Injection Volume Research Articles

A novel RP-HPLC method for the simultaneous quantification of azithromycin and dexamethasone in marketed ophthalmic drops

A straightforward, precise, accurate, specific, and sensitive RP-HPLC technique has been established for the quantification of Azithromycin Dihydrate and Dexamethasone Sodium Phosphate in their commercial formulation. The wavelength maxima for Azithromycin and Dexamethasone were considered to be 215 nm for estimation. In RP-HPLC separations were carried out on a Zorbax SB C18 column (250mm X 4.6mm, 5 μm) and mobile phase consisting of Acetonitrile: Monobasic Potassium Phosphate (KH2PO4) buffer in the proportion of 75:25 v/v and pH of the buffer was adjusted to 5.5 with OPA. The estimation was carried out at 215 nm using UV detector keeping the flow rate of 1.2 ml/min and injection volume of 50 μl. The current method demonstrates good linearity over the range of 20 - 120 μg/ml and 2 - 12 μg/ml for Azithromycin and Dexamethasone respectively. No interference of excipients was found during estimation. The recommended techniques were verified and determined to be specific, accurate, and exact. The approaches were effectively used for the concurrent quantification of both medicines in pharmaceutical formulations, making them suitable for regular quality control examination.

A Simple HPLC-DAD Method for the Therapeutic Monitoring of Clozapine and Related Metabolites in Human Plasma and Urine Samples

Clozapine and its metabolites require close therapeutic monitoring (TDM) in patients due to poor correlation between the administrated doses and resulting plasma concentrations, the narrow therapeutic interval, high inter-individual variability, and the risk of serious side effects once toxic levels are exceeded. The aim of the study was to develop a simple (relatively cheap) LC-UV method for the quantification of clozapine and its metabolites in plasma and urine samples. For sample preparation, liquid-liquid extraction (LLE) in n-octanol was more efficient and less limiting in injection volumes compared to the in-situ formation of SUPRAS. When analyzing urine, an alkalinization step before extraction was required. The proposed method produced linear concentration responses with/without internal standard (IS) for the target analytes, with LLOQs within the targeted range of 50 ppb and %RSD within the acceptable 15% range. Furthermore, sample stability studies proved that pre-extracted samples were stable for the short term at room temperature and long-term when frozen.

The "4.3," A New Filler Lips Technique.

The "4.3" technique is a hybrid lip augmentation approach that combines the aesthetic benefits of the vertical-lip technique with the fewer entry points of the retrograde linear technique. This method aims to create natural-looking, harmonious, and defined lips using hyaluronic acid (HA)-based fillers, to enhance volume and contour. The objective of this study is to evaluate the effectiveness, safety, and reproducibility of the "4.3" technique in achieving natural lip augmentation with minimal filler volume and reduced injections. This technique is applied to improve the shape and volume of the lips while minimizing the risk of complications. The technique was applied to male and female patients with standard anatomical features who desired subtle enhancements in lip contour, projection, and volume. The procedure involved four injections in the upper lip and three in the lower lip, using a combination of retrograde linear and vertical techniques. A total of 0.7 mL of HA filler were used for each patient. The "4.3" technique achieved consistent and aesthetically pleasing results across all patients, with improvements in lip volume, shape, and definition. The reduced number of injections minimized discomfort and risk of vascular complications. The use of Tri-Hyal technology contributed to smooth, plump lips with harmonious proportions. The "4.3" technique is a standardized, intuitive, and reproducible method suitable for most patients, regardless of sex. It allows for natural-looking lip augmentation using a reduced volume of filler and fewer injections, making it a safe and effective option for enhancing lip aesthetics.

