Effective Concentration Range Research Articles

Target concentration achievement for efficacy and safety of patients with osteosarcoma treated with high-dose methotrexate based on individual pharmacokinetics: A retrospective study.

In the high-dose methotrexate (HD-MTX) treatment of patients with osteosarcoma, a dose-adjustment method using individual pharmacokinetic parameters (PK method) to optimize the concentration was developed in 2010. However, to the best of our knowledge, the clinical usefulness of the PK method has not been verified until now. In the present retrospective study, to assess the usefulness of the PK method, the achievement rate of an effective and safe concentration range was evaluated. A total of 43 patients with osteosarcoma who were administered HD-MTX therapy (43 first courses and 200 subsequent courses) were enrolled. The MTX dose in the first course was determined using a common method based on body surface area (BSA method); a total of 8-12 g/m2 was administered as an initial dose for 1 h and a maintenance dose for 5 h. In the subsequent courses, loading and maintenance doses were calculated by the PK method based on the serum MTX concentration profile of the previous course. The effective target concentration during 1-6 h after the start of MTX administration was 700-1,000 µmol/l, whereas the target safe MTX level was less than 10, 1 and 0.1 µmol/l at 24, 48 and 72 h, respectively. Notably, the rate of achieving the effective target concentration was significantly higher when using the PK method as compared to that when using the BSA method. The achievement rate of the safe target concentration at 24, 48 and 72 h when using the PK method was significantly higher. Additionally, the incidence of abnormal laboratory values of aspartate aminotransferase and alanine aminotransferase was significantly lower when using the PK method. Therefore, the PK method was suggested to be very useful in HD-MTX therapy for patients with osteosarcoma.

3D printed biodegradable multifunctional implants for effective breast cancer treatment

By carefully controlling the dose administered and the drug release rate from drug-eluting implants, safety and efficacy of the therapeutic agent dispensed can be improved. The present work focuses on the promising advantages of 3D Bioprinting process in developing two layers’ implantable scaffolds. The two layers have different functions, in order to ensure a more effective and synergistic breast cancer therapy. First layer involves use of polymers such as Poly- ε-Caprolactone (PCL) and Chitosan (CS), and incorporation of 5-Fluorouracil (5-FU). The aim of the first layer is releasing the drug within 4 weeks, obtaining a prolonged and modified release. According to in vitro drug release tests performed, ∼32 % of 5-FU was released after one month, after an initial burst effect of 17.22 %. The sudden release of the drug into the body would quickly reach an effective therapeutic concentration, while the drug sustained release maintains an effective therapeutic concentration range during the administration time. The second layer is made exclusively from PCL as polymeric matrix, into which Gold Nanoparticles (AuNPs) were subsequently loaded, and its main purpose is to be radiation enhancement. The long biodegradation time of PCL would make the non-soluble scaffold an alternative to conventional chemotherapy, optimizing drug release to the specific needs of the patients.

Nanostructured ZnO-Based Electrochemical Sensor with Anionic Surfactant for the Electroanalysis of Trimethoprim.

In this research, detection of trimethoprim (TMP) was carried out using a nanostructured zinc oxide nanoparticle-modified carbon paste electrode (ZnO/CPE) with an anionic surfactant and sodium dodecyl sulphate (SDS) with the help of voltametric techniques. The electrochemical nature of TMP was studied in 0.2 M pH 3.0 phosphate-buffer solution (PBS). The developed electrode displayed the highest peak current compared to nascent CPE. Effects of variation in different parameters, such as pH, immersion time, scan rate, and concentration, were investigated. The electrode process of TMP was irreversible and diffusion controlled with two electrons transferred. The effective concentration range (8.0 × 10−7 M–1.0 × 10−5 M) of TMP was obtained by varying the concentration with a lower limit of detection obtained to be 2.58 × 10−8 M. In addition, this approach was effectively employed in the detection of TMP in pharmaceutical dosages and samples of urine with the excellent recovery data, suggesting the potency of the developed electrode in clinical and pharmaceutical sample analysis.

