FAPI PET uptake patterns after invasive medical interventions: a single center retrospective analysis.

PURPOSE: Fibroblast activation protein (FAP)-inhibitor (FAPI)-PET tracers allow imaging of the FAP-expressing cancer associated fibroblasts (CAF) and also the normal activated fibroblasts (NAF) involved in inflammation/fibrosis that may be present after invasive medical interventions. We evaluated [68Ga]Ga-FAPI-46 uptake patterns post-medical/invasive non-systemic interventions. METHODS: This single-center retrospective analysis was conducted in 79 consecutive patients who underwent [68Ga]Ga-FAPI-46 PET/CT. Investigators reviewed prior patient medical/invasive interventions (surgery, endoscopy, biopsy, radiotherapy, foreign body placement (FBP) defined as implanted medical/surgical material present at time of scan) and characterized the anatomically corresponding FAPI uptake intensity both visually (positive if above surrounding background) and quantitatively (SUVmax). Interventions with missing data/images or confounders of [68Ga]Ga-FAPI-46 uptake (partial volume effect, other cause of increased uptake) were excluded. Available correlative FDG, DOTATATE and PSMA PET/CTs were analyzed when available. RESULTS: 163 medical/invasive interventions (mostly surgeries (49%), endoscopies (18%) and non-surgical biopsies (10%)) in 60 subjects were included for analysis. 43/163 (26%) involved FBP. FAPI uptake occurred in 24/163 (15%) of interventions (average SUVmax 3.2 (mild), range 1.5-5.1). The median time-interval post-intervention to FAPI-PET was 47.5 months and was shorter when FAPI uptake was present (median 9.5 months) than when absent (median 60.1 months; p = 0.001). Cut-off time beyond which no FAPI uptake would be present post-intervention without FBP was 8.2 months, with a sensitivity, specificity, positive predictive value and negative predictive value of 82, 90, 99 and 31% respectively. No optimal cutoff point could be determined when considering interventions with FBP. No significant difference was detected between frequency of [68Ga]Ga-FAPI-46 and [18F]FDG uptake in intervention sites. Compared to [68Ga]Ga-PSMA-11, [68Ga]Ga-FAPI-46 revealed more frequent and intense post-interventional tracer uptake. CONCLUSION: [68Ga]Ga-FAPI-46 uptake from medical/invasive interventions without FBP appears to be time dependent, nearly always absent beyond 8 months post-intervention, but frequently present for years with FBP.

STING-driven interferon signaling triggers metabolic alterations in pancreas cancer cells visualized by [18F]FLT PET imaging.

Type I interferons (IFNs) are critical effectors of emerging cancer immunotherapies designed to activate pattern recognition receptors (PRRs). A challenge in the clinical translation of these agents is the lack of noninvasive pharmacodynamic biomarkers that indicate increased intratumoral IFN signaling following PRR activation. Positron emission tomography (PET) imaging enables the visualization of tissue metabolic activity, but whether IFN signaling-induced alterations in tumor cell metabolism can be detected using PET has not been investigated. We found that IFN signaling augments pancreatic ductal adenocarcinoma (PDAC) cell nucleotide metabolism via transcriptional induction of metabolism-associated genes including thymidine phosphorylase (TYMP). TYMP catalyzes the first step in the catabolism of thymidine, which competitively inhibits intratumoral accumulation of the nucleoside analog PET probe 3'-deoxy-3'-[18F]fluorothymidine ([18F]FLT). Accordingly, IFN treatment up-regulates cancer cell [18F]FLT uptake in the presence of thymidine, and this effect is dependent upon TYMP expression. In vivo, genetic activation of stimulator of interferon genes (STING), a PRR highly expressed in PDAC, enhances the [18F]FLT avidity of xenograft tumors. Additionally, small molecule STING agonists trigger IFN signaling-dependent TYMP expression in PDAC cells and increase tumor [18F]FLT uptake in vivo following systemic treatment. These findings indicate that [18F]FLT accumulation in tumors is sensitive to IFN signaling and that [18F]FLT PET may serve as a pharmacodynamic biomarker for STING agonist-based therapies in PDAC and possibly other malignancies characterized by elevated STING expression.