Enhanced bone cement distribution in percutaneous vertebroplasty using a curved guide wire: a propensity score matching analysis

BackgroundOsteoporotic vertebral compression fractures (OVCF) severely affect the quality of life in the aged population. Percutaneous vertebroplasty (PVP) alleviates pain and stabilizes vertebrae, but suboptimal bone cement distribution can cause complications. Hence, this study aimed to clarify whether a new technique for PVP, using a curved guide wire, enhances the distribution of bone cement and improves clinical outcomes in patients with OVCF.MethodsPatients with single-segment OVCF underwent PVP or curved guide wire percutaneous vertebroplasty (C-PVP). Propensity score matching (PSM) was employed to balanced the baseline characteristics. The primary outcomes were the visual analog scale (VAS) and Oswestry disability index (ODI) scores. The secondary outcomes included assessments of bone cement distribution, bone cement injection volume, radiological parameters, and general clinical results. Additionally, Complications and adverse events were documented.ResultsAfter PSM analysis, each group comprised 54 patients, which significantly reduced baseline differences. The C-PVP group showed better clinical outcomes compared to the traditional PVP group. One month after surgery, the C-PVP group had significantly lower VAS and ODI scores (p < 0.001). These improvements persisted at six months and the final follow-up. Additionally, bone cement distribution scores were better (p < 0.001), injection volume was higher (p = 0.03), leakage was less frequent (p = 0.02), and adjacent vertebral fractures occurred less frequently (p = 0.04) in the C-PVP group. Radiological parameters and overall clinical outcomes revealed no significant differences between the two groups.ConclusionThe use of curved guide wire in PVP significantly improves bone cement distribution and injection volume, resulting in better clinical efficacy in patients with OVCF.

Ultrasound visualization of Botulinum toxin injection: Identifying clinical correlates to optimize outcomes in spasticity management.

Botulinum toxin injections are well established and commonly used for spasticity management. Clinicians strive to optimize outcomes from toxin injections. One potential complication is toxin spread beyond the intended muscle, which can lead to unwanted weakness. The utilization of ultrasound allows direct visualization of target muscles and identification of toxin leakage from the target muscle. Ultrasound evaluation of clinical factors that correlate to toxin leakage have not been studied. To identify cases of botulinum toxin injectate leak beyond the targeted muscle during ultrasound-guided spasticity injections and associate cases of leak with predictive clinical factors, which include muscle size, fibroadipose changes, and number of previous injections. This was a prospective observational study. An outpatient clinic in an academic medical center. Patients who demonstrated wrist flexor spasticity warranting intervention were invited to participate. Patients received standard-of-care spasticity management with injection of onabotulinumtoxinA into the flexor carpi radialis muscle based upon clinical presentation and prescribing guidelines. Ultrasound video was recorded, and a blinded review was conducted by the study team. The primary outcome measure was visualized leak of injectate on recorded ultrasound video. Documented leak was then associated with clinical factors including diameter of the flexor carpi radialis, volume of injectate used, history of prior injections, and fibrotic change of the muscle. The study included 54 patients, 77.8% of whom had an underlying diagnosis of cerebrovascular accident. Injectate leak was observed in 18.5% of injections and could not be confirmed in 9.3% of injections. Multivariable analysis demonstrated increased odds of leak with higher Modified Heckmatt Scale score. No statistically significant increase in leak was noted with higher volume of injectate or smaller muscle diameter. Extramuscular leak of botulinum toxin injection may be associated with fibroadipose muscle change.

Cleaning Method Validation for Determination of Residues in Anti-Cancer Drug product for Injection by Using RP-HPLC Technique

Cleaning method validation is a part of good practices in pharmaceutical sector and need to seek the contamination present in production area. OBJECTIVE: An RP-HPLC method for the cleaning samples analysis for Anti-Cancer Drug product Melphalan Hydrochloride for Injection was develop and validated. The method was developed and validated for quantitation of Cleaning of residue left in the vessels of the production equipment’s. The analytical method used to determine the complete cleaning for Melphalan Hydrochloride for Injection by HPLC method. METHOD: The Cleaning validation was performed on Inertsil ODS,C18,(150mm×4.6mm,5μm) chromatographic column temperature at 40°C, and the detection wavelength was set at 260nm. Mobile Phase-A:10mL ammonium acetate, 88mL Purified water, 10mL acetic acid, 2mL Triethylamine, and Mobile Phase-B: 1mL Buffer, 10mL acetonitrile,190mL Purified water, and at a flow rate of 1.5 mL/min, and the injection volume was 10μL. RESULTS: The validation results of Melphalan Hydrochloride were linear over the concentration from 0.10 µg/mL to 0.75µg/mL (r = 1.00) and the recoveries from LOQ to 150% and precision ranged from 50% to 76% (RSD &lt; 30%, n =9). CONCLUSION: This method has been validated successfully and all the results met the acceptance criteria. Hence method of Cleaning Validation is suitable for testing of residue sample of Melphalan Hydrochloride for Injection.

