Treatment of H. pylori infection and gastric ulcer: Need for novel Pharmaceutical formulation.

Peptic ulcer disease (PUD) is one of the most prevalent gastro intestinal disorder which often leads to painful sores in the stomach lining and intestinal bleeding. Untreated Helicobacter pylori (H. pylori) infection is one of the major reasons for chronic PUD which, if left untreated, may also result in gastric cancer. Treatment of H. pylori is always a challenge to the treating doctor because of the poor bioavailability of the drug at the inner layers of gastric mucosa where the bacteria resides. This results in ineffective therapy and antibiotic resistance. Current treatment regimens available for gastric ulcer and H. pylori infection uses a combination of multiple antimicrobial agents, proton pump inhibitors (PPIs), H2-receptor antagonists, dual therapy, triple therapy, quadruple therapy and sequential therapy. This polypharmacy approach leads to patient noncompliance during long term therapy. Management of H. pylori induced gastric ulcer is a burning issue that necessitates alternative treatment options. Novel formulation strategies such as extended-release gastro retentive drug delivery systems (GRDDS) and nanoformulations have the potential to overcome the current bioavailability challenges. This review discusses the current status of H. pylori treatment, their limitations and the formulation strategies to overcome these shortcomings. Authors propose here an innovative strategy to improve the H. pylori eradication efficiency.

Validated HPLC method for ceftriaxone from dried blood spots for pharmacokinetic studies and therapeutic drug monitoring in neonatal population.

Background: Pharmacokinetic evaluation is essential for the precise dosing of ceftriaxone in neonates. There is a need for developing a sensitive, affordable and convenient analytical method that can estimate ceftriaxone from dried blood spot (DBS) samples of neonates. Method: An HPLC-UV method was developed and validated as per ICH M10 for ceftriaxone from DBS and plasma using an Inertsil-ODS-3V column with gradient elution. DBS samples were extracted with methanol. Clinical validation was performed using neonatal samples. Results: The developed plasma- and DBS-based-HPLC method were linear from 2-700 µg/ml and 2-500 µg/ml, respectively, for ceftriaxone. Bland-Altman analysis indicated a strong interconvertibility between the plasma and DBS assays. Conclusion: Observed concentrations in clinical samples were comparable to the predicted concentrations, proving the clinical validity of the method.

Neonatal meningitis is usually treated with the drug ceftriaxone. It is essential to determine the amount of ceftriaxone in the blood for precise dosing that is safe and effective in newborn children. Dried blood spot (DBS) sampling from a heel prick is a less invasive sample collection method for newborn children than withdrawing blood from a vein. In this study we developed a robust analytical method based on a commonly available analytical platform to measure ceftriaxone in DBS samples. The results of ceftriaxone analysis obtained using the developed DBS-based method were compared with the results of traditional plasma sample analysis to make sure that they are accurate and reproducible. The range of analysis of the method is 2­500 µg/ml, which is suitable for the measurement of ceftriaxone concentration levels in newborns' blood. The effect of varying proportions of red blood cells in whole blood (30­50%) and volume of blood (20­60 µl) applied on the DBS card were not found to influence the results. The method was validated with clinical samples from newborn children and resulted in the expected concentrations. The developed method is affordable and can be used for therapeutic drug monitoring and precise dosing of ceftriaxone in newborn children.

Predictive Performance of Population Pharmacokinetic Models for Amikacin in Term Neonates.