Rapid Purification and Formulation of Radiopharmaceuticals via Thin-Layer Chromatography.

Before formulating radiopharmaceuticals for injection, it is necessary to remove various impurities via purification. Conventional synthesis methods involve relatively large quantities of reagents, requiring high-resolution and high-capacity chromatographic methods (e.g., semi-preparative radio-HPLC) to ensure adequate purity of the radiopharmaceutical. Due to the use of organic solvents during purification, additional processing is needed to reformulate the radiopharmaceutical into an injectable buffer. Recent developments in microscale radiosynthesis have made it possible to synthesize radiopharmaceuticals with vastly reduced reagent masses, minimizing impurities. This enables purification with lower-capacity methods, such as analytical HPLC, with a reduction of purification time and volume (that shortens downstream re-formulation). Still, the need for a bulky and expensive HPLC system undermines many of the advantages of microfluidics. This study demonstrates the feasibility of using radio-TLC for the purification of radiopharmaceuticals. This technique combines high-performance (high-resolution, high-speed separation) with the advantages of a compact and low-cost setup. A further advantage is that no downstream re-formulation step is needed. Production and purification of clinical scale batches of [18F]PBR-06 and [18F]Fallypride are demonstrated with high yield, purity, and specific activity. Automating this radio-TLC method could provide an attractive solution for the purification step in microscale radiochemistry systems.

Application of liquid-phase microextraction to the analysis of plant and herbal samples.

INTRODUCTION: The analysis of plant and herbal samples is a challenging task for analytical chemists due to the complexity of the matrix combined with the low concentration of analytes. In recent years different liquid-phase microextraction (LPME) techniques coupled with a variety of analytical equipment have been developed for the determination of both organic and inorganic analytes. OBJECTIVE: Over the past few years, the number of research papers in this field has shown a markedly growing tendency. Therefore, the purpose of this review paper is to summarise and critically evaluate research articles focused on the application of LPME techniques for the analysis of plant and herbal samples. RESULTS: Due to the complex nature of the samples, the direct application of LPME techniques to the analysis of plants has not often been done. LPME techniques as well as their modalities have been commonly applied in combination with other pretreatment techniques, including a solid-liquid extraction technique supported by mechanical agitation or auxiliary energies for plant analysis. Applications and the most important parameters are summarised in the tables. CONCLUSION: This review summarises the application of the LPME procedure and shows the major benefits of LPME, such as the low volume of solvents used, high enrichment factor, simplicity of operation and wide selection of applicable detection techniques. We can expect further development of microextraction analytical methods that focus on direct sample analysis with the application of green extraction solvents while fully automating procedures for the analysis of plant materials.

Meropenem and ciprofloxacin in complicated gastric surgery for cancer patients: A simple SPE-UHPLC-PDA method for their determination in human plasma.

A simple and rapid ultra-high-performance liquid chromatographic (UHPLC) for the simultaneous determination of meropenem and ciprofloxacin in human plasma was developed and validated. All of the analytes were separated in <5 min. A solid-phase extraction method was applied from sample preparation. Analytical separation was performed on a Poroshell SB C18 column (50 × 2.1 mm, 2.7 µm particle size) with photodiode array (PDA) detection. Meropenem and ciprofloxacin were determined at wavelengths of 300 and 277 nm, respectively. The mobile phase was a mixture of acetonitrile-10 mm ammonium acetate-methanol in gradient elution. The method has been validated for both drugs in gastric surgery for cancer patients. The method showed good linearity with correlation coefficients, r2  = 0.994 for the two drugs, as well as high precision (RSD < 10.5% in each case); accuracy ranged from -5.8 to +6.0%. The limit of quantitation of the two drugs was established at 0.02 and 0.01 µg/mL, respectively. Meropenem, ciprofloxacin and the internal standard were extracted from human plasma with a mean recovery ranging from 92.5 to 98.6%. The method was applied to quantify the drugs dosage in complicated gastric surgery patients.

