Biomolecular interactions between Plasmodium and human host: A basis of targeted antimalarial therapy.

Malaria is one of the serious health concerns worldwide as it remains a clinical challenge due to the complex life cycle of the malaria parasite and the morphological changes it undergoes during infection. The malaria parasite multiplies rapidly and spreads in the population by changing its alternative hosts. These various morphological stages of the parasite in the human host cause clinical symptoms (anemia, fever, and coma). These symptoms arise due to the preprogrammed biology of the parasite in response to the human pathophysiological response. Thus, complete elimination becomes one of the major health challenges. Although malaria vaccine(s) are available in the market, they still contain to cause high morbidity and mortality. Therefore, an approach for eradication is needed through the exploration of novel molecular targets by tracking the epidemiological changes the parasite adopts. This review focuses on the various novel molecular targets.

Dual antitubercular drug loaded liposomes for macrophage targeting: development, characterisation, ex vivo and in vivo assessment.

AIM: The present study was conducted to formulate and investigate liposomes for the dual drug delivery based on anti-tubercular drug(s) combination i.e. Isoniazid (INH) and Rifampicin (RIF). MATERIALS AND METHODS: Mannosylated and non mannosylated liposomes were prepared by lipid thin film hydration method, using DSPC: Chol at a molar ratio 6:4 while in case of mannosylated liposomes DSPC: Chol: Man-C4-Chol at a molar ratio 6.0:3.5:0.5 were used and extensively characterised. The particle size and zeta potential were recorded to be 1.29 ± 0.24 µm and -9.1 ± 0.11 mV. The drug entrapment (%) was recorded to be 84.7 ± 1.25% for Rifampicin and 31.8 ± 0.12% for Isoniazid. RESULTS: The antitubercular activity studied in Balb/C mice was maximum in the case of mannosylated liposomes. The biodistribution studies also revealed higher drug(s) concentration (accumulation) maintained over a protracted period. CONCLUSIONS: The liposomal preparations are passively as well as actively uptaken by the alveolar macrophages which are the cellular tropics of infection. The mannosylated liposomes appear to be a potential carrier for dual drug delivery and targeted antitubercular therapy.

Retraction Note: Engineered Polyallylamine Nanoparticles for Efficient In Vitro Transfection.

This article has been retracted. Please see the Retraction Notice for more detail: https://doi.org/10.1007/s11095-020-02971-0.

Lipid-Based Nanocarriers for Lymphatic Transportation.

The effectiveness of any drug is dependent on to various factors like drug solubility, bioavailability, selection of appropriate delivery system, and proper route of administration. The oral route for the delivery of drugs is undoubtedly the most convenient, safest and has been widely used from past few decades for the effective delivery of drugs. However, despite of the numerous advantages that oral route offers, it often suffers certain limitations like low bioavailability due to poor water solubility as well as poor permeability of drugs, degradation of the drug in the physiological pH of the stomach, hepatic first-pass metabolism, etc. The researchers have been continuously working extensively to surmount and address appropriately the inherent drawbacks of the oral drug delivery. The constant and continuous efforts have led to the development of lipid-based nano drug delivery system to overcome the aforesaid associated challenges of the oral delivery through lymphatic transportation. The use of lymphatic route has demonstrated its critical and crucial role in overcoming the problem associated and related to low bioavailability of poorly water-soluble and poorly permeable drugs by bypassing intestinal absorption and possible first-pass metabolism. The current review summarizes the bonafide perks of using the lipid-based nanocarriers for the delivery of drugs using the lymphatic route. The lipid-based nanocarriers seem to be a promising delivery system which can be optimized and further explored as an alternative to the conventional dosage forms for the enhancement of oral bioavailability of drugs, with better patient compliance, minimum side effect, and improved the overall quality of life.

Nanocarrier-Based Combination Chemotherapy for Resistant Tumor: Development, Characterization, and Ex Vivo Cytotoxicity Assessment.