BACKGROUND AND OBJECTIVE: Amikacin is preferred in treating Gram-negative infections in neonates and it has a narrow therapeutic window. The population pharmacokinetic modeling approach can aid in designing optimal dosage regimens for amikacin in neonates. In this study, we attempted to identify the suitable population pharmacokinetic model from the published reports for the study population from an Indian setting. METHODS: Published population pharmacokinetic studies for amikacin in neonates were identified. Data on structural models and typical pharmacokinetic parameters were extracted from the studies. For the clinical study, neonates who met the inclusion criteria were enrolled in the study from the NICU, Kasturba Medical College, Manipal, during Jan 2020 to March 2022. Drug concentrations were estimated, and demographic and clinical data were collected. Identified population pharmacokinetic models were used to predict the amikacin concentrations in neonates. Predicted concentrations were compared against the observed concentrations. Differences between predicted and observed concentrations were quantified using statistical measures. The population pharmacokinetic model, which was able to predict the data well, is considered a suitable model for the study population. Dosing regimens were suggested for neonates using the pharmacometric simulation approach generated by the selected model. RESULTS: A total of 43 plasma samples were collected from 31 neonates. Twelve population pharmacokinetic models were found for amikacin in neonates. The predictive performance of the 12 studies was performed using clinical data. A two-compartment model reported by Illamola et al. predicted the amikacin concentrations better than other models. Illamola et al. reported creatinine clearance and body weight as the significant covariates impacting the pharmacokinetic parameters of amikacin. This model was able to predict the clinical data with 29.97% and 0.686 of relative median absolute prediction error and relative root mean square error, respectively, which is the best among the published models. The Illamola et al. model was selected as the final model to perform pharmacometric simulations for the subjects with different combinations of creatinine clearance and body weight. Dosage regimens were designed to attain target therapeutic concentrations for the virtual subjects and a nomogram was developed. CONCLUSIONS: The population pharmacokinetic model reported by the Illamola et al. model was selected as the final model to explain the clinical data with the lowest relative median absolute prediction error and relative root mean square error when compared with other models. An amikacin nomogram was developed for the neonates whose creatinine clearance and body weight ranged between 10 and 90 mL/min and between 2 and 4 kg, respectively. A developed nomogram can assist clinicians to design an optimal dosage regimen of amikacin for term neonates.

In vitro antibacterial activity and in vivo pharmacokinetics of intravenously administered Amikacin-loaded Liposomes for the management of bacterial septicaemia.

Systemic delivery of amikacin is a widely adopted treatment modality for severe infections like sepsis. However, the current course of treatment requires repeated bolus doses of amikacin, prolonged hospitalization, and continuous therapeutic monitoring to manage the severe adverse effects. Amikacin has short half-life, which further challenges the delivery of sufficient systemic concentrations when administered by intravenous route. To solve this issue, novel delivery systems, amikacin liposomes (Ak-lip) were developed and evaluated for its antibacterial efficacy (agar plate diffusion and resazurin microtiter assay) and in vivo drug release in Sprague-Dawley rats. The Ak-lip were prepared by modified thin film hydration method and optimized based on particle size and Zeta potential. The zone of inhibition for Ak-lip and amikacin was found to be 22 mm and 26 mm against Staphylococcus aureus. The minimum inhibitory concentrations (MIC) of amikacin and Ak-lip against Staphylococcus aureus were found to be 3 µg/mL and 9 µg/mL, and for Pseudomonas aeruginosa were 0.6 µg/mL and 0.9 µg/mL respectively. The in vivo pharmacokinetic parameters were determined using Gastroplus™. A significant difference in the pharmacokinetic parameters (AUC, Cmax) was observed between amikacin and Ak-lip. The developed formulation showed good colloidal stability and sustained release profile up to 72 h which can reduce dosing frequency, minimize hospitalization and improve bactericidal activity at lower concentrations paving the path for improved therapeutic interventions in the treatment of sepsis.

Need and Viability of Newborn Screening Programme in India: Report from a Pilot Study.

India, a country with the second largest population in the world, does not have a national newborn screening programme as part of its health policy. With funding support from the Grand Challenges Canada, a pilot newborn screening programme was implemented for the Udupi district of South India to study the need and viability of a national programme in India. Six disorders were selected for the study based on the availability of funding and recommendation from pediatricians in the district. Here, we report the observed incidence during the study. A cost-effectiveness analysis of implementing newborn screening in India was performed. It is evident from our analysis that the financial loss for the nation due to these preventable diseases is much higher than the overall expenditure for screening, diagnosis, and treatment. This cost-effectiveness analysis justifies the need for a national newborn screening programme in India.

Bioanalytical method development and validation of highly selective and sensitive LC-MS/MS method for determination of teriparatide (parathyroid hormone fragment 1-34) in human serum through direct detection of intact teriparatide molecule.