Intravenous tocilizumab for the treatment of giant cell arteritis: a phase Ib dose-ranging pharmacokinetic bridging study

BackgroundSubcutaneous tocilizumab (TCZ SC) is approved globally for giant cell arteritis (GCA). This phase Ib study investigated the pharmacokinetics, pharmacodynamics, safety, and exploratory efficacy of intravenous (IV) TCZ 6 and 7 mg/kg in patients with GCA. This study explored an IV dose resulting in a minimum exposure level within the range of effective trough concentrations achieved with TCZ SC dosing in GCA and not exceeding the exposure of the well-tolerated 8 mg/kg IV every 4 weeks (Q4W) in rheumatoid arthritis (RA).MethodsPatients with GCA who had received ≥ 5 doses of TCZ IV 8 mg/kg Q4W and achieved remission were enrolled. Patients received 5 doses of TCZ IV 7 mg/kg Q4W in period 1 and, if still in remission, 5 doses of 6 mg/kg Q4W in period 2. Pharmacokinetic endpoints were maximum concentration (Cmax), minimum concentration (Ctrough), area under the curve over a dosing interval (AUCτ), and mean concentration (Cmean) of TCZ after the last dose of each period. Other endpoints included pharmacodynamic markers, safety, and exploratory efficacy.ResultsIn 24 patients, the median (range) age was 65.5 (57–90) years, and 62.5% were female. TCZ exposures (Cmax and AUCτ) were 11.2% and 20.0% lower at the 6- than 7-mg/kg dose. The mean interleukin 6 (IL-6) serum concentrations were elevated at baseline and remained elevated, with slightly higher concentrations in period 1 than in period 2. The mean serum soluble IL-6 receptor concentrations were elevated at baseline and comparable between the 2 doses at steady state. C-reactive protein levels and most erythrocyte sedimentation rates were within normal ranges throughout the study. Overall, 22 patients (91.7%) had ≥ 1 adverse event, and 4 (16.7%) had a serious adverse event. No patients experienced a GCA flare, and all remained in remission throughout the study.ConclusionsBoth doses of TCZ IV Q4W were generally well tolerated in patients with GCA. The Cmax and Cmean achieved with 6 mg/kg IV Q4W in patients with GCA were similar to those in patients with RA treated with 8 mg/kg IV Q4W, and Ctrough was within the range observed in patients with GCA treated with SC dosing every week or every 2 weeks.Trial registrationClinicalTrials.gov, NCT03923738

Caspofungin Cerebral Penetration and Therapeutic Efficacy in Experimental Cerebral Aspergillosis.

ABSTRACTDespite best available therapy, cerebral aspergillosis is an often-lethal complication of disseminated aspergillosis. There is an urgent need to expand the currently limited therapeutic options. In this study, we assessed cerebral drug exposure and efficacy of caspofungin (CAS) using a lethal infant rat model of cerebral aspergillosis. Eleven-day-old Wistar rats were infected by intracisternal injection of Aspergillus fumigatus conidia. Treatment started after 22 h and was continued for 10 days. Regimens were CAS 1 mg/kg/day intraperitoneally (i.p.), liposomal amphotericin B (L-AmB) 5 mg/kg/day i.p., and both drugs combined at the same dose i.p. Infected controls were given NaCl 0.85% i.p. Primary endpoints assessed were survival, cerebral fungal burden, galactomannan index, and drug concentrations in brain homogenate at 2, 3, 5, and 11 days after infection. Compared to those of controls (4.4 ± 2.7 days), survival times were increased by treatment with CAS alone (10.3 ± 1.7 days; P < 0.0001) and CAS combined with L-AmB (9.3 ± 2.8 days; P < 0.0001). In contrast, survival time of L-AmB-treated animals (4.3 ± 3.1 days) was not different from that of controls. Cerebral fungal burden and galactomannan index declined in all animals over time, without significant differences between controls and treated animals. CAS trough levels in brain tissue were between 0.84 and 1.4 μg/g, concentrations we show to be associated with efficacy. AmB trough levels in brain tissue were higher than the MIC of the A. fumigatus isolate. In summary, CAS concentrations in brain tissue suggest it may be therapeutically relevant and it significantly improved survival in this lethal model of cerebral aspergillosis in nonneutropenic rats. The clinical efficacy of CAS treatment for cerebral aspergillosis merits further study.IMPORTANCE Treatment options for cerebral aspergillosis, an often-lethal disease, are limited. The echinocandins (caspofungin is one of them) are not recommended treatment because their brain tissue penetration is often considered insufficient. In a nursing rat model of cerebral aspergillosis that mimics human disease, we found potentially therapeutically relevant concentrations of caspofungin in brain tissue and prolonged survival of caspofungin-treated animals. The efficacy of caspofungin in the treatment of cerebral aspergillosis documented here, if confirmed in other animal models (especially immunosuppressed murine models) and by using additional Aspergillus isolates across a range of CAS minimal effective concentrations (MECs), would suggest that caspofungin merits further study as a treatment option for patients suffering from aspergillosis disseminated to the brain.

