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European Journal of Pharmaceutics and... Jul 2024Peptides, despite their therapeutic potential, face challenges with undesirable pharmacokinetic (PK) properties and biodistribution, including poor oral absorption and...
Peptides, despite their therapeutic potential, face challenges with undesirable pharmacokinetic (PK) properties and biodistribution, including poor oral absorption and cellular uptake, and short plasma elimination half-lives. Lipidation of peptides is a common strategy to improve their physicochemical and PK properties, making them viable drug candidates. For example, the plasma half-life of peptides has been extended via conjugation to lipids that are proposed to promote binding to serum albumin and thus protect against rapid clearance. Recent work has shown that lipid conjugation to oligodeoxynucleotides, polymers and small molecule drugs results in association not only with albumin, but also with lipoproteins, resulting in half-life prolongation and transport from administration sites via the lymphatics. Enhancing delivery into the lymph increases the efficacy of vaccines and therapeutics with lymphatic targets such as immunotherapies. In this study, the plasma PK, lymphatic uptake, and bioavailability of the glucagon-like peptide-1 (GLP-1) receptor agonist peptides, liraglutide (lipidated) and exenatide (non-lipidated), were investigated following subcutaneous (SC) administration to rats. As expected, liraglutide displayed an apparent prolonged plasma half-life (9.1 versus 1 h), delayed peak plasma concentrations and lower bioavailability (∼10 % versus ∼100 %) compared to exenatide after SC administration. The lymphatic uptake of both peptides was relatively low (<0.5 % of the dose) although lymph to plasma concentration ratios were greater than one for several early timepoints suggesting some direct uptake into lymph. The low lymphatic uptake may be due to the nature of the conjugated lipid (a single-chain C16 palmitic acid in liraglutide) but suggests that other peptides with similar lipid conjugations may also have relatively modest lymphatic uptake. If delivery to the lymph is desired, conjugation to more lipophilic moieties with higher albumin and/or lipoprotein binding efficiencies, such as diacylglycerols, may be appropriate.
Topics: Animals; Exenatide; Liraglutide; Rats; Male; Peptides; Rats, Sprague-Dawley; Lipids; Half-Life; Venoms; Biological Availability; Tissue Distribution; Injections, Subcutaneous; Lymph; Glucagon-Like Peptide-1 Receptor; Glucagon-Like Peptide 1; Lymphatic System; Hypoglycemic Agents
PubMed: 38789061
DOI: 10.1016/j.ejpb.2024.114339 -
European Journal of Nuclear Medicine... May 2024The advancement of heterodimeric tracers, renowned for their high sensitivity, marks a significant trend in the development of radiotracers for cancer diagnosis. Our...
PURPOSE
The advancement of heterodimeric tracers, renowned for their high sensitivity, marks a significant trend in the development of radiotracers for cancer diagnosis. Our prior work on [Ga]Ga-HX01, a heterodimeric tracer targeting CD13 and integrin αβ, led to its approval for phase I clinical trials by the China National Medical Production Administration (NMPA). However, its fast clearance and limited tumor retention pose challenges for broader clinical application in cancer treatment. This study aims to develop a new radiopharmaceutical with increased tumor uptake and prolonged retention, rendering it a potential therapeutic candidate.
METHODS
New albumin binder-conjugated compounds were synthesized based on the structure of HX01. In vitro and in vivo evaluation of these new compounds were performed after labelling with Ga. Small-animal PET/CT imaging were conducted at different time points at 0.5-6 h post injection (p.i.) using BxPC-3 xenograft mice models. The one with the best imaging performance was further radiolabeled with Lu for small-animal SPECT/CT and ex vivo biodistribution investigation.
RESULTS
We have synthesized novel albumin binder-conjugated compounds, building upon the structure of HX01. When radiolabeled with Ga, all compounds demonstrated improved pharmacokinetics (PK). Small-animal PET/CT studies revealed that these new albumin binder-conjugated compounds, particularly [Ga]Ga-L6, exhibited significantly enhanced tumor accumulation and retention compared with [Ga]Ga-L0 without an albumin binder. [Ga]Ga-L6 outperformed [Ga]Ga-L7, a compound developed using a previously reported albumin binder. Furthermore, [Lu]Lu-L6 demonstrated rapid clearance from normal tissues, high tumor uptake, and prolonged retention in small-animal SPECT/CT and biodistribution studies, positioning it as an ideal candidate for radiotherapeutic applications.
