Determination of Letrozole in Tablet Formulations by Reversed Phase High Performance Liquid Chromatography

Purpose: To develop a simple, rapid, accurate and cost-effective reversed phase high performance liquid chromatography (RP-HPLC) method for letrozole in bulk and in tablets. Methods: Development of a method for the determination of letrozole, an anti-cancer drug, by RPHPLC was undertaken using a new mobile phase of acetonitrile:water (50:50, v/v). The eluent was monitored at 265 nm. Results: The optimized conditions developed showed a linear response from 160 to 240 μg/mL, with a correlation coefficient (R2) of 0.999. The limit of detection (LOD) and limit of quantification ( LOQ) were 136 and 160 μg/mL, respectively. The assay values for the two branded letrozole tablets tested were 99.2 and 100.2 %, respectively with % relative standard deviation (RSD) of 0.781 and 0.568, respectively. The bench top stability data of the drug in the mobile phase indicate that the drug was stable in the mobile phase for 24 h. Recovery data were good. Placebo study for specificity and interference of common excipients showed that the method was specific and free from interfering substances. Conclusion: Therefore, the fully validated method developed was sensitive enough to carry out routine analysis of letrozole in tablet formulations with regard to its run time, simplicity of sample preparation and accuracy.Key words: Letrozole, Assay, HPLC, Validation, Tablet formulation

Mesocorticolimbic monoamine correlates of methamphetamine sensitization and motivation.

Methamphetamine (MA) is a highly addictive psychomotor stimulant, with life-time prevalence rates of abuse ranging from 5-10% world-wide. Yet, a paucity of research exists regarding MA addiction vulnerability/resiliency and neurobiological mediators of the transition to addiction that might occur upon repeated low-dose MA exposure, more characteristic of early drug use. As stimulant-elicited neuroplasticity within dopamine neurons innervating the nucleus accumbens (NAC) and prefrontal cortex (PFC) is theorized as central for addiction-related behavioral anomalies, we used a multi-disciplinary research approach in mice to examine the interactions between sub-toxic MA dosing, motivation for MA and mesocorticolimbic monoamines. Biochemical studies of C57BL/6J (B6) mice revealed short- (1 day), as well as longer-term (21 days), changes in extracellular dopamine, DAT and/or D2 receptors during withdrawal from 10, once daily, 2 mg/kg MA injections. Follow-up biochemical studies conducted in mice selectively bred for high vs. low MA drinking (respectively, MAHDR vs. MALDR mice), provided novel support for anomalies in mesocorticolimbic dopamine as a correlate of genetic vulnerability to high MA intake. Finally, neuropharmacological targeting of NAC dopamine in MA-treated B6 mice demonstrated a bi-directional regulation of MA-induced place-conditioning. These results extend extant literature for MA neurotoxicity by demonstrating that even subchronic exposure to relatively low MA doses are sufficient to elicit relatively long-lasting changes in mesocorticolimbic dopamine and that drug-induced or idiopathic anomalies in mesocorticolimbic dopamine may underpin vulnerability/resiliency to MA addiction

Crude oil depletion by bacterial strains isolated from a petroleum hydrocarbon impacted solid waste management site in California

This research is part of a multidisciplinary research program to develop a bioremediation protocol for a solid waste management (SWM) site in Northern California - a site which is heavily contaminated with petroleum hydrocarbons. In this initial study, 30 bacterial strains were isolated and evaluated for their efficiencies to deplete crude oil. The 3 most efficient bacterial isolates for crude oil depletion were designated as S1BD1, OPKDS2, and OSDS1; they were identified as Serratia proteamaculans, Alcaligenes sp. and Rhodococcus erythropolis, respectively, based on partial 16S rRNA gene sequences. Determination of crude oil depletion efficiency by gas chromatography–mass spectrometry (GC-MS) revealed that Serratia proteamaculans S1BD1 was the most efficient (68.0 ± 1.78%), followed by Alcaligenes sp. OPKDS2 (63.7 ± 3.28%), and Rhodococcus erythropolis OSDS1 (54.9 ± 5.07%). S. proteamaculans S1BD1 was able to deplete a wide spectrum of carbon compounds within the individual components of crude oil. Alcaligenes sp. OPKDS2 was the most efficient at depleting BTEX (91.2 ± 1.90%), and R. erythropolis OSDS1 exhibited a substrate preference of n-alkanes. All three strains exhibited unusually high crude oil depletion efficiencies and tolerated a wide range of salinity and pH levels, which makes them excellent candidates for bioaugmentation of the SWM site