Geophysical Monitoring Technologies for the Entire Life Cycle of CO2 Geological Sequestration

Geophysical monitoring of CO2 geological sequestration represents a critical technology for ensuring the long-term safe storage of CO2 while verifying its characteristics and dynamic changes. Currently, the primary geophysical monitoring methods employed in CO2 geological sequestration include seismic, fiber optic, and logging technologies. Among these methods, seismic monitoring techniques encompass high-resolution P-Cable three-dimensional seismic systems, delayed vertical seismic profiling technology, and four-dimensional distributed acoustic sensing (DAS). These methods are utilized to monitor interlayer strain induced by CO2 injection, thereby indirectly determining the injection volume, distribution range, and potential diffusion pathways of the CO2 plume. In contrast, fiber optic monitoring primarily involves distributed fiber optic sensing (DFOS), which can be further classified into distributed acoustic sensing (DAS) and distributed temperature sensing (DTS). This technology serves to complement seismic monitoring in observing interlayer strain resulting from CO2 injection. The logging techniques utilized for monitoring CO2 geological sequestration include neutron logging methods, such as thermal neutron imaging and pulsed neutron gamma-ray spectroscopy, which are primarily employed to assess the sequestration volume and state of CO2 plumes within a reservoir. Seismic monitoring technology provides a broader monitoring scale (ranging from dozens of meters to kilometers), while logging techniques operate at centimeter to meter scales; however, their results can be significantly affected by the heterogeneity of a reservoir.

A prediction method of oil recovery for hot water chemical flooding in heavy oil reservoirs: Semi-analytical stream tube model

Abstract Chemical agents (polymer and surfactant) assisted hot water flooding is an effective means of enhancing oil recovery in heterogeneous and heavy oil reservoirs. The rapid prediction of oil recovery through hot water chemical flooding is very important. The stream tube model is a fast analytical method for predicting water flooding recovery, but it is not suitable for hot water chemical flooding. In this paper, a permeability distribution model for multi-stream tubes is established based on permeability variation coefficient using normal distribution function for reservoir heterogeneity, Using GOMPERTZ growth function model to characterize the changes in stream tube temperature, polymer viscosity, and surfactant concentration with injection volume, Using Brooks-Corey model to describe the influence of interfacial tension and temperature on the relative permeability curve. Finally, an analytical stream tube model for hot water chemical flooding of heavy oil reservoirs was established. The time discrete method is used to solve the model, then the graphs of the relationship between oil recovery and water cut are obtained. Compared with numerical simulation methods, the prediction error of oil recovery is less than 2%, and the calculation time is reduced by 89%. This model has been successfully applied to X oilfield. Based on historical fitting, it is predicted that hot water chemical flooding can enhance oil recovery by 6.3% compared to water flooding. This paper provides a fast calculation method for predicting and evaluating the effectiveness of hot water chemical flooding in heavy oil reservoirs.

Key issues in diagnostic accuracy of sentinel lymph node biopsy in early-stage ovarian cancer: systematic review and meta-analysis

ObjectiveSentinel lymph node (SLN) mapping may reduce the morbidity of lymphadenectomy while maintaining diagnostic accuracy. Nevertheless, SLN mapping in epithelial ovarian cancer is still under investigation. This systematic review and...