CONCLUSION
A new integrin αβ and CD13 targeting compound was screened out. This compound bears a novel albumin binder and exhibits increased tumor uptake and prolonged tumor retention in BxPC-3 tumors and low background in normal organs, making it a perfect candidate for radiotherapy when radiolabeled with Lu.
PubMed: 38787395
DOI: 10.1007/s00259-024-06766-y -
BMC Gastroenterology May 2024Intussusception presents a significant emergency that often necessitates bowel resection, leading to severe complications and management challenges. This study aims to...
BACKGROUND
Intussusception presents a significant emergency that often necessitates bowel resection, leading to severe complications and management challenges. This study aims to investigate and establish a scoring system to enhance the prediction of bowel resection necessity in pediatric intussusception patients.
METHODS
This retrospective study analyzed 660 hospitalized patients with intussusception who underwent surgical management at a pediatric hospital in Southwest China from April 2008 to December 2020. The necessity of bowel resection was assessed and categorized in this cohort. Variables associated with bowel resection were examined using univariate and multivariate logistic regression analyses. Based on these analyses, a scoring system was developed, grounded on the summation of the coefficients (β).
RESULTS
Among the 660 patients meeting the inclusion criteria, 218 required bowel resection during surgery. Bowel resection occurrence was linked to an extended duration of symptoms (Odds Ratio [OR] = 2.14; 95% Confidence Interval [CI], 1.03-5.23; P = 0.0015), the presence of gross bloody stool (OR = 8.98; 95% CI, 1.76-48.75, P < 0.001), elevated C-reactive protein levels (OR = 4.79; 95% CI, 1.12-28.31, P = 0.0072), lactate clearance rate (LCR) (OR = 17.25; 95% CI, 2.36-80.35; P < 0.001), and the intussusception location (OR = 12.65; 95% CI, 1.46-62.67, P < 0.001), as determined by multivariate logistic regression analysis. A scoring system (totaling 14.02 points) was developed from the cumulative β coefficients, with a threshold of 5.22 effectively differentiating infants requiring surgical intervention from others with necrotizing enterocolitis (NEC), exhibiting a sensitivity of 78.3% and a specificity of 71.9%.
CONCLUSIONS
This study successfully identified multiple risk factors for bowel resection and effectively used a scoring system to identify patients for optimal clinical management.
Topics: Humans; Intussusception; Retrospective Studies; Male; Female; Infant; Child, Preschool; China; C-Reactive Protein; Digestive System Surgical Procedures; Logistic Models; Child; Risk Factors
PubMed: 38778288
DOI: 10.1186/s12876-024-03243-6 -
Antimicrobial Agents and Chemotherapy May 2024The aim of this study was to analyze the population pharmacokinetics of total and unbound concentrations of prophylactic cefazolin (CFZ) in patients with prostatectomy...
Population pharmacokinetics and pharmacodynamic target attainment analysis of cefazolin using total and unbound serum concentration in patients with prostatectomy or nephrectomy.
The aim of this study was to analyze the population pharmacokinetics of total and unbound concentrations of prophylactic cefazolin (CFZ) in patients with prostatectomy or nephrectomy. We also aimed to calculate a pharmacodynamics target unbound concentration that exceeded the minimum inhibitory concentration (MIC), to design an effective dosing regimen. Briefly, 614 total concentration and 610 unbound concentration samples from 152 individuals were evaluated, using a nonlinear mixed-effects model. The obtained pharmacodynamics index target value reflected the probability of maintaining CFZ unbound trough concentrations exceeding MIC, 0.5 mg/L, and MIC, and 1.0 mg/L, to account for methicillin-susceptible (MSSA) or . Population pharmacokinetics were estimated using a two-compartment model with nonlinear protein binding. Unbound systemic clearance (CL) was significantly associated with creatinine clearance, while the maximum protein-binding constant was significantly associated with albumin levels. The probability of achieving an unbound concentration exceeding the MIC for or MIC for MSSA in a patient with normal renal function following a 1 g CFZ infusion over 15 min was above 90% at 3 h after the initial dose. Our findings indicated that population pharmacokinetic parameters are useful for determining unbound CFZ pharmacokinetics and evaluating intraoperative CFZ redosing intervals.
PubMed: 38771029
DOI: 10.1128/aac.00267-24 -
Antimicrobial Agents and Chemotherapy May 2024Ravidasvir (RDV) is a novel NS5A inhibitor that exhibits potent pan-genotypic inhibition of hepatitis C virus (HCV) replication. Sofosbuvir (SOF) plus RDV was...
