Native Drug Research Articles

Electrochemical Method for Real-Time ROS Measurements in Single Cells

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are important regulatory factors for cell growth and survival. Most chemotherapeutic drugs increase the intracellular concentration of ROS/RNS, and many drugs can alter the redox homeostasis of cancer cells. The study of intracellular ROS levels may represent one possibility to research the effects of drugs in cancer cells. ROS that released from cells during apoptosis play a crucial role in the development of cancer and neurodegenerative diseases. Nowadays, there is the problem of developing methods for treating cancer tumors, thus, quick evaluation of the anticancer drugs efficiency is the priority. The ROS determination using nanosensors in single cells has gained increasing attention. However, traditional fluorescent dyes have a number of disadvantages. These dyes are known to be intrinsically cytotoxic and thus can significantly alter cellular metabolism. Here, we have developed an electrochemical method for determining the ROS inside the single cells. Using this method, it is possible to evaluate the effect of the developed drugs on the cells. We evaluated the effect of ASGP-R (Asialoglycoprotein receptor) - specific carrier equipped by docetaxel on cancer cell lines with (HepG2) and without (PC-3) ASGP receptors. Our data obtained by using carbon-filled quartz nanopipettes with platinum tips showed a ROS increase using conjugates compared with native drugs. In the future, this method may allow evaluating the effect of drugs in vitro and to help validate drug candidates for preclinical evaluation. The biological experiments with cell cultures were supported by the Ministry of Education and Science of the Russian Federation in the framework of increase Competitiveness Program of NUST “MISIS”, implemented by a governmental decree dated March 16, 2013, No. 211. Nanoelectrode measurements were supported by the Russian Science Foundation Grant 20-14-00312.

Isostructural cocrystals of metaxalone with improved dissolution characteristics.

Muscle relaxant and pain reliever metaxalone (MET) is a biopharmaceutical classification systems (BCS) class II drug with poor aqueous solubility and high permeability. The presence of an aromatic skeleton and cyclic carboxamate moiety are the probable reasons for the decreased aqueous solubility, which impacts on its low bioavailability. A high dose (800 mg) of the drug often creates adverse side effects on the central nervous system that needs urgent remedy. Cocrystallization of MET with nicotinamide (NAM), salicylamide (SAM), and 4-hydroxybenzoic acid (HBA) resulted in multicomponent solids that were characterized by PXRD, DSC and single crystal X-ray diffraction. Cocrystals with SAM and NAM form 2D isostructural cocrystals, whereas with HBA the result is a differently packed cocrystal hydrate (or anisole hemisolvate) depending upon the crystallization medium. Similar to the reported MET cocrystals, these cocrystals also confirm the preference for an imide⋯imide homosynthon in the drug. The dominance of the drug–drug homodimer over drug-coformer heterodimers was demonstrated based on binding energy calculations. Further, powder dissolution experiments in pH 6.8 phosphate buffer indicate that the cocrystals improved the apparent solubility compared to the native drug by 3–9 fold. The absence of stronger heterosynthons between MET and the coformers, their lower melting points and the high solubility of the coformers are the probable reasons for the enhanced solubility of the bioactive component. The MET–NAM cocrystal exhibited the highest solubility/dissolution rate among the three binary solid forms, which may offer improved bioavailability and a lower dose with minimal side effects.

Acid-sensitive PEGylated cabazitaxel prodrugs for antitumor therapy

Although the antitumor drug cabazitaxel shows great therapeutic potential, its high toxicity and poor water solubility limit its utility. However, the use of stimuli-responsive prodrugs is a promising strategy for overcoming these limitations. Herein, we report the synthesis of two highly water soluble, acid-sensitive PEGylated acyclic-ketal-linked cabazitaxel prodrugs (PKCs) with improved antitumor efficacy. In an acidic tumor microenvironment, the PKCs hydrolyzed rapidly to release the native drug, whereas they were stable in the normal physiological environment. Compared with cabazitaxel injection, the PKCs had much higher maximum tolerated doses; and in an MDA-MB-231 subcutaneous xenograft nude mouse model, the PKCs showed better antitumor efficacy and safety than cabazitaxel injection. The prodrug strategy reported herein could be useful for the development of other water soluble, acid-sensitive prodrugs with improved efficacy.