A Novel Biological Role of α-Mangostin in Modulating Inflammatory Response Through the Activation of SIRT-1 Signaling Pathway.

Several studies have shown that xanthones obtained from Garcinia Mangostana (GM) have remarkable biological activities. α-mangostin (α-MG) is the main constituent of the fruit hull of the GM. Several findings have suggested that SIRT-1, a nuclear histone deacetylase, could influence cellular function by the inhibition of NF-kB signaling. ROS can inhibit SIRT-1 activity by initiating oxidative modifications on its cysteine residues, and suppression of SIRT-1 enhances the NF-κB signaling resulting in inflammatory responses. The goals of the present study were to evaluate the quantity of α-MG in the methanolic extract of GM (Vithagroup Spa) and to investigate the activity of this xanthone in U937 cell line and in human monocytes from responsive to inflammatory insult analyzing the possible changes on the activation of SIRT-1 protein via NF-Kb. Cells were treated with the methanolic extract of GM and/or LPS. The chromatographic separation of α-MG was performed by an HPLC analysis. EX 527, a specific SIRT-1 inhibitor, was used to determine if SIRT-1/NfkB signaling pathway might be involved in α-MG action on cells. Our results show that α-MG inhibits p65 acetylation and down-regulates the pro-inflammatory gene products as COX-2, iNOS via SIRT-1 activation. Cells treated with EX 527 showed an up-regulation of NFkB acetylation and an over expression of inducible enzymes and their product of catalysis (NO and PGE2). These results suggest that α-MG may be useful for the development of alternative pharmacological strategies aimed at reducing the inflammatory process. J. Cell. Physiol. 231: 2439-2451, 2016. © 2016 Wiley Periodicals, Inc.

Stability study of Prulifloxacin and Ulifloxacin in human plasma by HPLC-DAD.

A new and specific HPLC-DAD method for the direct determination of Prulifloxacin and its active metabolite, Ulifloxacin, in human plasma has been developed. Plasma samples were analysed after a simple solid phase extraction (SPE) clean-up using a new HILIC stationary phase based high-performance liquid chromatography (HPLC) column and an ammonium acetate buffer (5 mM, pH 5.8)/acetonitrile (both with 1% Et(3)N, v/v) mobile phase in isocratic elution mode, with Danofloxacin as the internal standard. Detection was performed using DAD from 200 to 500 nm and quantitative analyses were carried out at 278 nm. The LOQ of the method was 1 µg/mL of the cited analytes and the calibration curve showed a good linearity up to 25 µg/mL. For both analytes the precision (RSD%) and the trueness (bias%) of the method fulfil with International Guidelines. The method was applied for stability studies, at three QC concentration levels, in human plasma samples stored at different temperature of + 25, + 4 and -20 °C in order to evaluate plasma stability profiles.

Combined derivatization and high-performance liquid chromatography with fluorescence and ultraviolet detection for simultaneous analysis of octreotide and gabexate mesylate metabolite in human pancreatic juice samples.