Ravidasvir (RDV) is a novel NS5A inhibitor that exhibits potent pan-genotypic inhibition of hepatitis C virus (HCV) replication. Sofosbuvir (SOF) plus RDV was demonstrated to be efficacious and safe in adults with active HCV infection, including those living with HIV (LWHIV), in the STORM-C-1 trial. We assessed the population pharmacokinetics (PK) of RDV in a sub-study nested within STORM-C-1 conducted in Thailand and Malaysia. SOF (400 mg) plus RDV (200 mg) was administered orally once daily for 12 weeks to adults with chronic HCV infection, but without cirrhosis and for 24 weeks to those with compensated cirrhosis. Intensive and sparse PK samples were collected at 4, 8, and 12 weeks after treatment initiation. Population PK parameters of RDV and the impact of covariates were evaluated using nonlinear mixed-effects modeling. Five hundred ninety-four participants were included, 235 (40%) had compensated cirrhosis, and 189 (32%) were LWHIV. RDV plasma concentrations were best described by a two-compartment model with first-order elimination. Oral clearance (CL/F) and volume of distribution (Vd/F) parameters were allometrically scaled on fat-free mass. Concomitant antiretroviral treatment (ART) increased RDV CL/F by 30%-60%, with efavirenz-based ART having the largest impact. Females had 16% lower RDV CL/F than males, and higher albumin levels reduced RDV central volume of distribution. While several covariates impact RDV CL/F and Vd/F, the effect on RDV exposures was not clinically relevant based on the efficacy data reported in this diverse Asian adult population. There were no meaningful drug-drug interactions in adults LWHIV on ART.
PubMed: 38767383
DOI: 10.1128/aac.00008-24 -
Colloids and Surfaces. B, Biointerfaces Jul 2024Delamanid is an anti-tuberculosis drug used for the treatment of drug-resistant tuberculosis. Since delamanid has a high protein bound potential, even patients with low...
Evaluating the biomolecular interaction between delamanid/formulations and human serum albumin by fluorescence, CD spectroscopy and SPR: Effects on protein conformation, kinetic and thermodynamic parameters.
Delamanid is an anti-tuberculosis drug used for the treatment of drug-resistant tuberculosis. Since delamanid has a high protein bound potential, even patients with low albumin levels should experience high and rapid delamanid clearance. However, the interaction between delamanid and albumin should be better controlled to optimize drug efficacy. This study was designed to evaluate the binding characteristics of delamanid to human serum albumin (HSA) using various methods: fluorescence spectroscopy, circular dichroism (CD), surface plasmon resonance (SPR), and molecular docking simulation. The fluorescence emission band without any shift indicated the interaction was not affected by the polarity of the fluorophore microenvironment. The reduction of fluorescence intensity at 344 nm was proportional to the increment of delamanid concentration as a fluorescence quencher. UV-absorbance measurement at the maximum wavelength (λ, 280 nm) was evaluated using inner filter effect correction. The HSA conformation change was explained by the intermolecular energy transfer between delamanid and HSA during complex formation. The study, which was conducted at temperatures of 298 K, 303 K, and 310 K, revealed a static quenching mechanism that correlated with a decreased of bimolecular quenching rate constant (kq) and binding constant (Ka) at increased temperatures. The Ka was 1.75-3.16 × 10 M with a specific binding site with stoichiometry 1:1. The negative enthalpy change, negative entropy change, and negative Gibbs free energy change demonstrated an exothermic-spontaneous reaction while van der Waals forces and hydrogen bonds played a vital role in the binding. The molecular displacement approach and molecular docking confirmed that the binding occurred mainly in subdomain IIA, which is a hydrophobic pocket of HSA, with a theoretical binding free energy of -9.33 kcal/mol. SPR exhibited a real time negative sensorgram that resulted from deviation of the reflex angle due to ligand delamanid-HSA complex forming. The binding occurred spontaneously after delamanid was presented to the HSA surface. The SPR mathematical fitting model revealed that the association rate constant (k) was 2.62 × 10 sM and the dissociation rate constant (k) was 5.65 × 10 s. The complexes were performed with an association constant (K) of 4.64 × 10 M and the dissociation constant (K) of 2.15 × 10 M. The binding constant indicated high binding affinity and high stability of the complex in an equilibrium. Modified CD spectra revealed that conformation of the HSA structure was altered by the presence of delamanid during preparation of the proliposomes that led to the reduction of secondary structure stabilization. This was indicated by the percentage decrease of α-helix. These findings are beneficial to understanding delamanid-HSA binding characteristics as well as the drug administration regimen.