Biodiversity in Bacterial Phyla Composite in Arid Soils of the Community of Desert Medicinal Plant Rhazya stricta

Rhazya stricta is an important medicinal plant used as native herbal drug to cure various diseases across Asia. Plant-microbe interactions represented by different environment abiotic stress factors that shows effects also on the host plants or on the associated microbial communities. Soil microorganism can be adapted to specific stress conditions and evolve tolerance to this stress. The adjustment of the plant microbiome can productively improve the yield production of essential crops. In the present study, metagenomics analysis of bacterial communities associated with five desert plants (Rhazya stricta, Enneapogon desvauxii, Citrullus colocynthis, Senna italica, and Zygophyllum simplex) was used to highlights the bacterial diversity in the communities of these desert plants, as they also have an importance as folkloric medicinal plants, in addition to their important roles in the ecological and agricultural applications. The results of the bacterial community’s taxonomy showed eleven phyla in each sample, and the most abundant were highlighted for further analysis as it was unassigned phyla. Results indicated that the most commonlyknownphylawere; Actinobacteria, Proteobacteria, Chloroflexi, Firmicutes, Acidobacteria, Gemmatimonadetes, and Bacteroidetes. Further bioinformatics and functional analysis of bacteria are needed to investigate their effectiveness in promoting plant growth and understanding symbiotic relationships under drought-stress conditions, meanwhile, introducing the pinpointed ones in this study will help in achieving this task.

Organic molecular salts of allopurinol with improved solubility

Abstract Allopurinol is considered to be one of the most effective medications, which is regularly prescribed to reduce urate level and treat chronic gout. The drug belongs to biopharmaceutics Classification System (BCS) class IV category with poor aqueous solubility and permeability. High-throughput solid-form screening of the active pharmaceutical ingredient for new binary solid forms was carried out in order to improve drug properties. Multicomponent solids with oxalic acid and maleic acid were obtained during liquid assisted grinding of equivalent stoichiometry. The novel binary systems were characterized by PXRD, FT-IR, DSC, TGA and SEM images. Vibrational spectroscopy was exploited to confirm the ionization states of the multicomponent systems. Thermal analysis indicates the new solid phases with the possibility of hydrates in the oxalate and maleate salts, which degraded to allopurinol after melting. Powder dissolution experiment was carried out on the drug and the salts in pH-1.2 (acidic) and pH-7 (phosphate buffer, neutral) medium, which suggests that salts improved dissolution up to 4 fold compared to the native drug. In both the aqueous medium, maleate salt exhibited higher dissolution rate compared to the oxalate salt, which is correlated with its (former) lower melting point and higher crystal surface area.

Fabrication of poly(sarcosine), poly (ethylene glycol), and poly (lactic-co-glycolic acid) polymeric nanoparticles for cancer drug delivery

The most significant advantage of polymeric nanoparticles is their systematic and target specific drug delivery properties. These polymeric nanoparticles have the potential to sustain itself within the bloodstream for a longer period so that drugs can be infused in blood steadily. To understand such a phenomenon, in this experiment, an attempt was made to prepared Docetaxel loaded poly(sarcosine)(PSar) and poly (ethylene glycol) (PEG) coated poly (lactic-co-glycolic acid) [PLGA] nanoparticles; which could efficiently encapsulate any hydrophobic drugs. These types of PEG-coated nanoparticles have a marked tendency to avoid reticuloendothelial opsonization process by restricting macrophage uptake, which ultimately leads to enhance bioavailability and tissue distribution of drugs. In this research work categorically, the concentration of PSar and PEG was optimized. The cellular uptake efficiency percentage and IC50 value of Docetaxel and Docetaxel loaded different polymeric nanoparticles evaluated in various human cancer cell lines (U-87 MG, HeLa. C2BBe1, HCT-116, NCI–N87, NCI–H929-Luc-mCh-Puro). The PSar-PLGA-PEG-NPs have shown sustainable retention in blood with minimum macrophage uptake as compared to PLGA-NPs and PSar-PLGA-NPs. Enhanced anti-tumor proliferative effects were shown in all the Docetaxel loaded nanoparticles as compared to native Docetaxel drug, which may be because of enhanced antiproliferative activities of nanoparticles. Thus, from the research outcomes, one thing is inevitable, i.e., the presence of PSar and PEG would increase the blood circulation time, and it can be used as a suitable carrier for any hydrophobic drug.