A folic acid-conjugated paclitaxel (PTX)-doxorubicin (DOX)-loaded nanostructured lipid carrier(s) (FA-PTX-DOX NLCs) were prepared by using emulsion-evaporation method and extensively characterized for particle size, polydispersity index, zeta potential, and % entrapment efficiency which were found to be 196 ± 2.5 nm, 0.214 ± 0.04, +23.4 ± 0.3 mV and 88.3 ± 0.2% (PTX), and 89.6 ± 0.5% (DOX) respectively. In vitro drug release study of optimized formulation was carried out using dialysis tube method. FA-conjugated PTX-DOX-loaded NLCs showed 75.6 and 78.4% (cumulative drug release) of PTX and DOX respectively in 72 h in PBS (pH 7.4)/methanol (7:3), while in the case of FA-conjugated PTX-DOX-loaded NLCs, cumulative drug release recorded was 80.4 and 82.8% of PTX and DOX respectively in 72 h in PBS (pH 4.0)/methanol (7:3). Further, the formulation(s) were evaluated for ex vivo cytotoxicity study. The cytotoxicity assay in doxorubicin-resistant human breast cancer MCF-7/ADR cell lines revealed lowest GI50 value of FA-D-P NLCs which was 1.04 ± 0.012 µg/ml, followed by D-P NLCs and D-P solution with GI50 values of 3.12 ± 0.023 and 3.89 ± 0.007 µg/ml, respectively. Findings indicated that the folic acid-conjugated PTX and DOX co-loaded NLCs exhibited lower GI50 values as compared to unconjugated PTX and DOX co-loaded NLCs; thus, they have relatively potential anticancer efficacy against resistant tumor.

Influence of various lipid core on characteristics of SLNs designed for topical delivery of fluconazole against cutaneous candidiasis.

Dermal delivery of fluconazole (FLZ) is still a major limitation due to problems relating to control drug release and achieving therapeutic efficacy. Recently, solid lipid nanoparticles (SLNs) were explored for their potential of topical delivery, possible skin compartments targeting and controlled release in the skin strata. The retention and accumulation of drug in skin is affected by composition of SLNs. Hence, the aim of this study was to develop FLZ nanoparticles consisted of various lipid cores in order to optimize the drug retention in skin. SLNs were prepared by solvent diffusion method and characterized for various in vitro and in vivo parameters. The results indicate that the SLNs composed of compritol 888 ATO (CA) have highest drug encapsulation efficiency (75.7 ± 4.94%) with lower particle size (178.9 ± 3.8 nm). The in vitro release and skin permeation data suggest that drug release followed sustained fashion over 24 h. The antifungal activity shows that SLNs made up of CA lipid could noticeably improve the dermal localization. In conclusion, CA lipid based SLNs are represents a promising carrier means for the topical treatment of skin fungal infection as an alternative to the systemic delivery of FLZ.

Rationally designed block copolymer-based nanoarchitectures: An emerging paradigm for effective drug delivery.

Various polymeric materials have been investigated to produce unique modes of delivery for drug modules to achieve either temporal or spatial control of bioactives delivery. However, after intravenous administration, phagocytic cells quickly remove these nanostructures from the systemic circulation via the reticuloendothelial system (RES). To overcome these concerns, ecofriendly block copolymers are increasingly being investigated as innovative carriers for the delivery of bioactives. In this review, we discuss the design, fabrication techniques, and recent advances in the development of block copolymers and their applications as drug carrier systems to improve the physicochemical and pharmacological attributes of bioactives.

Targeted intracellular delivery of antitubercular bioactive(s) to Mtb infected macrophages via transferrin functionalized nanoliposomes.

