous preparation of sterile microparticles. An amazingly simple approach, in situ technology circumvents the stability, and scale up challenges as well as sterilization issues associated with long-acting particulate systems. Monophasic preconcentrates of donepezil base (DPZ), a model drug with a biodegradable polymer poly (DL-lactide-co-glycolide) (PLGA), with stabilizer were prepared by simple solution and sterilized by filtration (0.22 micron). The sterile preconcentrates when added to aqueous dextrose solution (total volume < 3 mL) generated ready-to-inject DPZ PLGA microparticles (DPZ-PLGA-MP) with high reproducibility, entrapment efficiency (> 80%), and size ~ 80 micron. DPZ micro suspension (DPZ-MS) with high precipitation efficiency (> 90%) and size ~ 80 micron was obtained in a similar manner omitting PLGA. XRD and DSC study confirmed decreased crystallinity in the presence of PLGA. No interaction between PLGA and DPZ was evident in the FTIR study. The microparticulate dispersions exhibited good in vitro injectability when tested using the texture analyzer (force < 5 N). When evaluated using the dialysis bag method (Himedia 12-14 kDa molecular weight cutoff), both microparticulate formulations exhibited controlled release up to 1 week in vitro. Further, low burst release of ~ 10% at the end of 6 h in the ex vivo chicken muscle study proposes great promise. Our data propose the facile extemporaneous generation of microparticles as a practical and promising approach for development of long-acting injectables. This facile approach could serve as platform technology for other drug candidates.

In-silico approach as a tool for selection of excipients for safer amphotericin B nanoformulations

Safer and efficacious Amphotericin B (AmB) nanoformulations can be designed by augmenting AmB in the monomeric or super-aggregated state, and restricting the aggregated state, by choosing the appropriate excipient, which can be facilitated by employing in-silico prediction as a tool. Excipients selected for the study included linear fatty acids from caprylic (C₈) to stearic(C₁₈) and the stearate based amphiphilic surfactants polyoxyl-15-hydroxystearate (PS15) and polyoxyl-40-stearate (PS40). Blend module was employed to determine the two miscibility parameters mixing energy (E_mix) and interaction parameter (χ). AmB-excipient interactions were modelled using molecular docking software. The fatty acids revealed a decrease in E_mix and χ values with increase in carbon chain length, suggesting enhanced affinity with increase in fatty acid hydrophobicity. Significantly higher affinity was observed with amphiphilic surfactants, in particular PS40 which exhibited negative values of E_mix and χ proposing very high degree of miscibility. Molecular docking study confirmed extensive interaction of all the excipients with the AmB polyene chain. PS15 and PS40 displayed in addition hydrophilic interactions with the mycosamine and polyol moieties with PS40 exhibiting complete wrapping of the AmB molecule. PS15 demonstrated only partial wrapping, attributed to the shorter ethylene oxide chain. AmB nanosuspensions (NS) were prepared by in situ nanoprecipitation using the excipients and the AmB state identified by UV scanning between 300 and 500 nm. AmB NS with fatty acids and PS15-AmB NS revealed a high intensity peak between 330 nm-350 nm of aggregated AmB and low intensity monomeric peaks between 405 and 415 nm reflecting predominance of the aggregated state. PS40-AmB NS on the other hand revealed complete absence of aggregated state and a high intensity peak between 321 and 325 nm which corresponded to the super-aggregated state. Also, the super-aggregated state slowly released the safe monomeric form without aggregate formation. Furthermore, very low hemolysis seen with PS40-AmB NS confirmed low toxicity attributed to the safer super-aggregated state and while higher hemolysis as anticipated was seen with PS15-AmB NS (aggregated state). The basis for selection of the appropriate excipient for design of safer AmB nanoformulations would be those excipients that exhibit negative values of miscibility parameters E_mix and χ, exhibit interaction with the hydrophobic and hydrophilic regions of AmB and demonstrate complete wrapping of AmB in the molecular docking study. Our study thus demonstrates feasibility of in-silico prediction as a practical tool for excipient selection for safer AmB nanoformulations.