Synthesis, Characterization and In vitro Antimicrobial Activity of Florfenicol-Chitosan Nanocomposite

In this paper, rapid, easy and cheap sonochemical method was described for synthesis of florfenicol-chitosan nanocomposite and evaluating its anti-bacterial effect against Escherichia coli (ATCC35218), Salmonella typhymurium (ATCC14028) and Staph. aureus (ATCC29213). Florfenicol-chitosan nanocomposite was full characterized for index, identification and morphology properties. Characterization results showed zeta sizing of florfenicol was 30.6 nm, while florfenicol-chitosan nanocomposite was 67.22 nm with zeta potential -14.5 and -28, respectively. Brunner-Emmett-Teller theory (BET) surface area was found to be 13.3, 73.2 and 103.69 m2/g for florfenicol, chitosan nanoparticles and florfenicol-chitosan nanocomposite, respectively. Raman charts confirmed the formation of florfenicol-chitosan nanocomposite without any contamination. Transmission electron microscope (TEM), scanning electron microscope (SEM) and atomic force microscope (AFM) images and data illustrated spherical to sub spherical shape of florfenicol nanoparticles on sheet shape of chitosan with size less than 75 nm. Remarkable results of florfenicol-chitosan nanocomposite as anti-bacterial agent illustrated the power of nanotechnology. However, antimicrobial activity was screened where the zone of inhibitions caused by the prepared nanocomposite were 24.7 mm, 30.6 mm and 29.3 mm compared to 17.7 mm, 16 mm and 18.7 mm of the native drug against E. coli, Salmonella typhymurium and Staphylococcus aureus, respectively.

Molecular Engineering of Ultrasmall Silica Nanoparticle–Drug Conjugates as Lung Cancer Therapeutics

Small-molecule inhibitors have had a major impact on cancer care. While treatments have demonstrated clinically promising results, they suffer from dose-limiting toxicities and the emergence of refractory disease. Considerable efforts made to address these issues have more recently focused on strategies implementing particle-based probes that improve drug delivery and accumulation at target sites, while reducing off-target effects. Ultrasmall (<8 nm) core-shell silica nanoparticles, C' dots, were molecularly engineered to function as multivalent drug delivery vehicles for significantly improving key in vivo biological and therapeutic properties of a prototype epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, gefitinib. Novel surface chemical components were used to conjugate gefitinib-dipeptide drug-linkers and deferoxamine (DFO) chelators for therapeutic delivery and PET imaging labels, respectively. Gefitinib-bound C' dots (DFO-Gef-C' dots), synthesized using the gefitinib analogue, APdMG, at a range of drug-to-particle ratios (DPR; DPR = 11-56), demonstrated high stability for DPR values≤ 40, bulk renal clearance, and enhanced in vitro cytotoxicity relative to gefitinib (LD50 = 6.21 nmol/L vs. 3 μmol/L, respectively). In human non-small cell lung cancer mice, efficacious Gef-C' dot doses were at least 200-fold lower than that needed for gefitinib (360 nmoles vs. 78 μmoles, respectively), noting fairly equivalent tumor growth inhibition and prolonged survival. Gef-C' dot-treated tumors also exhibited low phosphorylated EFGR levels, with no appreciable wild-type EGFR target inhibition, unlike free drug. Results underscore the clinical potential of DFO-Gef-C' dots to effectively manage disease and minimize off-target effects at a fraction of the native drug dose.

Targeting Gemcitabine hydrochloride to tumor microenvironment through stimuli-responsive Nano-conjugate: Synthesis, characterization, and in vitro assessment

The study revolves around synthesizing stimuli-responsive drug-polymer conjugate of Gemcitabine hydrochloride and PNIPAAm-co-AAc and to investigate the delivery of Gemcitabine to cancerous cells by the formulation of stimuli-responsive Gem-conjugate. Gemcitabine HCl conjugated to a thermoresponsive polymer was undergone through the amine group at the N4 position of Gemcitabine hydrochloride linked with the carboxylic group of the stimuli-responsive polymer, leading to the construction of amide linkage amongst the drug and polymer. The subsequent Gem-conjugate was characterized by several analytical methods viz. Elemental, DSC, TGA, XRD, FESEM, TEM, DLS and 1H NMR. Finally, in vitro cytotoxicity assay was carried out on Panc-1 cancer cell lines. The prepared stimuli-responsive Gemcitabine nanoconjugate was found to be 55.05 nm in size with a capacity to release 80.72% drug over a period of 24 h in a medium of pH 5.0 following Fickian release kinetics. The cytotoxicity assay revealed that nanoconjugate notably inhibited the growth of Panc-1 cells compared to the free drug in a dose-dependent manner. The CLSM study revealed that Gem-conjugate induces more apoptosis to Panc-1 cell as compared to the native drug. The stimuli-responsive nano conjugate was found stable at 25 °C in dark environment. Overall, the data suggest that Gemcitabine HCl conjugated to a stimuli-responsive polymer can intensify the delivery of Gemcitabine to Panc-1 cancer cell lines, which might hold substantially proven potential in the treatment pancreatic cancer. The conjugate holds an alternative direction for further applications of Gemcitabine hydrochloride.