Application of Porcine Kidney-Derived Extracellular Matrix as Coating, Hydrogel, and Scaffold Material for Renal Proximal Tubular Epithelial Cell.

Background Human renal proximal tubular epithelial (RPTE) cell is a very useful tool for kidney-related experiments in vitro/ex vivo. However, only a few primary RPTE cells can be obtained through kidney biopsy, the proliferation rate of primary cell is very low, and the cultured cell properties are easily altered in artificial conditions. Thus, RPTE cell usage is very tricky; we applied porcine kidney-derived extracellular matrix (renal ECM) as coating, hydrogel, and scaffold material to increase cell proliferation and maintain cellular properties providing three-dimensional (3D) niche, which can be a valuable cell delivery vehicle. Methods Porcine renal ECM was prepared by decellularization using 1% Triton X-100, solubilized with 0.5 M acetic acid. The final protein concentration was adjusted to 10 μg/μL (pH 7.0). The efficacies as coating, hydrogel, and scaffold materials were analyzed through cell morphology, proliferation rate, renal-associated gene expressions, chemical composition, and microstructure evaluation. The efficacies as a coating material were compared with Matrigel, collagen type 1 (col1), gelatin, fibrinogen, and thrombin. After confirmation of coating effects, the effective concentration range was decided. The efficacies as hydrogel and scaffold materials were compared with hyaluronic acid (HA) and col1, respectively. Results As the coating material, renal ECM showed a higher cell proliferation rate compared to other materials, except for Matrigel. Renal-associated gene expressions were significantly enhanced in the renal ECM than other materials. Coating effect on cell proliferation was dependent on the renal ECM concentration, and the effective concentration ranged from 30 to 100 μg. As the hydrogel material, renal ECM showed a distinct inner cell network morphology and significantly increased renal-associated gene expressions, compared to HA hydrogel. As the scaffold material, renal ECM showed specific amide peaks, enhanced internal porosity, cell proliferation rate, and renal-associated gene expression compared to the col1 scaffold. Conclusions We concluded that renal ECM can be a suitable material for RPTE cell culture and usage. More practically, the coated renal ECM stimulates RPTE cell proliferation, and the hydrogel and scaffold of renal ECM provide useful 3D culture niche and cell delivery vehicles maintaining renal cell properties.

Does toxicity test variability support bioavailability model predictions being within a factor of 2?

Environmental context Having appropriate and robust models used for developing water quality guidelines is critical for sound environmental management. Methods used to validate models have only been demonstrated appropriate for a small portion of data types used in these models. This study has found that models using certain data types would be more appropriately validated using alternative evaluation criteria. This study serves as an important reference for developing and evaluating robust models. Rationale Bioavailability-based toxicity models for metals often have performance assessed by whether it can predict toxicity data within a factor of 2 of their paired observed toxicity data. This method has only been verified for median effect values (EC50) for acute fish and daphnia data, however toxicity models have been developed for a much broader range of effect levels (i.e. EC10/EC20) and species (e.g. microalga). This study tested whether the factor-of-2 rule is appropriate for a wider range of organisms and effect concentrations than previously studied. Methodology Toxicity estimate data from repeated tests conducted under the same conditions were collated to assess variation in results and compare this variation to a range of 4 (a factor of 2 above and below the mean) and a range of 9 (a factor of 3 above and below the mean) to assess if a factor-of-3 rule may be more appropriate for some species and effect levels. Results and discussion Overall, the factor-of-2 rule is broadly applicable for metal toxicity to a range of species for EC50 data. The EC10 datasets highlighted that larger variability exists in low effect levels and supported the use of a factor-of-3 rule, while the either the factor-of-2 or factor-of-3 rule could be applied to microalgae. The level of performance evaluation chosen may depend on the application of the bioavailability model. This study also found that while repeated toxicity test data is routinely generated, it is rarely published. Publication of such data would enable expansion of the present study to include inter-laboratory comparisons, an important consideration as most bioavailability models are based on data pooled from multiple sources.