Optimization of a Typical Gas Injection Pressurization Process in Underground Gas Storage

In the early construction of an underground gas storage facility in an oil and gas field in southwest China, the increasing gas injection volume led to a continuous rise in energy consumption, which affects the economic sustainability of gas injection and extraction. In order to improve efficiency and reduce energy consumption, optimization of the pressurization process was carried out. An optimization model for the process of pressurization in underground gas storage has been established. Based on the model, a joint optimization approach is applied, where MATLAB is responsible for the iterative process of finding the optimal parameter combinations and HYSYS is responsible for the establishment of the process and calculation of the results of the process parameters. The key parameters include the outlet parameters of the compressor and the air cooler, which are critical in determining the overall energy consumption and operational performance of the system. Accordingly, the results related to the optimal parameter combinations for two-stage compression and three-stage compression were obtained in the case study. Compared with one-stage compression, two-stage and three-stage compression can diminish energy consumption by 1,464,789 kJ/h and 2,177,319 kJ/h, respectively. The reduced rate of energy consumption of three-stage compression was 16.10%, which was higher than that of two-stage compression by 10.83%. Although the construction costs of three-stage compression were higher than those of two-stage compression, from the perspective of long-term operation, three-stage compression had lower operating costs and superior economy and applicable value. The research results provided scientific references and new ideas for the optimization and adjustment of the pressurization process in underground gas storage.

Research on the Injection–Production Law and the Feasibility of Underground Natural Gas Storage in a Low-Permeability Acid-Containing Depleted Gas Reservoir

Depleted gas reservoirs are important places for the rebuilding of gas-storage reservoirs. In order to demonstrate the feasibility of constructing and operating such underground gas storage, a low-permeability gas-storage seepage model considering fracture development was developed and established. The model was solved using semi-analytical methods, and the pressure–response characteristics during natural gas injection were analyzed. The impact of gas injection volume on formation pressure has been clarified, and the calculation method for ultimate injection pressure has been determined. Additionally, through numerical simulation methods, the migration law of acidic gas during gas injection, the variation law of produced acidic gas concentration, and the main control factors affecting the concentration of the produced acidic gas were studied. Furthermore, measures to reduce the concentration of the acidic gas produced were proposed. Finally, injection and production plans were designed for typical depleted acidic gas reservoirs, simulating the operation of gas storage for 12 cycles. The results indicate that the quality of natural gas produced in the third cycle can meet the Class II standard for commercial natural gas. Through this study, the feasibility of constructing gas-storage facilities for acidic depleted gas reservoirs has been demonstrated, and injection and production strategies for this type of gas reservoir have been proposed.

Simulating Upper Eyelid Ptosis During Neuromodulator Injections-An Exploratory Injection and Dissection Study.

Aesthetic neuromodulator injections of the upper face are frequently performed to temporarily block muscular actions of the periorbital muscles to ultimately reduce skin rhytids. However, the adverse event rate in the literature for toxin-induced blepharoptosis ranges from 0.51% to 5.4%. To identify access pathways by which injected neuromodulator product can travel from extra- to intra-orbital and therefore affect the levator palpebrae superioris muscle. Nine non-embalmed human body donors were investigated in this study with a mean age at death of 72.8 (16.1) years. The 18 supraorbital regions were injected in 28 times (14 for supratrochlear and 14 for supraorbital) with 0.5 cc, whereas eight cases (four for supratrochlear and four supraorbital) were injected with 0.1 cc of colored product. Anatomic dissections were conducted to identify structures stained by the injected color. The results of this injection- and dissection-based study revealed that both the supratrochlear and the supraorbital neurovascular bundles are access pathways for injected neuromodulator products to reach the intra-orbital space and affect the levator palpebrea superioris muscle. Out of 36 conducted injection passes, seven (19.44%) resulted in affection of the sole elevator of the eyelid of which 100% occurred only at an injection volume of 0.5 cc and not at 0.1 cc. Clinically, the results indicate that a low injection volume, a superficial injection for the supraorbital location, and angling the needle tip away from the supratrochlear foramen (toward the contralateral temple) when targeting the corrugator supercilii muscles, can increase the safety profile of an aesthetic toxin glabellar treatment.