Traditional Herbal Medicine in Mesoamerica: Toward Its Evidence Base for Improving Universal Health Coverage.

The quality of health care in Mesoamerica is influenced by its rich cultural diversity and characterized by social inequalities. Especially indigenous and rural communities confront diverse barriers to accessing formal health services, leading to often conflicting plurimedical systems. Fostering integrative medicine is a fundamental pillar for achieving universal health coverage (UHC) for marginalized populations. Recent developments toward health sovereignty in the region are concerned with assessing the role of traditional medicines, and particularly herbal medicines, to foster accessible and culturally pertinent healthcare provision models. In Mesoamerica, as in most regions of the world, a wealth of information on traditional and complementary medicine has been recorded. Yet these data are often scattered, making it difficult for policy makers to regulate and integrate traditionally used botanical products into primary health care. This critical review is based on a quantitative analysis of 28 survey papers focusing on the traditional use of botanical drugs in Mesoamerica used for the compilation of the “Mesoamerican Medicinal Plant Database” (MAMPDB), which includes a total of 12,537 use-records for 2188 plant taxa. Our approach presents a fundamental step toward UHC by presenting a pharmacological and toxicological review of the cross-culturally salient plant taxa and associated botanical drugs used in traditional medicine in Mesoamerica. Especially for native herbal drugs, data about safety and effectiveness are limited. Commonly used cross-culturally salient botanical drugs, which are considered safe but for which data on effectiveness is lacking constitute ideal candidates for treatment outcome studies.

Synthesis and Characterization of Florfenicol-silver Nanocomposite and its Antibacterial Activity against some Gram Positive and Gram-negative Bacteria

In this paper, easy, rapid and cheap synthetic method was described for florfenicol-silver nanocomposite by sonochemical method. Florfenicol-silver nanocomposite was characterized based on three classes namely index, identification and morphology class. Index characterization was carried out by zeta sizing, BET surface area and zeta potential. Identification characterization was performed using X-ray diffraction (XRD) and Raman spectrometry. Morphology characterization was done utilizing transmission electron microscope (TEM), scanning electron microscope (SEM) and atomic force microscope (AFM). Characterization results showed zeta sizing of florfenicol was 30.44nm, while florfenicol-silver nanocomposite was 33.5 nm with zeta potential -14.1 and -18, respectively. BET surface area was found to be 13.3, 73.2 and 103.69 m2/g for florfenicol, silver nanoparticles and florfenicol-silver nanocomposite respectively. XRD and Raman charts confirmed the formation of florfenicol-silver nanocomposite without any contamination. TEM, SEM and AFM spectral data illustrated spherical to sub spherical shape of silver nanoparticles on cubic to sheet shape of florfenicol with size less than 50 nm. Antimicrobial activity was screened where the average zone of inhibitions caused by the prepared nanocomposite were 28.3 mm, 24 mm, 27.3 mm and 24 mm compared to 17.7 mm, 16 mm, 18.7 mm and 13.3 mm of the native drug and 13 mm, 10 mm, 14.3 mm and 15 mm of the used positive reference standards against E. coli, Salmonella typhymurium, Staphylococcus aureus and Staph.aureus MRSA respectively.

An Elvitegravir Nanoformulation Crosses the Blood-Brain Barrier and Suppresses HIV-1 Replication in Microglia.

