A combination of nanosystems for the delivery of cancer chemoimmunotherapeutic combinations: 1-Methyltryptophan nanocrystals and paclitaxel nanoparticles

Bimetallic peroxide-based nanotherapeutics for immunometabolic intervention and induction of immunogenic cell death to augment cancer immunotherapy

Immunotherapy has transformed cancer treatment, but its efficacy is often limited by the immunosuppressive characteristics of the tumor microenvironment (TME), which are predominantly influenced by the metabolism of cancer cells. Among these metabolic pathways, the indoleamine 2,3-dioxygenase (IDO) pathway is particularly crucial, as it significantly contributes to TME suppression and influences immune cell activity. Additionally, inducing immunogenic cell death (ICD) in tumor cells can reverse the immunosuppressive TME, thereby enhancing the efficacy of immunotherapy. Herein, we develop CGDMRR, a novel bimetallic peroxide-based nanodrug based on copper-cerium peroxide nanoparticles. These nanotherapeutics are engineered to mitigate tumor hypoxia and deliver therapeutics such as 1-methyltryptophan (1MT), glucose oxidase (GOx), and doxorubicin (Dox) in a targeted manner. The design aims to alleviate tumor hypoxia, reduce the immunosuppressive effects of the IDO pathway, and promote ICD. CGDMRR effectively inhibits the growth of 4T1 tumors and elicits antitumor immune responses by leveraging immunometabolic interventions and therapies that induce ICD. Furthermore, when CGDMRR is combined with a clinically certified anti-PD-L1 antibody, its efficacy in inhibiting tumor growth is enhanced. This improved efficacy extends beyond unilateral tumor models, also affecting bilateral tumors and lung metastases, due to the activation of systemic antitumor immunity. This study underscores CGDMRR's potential to augment the efficacy of PD-L1 blockade in breast cancer immunotherapy.

Improving the Anti-Tumor Effect of Indoleamine 2,3-Dioxygenase Inhibitor CY1-4 by CY1-4 Nano-Skeleton Drug Delivery System

Background: CY1-4, 9-nitropyridine [2',3':4,5] pyrimido [1,2-α] indole -5,11- dione, is an indoleamine 2,3-dioxygenase (IDO) inhibitor and a poorly water-soluble substance. It is very important to increase the solubility of CY1-4 to improve its bioavailability and therapeutic effect. In this study, the mesoporous silica nano-skeleton carrier material Sylysia was selected as the carrier to load CY1-4, and then the CY1-4 nano-skeleton drug delivery system (MSNM@CY1-4) was prepared by coating the hydrophilic polymer material Hydroxypropyl methylcellulose (HPMC) and the lipid material Distearoylphosphatidyl-ethanolamine-poly(ethylene glycol)2000 (DSPE-PEG2000) to improve the anti-tumor effect of CY1-4. Methods: The solubility and dissolution of MSNM@CY1-4 were investigated, and its bioavailability, anti-tumor efficacy, IDO inhibitory ability and immune mechanism were evaluated in vivo. Results: CY1-4 was loaded in MSNM@CY1-4 in an amorphous form, and MSNM@CY1-4 could significantly improve the solubility (up to about 200 times) and dissolution rate of CY1-4. In vivo studies showed that the oral bioavailability of CY1-4 in 20 mg/kg MSNM@CY1-4 was about 23.9-fold more than that in 50 mg/kg CY1-4 suspension. In B16F10 tumor-bearing mice, MSNM@CY1-4 significantly inhibited tumor growth, prolonged survival time, significantly inhibited IDO activity in blood and tumor tissues, and reduced Tregs in tumor tissues and tumor-draining lymph nodes to improve anti-tumor efficacy. Conclusions: The nano-skeleton drug delivery system (MSNM@CY1-4) constructed in this study is a potential drug delivery platform for improving the anti-tumor effect of oral poorly water-soluble CY1-4.