Inhalable solid lipid nanoparticles for intracellular tuberculosis infection therapy: macrophage-targeting and pH-sensitive properties

Mycobacterium tuberculosis (MTB) is one of the most threatening pathogens for its latent infection in macrophages. The intracellular MTB isolated itself from drugs and could spread via macrophages. Therefore, a mannose-modified macrophage-targeting solid lipid nanoparticle, MAN-IC-SLN, loading the pH-sensitive prodrug of isoniazid (INH), was designed to treat the latent tuberculosis infection. The surface of SLNs was modified by a synthesized 6-octadecylimino-hexane-1,2,3,4,5-pentanol (MAN-SA) to target macrophages, and the modified SLNs showed a higher cell uptake in macrophages (97.2%) than unmodified SLNs (42.4%). The prodrug, isonicotinic acid octylidene-hydrazide (INH-CHO), was synthesized to achieve the pH-sensitive release of INH in macrophages. The INH-CHO-loaded SLNs exhibited a pH-sensitive release profile and accomplished a higher accumulated release in pH 5.5 media (82.63 ± 2.12%) compared with the release in pH 7.4 media (58.83 ± 3.84%). Mycobacterium smegmatis was used as a substitute for MTB, and the MAN-IC-SLNs showed a fourfold increase of intracellular antibiotic efficacy and enhanced macrophage uptake because of the pH-sensitive degradation of INH-CHO and MAN-SA in SLNs, respectively. For the in vivo antibiotic efficacy test, the SLNs group displayed an 83% decrease of the colony-forming unit while the free INH group only showed a 60% decrease. The study demonstrates that macrophage targeting and pH-sensitive SLNs can be used as a promising platform for the latent tuberculosis infection. Graphical Abstract Table of contents: Macrophage-targeting and pH-sensitive solid lipid nanoparticles (SLN) were administrated to the lung via nebulization. Macrophage targeting was achieved by appropriate particle size and surface mannose modification with synthesized MAN-SA. After being swallowed by macrophages, the prodrug, Isonicotinic acid octylidene-hydrazide (INH-CHO), quickly released isoniazid, which was triggered by the intracellular acid environment. The SLNs exhibited higher intracellular antibiotic efficacy due to their macrophage-targeting and pH-sensitive properties.

Innovative Betulin Nanosuspension exhibits enhanced anticancer activity in a Triple Negative Breast Cancer Cell line and Zebrafish angiogenesis model

We present a nanosuspension of betulin, a BCS class II anticancer drug, particularly effective against resistant breast cancer. As anticancer efficacy of betulin is hampered by poor aqueous solubility, a nanosuspension with surface area was considered to enhance efficacy. An innovative approach wherein the betulin nanosuspension is generated instantaneously in situ, by adding a betulin preconcentrate (BeTPC) comprising drug and excipients, to aqueous medium, is successfully demonstrated. The optimal BeTPC when added to isotonic dextrose solution instantaneously generated an in situ nanosuspension (BeTNS-15) with high precipitation efficiency (92.7 ± 1.21%), average particle size (383.74 ± 7.24 nm) and good stability as per ICH guidelines. TEM revealed elongated particles while DSC and XRD indicated partial amorphization. Significantly higher cytotoxicity of BeTNS-15 (IC₅₀ 38.44 µg/ml) compared to betulin (BetS) (IC₅₀ 69.54 µg/ml) in the resistant triple negative human breast cancer cell line MDA-MB-231, was attributed to high intracellular uptake confirmed by HPLC and Imaging Flow cytometry (IFC). IFC confirmed superior anti-cancer efficacy of BeTNS-15 mediated by mitochondrial membrane disruption and inhibition of the G0/G1 phase. BeTNS-15 also exhibited significantly greater anti-angiogenic efficacy (p < 0.05) in the zebrafish model confirming superior efficacy. Simplicity of the innovative in situ approach coupled with superior efficacy proposes BeTNS as an innovative and highly promising anticancer formulation.