The packaging of antimicrobials/chemotherapeutics into nanoliposomes can enhance their activity while minimizing toxicity. However, their use is still limited owing to inefficient/inadequate loading strategies. Several bioactive(s) which are non ionizable, and poorly aqueous soluble cannot be easily encapsulated into aqueous core of liposomes by using conventional means. Such bioactive(s) however could be encapsulated in the liposomes by forming their water soluble molecular inclusion complex with cyclodextrins. In this study, we developed Rifampicin (RIF) - 2-hydroxylpropyl-ß-cyclodextrin (HP-ß-CD) molecular inclusion complex. The HP-ß-CD-RIF complex interaction was assessed by using computational analysis (molecular modeling). The HP-ß-CD-RIF complex and Isoniazid were co-loaded in the small unilamellar vesicles (SUVs). Further, the developed system was functionalized with transferrin, a targeting moiety. Transferrin functionalized SUVs (Tf-SUVs) could preferentially deliver their payload intracellularly in the endosomal compartment of macrophages. In in vitro study on infected Raw 264.7 macrophage cells revealed that the encapsulated bioactive(s) could eradicate the pathogen more efficiently than free bioactive(s). In vivo studies further revealed that the Tf-SUVs could accumulate and maintain intracellular bioactive(s) concentrations in macrophages. The study suggests Tf-SUVs as a promising module for targeted delivery of a drug combination with improved/optimal therapeutic index and effective clinical outcomes.

Recent advances in search of oral heparin therapeutics.

Unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) are first choices of clinicians among available anticoagulants. Currently, these agents are administered either parenterally or subcutaneously, which reduces patient compliance and acceptability. Oral heparin may serve as an alternative to both parenteral heparin as well as presently available oral anticoagulants such as warfarin. This review focuses mainly upon recent perspectives in the development of heparin as an oral anticoagulant. The possibility of its success with special emphasis to nanotechnological approaches has been elaborated. Important strategies such as the use of penetration enhancers, the development of lipid conjugates of heparin, and the incorporation of heparin in polymeric matrix systems have been discussed. Additionally, introductory information on biological activities, physiochemical aspects, and pharmacokinetic and pharmacodynamic parameters of heparin is summarized. A brief comparison of UFH and LMWH is also included for reader's benefit. Informative discussion on clinical trials with the successes and limitations of oral heparin formulations is also presented. Overall, the present review provides complete insight to the research that has been carried out for the development of heparin as oral anticoagulant.

Estrogen-anchored pH-sensitive liposomes as nanomodule designed for site-specific delivery of doxorubicin in breast cancer therapy.

The present investigation reports the development of nanoengineered estrogen receptor (ER) targeted pH-sensitive liposome for the site-specific intracellular delivery of doxorubicin (DOX) for breast cancer therapy. Estrone, a bioligand, was anchored on the surface of pH-sensitive liposome for drug targeting to ERs. The estrone-anchored pH-sensitive liposomes (ES-pH-sensitive-SL) showed fusogenic potential at acidic pH (5.5). In vitro cytotoxicity studies carried out on ER-positive MCF-7 breast carcinoma cells revealed that ES-pH-sensitive-SL formulation was more cytotoxic than non-pH-sensitive targeted liposomes (ES-SL). The flow cytometry analysis confirmed significant enhanced uptake (p < 0.05) of ES-pH-sensitive-SL by MCF-7 cells. Intracellular delivery and nuclear localization of the DOX was confirmed by fluorescence microscopy. The mechanism for higher cytotoxicity shown by estrone-anchored pH-sensitive liposomal-DOX was elucidated using reactive oxygen species (ROS) determination. The in vivo biodistribution studies and antitumor activities of formulations were evaluated on tumor bearing female Balb/c mice followed by intravenous administration. The ES-pH-sensitive-SL efficiently suppressed the breast tumor growth in comparison to both ES-SL and free DOX. Serum enzyme activities such as LDH and CPK levels were assayed for the evaluation of DOX induced cardiotoxicity. The ES-pH-sensitive-SL accelerated the intracellular trafficking of encapsulated DOX, thus increasing the therapeutic efficacy. The findings support that estrone-anchored pH-sensitive liposomes could be one of the promising nanocarriers for the targeted intracellular delivery of anticancer agents to breast cancer with reduced systemic side effects.

Development and evaluation of tripalmitin emulsomes for the treatment of experimental visceral leishmaniasis.