The beneficial health effects of puerarin in the treatment of cardiovascular diseases: from mechanisms to therapeutics

Cardiovascular diseases (CVDs) are the leading causes of death globally that seriously threaten human health. Although novel western medicines have continued to be discovered over the past few decades to inhibit the progression of CVDs, new drug research and development for treating CVDs with less side effects and adverse reactions are continuously being desired. Puerarin is a natural product found in a variety of medicinal plants belonging to the flavonoid family with potent biological and pharmacological activities. Abundant research findings in the literature have suggested that puerarin possesses a promising prospect in treating CVDs. In recent years, numerous new molecular mechanisms of puerarin have been explored in experimental and clinical studies, providing new evidence for this plant metabolite to protect against CVDs. This article systematically introduces the history of use, bioavailability, and various dosage forms of puerarin and further summarizes recently published data on the major research advances and their underlying therapeutic mechanisms in treating CVDs. It may provide references for researchers in the fields of pharmacology, natural products, and internal medicine.

In vitro and vivo anti-tumor activity and mechanisms of the new cryptotanshinone derivative 11 against hepatocellular carcinoma

Global burden of hepatocellular carcinoma (HCC) is increasing. Chemotherapy and immunotherapy are the prevailing options for therapy. Developing new therapeutic strategies for HCC patients is still highly desirable. Recent studies demonstrate that cryptotanshinone is capable of inhibiting tumor growth in HCC and induces antitumor immunity in vitro. In our previous research, we discovered a new cryptotanshinone derivative 11 as an effective immunoregulatory enzyme indoleamine 2, 3-dioxygenase 1 (IDO1) inhibitor. This study aims to evaluate its in vitro and in vivo antitumor activity against hepatocellular carcinoma. 11 displayed robust anti-proliferative activity against HCC cell lines and promoted apoptosis of HCC cell line through the mitochondrial-mediated apoptotic pathway. In H22 tumor-bearing mice models, 11 exhibited significant in vivo anti-tumor activity with different administration routes. And no obvious toxicity was observed. RNA-seq analysis demonstrated the differential expressed genes and alteration of key pathways associated with immune responses after administration of 11. Up-regulation of anti-tumor cytokines and down-regulation of cytokines that promote tumor growth were indicated and further validated. Our study demonstrates that 11 exhibits promising anti-tumor activity both in vitro and in vivo against hepatocellular carcinoma cancer. It is a lead compound for HCC immunotherapy and is worthy for further development.

Assessment of an Anticancer Effect of the Simultaneous Administration of MM-129 and Indoximod in the Colorectal Cancer Model

(1) Background: The purpose of the given study was to examine the antitumor activity of the simultaneous administration of MM-129, a 1,2,4-triazine derivative, and indoximod (IND), the kynurenine pathway inhibitor, toward colon cancer. (2) Methods: The efficiency of the co-administration of the studied compounds was assessed in xenografted zebrafish embryos. Then, the effects of the combined administration of compounds on cellular processes such as cell viability, apoptosis, and intracellular signaling pathways were evaluated. In vitro studies were performed using two colorectal cancer cell lines, namely, DLD-1 and HT-29. (3) Results: The results indicated that the simultaneous application of MM-129 and indoximod induced a stronger inhibition of tumor growth in zebrafish xenografts. The combination of these compounds intensified the process of apoptosis by lowering the mitochondrial potential, enhancing the externalization of phosphatidylserine (PS) and activation of caspases. Additionally, the expression of protein kinase B (AKT) and indoleamine 2,3-dioxygenase-(1IDO1) was disrupted under the applied compound combination. (4) Conclusions: Simultaneous targeting of ongoing cell signaling that promotes tumor progression, along with inhibition of the kynurenine pathway enzyme IDO1, results in the enhancement of the antitumor effect of the tested compounds against the colon cancer cells.

Oral Administration of Nanoformulated Indoximod Ameliorates Ulcerative Colitis by Promoting Mitochondrial Function and Mucosal Healing

Ulcerative colitis (UC) is a chronic relapsing inflammatory bowel disease with serious mucosal inflammation mainly in the colon and rectum. Currently, there is no effective therapeutics for UC. Indoximod (IND) is a water-insoluble inhibitor for indolamine 2, 3-dioxygenase (IDO) and has been mainly reported in cancer therapy. Here, we prepared orally administrated IND nanoparticles (IND-NPs) for UC treatment and investigated their functions and mechanisms in cellular and animal inflammatory models. Confocal imaging demonstrated that IND-NPs maintained the expression level of ZO-1, Occludin and E-cadherin, thereby stabilizing of intercellular junction in Caco-2 cells. It was found that IND-NPs could lower the ROS level and increase mitochondrial membrane potential as well as ATP level, indicating that IND-NPs could restore DSS-induced mitochondrial dysfunction. In the mice model with DSS-induced colitis, IND-NPs were found to alleviate UC-associated symptoms, inhibit inflammatory response, and improve the integrity of epithelial barrier. The untargeted metabolomics analysis validated that IND-NPs also contributed to regulate the metabolite levels to normal. As an agonist of aryl hydrocarbon receptor (AhR), IND-NPs might repair mucosa via the AhR pathway. These findings demonstrated that IND-NPs prominently ameliorated DSS-induced colonic injury and inflammation and preserved intestinal barrier integrity, showing a promising potential in UC treatment.