Temperature distribution considering the film-wise condensation and its impact on multi-stage oil production during the co-injection of steam-CO2

The co-injection of steam and CO2 into oil sands reservoirs has proved to be one of the most efficient and environmentally friendly methods to produce bitumen. Nevertheless, the condensation mechanism of steam in the reservoir is film-wise condensation under the effect of CO2, which reduces the heat transfer efficiency of steam. To obtain accurate oil production during the co-injection of steam-CO2, it is critical to predict the temperature distribution considering the film-wise condensation and clear its impact on oil production. In this study, laboratory experiments with different injectors were conducted to clear the effect of film-wise condensation on temperature distribution in the formation. Then, a mathematical model considering film-wise condensation was established to predict the temperature distribution and oil production, compared with the measured experiment result and multi-stage oil production from field data. Finally, the effect of temperature distribution on multi-stage oil production was analyzed through different injection volumes. The results indicated that the impact of film-wise condensation inhibits the development of the steam zone(Ts) but explicitly expands the hot water zone(Ts ∼ Tr). Moreover, the different injection components affect film-wise condensation, and CO2 has a more pronounced effect, whereas steam has little impact on the hot water zone despite its significant effect on steam zone expansion by weakening the film-wise condensation. Furthermore, the oil production exhibits the multi-stage characteristic controlled by different heating zones(the steam zone and the hot water zone), such that the steam zone contributes to higher oil production in the rising stage, and a larger hot water zone induces a longer life of the rising stage and the stable stage.

Overcoming the Strong Sample Solvent Effect for Sustainability Measurement Challenges in Liquid Chromatography. Example for Bisphenol-A.

This paper describes an approach to achieve low parts per billion (ppb) concentration level detection using a reversed-phase ultrahigh-performance liquid chromatographic ultraviolet absorbance detection method with large-volume feed injection (FI) for analytes in dichloromethane (DCM). FI is a novel technology that allows sample injection at a defined speed into the LC mobile phase. We demonstrate this approach for a mixture of bisphenol A and its diglycidyl ether derivatives in DCM. DCM is a very strong injection solvent at reversed-phase LC conditions and is typically immiscible with a starting reversed-phase gradient mobile phase containing a high percentage of water. As a result, reduced separation performance and even peak splitting are seen with classic flow-through injection. The method setup comprised an octyl-bonded core-shell stationary phase (150 × 4.6 mm i.d., 2.7 μm particle size) with a water/acetonitrile mobile phase gradient and an exceptionally high injection volume of 45 μL of DCM solution using FI. Optimization of feed speed (1%) and isocratic hold duration (4 min) was crucial for final separation conditions. FI delivered more than a 20-fold improvement in the limit of detection (LOD) compared to standard flow-through injection while maintaining peak resolution. The LOD of the final method ranged between 1 and 10 ppb in the polymer resin. This methodology has high potential for trace analysis in a large variety of applications that suffer from the "strong solvent effect".

New prefilled syringe aflibercept design. A cause of symptomatic IOP spike after aflibercept PFS?

To describe ocular hypertension cases after using a new aflibercept prefilled syringe and to assess the main characteristics of these eyes and their possible association with intraocular pressure (IOP) changes. Case series. We reported all the cases of ocular hypertension following aflibercept prefilled syringes (PFS) treatment in our department between April 2021 and December 2023. A total of 4183 eyes were treated with aflibercept PSF. Thirteen transitory IOP elevations were observed immediately after injection (0.3%). Two eyes had an IOP between 30-35 mmHg, five eyes had an IOP between 36-55 mmHg and three eyes had an IOP > 56 mmHg. The mean IOP was 45.5 mmHg±11.33. Only six eyes needed anterior chamber paracentesis (37.5%). The other patients were treated conservatively (ocular massage and/or IOP-lowering drops). The mean IOP after treatment was 15.71 mmHg±7.20. Visual acuity improved after treatment in all the patients. Compared with other injectors, reports have indicated a higher incidence of moderate and severe IOP spikes with aflibercept PSF. The European Medicine Agency (EMA) has associated this significant increase with incorrect syringe handling, leading to higher injection volumes. Although plunger misalignment seems to play a role in the IOP spikes, some other characteristics of this new injector could play a role. Factors such as syringe diameter, plunger alignment, and injection force may contribute to this issue. The reason some authors found no significant differences in IOP elevation after IVI, with aflibercept PFS, could be due to variations in patient characteristics, which may also play an important role in post-IVI pressure changes. Intraocular pressure spikes after aflibercept PFS can be explained by injector characteristics. The PFS of aflibercept has a domed plunger. Incorrect alignment between the base of the plunger and the black dosing line could cause an increase in the injected volume. Furthermore, the wider syringe diameter of aflibercept PFS could imply a larger injection force, increasing the risk of IOP elevation. Patient characteristics, such as previous VPP, axial length, or glaucoma history, may also play a role. Further studies are required to develop an ideal intravitreal syringe.

