Development of an Accelerated Rotator-based Drug Release Method for the Evaluation of Bupivacaine Multivesicular Liposomes.

PURPOSE: A multivesicular liposome (MVL) is a liposomal vehicle designed to achieve sustained release characteristics for drugs with short half-lives. For example, a commercial MVL formulation of bupivacaine has been approved by the U.S. Food and Drug Administration for local and regional analgesia. For complex formulations like those containing MVLs, challenges in developing an in vitro release testing (IVRT) method may hinder generic development and regulatory approval. In this study, we developed an accelerated rotator-based IVRT method with the ability to discriminate bupivacaine MVLs with different quality attributes. METHODS: Three IVRT experimental setups including mesh tube, horizontal shaker, and vertical rotator were screened to ensure that at least 50% of bupivacaine can release from MVLs in 24 h. Sample dilution factors, incubation temperature, and the release media pH were optimized for the IVRT. The reproducibility of the developed IVRT method was validated with commercial bupivacaine MVLs. The discriminative capacity was assessed via comparing commercial and compromised bupivacaine MVL formulations. RESULTS: The rotator-based release setup was chosen due to the capability to obtain 70% of drug release within 24 h. The optimized testing conditions were chosen with a 50-fold dilution factor, a temperature of 37ºC, and a media pH of 7.4. CONCLUSIONS: An accelerated rotator-based IVRT method for bupivacaine MVLs was developed in this study, with the discriminatory ability to distinguish between formulations of different qualities. The developed IVRT method was a robust tool for generic development of MVL based formulations.

Fragile Watermark in Medical Image Based on Prime Number Distribution Theory.

The research of medical image in the field of anti-counterfeiting and authentication plays a crucial role in the development of hospital digitization. In this paper, a new fragile medical watermarking scheme is proposed using the prime number distribution theorem, chaotic mapping, and Hash. Firstly, an approximate pixel set is constructed according to the distribution of prime numbers, and then the parity of the pixel value is re-granted with chaotic mapping, and Hash. The embedding and extraction of the watermark are done by using logical operations to adjust the pixel value according to the parity of the pixel value and the number of prime numbers contained in the pixel value. The experimental results demonstrate that the proposed scheme is imperceptible, efficient, and safe. Compared with the existing methods, the proposed scheme achieves the binding of medical image and patient information, as well as exhibits excellent detection and positioning capability, and will have good application prospects in medical image content authentication and tampering detection.

Phospholipid Component Defines Pharmacokinetic and Pharmacodynamic Properties of Synthetic High-Density Lipoproteins.

Synthetic high-density lipoprotein (sHDL) nanoparticles composed of apolipoprotein A-I mimetic peptide and phospholipids have been shown to reduce atherosclerosis in animal models. Cholesterol is mobilized from atheroma macrophages by sHDL into the blood compartment and delivered to the liver for elimination. Historically, sHDL drug discovery efforts were focused on optimizing peptide sequences for interaction with cholesterol cellular transporters rather than understanding how both sHDL components, peptide and lipid, influence its pharmacokinetic and pharmacodynamic profiles. We designed two sets of sHDL having either identical phospholipid but variable peptide sequences with different plasma stability or identical peptide and phospholipids with variable fatty acid chain length and saturation. We found that sHDL prepared with proteolytically stable 22A-P peptide had 2-fold longer circulation half-time relative to the less stable 22A peptide. Yet, longer half-life did not translate into any improvement in cholesterol mobilization. In contrast, sHDL with variable phospholipid compositions showed significant differences in phospholipid PK, with distearoyl phosphatidylcholine-based sHDL demonstrating the longest half-life of 6.0 hours relative to 1.0 hour for palmitoyl-oleoyl phosphatidylcholine-based sHDL. This increase in half-life corresponded to an approx. 6.5-fold increase in the area under the curve for the mobilized cholesterol. Therefore, the phospholipid component in sHDL plays a major role in cholesterol mobilization in vivo and should not be overlooked in the design of future sHDL. SIGNIFICANCE STATEMENT: The phospholipid composition in sHDL plays a critical role in determining half-life and cholesterol mobilization in vivo.

Development and optimization of an in vitro release assay for evaluation of liposomal irinotecan formulation.