A simple and sensitive method based on the combination of derivatization and high-performance liquid chromatography with ultraviolet and fluorimetric detection was developed for the simultaneous determination of octreotide and gabexate mesylate metabolite in human pancreatic juice samples. Parameters of the derivatization procedure affecting extraction efficiency were optimized. The developed method was validated according to the International Conference on Harmonization guidelines. The calibration curves were linear over a range of 0.1-15 µg/mL for octreotide and 0.20-15 µg/mL for gabexate mesylate metabolite. Derivatized products of octreotide and gabexate mesylate metabolite were separated on a Luna C18 column (4.6 × 250 mm; 5 µm particle size) using a gradient with a run time of 36 min, without further purification. The limits of detection were 0.025 and 0.05, respectively, for octreotide and gabexate mesylate metabolite. This paper reports the validation of a quantitative high performance liquid chromatography-photodiode array-fluorescence (HPLC-PDA-FL) method for the simultaneous analysis of octreotide and gabexate mesylate metabolite in pancreatic juice by protein precipitation using zinc sulfate-methanol-acetonitrile containing the derivatizing reagent, 4-fluoro-7-nitro-[2,1,3]-benzoxadiazole (NBD-F). Derivatized products of octreotide and gabexate mesylate metabolite were separated on a Luna C18 column (4.6 × 250 mm; 5 µm particle size) using a gradient with a run time of 36 min, without further purification. The method was validated over the concentration ranges 0.1-15 and 0.2-15 µg/mL for octreotide and gabexate mesylate metabolite, respectively, in human pancreatic juice. Biphalin and methyl-p-hydroxybenzoate were used as the internal standards. This method was successfully utilized to support clinical studies in humans. The results from assay validations show that the method is selective, sensitive and robust. The limit of quantification of the method was 0.1 µg/mL for octreotide and 0.2 µg/mL for gabexate mesylate metabolite, and matrix matched standard curves showed a good linearity up to 15 µg/mL. In the entire analytical range the intra- and inter-day precision (RSD%) values were respectively ≤5.9% and ≤3.1% for octreotide and ≤2.0% and ≤3.9% for gabexate mesylate metabolite. For both analytes the intra- and inter-day accuracy (bias) values ranged respectively from -6.8 to -2.5% and from -4.6 to -5.7%. This method utilizes derivatization with NBD-F and provides adequate sensitivity for both drugs.

Analysis of biologically active oxyprenylated ferulic acid derivatives in Citrus fruits.

4'-Geranyloxyferulic (GOFA) and boropinic acid have been discovered during the last decade as interesting phytochemicals having valuable pharmacological effects as cancer chemopreventive, anti-inflammatory, neuroprotective, and anti-Helicobacter pylori agents. A reverse-phase HPLC-UV/Vis method for the separation and quantification of the title oxyprenylated ferulic acid derivatives in extracts obtained from peels of nine edible Citrus and Fortunella fruits was successfully applied. Concentration values showed a great variation between the different species, being orange (C. sinensis) the fruit richest in GOFA (0.141 ± 0.011 mg/g of exocarp fresh weight) and kumquat (Fortunella japonica) the one in which boropinic acid was recorded as the most abundant phytochemical (0.206 ± 0.002 mg/g of exocarp fresh weight). Both secondary metabolites were not detected only in three species. The set-up methodology showed limits of quantification (LOQ) values, that were able to selectively quantify both GOFA and boropinic acid. Results described herein depict a potential chemopreventive dietary feeding role for the Rutaceae spp. under investigation.

Evaluation of a technetium-99m labeled bombesin homodimer for GRPR imaging in prostate cancer.

Multimerization of peptides can improve the binding characteristics of the tracer by increasing local ligand concentration and decreasing dissociation kinetics. In this study, a new bombesin homodimer was developed based on an ε-aminocaproic acid-bombesin(7-14) (Aca-bombesin(7-14)) fragment, which has been studied for targeting the gastrin-releasing peptide receptor (GRPR) in prostate cancer. The bombesin homodimer was conjugated to 6-hydrazinopyridine-3-carboxylic acid (HYNIC) and labeled with (99m)Tc for SPECT imaging. The in vitro binding affinity to GRPR, cell uptake, internalization and efflux kinetics of the radiolabeled bombesin dimer were investigated in the GRPR-expressing human prostate cancer cell line PC-3. Biodistribution and the GRPR-targeting potential were evaluated in PC-3 tumor-bearing athymic nude mice. When compared with the bombesin monomer, the binding affinity of the bombesin dimer is about ten times lower. However, the (99m)Tc labeled bombesin dimer showed a three times higher cellular uptake at 4 h after incubation, but similar internalization and efflux characters in vitro. Tumor uptake and in vivo pharmacokinetics in PC-3 tumor-bearing mice were comparable. The tumor was visible on the dynamic images in the first hour and could be clearly distinguished from non-targeted tissues on the static images after 4 h. The GRPR-targeting ability of the (99m)Tc labeled bombesin dimer was proven in vitro and in vivo. This bombesin homodimer provides a good starting point for further studies on enhancing the tumor targeting activity of bombesin multimers.