Percutaneous Mesh-Container-Plasty versus Percutaneous Kyphoplasty in the Treatment of Osteoporotic Compression Fractures with Up-Endplate Injury: A Retrospective Study

Percutaneous mesh-container-plasty(PMCP), a modified traditional percutaneous kyphoplasty(PKP)technique, is increasingly being used to treat osteoporotic vertebral compression fractures(OVCF) with up-endplate injury. This retrospective study aimed to compare the clinical and radiological results of PKP and PMCP for the treatment of this disease. We retrospectively analyzed the medical records of patients with osteoporotic compression fractures and upper endplate injuries treated at our hospital between January 2019 and December 2021. A total of 192 patients who met the inclusion and exclusion criteria were enrolled. Of these, 103 underwent PKP and 89 underwent PMCP. Key outcome measures included surgical safety, clinical efficacy, and radiological results. Both the PKP and PMCP groups showed significant improvements in VAS (Visual Analog Scale) and ODI (Oswestry Disability Index) scores postoperatively. Additionally, anterior vertebral body height ratio (AVBHr) and Cobb's angle improved in both groups, though no statistically significant difference was observed between them. The hospital stay duration was similar between the two cohorts. Notably, the PMCP group required a larger volume of bone cement injection, yet exhibited a significantly lower incidence of cement leakage and adjacent vertebral fractures (9/89 and 2/89, respectively) compared to the PKP group (24/103 and 11/103, respectively) (p < 0.05). Moreover, the PMCP group had shorter operation times (34.64 ± 9.88 minutes) and reduced fluoroscopy frequency (35.43 ± 5.46 instances) compared to the PKP group (27.23 ± 8.54 minutes and 23.87 ± 5.59 instances, respectively) (p < 0.05). PMCP provided superior clinical outcomes for the management of osteoporotic compression fractures with upper endplate injuries. It was associated with reduced operation and fluoroscopy times, as well as lower risks of adjacent vertebral fractures and cement leakage, compared to PKP.

8239 Recurrent Superior Laryngeal Nerve Glucocorticoid Injections: A Likely Cause Of Secondary Adrenal Insufficiency In An Otherwise Healthy Man

Abstract Disclosure: A. Lorin: None. M.C. Pranger: None. J. Park: None. C.A. Clutter: None. Background: Secondary adrenal insufficiency is well described in the literature with various offending agents implicated. Superior laryngeal nerve (SLN) glucocorticoid injections, however, have rarely been recorded as causal agents of secondary adrenal insufficiency. We present a case of a generally healthy man with secondary adrenal insufficiency after chronic administration ofsuperior laryngeal nerve glucocorticoid injections without other identifiable etiologies. Clinical Case: A 68-year-old man with no significant medical history presented to endocrinology clinic due to persistent nausea and severe fatigue. His initial labs were notable for morning cortisol of 1.66 mcg/dL (5-25) and an undetectable ACTH (&amp;lt;3.2 pg/mL, 10-60) suggestive of adrenal insufficiency. FSH/LH, testosterone, FT4, and IGF-1 were otherwise normal. On initial review of his medication history, the only glucocorticoid exposure appeared to be intranasal beclomethasone, with remote courses of oral prednisone. Further history revealed that the patient was receiving superior laryngeal nerve glucocorticoid injections for chronic cough every three weeks for over a year. The injection consisted of 1:1 mixture of 1 mL of triamcinolone acetonide 200 mg/5 mL and local anesthetic, which is equivalent to triamcinolone 40 mg or hydrocortisone 200 mg. Given the volume and chronicity of the glucocorticoid injections, the patient developed secondary adrenal insufficiency as above. Since the diagnosis, the patient discontinued SLN glucocorticoid injections and was placed on physiologic hydrocortisone replacement, with gradual recovery of his HPA axis. Conclusions: Sequelae of percutaneous glucocorticoid injection into the superior laryngeal nerve for treatment of chronic cough are not well documented in terms of their effects on the HPA axis. While an effective and increasingly common treatment for chronic cough, SLN glucocorticoid injection has the potential to cause suppression of the HPA axis and cause secondary adrenal insufficiency. Excess glucocorticoid appeared to solely inhibit ACTH production, as the other anterior pituitary hormones were not affected. Understanding consequences of glucocorticoid use in any formulation is important when considering such therapies, as these may alter normal HPA function with recurrent dosing. Recovery from a disrupted HPA axis may be achieved with the use of physiologic doses of hydrocortisone replacement in the case of secondary adrenal insufficiency. Presentation: 6/3/2024