The antifungal and antileishmanial agent amphotericin B (AmB) was formulated in tripalmitin based nanosize lipid partices (emulsomes) for macrophage targeting for the treatment of visceral leishmaniasis (VL). Emulsomes were modified by coating them with macrophage-specific ligand (O-palmitoyl mannan, OPM). The antileishmanial activity of AmB (0.5 and 1 mg/kg) was investigated in-vivo against VL by the inhibition of parasitic load in the spleen of L. donovani infected hamsters after intraperitoneal injections of AmB-Doc (Mycol), plain emulsomes (TPEs) and OPM coated emulsomes (TPEs-OPM). The formulations were found to be less effective at the dose of 0.5 mg/kg. At the dose of 1 mg/kg, formulation TPEs-OPM eliminated intracellular amastigotes of L. donovani within splenic macrophages more efficiently (62.76 ± 3.54 % parasite inhibition) than the formulation TPEs (42.68 ± 2.36 % parasite inhibition) (P < 0.01) or AmB-Doc (25.87 ± 3.87 % parasite inhibition) (P < 0.001). Our results suggest that these formulations (plain and ligand grafted emulsomes) are a promising substitute to the conventional AmB-Doc formulation for the treatment of VL.

Biomimetic solid lipid nanoparticles for oral bioavailability enhancement of low molecular weight heparin and its lipid conjugates: in vitro and in vivo evaluation.

Low molecular weight heparin (LMWH) is an anionic oligosaccharide macromolecule, which is commonly administered via parenteral routes for the treatment of vascular disorders like deep vein thrombosis (DVT) and pulmonary embolism (PE). Oral heparin delivery can tremendously improve the treatment of such disorders but is restricted due to its large size and anionic character. The present investigation describes synthesis of LMWH-lipid conjugates and their encapsulation in phosphatidylcholine stabilized biomimetic solid lipid nanoparticles (SLNs) for LMWH's oral bioavailability enhancement. Briefly, LMWH was conjugated with different saturated lipids of varying chain length (stearic acid, palmitic acid and myristic acid) using carbodiimide chemistry. The conjugation was confirmed with IR and (1)H NMR spectroscopy. The LMWH-lipid conjugate loaded SLNs were characterized for various parameters like shape, size, zeta potential, entrapment efficiency and in vitro release behavior in different simulated GIT pH mediums. The GIT toxicity of LMWH-lipid conjugate loaded SLNs to different tissues of intestinal epithelium was observed using H&E staining followed by microscopic observation at cellular level. The LMWH-lipid conjugate loaded SLNs were found to be safe for oral administration. The plasma concentration of LMWH was estimated using anti-FXa chromogenic assay. A significantly higher bioavailability (p < 0.05) of LMWH was observed using LMWH-lipid conjugates loaded SLNs in comparison to LMWH loaded SLNs and free LMWH. The order of different conjugates in bioavailability enhancement was LMWH-stearic acid > LMWH-palmitic acid > LMWH-myristic acid. This strategy holds promise for future applications of oral delivery of LMWH conjugates in the form of SLNs particularly for the treatment of cardiovascular disease like DVT and PE.

Novel approaches to oral immunization for hepatitis B.

Hepatitis B is a necroinflammatory liver disease manifested with subacute to acute symptoms, liver cirrhosis, and mortality. Parenteral alum-adsorbed hepatitis B surface antigenic (HBsAg) vaccination, although available, poses serious concerns regarding inability to induce both cell-mediated and mucosal immune response. In this context, oral delivery may be a prospective solution to the issues associated with conventional vaccination. However, the strategy is detrimental to the antigenic substances, suffers various physical/chemical barriers, and impedes poor transcytosis via mucosal route. Therefore, surface-engineered novel carrier-based approaches are reportedly promising for effective HBsAg oral vaccine delivery. This review focuses on the efforts for developing oral mucosal vaccine against hepatitis B, with considerable attention on novel drug delivery systems for spatial distribution of antigenic substance to the immune effector cells and organs.

Effect of surfactants on the characteristics of fluconazole niosomes for enhanced cutaneous delivery.