Topics: Humans; Thermodynamics; Serum Albumin, Human; Kinetics; Molecular Docking Simulation; Spectrometry, Fluorescence; Circular Dichroism; Surface Plasmon Resonance; Protein Conformation; Protein Binding; Oxazoles
PubMed: 38761495
DOI: 10.1016/j.colsurfb.2024.113964 -
ACS Pharmacology & Translational Science May 2024The calcium sensing receptor (CaSR) is a ubiquitously expressed G-protein coupled receptor (GPCR) that regulates extracellular calcium signals the parathyroid glands....
The calcium sensing receptor (CaSR) is a ubiquitously expressed G-protein coupled receptor (GPCR) that regulates extracellular calcium signals the parathyroid glands. CaSR has recently also been implicated in noncalcitropic pathophysiologies like asthma, gut inflammation, and cancer. To date, molecular tools that enable the bioimaging of CaSR in tissues are lacking. Based on analyses of available structure-activity relationship data on CaSR ligands, we designed and prepared silicon-rhodamine (SiR) conjugates of the clinically approved drug evocalcet. The new probes EvoSiR4 and EvoSiR6, with differing linker lengths at the evocalcet carboxyl end, both showed a 6-fold and 3-fold increase in potency toward CaSR (EC < 45 nM) compared to evocalcet and the evocalcet-linker conjugate, respectively, in an FLIPR-based cellular functional assay. The specificity of the EvoSiR probes toward CaSR binding and the impact of albumin was evaluated in live cell experiments. Both probes showed strong albumin binding, which facilitated the clearance of nonspecific binding interactions. Accordingly, in zebrafish embryos, EvoSiR4 specifically labeled the high CaSR expressing neuromasts of the lateral line . EvoSiR4 was also assessed in human parathyroid tissues , showing a specific absolute CaSR-associated fluorescence compared to that of parathyroid autofluorescence. In summary, functionalization of evocalcet by SiR led to the preparation of potent and specific fluorescent CaSR probes. EvoSiR4 is a versatile small-molecular probe that can be employed in CaSR-related biomedical analyses where antibodies are not applicable.
PubMed: 38751613
DOI: 10.1021/acsptsci.4c00096 -
Mycotoxin Research May 2024Ochratoxin A (OTA) is known to be strongly bound to serum albumin, but it remains unknown how albumin affects its metabolism and kinetics. To close this gap, we used a...
Ochratoxin A (OTA) is known to be strongly bound to serum albumin, but it remains unknown how albumin affects its metabolism and kinetics. To close this gap, we used a mouse model, where heterozygous albumin deletion reduces serum albumin to concentrations similar to hypoalbuminemic patients and completely eliminates albumin by a homozygous knockout. OTA and its potential metabolites (OTα, 4-OH-OTA, 7'-OH-OTA, OTHQ, OP-OTA, OTB-GSH, OTB-NAC, OTB) were time-dependently analyzed in plasma, bile, and urine by LC-MS/MS and were compared to previously published hepatotoxicity and nephrotoxicity data. Homozygous albumin deletion strongly accelerated plasma clearance as well as biliary and urinary excretion of the parent compound and its hydroxylation products. Decreasing albumin in mice by the heterozygous and even more by the homozygous knockout leads to an increase in the parent compound in urine which corresponded to increased nephrotoxicity. The role of albumin in OTA-induced hepatotoxicity is more complex, since heterozygous but not homozygous nor wild-type mice showed a strong biliary increase in the toxic open lactone OP-OTA. Correspondingly, OTA-induced hepatotoxicity was higher in heterozygous than in wild-type and homozygous animals. We present evidence that albumin-mediated retention of OTA in hepatocytes is required for formation of the toxic OP-OTA, while complete albumin elimination leads to rapid biliary clearance of OTA from hepatocytes with less formation of OP-OTA. In conclusion, albumin has a strong influence on metabolism and toxicity of OTA. In hypoalbuminemia, the parent OTA is associated with increased nephrotoxicity and the open lactone with increased hepatotoxicity.
PubMed: 38743341
DOI: 10.1007/s12550-024-00538-1 -
Molecular Pharmaceutics Jun 2024There is considerable interest in quantifying anti-PEG antibodies, given their potential involvement in accelerated clearance, complement activation, neutralization, and...