8475 Automated Insulin Delivery System with Concentrated Regular U500 Insulin in Cushing Syndrome

Abstract Disclosure: F. Erenler: None. J. Aurora: None. Background: Concentrated regular U-500 (U-500R) insulin is commonly used in patients with T2DM, who are highly insulin-resistant, requiring more than 200 units of insulin per day. Utilizing U-500R reduces the number of daily injections, decreases injection volume, and improves cost effectiveness. There has been a case report with U-500R in an automated insulin delivery (AID) system with successful results (1). To our knowledge there is no data on AID system use in Cushing patients with T2DM using U-500R. We present a case of a patient with Cushing Syndrome (CS) with poor BG control using &amp;gt;250 units/day of SC U-500R with improved BG control after switching to Omnipod 5 AID system. Clinical Case: A 57 y.o. male initially presented with hypogonadotropic hypogonadism and subsequently diagnosed with ACTH-dependent CS, which is complicated by obesity, uncontrolled T2DM, lower extremity wounds, and DVTs. He was diagnosed with CS with multiple abnormal 1 mg dexamethasone suppression tests (DST) (max AM cortisol 5.9 mcg/dL; RR &amp;lt;1.8 mcg/dL, dexamethasone level 300), elevated urine free cortisol (UFC) (max UFC/Cr 77.6 mcg/mg/L; RR: 5-64 mcg/24-hr) and elevated salivary cortisol (max cortisol 0.2 mcg/dL; RR: &amp;lt;0.09 mcg/dL). He had suppressed cortisol with 8 mg DST. An MRI sella showed left-sided hypoechoic 0.9 cm mass. Desmopressin (DDAVP) stimulation test and Ga-68 DOTATATE-PET scan were negative. As a result of his abnormal MRI sella and elevated cortisol, he underwent transsphenoidal surgery of the left pituitary. Pathology was non-diagnostic for a pituitary adenoma. Post-op 24-hr UFC and 1 mg DST levels remained high. DDAVP stimulation test and Ga-68 DOTATATE-PET were repeated post-op and were negative. Due to complications of CS, he was initially treated with cabergoline, but switched to osilodrostat due to intolerances. He is currently on 2 mg BID dose and 24-hr UFC has been normal since then (UFC 20 mcg/L, Cr 0.67 mg, UFC/Cr 12 mcg/mg/L). He continued to have uncontrolled hyperglycemia despite normalization of UFC. On his CGM data, he was in target range (70-180 mg/dL) 5% of the time despite using U-500R 95 units SC TID. Given his severe hyperglycemia and insulin resistance, he was switched to an AID system with U-500R and his time in target range improved over 60% after a month of use and his total daily dose of insulin decreased to less than 200 units. Conclusion: U-500R proved to be safe and effective with Omnipod 5 AID. To our knowledge, this is the first reported patient with CS using U-500R with Omnipod 5 AID. In patients without CS, the AID algorithm continuously kept BG well below the set target, especially overnight. Notably, our patient did not have this overnight hypoglycemia trend, which should be expected with his disease. We are hoping to increase the awareness of U-500R with AID systems, especially for patients with incurable CS. Reference:1.Aurora J Jr, Saraswat A. J Endocr Soc. 2023;7(Suppl 1):bvad114.873. Presentation: 6/3/2024