A phthalocyanine-based photosensitizer for effectively combating triple negative breast cancer with enhanced photodynamic anticancer activity and immune response

Although photodynamic therapy (PDT) has attracted great interest, the photosensitizers in clinical had weak inhibition on metastasis and invasion of cancers. Additionally the immune response induced by PDT was insufficient to eradicate cancer. Herein, indoximod, an inhibitor of indoleamine 2,3-dioxygenase (IDO), is introduced to concatenate with zinc phthalocyanines (ZnPc) for effectively overcoming above inadequacy. Due to indoximod moiety, photosensitizer 1-MT-Pc can obtain enhanced intracellular uptake and high reactive oxygen species (ROS) generation. More impressively, 1-MT-Pc can achieve remarkable photocytotoxicity towards TNBC cells and negligible damage to normal cells. Meanwhile, 1-MT-Pc effectively inhibits metastasis and invasion of TNBC cells. Importantly, 1-MT-Pc exhibit elevated inhibitory effect on 4T1 tumor by enhanced PDT and immunotherapy.

Preclinical studies of a high drug-loaded meloxicam nanocrystals injection for analgesia

Meloxicam (MLX) is considered to have significant analgesic properties. However, the analgesic effects of MLX are compromised by its poor water solubility and thus the low drug loading. The purpose of this study was to develop a high drug-loaded MLX injection by formulating it into nanocrystals (NCs) for the treatment of analgesia. The developed MLXNCs exhibited satisfactory particle sizes and remarkably in vitro dissolution behaviors. In addition, the plasma concentrations of MLXNCs were comparable with the MLX solution (formulated with 1.0% polyoxyethylene castor oil 35) in rats. The acetic acid-induced writhing tests, hot plate tests and hind paw incision experiments demonstrated that the MLXNCs had significant analgesic effects. The findings provide insights into the developed high drug-loaded MLXNCs and provide new therapeutic options for acute and chronic pain management.

Temozolomide: an Overview of Biological Properties, Drug Delivery Nanosystems, and Analytical Methods

Temozolomide (TMZ) is an imidazotetrazine prodrug used to treat glioblastoma multiforme. Its physicochemical prop-erties and small size confer the ability to cross the blood-brain barrier. The antitumor activity depends on pH-dependent hydrolysis of the methyldiazonium cation, which is capable of methylating purine bases (O6-guanine; N7-guanine, and N3-adenine) and causing DNA damage and cell death. TMZ is more stable in acidic media (pH ≤ 5.0) than in basic media (pH ≥ 7.0) due to the protonated form that minimizes the catalytic process. Because of this, TMZ has high oral bioavailability, but it has a half-life of 1.8 h and low brain distribution (17.8%), requiring a repeated dos-ing regimen that limits its efficacy and increases adverse events. Drug delivery Nanosystems (DDNs) improve the phys-icochemical properties of TMZ and may provide controlled and targeted delivery. Therefore, DDNs can increase the efficacy and safety of TMZ. In this context, to ensure the efficiency of DDNs, analytical methods are used to evaluate TMZ pharmacokinetic parameters, encapsulation efficiency, and the release profile of DDNs. Among the methods, high-performance liquid chromatography is the most used due to its detection sensitivity in complex matrices such as tissues and plasma. Micellar electrokinetic chromatography features fast analysis and no sample pretreatment. Spec-trophotometric methods are still used to determine encapsulation efficiency due to their low cost, despite their low sen-sitivity. This review summarizes the physicochemical and pharmacological properties of free TMZ and TMZ-loaded DDNs. In addition, this review addresses the main analytical methods employed to characterize TMZ in different ma-trices.