Classification of the Biodegradation Factors of Linear Alkylbenzene Sulfonate.

The conditions that significantly affect the biodegradability of linear alkylbenzene sulfonate (LAS) based on previous studies were categorized. Among these previous studies, we focused on those that used activated sludge and river water as inocula in biodegradation studies. Analyzing the results of these studies revealed two types of methylene blue active substances (MBAS) removal curves in primary biodegradation, and the study conditions that differentiated the two types were analyzed, along with verification studies. The effects of the LAS concentration and interfacial activity during biodegradation were analyzed to set the concentration of LAS in this study. Surface tension was measured as an indicator of interfacial activity and biodegradation was measured by oxygen demand. Two widely used surfactants, alcohol ethoxylate and sodium dodecyl sulfate, were evaluated to clarify the significance of the effective concentration range of LAS. The concentration of LAS was set at 10 or 20 mg/L in the verification study. Acclimatization and the concentration balance of LAS and river water were the strongest factors in studies using activated sludge and river water, respectively. Our classification chart may be helpful in analyzing and comparing the conditions of previous and current studies. Such understanding of the study conditions and practical evaluation may aid in avoiding misleading environmental impact assessments of LAS.

Bioprinted Cancer Model of Neuroblastoma in a Renal Microenvironment as an Efficiently Applicable Drug Testing Platform.

Development of new anticancer drugs with currently available animal models is hampered by the fact that human cancer cells are embedded in an animal-derived environment. Neuroblastoma is the most common extracranial solid malignancy of childhood. Major obstacles include managing chemotherapy-resistant relapses and resistance to induction therapy, leading to early death in very-high-risk patients. Here, we present a three-dimensional (3D) model for neuroblastoma composed of IMR-32 cells with amplified genes of the myelocytomatosis viral related oncogene MYCN and the anaplastic lymphoma kinase (ALK) in a renal environment of exclusively human origin, made of human embryonic kidney 293 cells and primary human kidney fibroblasts. The model was produced with two pneumatic extrusion printheads using a commercially available bioprinter. Two drugs were exemplarily tested in this model: While the histone deacetylase inhibitor panobinostat selectively killed the cancer cells by apoptosis induction but did not affect renal cells in the therapeutically effective concentration range, the peptidyl nucleoside antibiotic blasticidin induced cell death in both cell types. Importantly, differences in sensitivity between two-dimensional (2D) and 3D cultures were cell-type specific, making the therapeutic window broader in the bioprinted model and demonstrating the value of studying anticancer drugs in human 3D models. Altogether, this cancer model allows testing cytotoxicity and tumor selectivity of new anticancer drugs, and the open scaffold design enables the free exchange of tumor and microenvironment by any cell type.

Determination of Free Valproic Acid Concentration in 569 Clinical Samples by LC-MS/MS After Hollow Fiber Centrifugal Ultrafiltration Treatment.