There is considerable interest in quantifying anti-PEG antibodies, given their potential involvement in accelerated clearance, complement activation, neutralization, and acute reactions associated with drug delivery systems. Published and commercially available anti-PEG enzyme-linked immunosorbent assays (ELISAs) differ significantly in terms of reagents and conditions, which could be confusing to users who want to perform in-house measurements. Here, we optimize the ELISA protocol for specific detection of anti-PEG IgG and IgM in sera from healthy donors and in plasma from cancer patients administered with PEGylated liposomal doxorubicin. The criterion of specificity is the ability of free PEG or PEGylated liposomes to inhibit the ELISA signals. We found that coating high-binding plates with monoamine methoxy-PEG, as opposed to bovine serum albumin-PEG, and blocking with 1% milk, as opposed to albumin or lysozyme, significantly improve the specificity, with over 95% of the signal being blocked by competition. Despite inherent between-assay variability, setting the cutoff value of the optical density at the 80th percentile consistently identified the same subjects. Using the optimized assay, we longitudinally measured levels of anti-PEG IgG/IgM in cancer patients before and after the PEGylated liposomal doxorubicin chemotherapy cycle (1 month apart, three cycles total). Antibody titers did not show any increase but rather a decrease between treatment cycles, and up to 90% of antibodies was bound to the infused drug. This report is a step toward harmonizing anti-PEG assays in human subjects, emphasizing the cost-effectiveness and optimized specificity.
Topics: Humans; Doxorubicin; Polyethylene Glycols; Enzyme-Linked Immunosorbent Assay; Immunoglobulin G; Immunoglobulin M; Female; Male; Adult; Middle Aged; Liposomes; Neoplasms
PubMed: 38743264
DOI: 10.1021/acs.molpharmaceut.4c00278 -
Molecular Pharmaceutics Jun 2024One of the most significant reasons hindering the clinical translation of nanomedicines is the rapid clearance of intravenously injected nanoparticles by the mononuclear...
One of the most significant reasons hindering the clinical translation of nanomedicines is the rapid clearance of intravenously injected nanoparticles by the mononuclear phagocyte system, particularly by Kupffer cells in the liver, leading to an inefficient delivery of nanomedicines for tumor treatment. The threshold theory suggests that the liver's capacity to clear nanoparticles is limited, and a single high dose of nanoparticles can reduce the hepatic clearance efficiency, allowing more nanomedicines to reach tumor tissues and enhance therapeutic efficacy. Building upon this theory, researchers have conducted numerous validation studies based on the same nanoparticle carrier systems. These studies involve the use of albumin nanoparticles to improve the therapeutic efficacy of albumin nanomedicines as well as polyethylene glycol (PEG)-modified liposomal nanoparticles to enhance the efficacy of PEGylated liposomal nanomedicines. However, there is no research indicating the feasibility of the threshold theory when blank nanoparticles and nanomedicine belong to different nanoparticle carrier systems currently. In this study, we prepared two different sizes of albumin nanoparticles by using bovine serum albumin. We used the marketed nanomedicine liposomal doxorubicin hydrochloride injection (trade name: LIBOD, manufacturer: Shanghai Fudan-zhangjiang Biopharmaceutical Co., Ltd.), as the representative nanomedicine. Through in vivo experiments, we found that using threshold doses of albumin nanoparticles still can reduce the clearance rate of LIBOD, prolong its time in vivo, increase the area under the plasma concentration-time curve (AUC), and also lead to an increased accumulation of the drug at the tumor site. Furthermore, evaluation of in vivo efficacy and safety further indicates that threshold doses of 100 nm albumin nanoparticles can enhance the antitumor effect of LIBOD without causing harm to the animals. During the study, we found that the particle size of albumin nanoparticles influenced the in vivo distribution of the nanomedicine at the same threshold dose. Compared with 200 nm albumin nanoparticles, 100 nm albumin nanoparticles more effectively reduce the clearance efficiency of LIBOD and enhance nanomedicine accumulation at the tumor site, warranting further investigation. This study utilized albumin nanoparticles to reduce hepatic clearance efficiency and enhance the delivery efficiency of nonalbumin nanocarrier liposomal nanomedicine, providing a new avenue to improve the efficacy and clinical translation of nanomedicines with different carrier systems.
Topics: Doxorubicin; Animals; Nanoparticles; Polyethylene Glycols; Mice; Liposomes; Serum Albumin, Bovine; Tissue Distribution; Antibiotics, Antineoplastic; Mice, Inbred BALB C; Liver; Particle Size; Nanomedicine; Humans; Male; Female
PubMed: 38742943
DOI: 10.1021/acs.molpharmaceut.4c00097