Development and validation of a stability-indicating HPLC method for assay of tonabersat in pharmaceutical formulations

A stability-indicating reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed to assay tonabersat and assess its stability in pharmaceutical formulations. Chromatographic separation was achieved using a Kinetex® C18 column (2.6 µm, 150 x 3 mm, 100 Å) at 50 °C, with a 20 µL injection volume. A linear gradient of acetonitrile in water (5 – 33.5 %) was applied for 1 min, followed by a gradual increase to 100 % over 26 min at a flow rate of 0.5 mL/min. Tonabersat and its degradation products were detected at 275 nm and 210 nm, respectively. The optimized method was used to evaluate the stability of tonabersat in lipid-based pharmaceutical formulations at 5 ± 3 °C, 25 ± 2°C/60 ± 5 % RH, and 40 ± 2 °C/75 ± 5 % RH over 3 months. The method was validated as per ICH guidelines and demonstrated linearity in the range of 5 – 200 µg/mL (R2 = 0.99994) with good accuracy (98.25 – 101.58 % recovery) and precision (% RSD < 2.5 %). The limits of detection and quantitation were 0.8 µg/mL and 5 µg/mL, respectively. Forced degradation studies showed significant degradation on exposure to alkaline (90.33 ± 0.80 %), acidic (70.60 ± 1.57 %), and oxidative stress (33.95 ± 0.69 %) at 70 °C, but no degradation was observed on exposure to thermal or photolytic stress. No chemical degradation was observed in either formulation on storage. Thus, the method was sensitive, specific, and suitable for stability testing of tonabersat in pharmaceutical formulations.

B-161 Liquid chromatography/mass spectrometry analysis of ethyl glucuronide and ethyl sulfate using a perfluorophenyl stationary phase

Abstract Background Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are minor metabolites of ethanol that are excreted in urine. These two metabolites are often tested for to determine if an individual has recently consumed alcohol. EtG and EtS are very polar analytes, which make them difficult to chromatograph using reversed-phase chromatography. These analytes often elute early, which can lead to irreproducible results. When EtG and EtS are analyzed by LC/MS with a mobile phase that contains formic acid, the signal of these two analytes can be suppressed. This leads to increased LOQ and cutoffs. We examined the perfluorophenyl (PFP) stationary phase for its utility in analyzing EtG and EtS. This stationary phase has been shown to have greater retention of polar compounds than C18 reversed-phase columns. In addition, we compared the effect of formic acid to acetic acid on the separation. Methods Urine samples containing EtG and EtS were diluted 10:1, using 50mM acetic acid or 0.1% formic acid, into a 96-well microtiter filter plate containing a 0.2micron filter. Internal standards were added to the microtiter plate containing the urine samples. The samples were filtered through the filter plate and analyzed by LC/MS using the PFP column (50 x 2.7micron) with a 50mM acetic acid or 0.1% formic acid/acetonitrile mobile phase. The analytes were detected using negative mode ionization. The total analysis time was 4.5minutes. Results EtG and EtS showed improved retention using the PFP column. Retention times for EtG and EtS were 0.75 and 1.20 minutes respectively using the PFP column, compared to 0.4 and 0.3 minutes using the C18 column. The greater retention time improved the LOQ for both analytes.The LOQ for EtS and EtG were determined to be 125 and 250 ng/mL, respectively. Greater retention of EtG was observed by switching the modifier from formic acid to acetic acid. The retention time increased from 0.45 to 0.75 minutes. There was less signal suppression using acetic acid in place of formic acid. Improvement in peak shape was observed when the injection volume was reduced to 5microliters. The method was validated over a range of 250 to 10000 ng/mL for EtG and 125 to 5000 ng/mL for EtS. Acceptable linearity was obtained for both analytes. Accuracy was performed at three concentration levels. All three levels demonstrated acceptable accuracy with the difference between the measured and expected concentration being with in 20% of each other. Conclusions The PFP stationary can be used to test EtG and EtS. This stationary phase gave greater retention of EtS and EtG. The use of acetic acid improved the limit of detection by decreasing the ion suppression, which decreased the limit of detection. The assay was accurate and precise for both analytes, demonstrated in the validation.