To perform therapeutic drug monitoring of total and free plasma valproic acid (VPA) concentrations in clinical samples and to analyze the related factors. The total VPA concentration in plasma was determined by ultrahigh-performance liquid chromatography with precolumn derivatization with α-bromoacetophenone, and the free VPA concentration was determined by liquid chromatography-tandem mass spectrometry after the plasma was treated by hollow fiber centrifugal ultrafiltration. Regression analysis was performed to examine the associations between free plasma VPA, total plasma VPA, and the plasma protein binding rate. The impact of individual situations, outpatient or inpatient factors, and drug combinations on VPA concentrations were examined. Of the 569 clinical samples, 268 were inpatients and 301 were outpatients, and the total VPA concentration in 138 cases (24.2%) was lower than the effective treatment concentration range; the total and free VPA concentrations in outpatient samples were 11.0% and 26.1% higher than those of inpatients, respectively. There was no linear relationship between the free and total VPA concentrations. The relationship equation between the plasma protein binding rate and free VPA concentrations was as follows: Y = 0.0255X2 - 1.1357X + 97.429 (r = 0.8011). The total and free VPA concentrations were significantly decreased after the coadministration of phenobarbital (83.7% and 64.3% of the control group, P < 0.05) or carbapenem antibiotics (32.0% and 32.7% of the control group, P < 0.05). The total VPA concentrations in patients with epilepsy at our hospital was lower than the effective treatment concentration range, which was inadequate for epilepsy control; the total VPA concentrations of outpatients were higher than those of inpatients; as phenobarbital affects VPA metabolism, therapeutic drug monitoring is recommended. Carbapenem antibiotic coadministration with VPA should be avoided because carbapenem antibiotics can lead to the failure of VPA antiepileptic treatment.

Effects of valerate on intestinal barrier function in cultured Caco-2 epithelial cell monolayers.

Short-chain fatty acids (SCFAs) are a group of microbial metabolites of undigested dietary fiber, protein and unabsorbed amino acids in the colon, well-known for their gut health promoting benefits. A relatively high intestinal level of valerate was found in the healthy human subjects. However, the intestinal protection effects and the underlying mechanism of valerate are waiting to be verified and elucidated. In the present study, valerate, a SCFAs mainly converted from proteins or amino acids, was demonstrated to promote intestinal barrier function at its physiological concentrations of 0-4 mM in the Caco-2 cell monolayer model of intestinal barrier using transepithelial electrical resistance (TEER) assay and paracellular permeability assay. Valerate achieved the maximum increase in the TEER at 2 mM and reduced the paracellular permeability. Its intestinal barrier function promoting activity is similar to that of butyrate, with a broader range of effective concentrations than the later. Through western blot analysis, this activity is linked to the valerate-induced AMPK activation and tight junctions (TJs) assembly, but not to the reinforced expression of TJs related proteins. It provides direct experimental evidence supporting valerate's function in intestinal health, implying the once under-valued function of valerate and its amino acid precursors. The valerate's role in regulating intestine homeostasis and its possible synergetic effects with other SCFAs warranted to be further investigated.

Designing a novel CaO–MgO–SiO2-based multiphase bioceramic with adjustable ion dissolution behavior for enhancing osteogenesis

Many bioactive inorganic ions such as calcium (Ca), magnesium (Mg) and silicon (Si) have been confirmed to take part in bone regeneration through promoting the secretion of osteogenesis-related growth factors. However, it is not clear about the effective concentration range and action mechanism of ion combinations on synergistically facilitating osteogenesis. Besides, it is of great significance to design a novel bioceramic that could continuously release these effective inorganic ions to match the need for bone tissue repair. Thus, in this work, the concentration level of combined Ca, Mg, Si ions beneficial to osteogenesis of bone marrow-derived mesenchymal stem cells (BMSCs) was explored by orthogonal experimental design (OED) firstly. Meanwhile, eight single-phase ceramics in CaO–MgO–SiO2 system were synthesized, and the influences of their inherent properties on ion dissolution behaviors were systematically investigated. Finally, based on the above results, three multiphase bioceramics (named C1, C2 and C3) containing calcium silicate, diopside and akermanite as crystalline phase were designed and synthesized. It was found that the ionic extracts of bioceramic C1 were just within the above effective concentration range, displaying a predetermined ability of stimulating osteogenic differentiation of BMSCs through enhancing the expression of bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF). All the results indicated that this novel multiphase bioceramic with adjustable ion dissolution behavior has a great application potential in bone tissue engineering.