Even with an efficient combination of antiretroviral therapy (ART), which significantly decreases viral load in human immunodeficiency virus type 1 (HIV-1)-positive individuals, the occurrence of HIV-1-associated neurocognitive disorders (HAND) still exists. Microglia have been shown to have a significant role in HIV-1 replication in the brain and in subsequent HAND pathogenesis. However, due to the limited ability of ART drugs to cross the blood–brain barrier (BBB) after systemic administration, in addition to efflux transporter expression on microglia, the efficacy of ART drugs for viral suppression in microglia is suboptimal. Previously, we developed novel poly (lactic-co-glycolic acid) (PLGA)-based elvitegravir nanoparticles (PLGA-EVG NPs), which showed improved BBB penetration in vitro and improved viral suppression in HIV-1-infected primary macrophages, after crossing an in vitro BBB model. Our objective in the current study was to evaluate the efficacy of our PLGA-EVG NPs in an important central nervous system (CNS) HIV-1 reservoir, i.e., microglia. In this study, we evaluated the cyto-compatibility of the PLGA-EVG NPs in microglia, using an XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) assay and cellular morphology observation. We also studied the endocytosis pathway and the subcellular localization of PLGA NPs in microglia, using various endocytosis inhibitors and subcellular localization markers. We determined the ability of PLGA-EVG NPs to suppress HIV-1 replication in microglia, after crossing an in vitro BBB model. We also studied the drug levels in mouse plasma and brain tissue, using immunodeficient NOD scid gamma (NSG) mice, and performed a pilot study, to evaluate the efficacy of PLGA-EVG NPs on viral suppression in the CNS, using an HIV-1 encephalitic (HIVE) mouse model. From our results, the PLGA-EVG NPs showed ~100% biocompatibility with microglia, as compared to control cells. The internalization of PLGA NPs in microglia occurred through caveolae-/clathrin-mediated endocytosis. PLGA NPs can also escape from endo-lysosomal compartments and deliver the therapeutics to cells efficiently. More importantly, the PLGA-EVG NPs were able to show ~25% more viral suppression in HIV-1-infected human-monocyte-derived microglia-like cells after crossing the in vitro BBB compared to the EVG native drug, without altering BBB integrity. PLGA-EVG NPs also showed a ~two-fold higher level in mouse brain and a trend of decreasing CNS HIV-1 viral load in HIV-1-infected mice. Overall, these results help us to create a safe and efficient drug delivery method to target HIV-1 reservoirs in the CNS, for potential clinical use.

Novel elvitegravir nanoformulation for drug delivery across the blood-brain barrier to achieve HIV-1 suppression in the CNS macrophages

The use of antiretroviral therapy (ART) has remarkably decreased the morbidity associated with HIV-1 infection, however, the prevalence of HIV-1-associated neurocognitive disorders (HAND) is still increasing. The blood-brain barrier (BBB) is the major impediment for penetration of antiretroviral drugs, causing therapeutics to reach only suboptimal level to the brain. Conventional antiretroviral drug regimens are not sufficient to improve the treatment outcomes of HAND. In our recent report, we have developed a poloxamer-PLGA nanoformulation loaded with elvitegravir (EVG), a commonly used antiretroviral drug. The nanoformulated EVG is capable of elevating intracellular drug uptake and simultaneously enhance viral suppression in HIV-1-infected macrophages. In this work, we identified the clinical parameters including stability, biocompatibility, protein corona, cellular internalization pathway of EVG nanoformulation for its potential clinical translation. We further assessed the ability of this EVG nanoformulation to cross the in vitro BBB model and suppress the HIV-1 in macrophage cells. Compared with EVG native drug, our EVG nanoformulation demonstrated an improved BBB model penetration cross the in vitro BBB model and an enhanced HIV-1 suppression in HIV-1-infected human monocyte-derived macrophages after crossing the BBB model without altering the BBB model integrity. Overall, this is an innovative and optimized treatment strategy that has a potential for therapeutic interventions in reducing HAND.

Formulation and evaluation of hyaluronic acid-based mucoadhesive self nanoemulsifying drug delivery system (SNEDDS) of tamoxifen for targeting breast cancer