18F-FDG PET Visualizes Systemic STING Agonist-Induced Lymphocyte Activation in Preclinical Models.

Stimulator of interferon genes (STING) is a mediator of immune recognition of cytosolic DNA, which plays important roles in cancer, cytotoxic therapies, and infections with certain pathogens. Although pharmacologic STING activation stimulates potent antitumor immune responses in animal models, clinically applicable pharmacodynamic biomarkers that inform of the magnitude, duration, and location of immune activation elicited by systemic STING agonists are yet to be described. We investigated whether systemic STING activation induces metabolic alterations in immune cells that can be visualized by PET imaging. Methods: C57BL/6 mice were treated with systemic STING agonists and imaged with 18F-FDG PET after 24 h. Splenocytes were harvested 6 h after STING agonist administration and analyzed by single-cell RNA sequencing and flow cytometry. 18F-FDG uptake in total splenocytes and immunomagnetically enriched splenic B and T lymphocytes from STING agonist-treated mice was measured by γ-counting. In mice bearing prostate or pancreas cancer tumors, the effects of STING agonist treatment on 18F-FDG uptake, T-lymphocyte activation marker levels, and tumor growth were evaluated. Results: Systemic delivery of structurally distinct STING agonists in mice significantly increased 18F-FDG uptake in the spleen. The average spleen SUVmax in control mice was 1.90 (range, 1.56-2.34), compared with 4.55 (range, 3.35-6.20) in STING agonist-treated mice (P < 0.0001). Single-cell transcriptional and flow cytometry analyses of immune cells from systemic STING agonist-treated mice revealed enrichment of a glycolytic transcriptional signature in both T and B lymphocytes that correlated with the induction of immune cell activation markers. In tumor-bearing mice, STING agonist administration significantly delayed tumor growth and increased 18F-FDG uptake in secondary lymphoid organs. Conclusion: These findings reveal hitherto unknown functional links between STING signaling and immunometabolism and suggest that 18F-FDG PET may provide a widely applicable approach toward measuring the pharmacodynamic effects of systemic STING agonists at a whole-body level and guiding their clinical development.

Highlight selection of radiochemistry and radiopharmacy developments by editorial board.

BACKGROUND: The Editorial Board of EJNMMI Radiopharmacy and Chemistry releases a biannual highlight commentary to update the readership on trends in the field of radiopharmaceutical development. MAIN BODY: This selection of highlights provides commentary on 21 different topics selected by each coauthoring Editorial Board member addressing a variety of aspects ranging from novel radiochemistry to first-in-human application of novel radiopharmaceuticals. CONCLUSION: Trends in radiochemistry and radiopharmacy are highlighted. Hot topics cover the entire scope of EJNMMI Radiopharmacy and Chemistry, demonstrating the progress in the research field in many aspects.

Recent application of analytical methods to phase I and phase II drugs development: a review.