Teriparatide is a novel recombinant peptide fragment of the first 1-34 amino acids of human parathyroid recommended for treatment of osteoporosis. Therapeutic proteins and peptides are routinely estimated using ligand binding assay formats however LC-MS/MS technique which is routinely used in bioanalysis of small molecules has now gained importance in large molecule bioanalysis for the advantages it can offer over LBAs in terms of improved accuracy, selectivity and anti-body free method development. This paper presents a sensitive bioanalytical method for determination of teriparatide in human serum using ultra performance liquid chromatography aligned with tandem mass spectrometric detection. Teriparatide was isolated from human serum using solid phase extraction. The intact peptide was separated on a chromatograph and the multiply charged ion (+7) was detected using a mass spectrometer. The total run time was 4.0 min. The internal standard used was rat PTH 1-34 fragment. The mass transitions of m/z 589.3 > 656.3 for teriparatide and m/z 677.4 > 778.6 for internal standard were used for MS/MS detection. The sample extraction involved a solid phase extraction method followed by concentration of the eluent by evaporation and subsequent reconstitution. The non-specific binding effect caused by the adherence of the peptides/proteins to the vials/tube walls was significantly reduced by using BSA solution as blocking agent. The method has been validated over a linear range of 15.07-913.3 pg/mL with a correlation coefficient ≥ 0.99. The precision (%RSD) was 6.36 to 10.85 and accuracy was within 96.71% to 100.88%. A two-treatment, two-period, cross over study was conducted to establish bioequivalence between test and reference formulation (20 mcg/80 mL - solution for injection) and the method was successfully applied to quantify teriparatide in serum samples of this clinical study and about 1220 human serum samples were analyzed to determine teriparatide. This method is a promising anti-body free LC-MS/MS based methodology for estimation of teriparatide in human serum and may be applied as starting method for other such peptide molecules.

Validation of an HPLC method for estimation of cefotaxime from dried blood spot: alternative to plasma-based PK evaluation in neonates.

Aim: Pharmacokinetic evaluation of cefotaxime in neonates is currently a challenge due to the large volume requirement of blood for its analysis by existing methods. A dried blood spot (DBS) based method is the best alternative. Materials & methods: We validated an HPLC method for estimation of cefotaxime from DBS and plasma. Extraction employed a simple procedure using acetonitrile and buffer. Selective separation of cefotaxime was achieved on a C8 column using gradient programming. Results & conclusion: The linearity of the method ranged from 2 to 200 µg/ml with acceptable precision and accuracy for both plasma and DBS. Hematocrit was not affecting the assay accuracy. A strong correlation and interchangeability observed with the plasma method proves its clinical validity for application to PK evaluations.

Lay abstract Cefotaxime is a widely used antibiotic in the neonatal population for treating bacterial infections. At the same time, determining the dosage for this antibiotic in the vulnerable population is always a challenge for the treating doctor. In the case of neonates, organs are not fully developed and their response to drugs will be different from that of adults. In the current clinical practice, dosage for neonates is deduced from pediatric dose without addressing this difference in the response. The major challenge in addressing this issue is the collection of blood by venipuncture from neonates for drug analysis. In this report, a microsampling technique called dried blood spot is used for sampling and bioanalysis of cefotaxime. The method is validated for estimation of cefotaxime from the neonatal blood.

A selective and sensitive UPLC-ESI-MS/MS method for quantification of Pegylated Interferon Alfa-2b in human serum using signature peptide-based quantitation.

A sensitive method for determination of PEG-IFN-α-2b in human serum was developed using ultra performance liquid chromatography aligned with tandem mass spectrometric detection. A two-treatment, two-period, cross over study was conducted to establish bioequivalence between a test and reference formulation and the method was successfully applied to the quantification of PEG-IFN-α-2b in serum samples of this clinical study. The sample concentrations obtained from LC-MS/MS technique were compared with the concentrations obtained from ELISA technique. PEG-IFN-α-2b was isolated from serum using protein precipitation technique with isopropyl alcohol followed by overnight tryptic digestion. The signature peptide formed as result of tryptic digestion was separated on a chromatograph and detected using a mass detector. The mass transition ion-pair of m/z 741.3 → 1047.1 for PEG-IFN-α-2b and m/z 387.4 → 205.2 for internal standard were used for MS/MS detection. The sample extraction involves a simple protein precipitation method followed by tryptic digestion of the supernatant and further sample cleanup was not needed. The method has been validated over a linear range of 1.028-3200 ng/mL with a correlation coefficient ≥ 0.99. The precision (%RSD) was 5.52 to 7.90 and accuracy (%RE) was within -1.80 to 1.68. The total run time was 22.0 min. The sensitivity of LC-MS/MS method was 1.0 ng/ml which was found to be more sensitive than ELISA and resulted in improving the overall study data by being able to quantify all the samples without any below LOQ results helping to further improve the pharmacokinetic modeling. This improved method is a promising anti-body free LC-MS/MS based methodology for estimation of PEG-IFN-α-2b in human serum and may be applied for other such pegylated molecules.