Pulse purge thermal desorption ion mobility spectrometer for rapid and sensitive determination of intravenous anesthetic etomidate in blood

Rapid and sensitive determination of etomidate in blood is of great significance for anesthesiologists to adjust the depth of anesthesia, ensure the safety of operation and reduce the incidence of adverse reactions in patients, especially those with unstable hemodynamics. Herein, a positive photoionization ion mobility spectrometry method with acetone doped into the drift gas was developed, increasing the reaction efficiency of ion-molecule reactions and improving the detection sensitivity of etomidate in blood. Furthermore, the proposed injection method of pulse purge thermal desorption in bidirectional flow mode not only successfully improved the analysis performance of etomidate by increasing the effective injection amount of gaseous etomidate molecules, but also significantly reduced the impact of pressure fluctuation caused by the pulse on the quantitative accuracy. In view of the effective blood concentration range of etomidate from 1.25 to 3.75 ng μL−1, the proposed method with the quantitative range of 0.1–10 ng μL−1 was suitable for etomidate determination throughout the perioperative period. As a demonstration, the proposed method has been applied clinically to determine the concentration of etomidate in blood of patients undergoing tonsillectomy or nasal endoscopic functional sinus surgery.

WJCPR11 reverses the TNF-α-induced inhibition of adipocyte differentiation and glucose uptake

Berberine is a natural isoquinoline alkaloid present in various herbs and is effective against metabolic syndrome in the pre-diabetic stage and high insulin resistance. The present study aimed to determine the effectiveness of WJCPR11, a berberine derivative that is commonly used for diabetes treatment, in ameliorating insulin resistance and diabetes treatment. WJCPR11 promoted adipocyte differentiation to a higher extent than other berberine derivatives and showed no noticeable toxicity in its effective concentration range. It increased the mRNA expression levels and protein abundance of adipogenic markers, including peroxisome proliferator-activated receptor γ (PPARγ), glucose transporter type 4 (GluT4), and fatty acid synthase (FAS), and markedly enhanced the level of adiponectin, a distinct marker of insulin sensitivity. Meanwhile, the mRNA levels of inflammatory markers such as plasminogen activator inhibitor-1 (PAI-1), monocyte chemoattractant protein-1 (MCP-1), and interleukin 6 (IL-6) were reduced after WJCPR11 treatment. Furthermore, the tumor necrosis factor-α (TNF-α)-induced inhibition of adipocyte differentiation and downregulation of glucose uptake were markedly reversed by WJCPR11 treatment. Collectively, the findings of this study indicate that WJCPR11 has great potential for diabetes treatment.

Strontium-incorporated titanium implant surfaces treated by hydrothermal treatment enhance rapid osseointegration in diabetes: A preclinical vivo experimental study.

The aim of the current study was to explore effects of strontium-incorporated titanium implant surfaces by hydrothermal treatment on osseointegration in diabetic rats. The surface characteristics of SLA and SLA-Sr surfaces were detected by related instruments. Thirty-six male Sprague-Dawley rats were induced into diabetes, and thirty-six rats were normal. SLA and SLA-Sr implants were, respectively, inserted into bilateral tibial metaphysis of each rat. Percentage of bone-to-implant contact (BIC%) and percentage of bone area (BA%) were analyzed at 4 and 8weeks after implantation. Immunohistochemistry of osteoprotegerin (OPG) and Wnt5a were conducted at 1 and 4weeks. Gene expression levels of inflammatory cytokines and related signaling molecules in peri-implant bone tissue were detected at 3 and 7days. Strontium was uniformly distributed on SLA-Sr surfaces, and it was released in an effective concentration range. SLA-Sr surfaces showed significantly higher BIC% in diabetic rats at 4 (p<.05) and 8weeks (p<.05). Besides, it displayed higher BIC% at 4weeks (p<.05) in normal rats. Also, SLA-Sr surfaces upregulated expression of OPG at 4weeks (p<.05) in diabetic rats. What's more, SLA-Sr surfaces downregulated inflammation (TNF-α, IL-1β, and IL-6; p<.01) in diabetic rats at 3days. In addition, expression of Wnt5a and ROR2 was upregulated (p<.05) at 7days after implantation under diabetes. It is suggested that strontium-incorporated titanium implant surfaces by hydrothermal treatment could enhance implant osseointegration as compared with SLA implant surfaces in diabetic rats.