Immune Checkpoint Inhibitor-Based Strategies for Synergistic Cancer Therapy

Immune checkpoint blockade therapy (ICBT) targeting checkpoints, such as, cytotoxic T-lymphocyte associated protein-4 (CTLA-4), programmed death-1 (PD-1), or programmed death-ligand 1 (PD-L1), can yield durable immune response in various types of cancers and has gained constantly increasing research interests in recent years. However, the efficacy of ICBT alone is limited by low response rate and immune-related side effects. Emerging preclinical and clinical studies reveal that chemotherapy, radiotherapy, phototherapy, or other immunotherapies can reprogramm immunologically "cold" tumor microenvironment into a "hot" one, thus synergizing with ICBT. In this review, the working principle and current development of various immune checkpoint inhibitors are summarized, while the interactive mechanism and recent progress of ICBT-based synergistic therapies with other immunotherapy, chemotherapy, phototherapy, and radiotherapy in fundamental and clinical studies in the past 5 years are depicted and highlighted. Moreover, the potential issues in current studies of ICBT-based synergistic therapies and future perspectives are also discussed.

1-MT grafted carboxymethyl chitosan and its nanoparticles: Preparation, characterization and evaluation

This work aims to synthesize two novel 1-MT (1-Methyl-DL-tryptophan) grafted CMCS (carboxymethyl chitosan) polymer prodrugs CMCS-amido-1-MT and CMCS-ester-1-MT, and to further manufacture their nanoparticles for potential biomedical applications. The polymeric prodrugs are prepared by three-step chemical synthesis. The chemical structure of drugs is confirmed by FTIR and 1H-NMR. The drug loadings of the CMCS-amido-1-MT NPs and CMCS-ester-1-MT NPs are 11.43% and 10.18%, respectively. The surface morphology of the nanoparticles is spherical or nearly spherical, while the surface is smooth and the size distribution is uniform. The average particle size is both about 200 nm, while the polydispersity index is both about 0.15. The nanoparticles have a negative charge on the surface. The particle size and its distribution change little, when the two nanoparticles are tested in the simulated blood pH environment for 7 days. However, only the CMCS-ester-1-MT nanoparticles are pH-sensitive. The cell toxicity of the CMCS-ester-1-MT nanoparticles and the original drug are both in a dose- and time-dependent manner, while the nanoparticles enter cells by endocytosis. In ECA109 cells, the CMCS-ester-1-MT nanoparticles and the original drug both induce the apoptosis. CMCS-ester-1-MT NPs can activate the ATF4/CHOP pathway in endoplasmic reticulum stress, and achieve cancer suppression through mitochondrial-related apoptosis.

Codelivered Chemotherapeutic Doxorubicin via a Dual-Functional Immunostimulatory Polymeric Prodrug for Breast Cancer Immunochemotherapy

Immunochemotherapy is viewed as a promising approach for cancer therapy via combination treatment with immune-modulating drugs and chemotherapeutic drugs. A novel dual-functional immunostimulatory polymeric prodrug carrier PEG_2k-Fmoc-1-MT was developed for simultaneously delivering 1-methyl tryptophan (1-MT) of an indoleamine 2,3-dioxygenase (IDO) inhibitor and chemotherapeutic doxorubicin (DOX) for breast cancer immunochemotherapy. DOX/PEG_2k-Fmoc-1-MT micelles were more effective in cell proliferation inhibition and apoptosis induction in 4T1 cells. PEG_2k-Fmoc-1-MT prodrug micelles presented enhanced inhibition ability of IDO with decreased kynurenine production and increased the proliferation in dose-dependent manners of effector CD4⁺ and CD8⁺ T cells. DOX/PEG_2k-Fmoc-1-MT micelles exhibited prolonged blood circulation time and superior accumulation of DOX and 1-MT in tumors compared to that of DOX and 1-MT solutions. A significantly enhanced immune response of the DOX/PEG_2k-Fmoc-1-MT micelles was observed with the decreasing tryptophan/kynurenine ratio in blood and tumor tissue, promoting effector CD4⁺ and CD8⁺ T cells while reducing regulatory T cell (Tregs) expression. Meanwhile, the coreleased DOX-triggered immunogenic cell death action combined with the cleaved 1-MT promoted the related cytokine secretion of tumor necrosis factor-α, interleukin-2, and interferon-γ, further facilitating the T cell-mediated immune responses. More importantly, the DOX-loaded micelles led to a significantly improved inhibition on tumor growth and prolonged animal survival rate in a 4T1 murine breast cancer model. In conclusion, DOX codelivered by a PEG_2k-Fmoc-1-MT immunostimulatory polymeric prodrug showed a maximum immunochemotherapy efficacy against breast cancer.