Onivyde®, a pegylated irinotecan liposomal formulation, is approved by the USFDA for treating metastatic pancreatic adenocarcinoma. Despite the substantial interest in developing its generic versions, the unique structural and manufacturing complexities of liposomal formulations pose challenges. In this study, we address this gap by developing a robust in vitro release test (IVRT) using dialysis membrane techniques. The release of Onivyde® is influenced by several key factors, including the composition of the release medium, temperature, initial formulation concentration, the materials and molecular weight cut-offs of dialysis bags, and the pH of the release medium. Our optimized IVRT for Onivyde® incorporates a release medium containing 5 mM ammonium bicarbonate in a HEPES solution with a pH of 7.4. Additionally, the method includes an initial formulation concentration of 4.6 µg/mL and 50 kDa dialysis bags, while maintaining a temperature of 37 °C with continuous agitation at 80 rpm. This optimized IVR assay effectively differentiates between varying qualities of irinotecan liposomal formulations. Our findings contribute to optimizing IVRT for liposomal irinotecan formulations, enabling better quality control procedures. This assay serves as a reliable tool for evaluating generic irinotecan liposomal formulations, aiding in their development and ensuring in vitro comparability.

Characterization of exparel bupivacaine multivesicular liposomes.

Exparel is a bupivacaine multivesicular liposomes (MVLs) formulation developed based on the DepoFoam technology. The complex composition and the unique structure of MVLs pose challenges to the development and assessment of generic versions. In the present work, we developed a panel of analytical methods to characterize Exparel with respect to particle size, drug and lipid content, residual solvents, and pH. In addition, an accelerated in vitro drug release assay was developed using a rotator-facilitated, sample-and-separate experimental setup. The proposed method could achieve over 80% of bupivacaine release within 24 h, which could potentially be used for formulation comparison and quality control purposes. The batch-to-batch variability of Exparel was examined by the established analytical methods. Four different batches of Exparel showed good batch-to-batch consistency in drug content, particle size, pH, and in vitro drug release kinetics. However, slight variation in lipid contents were observed.

Phospholipids impact the protective effects of HDL-mimetic nanodiscs against lipopolysaccharide-induced inflammation.

Aim: The impacts of synthetic high-density lipoprotein (sHDL) phospholipid components on anti-sepsis effects were investigated. Methods: sHDL composed with ApoA-I mimetic peptide (22A) and different phosphatidylcholines were prepared and characterized. Anti-inflammatory effects were investigated in vitro and in vivo on lipopolysaccharide (LPS)-induced inflammation models. Results: sHDLs composed with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (22A-DMPC) most effectively neutralizes LPS, inhibits toll-like receptor 4 recruitment into lipid rafts, suppresses nuclear factor κB signaling and promotes activating transcription factor 3 activating. The lethal endotoxemia animal model showed the protective effects of 22A-DMPC. Conclusion: Phospholipid components affect the stability and fluidity of nanodiscs, impacting the anti-septic efficacy of sHDLs. 22A-DMPC presents the strongest LPS binding and anti-inflammatory effects in vitro and in vivo, suggesting a potential sepsis treatment.

Sepsis is triggered by endotoxins released by bacteria. These endotoxins trigger an exaggerated inflammatory response, leading to widespread inflammation and organ damage. Synthetic high-density lipoprotein (sHDL) is a potential treatment of sepsis by neutralizing endotoxins and regulating inflammatory responses. The phospholipid components of sHDL may affect the effectiveness of sHDL against sepsis. In this study, we prepared sHDLs with different phospholipids and compared their anti-septic effects on cells and in animal models. We found that sHDL made from DMPC presented the best anti-septic effects, possibly because DMPC-sHDL had the best fluidity at body temperature.

Zinc Finger MYND-Type Containing 8 (ZMYND8) Is Epigenetically Regulated in Mutant Isocitrate Dehydrogenase 1 (IDH1) Glioma to Promote Radioresistance.