Antidepressant-like effect of dehydrozingerone from Zingiber officinale by elevating monoamines in brain: in silico and in vivo studies.

BACKGROUND: Dehydrozingerone (DHZ) is an active ingredient of Zingiber officinale and structural half analogue of curcumin. In the present study, DHZ was evaluated for monoamine oxidase (MAO) inhibitory activity in silico and antidepressant activity in vivo. METHOD: The binding affinity of DHZ with MAO-A (PDB ID: 2Z5Y) was assessed using Schrodinger's Maestro followed by free energy calculation, pharmacokinetic property prediction using Qikprop and Molecular dynamics simulation using Desmond. In vivo antidepressant activity of DHZ was evaluated on C57 BL/6 male mice using Escilatopram as the standard antidepressant. Open field test (OFT), forced swimming test (FST) and tail suspension test (TST) were used to evaluate the antidepressant effect of the drugs on days 1 and 7. Following the behavioural study, neurotransmitters (noradrenaline, dopamine and serotonin) were estimated using liquid chromatography-mass spectrometry. RESULTS: DHZ demonstrated a greater binding affinity for the MAO-A enzyme compared to moclobemide in silico. Immobility in TST and FST were significantly (p < 0.05) reduced in vivo with 100mg/kg DHZ as compared to respective controls. DHZ treatment was more effective 1 h post treatment compared to vehicle control. A significant increase in levels of neurotransmitters was observed in mice brain homogenate in response to DHZ treatment, reassuring its antidepressant-like potential. CONCLUSION: DHZ demonstrated MAO-A inhibition in silico, and the increased neurotransmitter levels in the brain in vivo were associated with an antidepressant-like effect.

Biomarker profiling of vitamin responsive seizures: a potential tool to detect pediatric seizures of unknown aetiology.

Aim: Certain rare inborn errors of metabolism clinically present with intractable seizures that readily respond to vitamin therapy. If identified early, brain damage due to seizures can be prevented. Methodology: A LC-MS method was developed and validated for the simultaneous quantification of the biomarkers in selected vitamin responsive pediatric seizures from dried blood spots. Results: Application of the validated method to a seizure cohort of 46 patients indicated strong agreement of the method for clinical validity. Reference intervals for these biomarkers in dried blood spots were also determined for the population, after screening 956 neonates. Conclusion: The developed method was seen to be sensitive, linear, accurate and precise for testing vitamin responsive pediatric seizures.

Development and validation of a dried blood spot test for thiamine deficiency among infants by HPLC-fluorimetry.

Thiamine deficiency, if detected early in infancy, can be treated with thiamine supplementation and can prevent seizures, other disabilities and death. The dried blood spot (DBS) sampling technique is an attractive sample collection technique for infants. The present study reports the development and validation of a highly sensitive and precise method for quantification of thiamine diphosphate from DBS. The method utilizes full-spot analysis of a volumetrically deposited 40 µl DBS. The analyte was extracted from the DBS using 50% methanol and then derivatized using potassium ferricyanide to thiochrome. Separation was achieved with the help of an Inertsil ODS C18 column (5.0 µm, 250 × 4.6 mm) using 150 mm phosphate buffer pH 7-acetonitrile (90:10, % v/v) as the mobile phase. The use of a fluorimetric detector gave a good response to the thiochrome derivative offering good sensitivity for the method. The excitation and emission wavelengths were 367 and 435 nm, respectively. The limit of detection and lower limit of quantification were 5 and 10 ng/ml, respectively. Linearity was demonstrated from 10 to 1000 ng/ml, and precision (CV) was <12.08%, at all tested quality control levels. The method accuracy was 89.34-118.89% with recoveries >80%. Bland-Altman analysis of DBS sampling vs. whole blood demonstrated a mean bias of only 1.16 ng/ml, with a majority of the 60 investigated patient samples lying within 7.2% of the corresponding concentration measured in blood, thereby meeting the clinical desirable biological specification criterion and showing that the two methods are comparable.

Novel HILIC-ESI-MS method for urinary profiling of MSUD and methylmalonic aciduria biomarkers.