Site-specific MOF-based immunotherapeutic nanoplatforms via synergistic tumor cells-targeted treatment and dendritic cells-targeted immunomodulation

An efficient antitumor immune response relies on multiple cells-based process including tumor cells-targeted immunogenicity increment, dendritic cells (DCs)-targeted vaccine delivery and T cells-mediated tumor elimination. Only limited immune efficacy could be achieved by strengthening the function of single type of cells. Therefore, building an effective immunotherapeutic nanoplatform by simultaneously modulating the functions of multiple cells involved in immune process is urgently demanded. However, it is challenging to modulate multiple cells since the on-demand delivery of diverse agents to different cells is restricted by inherent different target sites. Herein, as a proof of concept, dual tailor-made metal organic framework (MOF) nanoparticles based on zeolitic imidazolate framework-8 (ZIF-8) are designed to comprehensively enhance the immunotherapy via the spatiotemporal cooperation of various therapeutic agents including photothermal agent IR820, adjuvant imiquimod (R837) and immunomodulator 1-methyl-d-tryptophan (1 MT). On one hand, IR820@ZIF-8 is modified with hyaluronic acid for realizing tumor-targeted photothermal therapy, accompanied with the release of tumor antigens. On the other hand, (R837+1 MT)@ZIF-8 is modified with mannan for achieving DCs-targeted immune amplification. The synergistic tumor cells-targeted treatment and DCs-targeted immunomodulation can efficiently overcome two major obstacles in immunotherapy: inadequate activation of immune response and immune evasion, offering powerful platform against invasive malignancy and rechallenged tumors.

Cell Membrane-Camouflaged Nanocarriers for Cancer Diagnostic and Therapeutic

Cell membrane (CM)-camouflaged nanocarriers (CMNPs) are the tools of a biomimetic strategy that has attracted significant attention. With a wide range of nanoparticle cores and CMs available, various creative CMNP designs have been studied for cancer diagnosis and therapy. The various functional CM molecules available allow CMNPs to demonstrate excellent properties such as prolonged circulation time, immune escape ability, reduced systemic toxicity, and homologous targeting ability when camouflaged with CMs derived from various types of natural cells including red and white blood cells, platelets, stem cells, and cancer cells. In this review, we summarize various CMNPs employed for cancer chemotherapy, immunotherapy, phototherapy, and in vivo imaging. We also predict future challenges and opportunities for fundamental and clinical studies.

Dual functional immunostimulatory polymeric prodrug carrier with pendent indoximod for enhanced cancer immunochemotherapy

Immunotherapy based on checkpoint blockade has been regarded as one of the most promising approaches towards many types of cancers. However, low response rate hinders its application due to insufficient tumor immunogenicity and immunosuppressive tumor microenvironment. To achieve an overall enhanced therapeutic outcome, we developed a dual-functional immuno-stimulatory polymeric prodrug carrier modified with pendent indoximod, an indoleamine 2,3-dioxygenase (IDO) inhibitor that can be used to reverse immune suppression, for co-delivery of Doxorubicin (Dox), a hydrophobic anticancer agent that can promote immunogenic cell death (ICD) and elicit antitumor immunity. The resulted carrier denoted as POEG-b-PVBIND, consisting of poly (oligo (ethylene glycol) methacrylate) (POEG) hydrophilic blocks and indoximod conjugated hydrophobic blocks, is rationally designed to improve immunotherapy by synergistically modulating the tumor microenvironment (TME). Our data showed that Dox-triggered ICD promoted intra-tumoral infiltration of CD8+ T cells and IFN-γ-production by CD8+ T cells. Meanwhile, cleaved indoximod significantly increased CD8+ T cell infiltration while reducing the immunosuppressive T regulatory cells (Tregs). More importantly, Dox/POEG-b-PVBIND micelles led to significantly improved tumor regression in an orthotopic murine breast cancer model compared to both Dox-loaded POEG-b-PVB micelles (a control inert carrier) and POEG-b-PVBIND micelles alone, confirming combination effect of indoximod and Dox in improving the overall antitumor activity. STATEMENT OF SIGNIFICANCE: Indoleamine 2,3-dioxygenase (IDO) is an enzyme that can induce immune suppressive microenvironment in tumors. As a well-studied IDO inhibitor, indoximod (IND) represents a promising agent for cancer immunotherapy and could be particularly useful in combination with other chemotherapeutic agents. However, three major problems hinder its application: (1) IND is barely soluble in water; (2) IND delivery efficiency is limited (3) simultaneous delivery of two agents into tumor site is still challenging. Currently, most reports largely focus on improving the pharmacokinetic profile of IND alone via different formulations such as IND prodrug and IND nanocrystal. However, there is limited information about IND based co-delivery systems, especially for delivering hydrophobic chemotherapeutic agents. Here, we developed a new dual-functional polymeric prodrug carrier modified with a number of pendent IND units (denoted as POEG-b-PVBIND). POEG-b-PVBIND shows immunostimulatory and antitumor activities by itself. More importantly, POEG-b-PVBIND polymer is able to self-assemble into nano-sized micelles that are highly effective in formulating and codelivering other hydrophobic agents including doxorubicin (Dox), sunitinib (Sun), and daunorubicin (Dau), which can elicit antitumor immunity via promoting immunogenic cell death (ICD). We have shown that our new combination therapy led to a significantly improved antitumor activity in an aggressive murine breast cancer model (4T1.2).