Fluconazole-loaded niosomes were prepared by the film hydration method with different surfactants (Span and Brij series) and characterized for various parameters. Results showed that niosomes composed of Span 40, Span 60, and Brij 72 were most stable with smaller size, i.e. 0.378 ± 0.022 µm, 0.343 ± 0.063 µm, and 0.287 ± 0.012 µm, respectively, along with higher entrapment efficiency (approx. > 41%). In vitro skin permeation and retention studies suggested that cutaneous accumulation was affected by surfactant property and vesicle size. Therefore the niosomes consisting of Span 40, Span 60, and Brij 72 surfactant are seemingly accumulated and form localized drug depots in the skin, thereby releasing the contents in a sustained manner and able to greatly enhance cutaneous retention of the drug.

Development and characterization of effective topical liposomal system for localized treatment of cutaneous candidiasis.

The localized delivery of fluconazole (FLZ) by conventional therapy is a major impediment in achieving its therapeutic efficacy against skin infections, such as cutaneous candidiasis. Therefore, the present study was aimed to develop FLZ-loaded vesicular construct(s), such as liposomes and niosomes, incorporated into carbopol gel (1%; w/w) for sustained, localized application. The liposomes and niosomes were prepared by the lipid/nonionic surfactant-based dry-film hydration method and were characterized for different parameters. In addition, antifungal activity was carried out on experimentally induced cutaneous candidiasis in immunosuppressed albino rats. The results showed that the size of liposomes and niosomes was found to be 0.348 ± 0.054 and 0.326 ± 0.033 µm with encapsulation efficiency of 31.8 ± 1.36 and 27.6 ± 1.08%, respectively. The skin-retention studies of FLZ from in vitro and in vivo experiments showed significantly higher accumulation of drug in the case of liposomal gel. The in vivo localization studies in viable skin showed that liposomal gel could produce 14.2-fold higher drug accumulation, compared with plain gel, while it was 3.3-fold more in the case of an equivalent-dose application in the form of niosomal gel. The antifungal study also confirmed the maximum therapeutic efficacy of liposomal gel, as the lowest number of cfu/mL was recorded following liposomal FLZ application. The studies signify the potential of liposomal gel for topical delivery of FLZ with increased accumulation of drug in various strata of skin vis-a-vis through sustained release of drug could maintain the localized effect, resulting in an effective treatment of a life-threatening cutaneous fungal infection.

Advances in novel drug delivery strategies for breast cancer therapy.

Breast cancer remains one of the world's most devastating diseases. However, better understanding of tumor biology and improved diagnostic devices could lead to improved therapeutic outcomes. Nanotechnology has the potential to revolutionize cancer diagnosis and therapy. Various nanocarriers have been introduced to improve the therapeutic efficacy of anticancer drugs, including liposomes, polymeric micelles, quantum dots, nanoparticles, and dendrimers. Recently, targeted drug delivery systems for anti-tumor drugs have demonstrated great potential to lower cytotoxicity and increase therapeutic effects. Various ligands/approaches have been explored for targeting breast cancer. This paper provides an overview of breast cancer, conventional therapy, potential of nanotechnology in management of breast cancer, and rational approaches for targeting breast cancer.

Preparation and evaluation of galactosylated vesicular carrier for hepatic targeting of silibinin.