Methyl malonic acid and branched-chain keto acids are important biomarkers for the diagnosis of cobalamin deficiencies and maple syrup urine disease. We report the development and validation of a HILIC-ESI-MS2 method for the quantification of these organic acids from neonatal urine. The samples were 100 times diluted and analyzed on a ZIC-HILIC column with 25-mM formic acid in water: 25-mM formic acid in acetonitrile (45:55) at a flow rate of 0.8 mL/min with a runtime of only 6 minutes. The method demonstrated a lower limit of detection of 10 ng/mL, Limit of Quantification (LOQ) of 50 ng/mL, linearity of r2 ≥ 0.990 and recoveries of 87-105% for all analytes. The intraday and interday precision CV's were <10% and 12%, respectively. Extensive stability studies demonstrated the analytes to be stable in stock and in matrix with a percent change within ±15%. The Bland-Altman analysis of the developed method with the gold standard GCMS method demonstrated a bias of 0.44, 0.11, 0.009 and -0.19 for methyl malonic acid, 3-methyl-2-oxovaleric acid, 2-hydroxy-3methylbutyric acid and 4-methyl-2-oxovaleric acid, respectively, proving the methods are comparable. The newly developed method involves no derivatization and has a simple sample preparation and a low runtime, enabling it to be easily automated with a high sample throughput in a cost-effective manner.

Cost-Effective HPLC-UV Method for Quantification of Vitamin D2 and D3 in Dried Blood Spot: A Potential Adjunct to Newborn Screening for Prophylaxis of Intractable Paediatric Seizures.

25-Hydroxyvitamin D (25-(OH)D) deficiency is recently been described as one of the multiple factors responsible for pediatric seizures. 25-Hydroxyvitamin D3 and 25-Hydroxyvitamin D2 are the well-known markers to determine Vitamin D status. In this work we report the development of a sensitive and cost effective HPLC technique for the quantification of the vitamin D metabolites from dried blood spot samples (DBS). The metabolites were extracted using acetonitrile-methanol-0.1% formic acid (60 : 20 : 20 (v/v)) and analyzed on an Acclaim C18 column (150 × 4.6 mm i.d., 3 µm) at a flow rate of 1 mL/min. The method was linear in the range of 10-80 ng/mL. Limit of detection and limit of quantification (LOQ) of the method were 5 and 10 ng/mL respectively. Extensive stability studies demonstrated the analytes to be stable in stock and matrix with a percent change within the acceptable range of ±15%. Comparison of the newly developed HPLC-DBS method with the reported LC-MS-DBS and electrochemiluminescence immunoassay (ECLIA) methods followed by Bland-Altman analysis demonstrated a bias of 0.08 and -0.14, respectively proving the methods are comparable. Application of the developed method to a pediatric seizure cohort depicted 46.6% of cases as deficient and 26.6% as insufficient for 25-(OH)D. Among deficient cases 8 samples were below 10 ng/mL and exact amount was not calculated since these were below the LOQ levels. The mean ± standard deviation (S.D.) in the remaining 6 deficient cases was 13.22 ± 2.80 ng/mL. The levels in healthy infants were 33.9 ± 6.11 ng/mL. The method can be used routinely for assessing 25-(OH)D deficiency in newborn.

Biomarker Profiling for Pyridoxine Dependent Epilepsy in Dried Blood Spots by HILIC-ESI-MS.

Pyridoxine dependent epilepsy is a condition where the affected infant or child has prolonged seizures (status epilepticus), which are nonresponsive to anticonvulsant therapy but can be treated with pharmacological doses of pyridoxine. If identified earlier and treated prophylactically with pyridoxine, severe brain damage due to seizures can be prevented. Alpha-amino adipic semialdehyde (AASA), piperidine-6-carboxylic acid (P6C), and pipecolic acid (PA) are known biomarkers of pyridoxine dependent epilepsy. We report the development and validation of a hydrophilic interaction liquid chromatography (HILIC) hyphenated with mass spectroscopy for the quantification of the above analytes from dried blood spot samples. The samples were extracted using methanol and analysed on a iHILIC fusion plus column with formic acid buffer (pH 2.5): acetonitrile (20:80) at a flow rate of 0.5 mL/min within 3 minutes. The method demonstrated a LOD of 10 ng/mL, LOQ of 50 ng/mL, linearity of r2 ≥ 0.990, and recovery of 92-101.98% for all analytes. The intra- and interday precision CVs were < 8% and 6%, respectively. Extensive stability studies demonstrated that the analytes were stable in stock solution and in matrix when stored at -80°C. We performed method comparison studies of the developed method with the literature reported method using normal samples and matrix matched spiked samples at pathological concentrations to mimic clinical validity. The Bland-Altman analysis for comparison of the analytical suitability of the method for the biomarkers in healthy and spiked samples with the literature reported method revealed a bias which suggested that the method was comparable. The newly developed method involves no derivatisation and has a simple sample preparation and a low run time enabling it to be easily automated with a high sample throughput in a cost-effective manner.