Design of phase measurement system using Hybrid Dual D-FIFO-FF synchronizer and PWM based duty cycle computation

Phase measurement system (PMS)s are playing the major role in real time communication applications. The digital PMS measures the exact value of phase compare to the analog PMS devices. However, the conventional digital PMSs failed to measure the accurate phase value and consumed the higher hardware resources like area, delay and power. Therefore, this work is focused on implementation of Hybrid Digital-PMS (HD-PMS) module for efficient phase value estimation. Initially, Hybrid Dual Data-First-In-First-Out-Flip Flop (D-FIFO-FF) synchronizer is introduced to improve the synthesis the data inputs, which synchronizes the data inputs with variable clock frequencies. Then, Phase Detector (PD) is used to identify the phase difference between data input1, data input 2. The PD is developed using XOR logical operation, which is high speed and area efficient. Then, data input1, data input 2 frequencies are changed by modifying the duty cycles through Pulse Width Modulation (PWM) controller. Here, PWM is used to change the duty cycles of data inputs using phase difference generated from PD. Finally, Phase Value Computation (PVC) module is introduced to estimate the digital phase levels using arithmetical operations using duty cycle levels. The simulations conducted using XILINX-ISE 14.7 reveled that, the proposed HD-PMS consumed lower hardware resources like look-up-tables (LUT), LUT-FFs, slice registers, path delays and power consumptions as compared to other PMS approaches

Effect of MWNTs and SiC-Coated MWNTs on Properties of PEEK/LCP Blend

Multiwall carbon nanotubes (MWNTs) were modified with polycarbosilane-derived silicon carbide (SiC) to improve its dispersion in the polymer matrix. PEEK/LCP/MWNTs nanocomposites were prepared by melt blending. TEM images show the improved dispersion of SiC-coated MWNTs against agglomerated structure of pure MWNTs in the blend. FESEM images shows better fibrillation of LCP in presence of SiC-coated MWNTs. TGA reveals that nanocomposites with SiC-coated MWNTs shows higher thermal stability than MWNTs filled blend system. Based on enhanced dispersion, storage modulus, tensile modulus and tensile strength were increased drastically with the incorporation of SiC-coated MWNTs. Glass transition temperature of the nanocomposites shows significant improvement with the incorporation of MWNTs

COVID-19 hospitalizations in five California hospitals: a retrospective cohort study

BackgroundThe novel coronavirus pandemic has had a differential impact on communities of color across the US. The University of California hospital system serves a large population of people who are often underrepresented elsewhere. Data from hospital stays can provide much-needed localized information on risk factors for severe cases and/or death.MethodsPatient-level retrospective case series of laboratory-confirmed COVID-19 hospital admissions at five UC hospitals (N = 4730). Odds ratios of ICU admission, death, and a composite of both outcomes were calculated with univariate and multivariate logistic regression based on patient characteristics, including sex, race/ethnicity, and select comorbidities. Associations between comorbidities were quantified and visualized with a correlation network.ResultsOverall mortality rate was 7.0% (329/4,730). ICU mortality rate was 18.8% (225/1,194). The rate of the composite outcome (ICU admission and/or death) was 27.4% (1298/4730). Comorbidity-controlled odds of a composite outcome were increased for age 75-84 (OR 1.47, 95% CI 1.11-1.93) and 85-59 (OR 1.39, 95% CI 1.04-1.87) compared to 18-34 year-olds, males (OR 1.39, 95% CI 1.21-1.59) vs. females, and patients identifying as Hispanic/Latino (OR 1.35, 95% CI 1.14-1.61) or Asian (OR 1.43, 95% CI 1.23-1.82) compared to White. Patients with 5 or more comorbidities were exceedingly likely to experience a composite outcome (OR 2.74, 95% CI 2.32-3.25).ConclusionsMales, older patients, those with multiple pre-existing comorbidities, and those identifying as Hispanic/Latino or Asian experienced an increased risk of ICU admission and/or death. These results are consistent with reported risks among the Hispanic/Latino population elsewhere in the United States, and confirm multiple concerns about heightened risk among the Asian population in California