The Opposite Effect of L-kynurenine and Ahr Inhibitor Ch223191 on Apoptotic Protein Expression in Pancreatic Carcinoma Cells (Panc-1)

BACKGROUND

L-kynurenine, derivate of L-tryptophan, is synthetized by indoleamine 2,3-dioxygenase (IDO). The effects of L-kynurenine depend on its binding to an aryl hydrocarbon receptor (AhR).

OBJECTIVE

The aim of this study was to investigate the changes within the apoptotic pathway in PANC-1 cells subjected to L-kynurenine or L-tryptophan considering the production of anti-apoptotic proteins from the IAPs and Bcl-2 family, as well as the regulation of NF-κB signaling.

METHODS

The investigated substances were added alone or in combination with the AhR inhibitor (CH223191) to cultures of PANC-1 cells. Cytoplasmic and nuclear proteins were analyzed by immunoblotting and cells were incubated with the investigated substances to determine cytotoxicity and proliferative effects.

RESULTS

Incubation of PANC-1 cells with L-kynurenine or L-tryptophan resulted in the increase in antiapoptotic cIAP-1, cIAP-2, XIAP and Bcl-2 expression and a decrease in pro-apoptotic Bax. These changes were accompanied by the reduction of active caspases -9, -3 and PARP-1. The treatment leads to translocation and enhanced production of nuclear NF-κB p50 and Bcl-3. Incubation of the cells with AhR blocker either alone or together with L-kynurenine or L-tryptophan resulted in the opposite effect, leading to the downregulation of IAPs and Bcl-2, upregulation of Bax and caspases expression.

CONCLUSION

1) L-kynurenine and its precursor promote anti-apoptotic effects through the modulation of IDOdependent pathway and regulation of IAPs, Bcl-2 and NF-κB family members in pancreatic carcinoma cells 2) inhibition of AhR by CH223191 exerts an apoptosis-promoting effect, and this observation might suggest the potential use of this compound in pancreatic cancer therapy.

Parenteral nanosuspensions: a brief review from solubility enhancement to more novel and specific applications

Advancements in in silico techniques of lead molecule selection have resulted in the failure of around 70% of new chemical entities (NCEs). Some of these molecules are getting rejected at final developmental stage resulting in wastage of money and resources. Unfavourable physicochemical properties affect ADME profile of any efficacious and potent molecule, which may ultimately lead to killing of NCE at final stage. Numerous techniques are being explored including nanocrystals for solubility enhancement purposes. Nanocrystals are the most successful and the ones which had a shorter gap between invention and subsequent commercialization of the first marketed product. Several nanocrystal-based products are commercially available and there is a paradigm shift in using approach from simply being solubility enhancement technique to more novel and specific applications. Some other aspects in relation to parenteral nanosuspensions are concentrations of surfactant to be used, scalability and in vivo fate. At present, there exists a wide gap due to poor understanding of these critical factors, which we have tried to address in this review. This review will focus on parenteral nanosuspensions, covering varied aspects especially stabilizers used, GRAS (Generally Recognized as Safe) status of stabilizers, scalability challenges, issues of physical and chemical stability, solidification techniques to combat stability problems and in vivo fate.