PURPOSE: Silibinin, the main flavonolignan of Silymarin, is used in the treatment of liver diseases of varying origins. Aiming at improving its poor bioavailability of oral products, galactosylated liposomes were introduced in this work for silibinin delivery and targeting to the lectin receptors present on the hepatocytes. METHODS: Small unilamellar liposomal vesicles were prepared and p-aminophenyl-beta-d-galactopyranoside was covalently coupled. The drug release from liposomes was studied by dialysis method. Plasma, tissue distribution and intrahepatic distribution of free, plain liposomal and galactosylated liposomal encapsulated silibinin were determined following a bolus intravenous injection in albino rats. Various formulations were evaluated regarding silibinin's hepatoprotective activity against CCl(4)-induced oxidative stress in albino rats. The degree of protection was measured using biochemical parameters like serum glutamic oxalacetate transaminase and serum glutamic pyruvate transaminase. RESULTS: Aggregation of galactosylated liposomes by Ricinus communis revealed the presence of galactose residues on the surface of liposomes. After 24 hours, cumulative drug release percent from galactosylated liposomes was found to be moderate (30.9 +/- 1.73%). The results of tissue distribution study indicated extensive localization of liposomal formulations in liver cells (galactosylated liposomes, 61.27 +/- 3.84% in 1 hour). Separation of the liver cells showed that galactosylated liposomes were preferentially taken up by the hepatocytes (79% of the total hepatic uptake in 1 hour). The introduced galactosylated silibinin produced a significant decrease in both transaminase levels when challenged with CCl(4) intraperitonially. CONCLUSION: A positive outcome of these studies gave an insight that galactosylated liposomes are more effective and suitable for targeted delivery of silibinin to hepatocytes.

Lipid Drug Conjugates for Improved Therapeutic Benefits.

Lipid drug conjugates (LDCs) are the chemical entities, which are commonly referred to as lipoidal prodrug. They contain the bioactive molecules, covalently or non-covalently linked with lipids like fatty acids, glycerides or phospholipids. Lipid drug conjugates are fabricated with the aim of increasing drug payload. It also prevents leakage of a highly polar bioactive(s) from the lipophilic matrix. Conjugating lipidic moieties to bioactive molecules improves hydrophobicity. It also modifies other characteristics of bioactive(s). These conjugates possess numerous merits encompassing enhanced tumor targeting, lymphatic system targeting, systemic bioavailability and decreased toxicity. Different conjugation approaches, chemical linkers and spacers can be used to synthesize LDCs based on the chemical behaviour of lipidic moieties and bioactive(s). The factors such as coupling/ conjugation methods, the linkers etc. regulate and control the release of bioactive(s) from the LDCs. It is considered as a crucial parameter for the better execution of the LDCs. The purpose of this review is to explore widely the potential of LDCs as an approach for improving the therapeutic indices of bioactive(s). In this review, the conjugation methods, various lipids used for preparing LDCs, and advantages of using LDCs are summarized. Though LDCs might be administered without using a carrier; however, majority of them are incorporated in an appropriate nanocarrier system. In the conjugates, the lipidic component may considerably improve the loading of lipoidal bioactive(s) in the lipid compartments. This results in high % drug entrapment in nanocarriers with greater stability. Several nanometric carriers such as polymeric nanoparticles, micelles, liposomes, emulsions and lipid nanoparticles, which have been explored, are reviewed here.

Functionalized nanocarrier(s) to image and target fungi infected immune cells.

The present study was aimed at the preparation, characterization, and evaluation of the performance of amphotericin B (AmB)-loaded aerosolized liposomes and emulsomes (core composed of solid lipid surrounded by phospholipid bilayers) for their selective presentation to lungs (alveolar macrophages), as this is the densest site of aspergillosis infection. Liposomes and emulsomes were modified by coating them with alveolar macrophage-specific ligands (O-palmitoyl mannan, OPM) and also with monoclonal antibody EBA-2. The prepared formulations were characterized in vitro for vesicle size, zeta potential and percent drug entrapment. We evaluated the therapeutic efficacy of the novel site-specific targetable lipid-based delivery systems in experimental pulmonary aspergillosis. Immunosuppressed rats with pulmonary aspergillosis were given 1 mg/kg of aerosolized liposomal and emulsomes formulations of AmB once by using an ultrasonic jet nebulizer on the third day after infection. The concentrations of AmB in lung were higher in surface modified liposomes and emulsomes than those of plain counterparts. Changes in lung histopathology were also assessed. Further, scintigraphy was also carried out using 99mTc labeled liposomes. From those results it was concluded that radiolabeled liposomes could be used for in vivo imaging of the infection site, and that site directed system(s) based on OPM/mAb coating exhibited great potential in targeted antifungal chemotherapy.