Pre-clinical evaluation of an innovative oral nano-formulation of baicalein for modulation of radiation responses

There is an unmet medical need for non-toxic and effective radiation countermeasures for prevention of radiation toxicity during planned exposures. We have earlier shown that intraperitoneal administration of baicalein (BCL) offers significant survival benefit in animal model. Safety, tolerability, pharmacokinetics (PK) and pharmacodynamics of baicalein has been reported in pre-clinical model systems and also in healthy human volunteers. However, clinical translation of baicalein is hindered owing to poor bioavailability due to lipophilicity. In view of this, we fabricated and characterized in-situ solid lipid nanoparticles of baicalein (SLNB) with effective drug entrapment and release kinetics. SLNB offered significant protection to murine splenic lymphocytes against 4 Gy ionizing radiation (IR) induced apoptosis. Oral administration of SLNB exhibited ~70% protection to mice against whole body irradiation (WBI 7.5 Gy) induced mortality. Oral relative bioavailability of BCL was enhanced by over ~300% after entrapment in the SLNB as compared to BCL. Oral dosing of SLNB resulted in transient increase in neutrophil abundance in peripheral blood. Interestingly, we observed that treatment of human lung cancer cells (A549) with radioprotective dose of SLNB exhibited radio-sensitization as evinced by decrease in survival and clonogenic potential. Contrary to antioxidant nature of baicalein in normal cells, SLNB treatment induced significant increase in cellular ROS levels in A549 cells probably due to higher uptake and inhibition of TrxR. Thus, a pharmaceutically acceptable SLNB exhibited improved bioavailability, better radioprotection to normal cells and sensitized cancer cells to radiation induced killing as compared to BCL suggesting its possible utility as an adjuvant during cancer radiotherapy.

Recent Advances in Polymeric Nanoparticle-Encapsulated Drugs against Intracellular Infections

Polymeric nanocarriers (PNs) have demonstrated to be a promising alternative to treat intracellular infections. They have outstanding performance in delivering antimicrobials intracellularly to reach an adequate dose level and improve their therapeutic efficacy. PNs offer opportunities for preventing unwanted drug interactions and degradation before reaching the target cell of tissue and thus decreasing the development of resistance in microorganisms. The use of PNs has the potential to reduce the dose and adverse side effects, providing better efficiency and effectiveness of therapeutic regimens, especially in drugs having high toxicity, low solubility in the physiological environment and low bioavailability. This review provides an overview of nanoparticles made of different polymeric precursors and the main methodologies to nanofabricate platforms of tuned physicochemical and morphological properties and surface chemistry for controlled release of antimicrobials in the target. It highlights the versatility of these nanosystems and their challenges and opportunities to deliver antimicrobial drugs to treat intracellular infections and mentions nanotoxicology aspects and future outlooks.

Intramacrophage Delivery of Dual Drug Loaded Nanoparticles for Effective Clearance of Mycobacterium tuberculosis

The escalating global burden of tuberculosis necessitates radical strategies to curb its spread. In this study, rifampicin (RIF), a first line anti-tubercular antibiotic and curcumin (CUR), a promising antimycobacterial compound were co-encapsulated in polymeric nanoparticles to achieve intramacrophage delivery and improved Mycobacterium tuberculosis clearance. The dual loaded nanoparticles revealed average size ∼400 nm, low polydispersity and zeta potential of -26.89 ± 2.9 mV. Near complete release of both drugs from nanoparticles in artificial lysosomal fluid proposed drug release after macrophage internalisation. Nanoparticles were nontoxic to RAW 264.7 macrophages and aided 1.5-fold higher drug internalisation compared to free drugs. Enriched intracellular internalisation and lysosomal presence of nanoparticles was ascertained by confocal microscopy. Comparable minimum inhibitory concentration (MIC) of free RIF and CUR and nanoparticle encapsulated RIF and CUR confirmed retention of drug properties. High efficacy against Mycobacterium tuberculosis infected macrophages with RIF-CUR nanoparticles at 25× MIC (98.03 ± 2.5%), with complete clearance above 50× MIC suggests the dual loaded nanoparticles as a promising new nanosystem for tackling tuberculosis.