The present study was intended to develop a papain grafted S-protected hyaluronic acid-lithocholic acid co-block (PAP-HA-ss-LCA) polymeric excipient as an amphiphilic muco permeating stabilizer for targeting breast cancer epithelial cells overexpressed with CD44 receptors. The mucopermeating, stabilizing and targeting capability of the PAP-HA-ss-LCA polymeric excipient was investigated by manufacturing tamoxifen (TMX) loaded self-nanoemulsifying drug delivery system (SNEDDS). TMX loaded PAP-HA-ss-LCA incorporated SNEDDS (TMX-PAP-HA-ss-LCA SNEDDS) were characterized for their surface chemistry, drug release, permeation enhancement, biocompatibility and antitumor activity. FTIR spectroscopic analysis showed successful synthesis of PAP-HA-ss-LCA polymer. X-ray diffraction (XRD) showed the amorphous form of TMX inside SNEDDS. The observed hydrodynamic diameter of TMX-PAP-HA-ss-LCA SNEDDS was 367.5 nm. Furthermore, Hyaluronic Acid-based Mucoadhesive Self Nanoemulsifying Drug Delivery System (SNEDDS) of TMX showed homogeneity in synthesis with low polydispersity and negative zeta potential due to stabilization with PAP-HA-ss-LCA polymer. The distinct spherical shape of the nanodroplets was evident by transmission electron microscopy (TEM). In vitro release kinetics indicated approximately >80% release within 48 h under sink conditions. Ex-vivo permeation study displayed 7.11-folds higher permeation of TMX by TMX-PAP-HA-ss-LCA in contrast to pure TMX. The biocompatibility study proved that SNEDDS formulation was safe and compatible against macrophages. In vitro cytotoxicity studies demonstrated that TMX-PAP-HA-ss-LCA SNEDDS could efficiently kill MCF-7 breast cancer cells as compared to the native TMX drug. Systemic toxicity studies proved the non-toxic nature of TMX-PAP-HA-ss-LCA in contrast to pure TMX. Based on these evidences, TMX-PAP-HA-ss-LCA SNEDDS formulation seems to be promising mucopermeating, augmented intracellular uptake with strong targeting potential for anti-proliferative activity.

Redox-Responsive Dipeptide Nanostructures toward Targeted Cancer Therapy.

Materials that exhibit responsiveness toward biological signals are currently subjected to intense research in the field of drug delivery. In our study, we tried to develop cancer-targeted and redox-responsive nanoparticles (NPs) from disulfide-linked oxidized cysteine-phenylalanine (CFO). The NPs were conjugated with folic acid (FA) to specifically target cancer cells, and the presence of disulfide bonds would enabled the disintegration of the particles in the presence of elevated levels of glutathione (GSH) in cancer cells. Anticancer drug doxorubicin (Dox) was successfully loaded inside the disulfide-linked nanoparticles (CFO-Dox-NPs), which further demonstrated stimuli-responsive drug release in the presence of GSH. We have also demonstrated enhanced uptake of FA-derivatized NPs (FA-CFO-NPs) in cancerous cells (C6 glioma and B16F10 melanoma cells) than in normal cells (HEK293T cells) due to the overexpression of FA receptors on the surface of cancer cells. Cytotoxicity studies in C6 cells and B16F10 cells further revealed enhanced efficacy of Dox loaded (FA-CFO-Dox-NPs) as compared to the native drug. The findings of this study clearly demonstrated that the disulfide-linked nanoparticle system may provide a promising selective drug delivery platform in cancer cells.

Structural basis for strand-transfer inhibitor binding to HIV intasomes.

The HIV intasome is a large nucleoprotein assembly that mediates the integration of a DNA copy of the viral genome into host chromatin. Intasomes are targeted by the latest generation of antiretroviral drugs, integrase strand-transfer inhibitors (INSTIs). Challenges associated with lentiviral intasome biochemistry have hindered high-resolution structural studies of how INSTIs bind to their native drug target. Here, we present high-resolution cryo-electron microscopy structures of HIV intasomes bound to the latest generation of INSTIs. These structures highlight how small changes in the integrase active site can have notable implications for drug binding and design and provide mechanistic insights into why a leading INSTI retains efficacy against a broad spectrum of drug-resistant variants. The data have implications for expanding effective treatments available for HIV-infected individuals.

Acid-Triggered Release of Native Gemcitabine Conjugated in Polyketal Nanoparticles for Enhanced Anticancer Therapy

Nucleoside analogue drugs are widely used in cancer therapy and antiviral therapy, while fast metabolism, drug resistance, and severe side effects significantly limit their clinical applications. To address these issues, a variety of ester- and amide-linked prodrugs and their nanoparticulate formulations have been devised. However, most of these prodrugs suffer from inefficient transformation to native drugs in tumor. Here, we report an approach to conjugate gemcitabine, a kind of anticancer nucleoside drug and widely used to treat cancers, to polyketal backbone via pH-sensitive ketal linkage, and prepared gemcitabine-containing polyketal prodrug nanoparticles with minimal drug release under physiological conditions and acid-triggerable release of native gemcitabine. Intracellular and intratumoral degradation of the pH-sensitive gemcitabine-containing polyketal prodrug and incorporation of gemcitabine into DNA were confirmed by confocal microscopy using EdU, an analogue of gemcitabine. One single intravenous injection of these gemcitabine-containing polyketal prodrug nanoparticles demonstrated notable anticancer efficacy in the A2780 ovarian xenograft tumor model with increased survival rate and good safety. Our approach can be adopted for other diol nucleoside analogues to synthesize pH-sensitive nucleoside-polyketal prodrugs for developing anticancer and antiviral formulations.