PURPOSE: Mutant isocitrate dehydrogenase 1 (mIDH1) alters the epigenetic regulation of chromatin, leading to a hypermethylation phenotype in adult glioma. This work focuses on identifying gene targets epigenetically dysregulated by mIDH1 to confer therapeutic resistance to ionizing radiation (IR). EXPERIMENTAL DESIGN: We evaluated changes in the transcriptome and epigenome in a radioresistant mIDH1 patient-derived glioma cell culture (GCC) following treatment with an mIDH1-specific inhibitor, AGI-5198. We identified Zinc Finger MYND-Type Containing 8 (ZMYND8) as a potential target of mIDH1 reprogramming. We suppressed ZMYND8 expression by shRNA knockdown and genetic knockout (KO) in mIDH1 glioma cells and then assessed cellular viability to IR. We assessed the sensitivity of mIDH1 GCCS to pharmacologic inhibition of ZMYND8-interacting partners: HDAC, BRD4, and PARP. RESULTS: Inhibition of mIDH1 leads to an upregulation of gene networks involved in replication stress. We found that the expression of ZMYND8, a regulator of DNA damage response, was decreased in three patient-derived mIDH1 GCCs after treatment with AGI-5198. Knockdown of ZMYND8 expression sensitized mIDH1 GCCs to radiotherapy marked by decreased cellular viability. Following IR, mIDH1 glioma cells with ZMYND8 KO exhibit significant phosphorylation of ATM and sustained γH2AX activation. ZMYND8 KO mIDH1 GCCs were further responsive to IR when treated with either BRD4 or HDAC inhibitors. PARP inhibition further enhanced the efficacy of radiotherapy in ZMYND8 KO mIDH1 glioma cells. CONCLUSIONS: These findings indicate the impact of ZMYND8 in the maintenance of genomic integrity and repair of IR-induced DNA damage in mIDH1 glioma. See related commentary by Sachdev et al., p. 1648.

Clinical Efficacy of ONC201 in H3K27M-Mutant Diffuse Midline Gliomas Is Driven by Disruption of Integrated Metabolic and Epigenetic Pathways.

Patients with H3K27M-mutant diffuse midline glioma (DMG) have no proven effective therapies. ONC201 has recently demonstrated efficacy in these patients, but the mechanism behind this finding remains unknown. We assessed clinical outcomes, tumor sequencing, and tissue/cerebrospinal fluid (CSF) correlate samples from patients treated in two completed multisite clinical studies. Patients treated with ONC201 following initial radiation but prior to recurrence demonstrated a median overall survival of 21.7 months, whereas those treated after recurrence had a median overall survival of 9.3 months. Radiographic response was associated with increased expression of key tricarboxylic acid cycle-related genes in baseline tumor sequencing. ONC201 treatment increased 2-hydroxyglutarate levels in cultured H3K27M-DMG cells and patient CSF samples. This corresponded with increases in repressive H3K27me3 in vitro and in human tumors accompanied by epigenetic downregulation of cell cycle regulation and neuroglial differentiation genes. Overall, ONC201 demonstrates efficacy in H3K27M-DMG by disrupting integrated metabolic and epigenetic pathways and reversing pathognomonic H3K27me3 reduction. SIGNIFICANCE: The clinical, radiographic, and molecular analyses included in this study demonstrate the efficacy of ONC201 in H3K27M-mutant DMG and support ONC201 as the first monotherapy to improve outcomes in H3K27M-mutant DMG beyond radiation. Mechanistically, ONC201 disrupts integrated metabolic and epigenetic pathways and reverses pathognomonic H3K27me3 reduction. This article is featured in Selected Articles from This Issue, p. 2293.

Immune and Metabolic Regulation Mechanism of Dangguiliuhuang Decoction against Insulin Resistance and Hepatic Steatosis.

Dangguiliuhuang decoction (DGLHD) is a traditional Chinese medicine (TCM) formula, which mainly consists of angelica, radix rehmanniae, radix rehmanniae praeparata, scutellaria baicalensis, coptis chinensis, astragalus membranaceus, and golden cypress, and used for the treatment of diabetes and some autoimmune diseases. In this study, we explored the potential mechanism of DGLHD against insulin resistance and fatty liver in vivo and in vitro. Our data revealed that DGLHD normalized glucose and insulin level, increased the expression of adiponectin, diminished fat accumulation and lipogenesis, and promoted glucose uptake. Metabolomic analysis also demonstrated that DGLHD decreased isoleucine, adenosine, and cholesterol, increased glutamine levels in liver and visceral adipose tissue (VAT) of ob/ob mice. Importantly, DGLHD promoted the shift of pro-inflammatory to anti-inflammatory cytokines, suppressed T lymphocytes proliferation, and enhanced regulatory T cells (Tregs) differentiation. DGLHD also inhibited dendritic cells (DCs) maturation, attenuated DCs-stimulated T cells proliferation and secretion of IL-12p70 cytokine from DCs, and promoted the interaction of DCs with Tregs. Further studies indicated that the changed PI3K/Akt signaling pathway and elevated PPAR-γ expression were not only observed with the ameliorated glucose and lipid metabolism in adipocytes and hepatocytes, but also exhibited in DCs and T cells by DGLHD. Collectively, our results suggest that DGLHD exerts anti-insulin resistant and antisteatotic effects by improving abnormal immune and metabolic homeostasis. And DGLHD may be a novel approach to the treatment of obesity-related insulin resistance and hepatic steatosis.