A simplified method for bortezomib determination using dried blood spots in combination with liquid chromatography/tandem mass spectrometry

Bortezomib, a proteinase inhibitor currently used to treat multiple myeloma and mantle cell lymphoma, has a high incidence of adverse reactions and large inter-individual differences in plasma concentrations. A simple, validated LC-MS/MS method for the quantitative analysis of bortezomib in dried blood spot (DBS) samples was developed to provide support for determining the effective concentration range of bortezomib for clinical use. Fifty (i50) μL of spiked blood were added onto Whatman protein saver cards to prepare the DBS samples. Circular cards of 6 mm diameter were punched, extracted by methanol containing the internal standard (apatinib), and injected into the LC-MS/MS system. The method validation included selectivity, linearity, accuracy and precision, stability, matrix effect, recovery and hematocrit. The calibration curve showed correlation coefficient values higher than 0.999 in the range of 0.2 – 20.0 ng/mL for bortezomib. The acceptance criteria of accuracy (relative error < 12.5%) and precision (coefficient of variation < 10.7%) were met in all cases. The matrix effect was<13.2%, and the recovery was between 87.3 and 100.2%. DBS samples were shown to be stable when stored in cold conditions or at room temperature. Different hematocrit values did not significantly affect the accuracy of the measured concentrations. And there are no significant differences between bortezomib concentrations in DBS samples and plasma samples. This new method was successfully used for clinical concentration determinations of bortezomib and can be applied in future therapeutic drug monitoring and pharmacokinetic studies of bortezomib especially in pediatric patients.

Polymer Optical Waveguide Grating-Based Biosensor to Detect Effective Drug Concentrations of Ginkgolide A for Inhibition of PMVEC Apoptosis.

In this work, we successfully developed a fluorinated cross-linked polymer Bragg waveguide grating-based optical biosensor to detect effective drug concentrations of ginkgolide A for the inhibition of pulmonary microvascular endothelial cell (PMVEC) apoptosis. Fluorinated photosensitive polymer SU-8 (FSU-8) as the sensing core layer and polymethyl methacrylate (PMMA) as the sensing window cladding were synthesized. The effective drug concentration range (5–10 µg/mL) of ginkgolide A for inhibition of PMVEC apoptosis was analyzed and obtained by pharmacological studies. The structure of the device was optimized to be designed and fabricated by direct UV writing technology. The properties of the biosensor were simulated with various refractive indices of different drug concentrations. The actual sensitivity of the biosensor was measured as 1606.2 nm/RIU. The resolution and detection limit were characterized as 0.05 nm and 3 × 10−5 RIU, respectively. The technique is suitable for safe and accurate detection of effective organic drug dosages of Chinese herbal ingredients.

Abstract 1248: ERGi-USU-6 salt derivatives, a selective inhibitor for ERG positive prostate cancer cells

Abstract Background: Approximately half of prostate cancer patients harbor the oncogenic TMPRSS2-ERG gene fusion expressing the ERG oncoprotein. Our lead compound, ERGi-USU, is a potent small molecule inhibitor that binds the atypical kinase RIOK2 leading to the inhibition of the growth of ERG positive cancer cells reducing ERG levels. We have developed a new and more effective derivative, ERGi-USU-6. We have reported the new salts formula EB3P0-16 of ERGi-USU-6 inhibiting the growth of ERG positive prostate cancer cells at IC50=89nM achieving the range of FDA approved drugs. Encouraged by this success we have designed and tested a broad array of new salt formulations to further improve the biological activity of ERGi-USU-6. Methods: From fifty potential salt formulations, we prioritized candidate salts based on the structure, solubility, ionic hydrophobic/hydrophilic characteristics. Series of salts were synthesized by chemical reactions with ERGI-USU-6. Selected formulas include, bisulfate, butyrate, carbonate, salicylate, tartrate salts. The different stages of salt formulation included the testing of a) preformulation, b) pre-formulation processing, c) physicochemical properties, d) solubility, e) pKa, f) partition coefficient, g) pH- solubility profiling, h) prodrug formulation, and i) polymorphism. The IC50 values for ERG protein inhibition was compared to the parental compound and were calculated in a 12-step dilution range and were repeated thrice. The protein levels were quantified by measuring protein levels in a wide range using iBright instrument. Results: A total of 21 salt formulas were prioritized and synthesized. The result confirmed the lead characteristics of EB3P0-16. However, among the new formulas four other salt derivatives showed improved ERG protein inhibition compared to the parental compound. Also, we gained new insights in designing the next generation of formula by the exclusion of chemical structures that did not lead to improvement. Conclusion: This study confirmed EB3P0-16 as the lead formula of ERGi-USU-6. We found four new salt formulas with improved activity achieving ERG protein inhibition within the effective concentration range. The significance of our findings opens the possibility of new deigns towards the pre-clinical testing of ERG inhibitors. Disclaimer: The opinions or assertions contained herein are the private ones of the author/speaker and are not to be construed as official or reflecting the views of the Department of Defense, the Uniformed Services University of the Health Sciences or any other agency of the U.S. Government. The identification of specific products, scientific instrumentation, or organization is considered an integral part of the scientific endeavor and does not constitute endorsement or implied endorsement on the part of the author, DoD, or any component agency. Citation Format: Binil Eldhose, Charles P. Xavier, Mallesh Pandrala, Albert Dobi, Sanjay V. Malhotra. ERGi-USU-6 salt derivatives, a selective inhibitor for ERG positive prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1248.