Drug development is a time-consuming and costly process. It is usually divided into four phases, although it is not always possible to draw a sharp line between the various stages. In phase I and II there are many molecules investigate and it is necessary to analyze all of them in a short period of time, with lower costs, and with high-throughput assay. During phase I relevant chemical-physical parameters like the acid dissociation constant, lipophilicity, solubility and stability must be analyzed. Classic techniques such as 'shake-flask' can be used, but instrumental analytical methods such as HPLC may be helpful to improve and enhance the productivity and reproducibility of the results. During phase II the activity of a drug and factors that may have an influence on it, like metabolic profile and transformations, impurities and plasma biding proteins, must be considered. In this field, recent hyphenated analytical methods, such as LC-MS/MS, GC-MS/MS or more complex couplings, can provide more complete information. The aim of this review is to report the processes required for the validation of drug efficacy with reference to the description of 'classic' and modern techniques used.

Highlight selection of radiochemistry and radiopharmacy developments by editorial board.

BACKGROUND: The Editorial Board of EJNMMI Radiopharmacy and Chemistry releases a biannual highlight commentary to update the readership on trends in the field of radiopharmaceutical development. MAIN BODY: This commentary of highlights has resulted in 21 different topics selected by each coauthoring Editorial Board member addressing a variety of aspects ranging from novel radiochemistry to first in man application of novel radiopharmaceuticals. CONCLUSION: Trends in radiochemistry and radiopharmacy are highlighted demonstrating the progress in the research field in various topics including new PET-labelling methods, FAPI-tracers and imaging, and radionuclide therapy being the scope of EJNMMI Radiopharmacy and Chemistry.

Correlation of 68Ga-FAPi-46 PET Biodistribution with FAP Expression by Immunohistochemistry in Patients with Solid Cancers: Interim Analysis of a Prospective Translational Exploratory Study.

Fibroblast activation protein (FAP)-expressing cancer-associated fibroblasts confer treatment resistance and promote metastasis and immunosuppression. Because FAP is overexpressed in many cancers, radiolabeled molecules targeting FAP are studied for their use as pancancer theranostic agents. This study aimed to establish the spectrum of FAP expression across various cancers by immunohistochemistry and to explore whether 68Ga FAP inhibitor (FAPi)-46 PET biodistribution faithfully reflects FAP expression from resected cancer and non-cancer specimens. Methods: We conducted a FAP expression screening using immunohistochemistry on a pancancer human tissue microarray (141 patients, 14 different types of cancer) and an interim analysis of a prospective exploratory imaging trial in cancer patients. Volunteer patients underwent 1 whole-body 68Ga-FAPi-46 PET/CT scan and, subsequently, surgical resection of their primary tumor or metastasis. 68Ga-FAPi-46 PET SUVmax and SUVmean was correlated with FAP immunohistochemistry score in cancer and tumor-adjacent non-cancer tissues for each patient. Results: FAP was expressed across all 14 cancer types on tissue microarray with variable intensity and frequency, ranging from 25% to 100% (mean, 76.6% ± 25.3%). Strong FAP expression was observed in 50%-100% of cancers of the bile duct, bladder, colon, esophagus, stomach, lung, oropharynx, ovary, and pancreas. Fifteen patients with various cancer types (colorectal [n = 4], head and neck [n = 3], pancreas [n = 2], breast [n = 2], stomach [n = 1], esophagus [n = 2], and uterus [n = 1]) underwent surgery after their 68Ga-FAPi-46 PET/CT scan within a mean interval of 16.1 ± 14.4 d. 68Ga-FAPi-46 SUVs and immunohistochemistry scores were higher in cancer than in tumor-adjacent non-cancer tissue: mean SUVmax 7.7 versus 1.6 (P < 0.001), mean SUVmean 6.2 versus 1.0 (P < 0.001), and mean FAP immunohistochemistry score 2.8 versus 0.9 (P < 0.001). FAP immunohistochemistry scores strongly correlated with 68Ga-FAPi 46 SUVmax and SUVmean: r = 0.781 (95% CI, 0.376-0.936; P < 0.001) and r = 0.783 (95% CI, 0.379-0.936; P < 0.001), respectively. Conclusion: In this interim analysis of a prospective exploratory imaging trial, 68Ga-FAPi-46 PET biodistribution across multiple cancers strongly correlated with FAP tissue expression. These findings support further exploration of FAPi PET as a pancancer imaging biomarker for FAP expression and as a stratification tool for FAP-targeted therapies.