Interviews with American Indian and Alaska Native People Who Inject Drugs.

This project gathered opinions, attitudes, and beliefs from American Indian and Alaska Native (AI/AN) people who inject drugs (PWID). The primary objective of this study was to build formative knowledge around AI/AN PWID to help define and develop health care services and strategies by better understanding existing services, barriers, and challenges to seeking care. A total of 32 semi-structured in-depth interviews were conducted. AI/AN PWID reported a number of structural, social, and geographical barriers when trying to access health care. PWID communities critically need integrative health care service strategies and improved education about injection drug use (IDU), outreach, and prevention programs and resources. More low-barrier and streamlined access to needles should be coupled with other health care services for PWID. PWID are a key resource to help health care providers and community members correct misconceptions and better understand IDU.

Rod-shape theranostic nanoparticles facilitate antiretroviral drug biodistribution and activity in human immunodeficiency virus susceptible cells and tissues.

Human immunodeficiency virus theranostics facilitates the development of long acting (LA) antiretroviral drugs (ARVs) by defining drug-particle cell depots. Optimal drug formulations are made possible based on precise particle composition, structure, shape and size. Through the creation of rod-shaped particles of defined sizes reflective of native LA drugs, theranostic probes can be deployed to measure particle-cell and tissue biodistribution, antiretroviral activities and drug retention.Methods: Herein, we created multimodal rilpivirine (RPV) 177lutetium labeled bismuth sulfide nanorods (177LuBSNRs) then evaluated their structure, morphology, configuration, chemical composition, biological responses and adverse reactions. Particle biodistribution was analyzed by single photon emission computed tomography (SPECT/CT) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) imaging.Results: Nanoformulated RPV and BSNRs-RPV particles showed comparable physicochemical and cell biological properties. Drug-particle pharmacokinetics (PK) and biodistribution in lymphoid tissue macrophages proved equivalent, one with the other. Rapid particle uptake and tissue distribution were observed, without adverse reactions, in primary blood-derived and tissue macrophages. The latter was seen within the marginal zones of spleen.Conclusions: These data, taken together, support the use of 177LuBSNRs as theranostic probes as a rapid assessment tool for PK LA ARV measurements.

New Method for Veterinary and Sanitary Control of Defrosted Meat and Fish

The freezing method allows you to extend the shelf life for a long period, however, when defrosting products there is a loss of nutrients. Currently, the assessment of the thermal state of meat and fish remains a topical issue, which today is carried out using organoleptic methods, as well as a histological method for the structure of muscle tissue. These methods lose their relevance in conditions of real circulation of meat and fish products due to subjectivity, as well as complexity. To ensure the release of benign chilled products into the market and to prevent the substitution of defrosted chilled meat, a fast, effective and easily reproducible method is required. We carried out studies to assess the thermal state of 69 experimental samples of meat of animals, poultry and fish according to organoleptic indicators and also proposed a new method for the manufacture of native drugs that allows us to evaluate the structure of muscle tissue. Native meat preparations were made from thin sections of muscle tissue, crushed between the glasses of the compressorium, followed by hematoxylon-eosin staining and microscopy. it was found that the number of fibrous sections of muscle tissue in defrosted products is 11.3 times more than in samples chilled; muscle fiber breaks - 47 times. A striking identification sign that allows to differentiate the thermal state of meat and fish raw materials is the presence of thickenings at the ends of muscle fibers, which are absent in preparations of chilled material. The obtained values are statistically significant. As a result of the studies, identification criteria were established, such as a violation of the structure of muscle tissue, which is manifested by the presence of fibrous areas, tearing of muscle fibers, as well as the presence of thickenings at the ends of muscle fibers. The obtained research results allow us to use the proposed method of manufacturing and microscopy of meat and fish preparations and establish the previous freezing of products.