Provider ankle brachial index and wound classification teaching as part of a comprehensive limb preservation outreach program

ObjectiveUtilization of evidence-based specialty guidelines is low in primary care settings. Early use of ankle-brachial index (ABI) testing and a validated wound classification system allows prompt referral of patients for specialty care. We implemented a program to teach providers ABI testing and the use of the Wound, Ischemia, and foot Infection (WIfI) classification tool. Here, we report program outcomes and provider perceptions.MethodsPhysicians and non-physicians from wound care centers, nursing and physician education programs, primary care offices, and federally qualified health centers were invited to participate in the educational program teaching ABI testing and the use of the WIfI tool. Pretest and posttest responses and intention to use content in the future were assessed with descriptive statistics.ResultsA total of 101 subjects completed the ABI module, and 84 indicated their occupation (59 physicians, 25 non-physicians). Seventy-nine subjects completed the WIfI module, and 89% indicated their occupation (50 physicians, 20 non-physicians). Physicians had lower pre-test knowledge scores for the ABI module than non-physicians (mean scores of 7.9 and 8.2, respectively). Both groups had improved knowledge scores on the post-test (physicians, 13.4; non-physicians, 13.8; P < .001). Non-physicians in practice longer than 10 years at wound care centers had the lowest baseline knowledge scores, whereas physicians in practice for over 10 years had the highest. In the ABI module, the largest knowledge gap included accurately calculating the ABI, followed by the correct use of the Doppler, and management of incompressible vessels. For the WIfI module, providers struggled to accurately score patients based on wound classification. The greatest barriers to the implementation of ABI testing were the availability of trained personnel, followed by limited time for testing. Barriers to the use of the WIfI tool for physicians included lack of time and national guideline support. For non-physicians, the most notable barrier was a lack of training.ConclusionsProvider understanding of ABI and WIfI tools are limited in wound care centers, primary care offices, and federally qualified health centers. Further barriers include a lack of training in the use of tools, limited potential for point-of-care testing reimbursement, and insufficient dissemination of WIfI guidelines. Such barriers discourage widespread adoption and result in delayed diagnosis of arterial insufficiency

Determination of Letrozole in Tablet Formulations by Reversed Phase High Performance Liquid Chromatography

Purpose: To develop a simple, rapid, accurate and cost-effective reversed phase high performance liquid chromatography (RP-HPLC) method for letrozole in bulk and in tablets. Methods: Development of a method for the determination of letrozole, an anti-cancer drug, by RPHPLC was undertaken using a new mobile phase of acetonitrile:water (50:50, v/v). The eluent was monitored at 265 nm. Results: The optimized conditions developed showed a linear response from 160 to 240 μg/mL, with a correlation coefficient (R2) of 0.999. The limit of detection (LOD) and limit of quantification ( LOQ) were 136 and 160 μg/mL, respectively. The assay values for the two branded letrozole tablets tested were 99.2 and 100.2 %, respectively with % relative standard deviation (RSD) of 0.781 and 0.568, respectively. The bench top stability data of the drug in the mobile phase indicate that the drug was stable in the mobile phase for 24 h. Recovery data were good. Placebo study for specificity and interference of common excipients showed that the method was specific and free from interfering substances. Conclusion: Therefore, the fully validated method developed was sensitive enough to carry out routine analysis of letrozole in tablet formulations with regard to its run time, simplicity of sample preparation and accuracy