68Ga-PSMA-11 NDA Approval: A Novel and Successful Academic Partnership.

The University of California Los Angeles (UCLA) and University of California San Francisco (UCSF) codeveloped 68Ga-PSMA-11 by conducting a bicentric pivotal phase 3 clinical trial for PET imaging for prostate cancer. On December 1, 2020, 2 separate new drug applications (NDAs) submitted by each institution (NDA 212642 for UCLA and NDA 212643 for UCSF) were approved by the Food and Drug Administration as the first drug for PET imaging of prostate-specific membrane antigen (PSMA)-positive lesions in men with prostate cancer. This article briefly describes the background, clinical development, regulatory approach, and regulatory process for NDA filing and approval. In the second part of this article, key chemistry, manufacturing, and controls (CMC) information is provided to facilitate abbreviated new drug application (ANDA) submission.

Highlight selection of radiochemistry and radiopharmacy developments by editorial board (January-June 2020).

BACKGROUND: The Editorial Board of EJNMMI Radiopharmacy and Chemistry releases a biyearly highlight commentary to describe trends in the field. RESULTS: This commentary of highlights has resulted in 19 different topics selected by each member of the Editorial Board addressing a variety of aspects ranging from novel radiochemistry to first in man application of novel radiopharmaceuticals. CONCLUSION: Trends in radiochemistry and radiopharmacy are highlighted demonstrating the progress in the research field being the scope of EJNMMI Radiopharmacy and Chemistry.

Highlight selection of radiochemistry and radiopharmacy developments by editorial board.

BACKGROUND: The Editorial Board of EJNMMI Radiopharmacy and Chemistry releases a biyearly highlight commentary to update the readership on trends in the field of radiopharmaceutical development. RESULTS: This commentary of highlights has resulted in 23 different topics selected by each member of the Editorial Board addressing a variety of aspects ranging from novel radiochemistry to first in man application of novel radiopharmaceuticals. CONCLUSION: Trends in radiochemistry and radiopharmacy are highlighted demonstrating the progress in the research field being the scope of EJNMMI Radiopharmacy and Chemistry.

HPLC-DAD method for the simultaneous determination of zofenopril and hydrochlorothiazide in oral pharmaceutical formulations.

An HPLC method with DAD detection was developed and validated for the simultaneous determination of zofenopril and hydrochlorothiazide in tablets. The separation was carried out through a gradient elution using an Agilent LiChrospher C18 column (250x4.0 mm id, 5 microm) and a mobile phase consisting of (A) water-TFA (99.9:0.1 v/v) and (B) acetonitrile-TFA (99.1:0.1 v/v) delivered at a flow-rate of 1.0 mL/min. 8-Chlorotheophylline was used as internal standard. Calibration curves were found to be linear for the two drugs over the concentration ranges of 5.0-40 and 1.0-20 microg/mL for zofenopril and hydrochlorothiazide, respectively. Linearity, precision, accuracy, specificity and robustness were determined in order to validate the proposed method, which was further applied to the analysis of commercial tablets. The proposed method is simple and rapid, and gives accurate and precise results.

RP-HPLC method with fluorescence detection for amino acids D/L ratio determination in fossil bones as a marker of DNA preservation.

Only a small proportion of old specimens contain DNA that can be amplified by PCR. Therefore, rapid screening methods are crucial to identify the large fraction of samples that are so badly preserved that there is no need to attempt DNA extraction. In particular, the extent of racemization of some amino acids has proved to be a very useful proxy for DNA preservation. In this study, a rigorous method for the determination of the D/L ratio for aspartic acid and alanine by RP-HPLC with fluorescence detection was developed with the aim to obtain a fast and cheap procedure for both sample preparation and amino acids analysis, without compromising precision and accuracy.