Utility of monitoring the serum levetiracetam concentration for intraoperative seizure control during awake craniotomy

Awake craniotomy is an established procedure for resecting brain tumors in eloquent lesions, and intraoperative seizure is one of the most important complications. Phenytoin is normally used to control intraoperative seizures. Recently, phenytoin was replaced with levetiracetam at our institution because the latter has fewer side effects. While the phenytoin dose is calibrated in accordance with the serum concentration, there is currently no consensus on a method of monitoring the serum concentration of levetiracetam or the effective concentration range needed to control intraoperative seizures during awake craniotomy. The present study therefore aimed to determine whether monitoring the serum levetiracetam concentration is useful for controlling intraoperative seizures during awake craniotomy. The intraoperative serum concentration of levetiracetam during awake craniotomy was measured in 34 patients and compared with that of phenytoin in 33 patients undergoing the same procedure. The levetiracetam concentration inversely correlated with body surface area (BSA) and estimated glomerular filtration rate (eGFR). Levetiracetam was superior to phenytoin in terms of the correlation between the serum concentration and the dose adjusted for BSA and eGFR (correlation coefficient, 0.49 vs 0.21). Furthermore, the serum levetiracetam concentration in patients with intraoperative seizures was below the 95% confidence interval (CI) of the regression line whereas the serum phenytoin concentration of two patients with seizures was within the 95% CI, indicating that evaluating the serum levetiracetam concentration against the BSA and eGFR-adjusted dosage may be useful in preventing intraoperative seizures during awake craniotomy by allowing prediction of the seizure risk and enabling more accurate dosage calibration.

Removal of antibiotic resistance genes and inactivation of antibiotic-resistant bacteria by oxidative treatments.

The persistence of antibiotics in the environment because of human activities, such as seafood cultivation, has attracted great attention as they can give rise to antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB). In this study, we explored the inactivation and removal efficiencies of Escherichia coli SR1 and sul1 (plasmid-encoded ARGs), respectively, in their extracellular and intracellular forms (eARGs and iARGs) by three commonly used fishery oxidants, namely chlorine, bromine, and potassium permanganate (KMnO4), at the practical effective concentration range (0.5, 5, and 15mg/L). Kinetics data were obtained using laboratory phosphate-buffered saline (PBS). Following the same fishery oxidation methods, the determined kinetics models were tested by studying the SR1 and sul1 disinfection efficiencies in (sterilized) pond water matrix. At concentrations of 5 and 15mg/L, all three oxidants achieved sufficient cumulative integrated exposure (CT values) to completely inactivate SR1 and efficiently remove sul1 (up to 4.0-log). The oxidation methods were then applied to an unsterilized pond water matrix in order to study and evaluate the indigenous ARB and ARGs disinfection efficiencies in aquaculture, which reached 1.4-log and 1.0-log during treatment with fishery oxidants used in pond preparation at high concentrations before stocking (5-15mg/L), respectively. A high chlorine concentration (15mg/L) could efficiently remove ARGs (or iARGs) from pond water, and the iARG removal efficiency was higher than that of eARGs in pond water. The method and results of this study could aid in guiding future research and practical disinfection to control the spread of ARGs and ARB in aquaculture.