Selected novel 5'-amino-2'-hydroxy-1, 3-diaryl-2-propen-1-ones arrest cell cycle of HCT-116 in G0/G1 phase.

A series of 5'-amino-2'-hydroxy-1,3-diaryl-2-propen-1-ones (AC1-AC15) were synthesized by Claisen-Schmidt condensation of 5'-acetamido-2'-hydroxy acetophenone with various substituted aromatic aldehydes. The synthesized compounds were characterized by FTIR, (1)H NMR and mass spectrometry and evaluated for their selective cytotoxicity using MTT assay on two cancer cell lines namely breast cancer cell line (MCF-7), colon cancer cell line (HCT-116) and one normal kidney epithelial cell line (Vero). Among the tested compounds, AC-10 showed maximum cytotoxic effect on MCF-7 cell line with IC50 value 74.7 ± 3.5 µM. On HCT-116 cells, AC-13 exhibited maximum cytotoxicity with IC50 value 42.1 ± 4.0 µM followed by AC-14 and AC-10 with IC50 values 62 ± 2.3 µM and 95.4 ± 1.7 µM respectively. All tested compounds were found to be safe on Vero cell line with IC50 value more than 200 µM. Based on their highest efficacy on HCT-116, AC-10, AC-13 and AC-14 were selected for mechanistic study on this cell line by evaluating changes nucleomorphological characteristics using acridine orange-ethidium bromide (AOEB) dual stain and by analyzing cell cycle with flow cytometry using propidium iodide stain. In AOEB staining, all three tested compounds showed significant (p < 0.05) increase in percentage apoptotic nuclei compared to control cells, with highest increase in apoptotic nuclei by AC-13 treatment (31 %). Flow cytometric studies showed cell cycle arrest by AC-10 and AC-14 treatment in G0/G1 phase and by AC-13 in G0/G1 and G2/M phase. The study reflected the potential of AC-10, AC-13 and AC-14 to be the lead molecules for further optimization.

Synthesis and Anti-cancer Activity of Novel Thiazolidinone Analogs of 6-Aminoflavone.

Novel heterocyclic analogs were synthesized by combining a flavone nucleus and thiazolidinone ring in an effort to potentiate the existing anti-cancer activity of flavone. The syntheses of 6-aminoflavone, 6-amino-3-methoxyflavone, 6-amino-3-methoxy-3',4'-dimethxyflavone and their corresponding thiazolidinone analogs were performed. Fifteen novel analogs were synthesized and evaluated for their anti-cancer activity using cell-based assay techniques and in vivo testing. As expected, the analogs improved cytotoxicity and were shown to increase the life span of cancer-bearing mice. Cytotoxicity was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assays in HeLa, MDA-MB-435, and Vero cell lines. In vivo evaluation of anti-cancer activity performed in albino mice bearing Dalton's ascites carcinoma showed that the new analogs enhanced life span and prevented increases in body weight owing to tumor volumes. Moreover, cell-cycle analysis and Hoechst staining analysis proved the apoptotic potential of these analogs. Preliminary pharmacokinetic evaluation was carried out on the synthesized compounds to determine the lipophilicity and pKa. Lipophilicity was determined using high-performance liquid chromatography and the results showed a direct correlation between the observed anti-cancer activity and log P value, while pKa values indicated the ionizing range which is a prediction tool for solubility and permeability.

Synthesis, in vitro anticancer and antioxidant activity of thiadiazole substituted thiazolidin-4-ones.

A series of novel 5-alkyl/aryl thiadiazole substituted thiazolidin-4-ones were synthesized by a two-step process. In the first step, 5-alkyl/aryl substituted 2-aminothiadiazoles were synthesized, which on reaction with substituted aromatic aldehydes and thioglycolic acid in the presence of dicyclohexylcarbodiimide afforded thiazolidin- 4-ones. All the compounds were synthesized in fairly good yields and their structures were confirmed by spectral and physical data. The title compounds were screened for in vitro anti-proliferative activity on human breast adenocarcinoma cells (MCF-7) by MTT assay. Most of the derivatives showed an IC50 less than 150 µmol L⁻¹. Among the compounds tested, 2-(2-nitrophenyl)- 3-(5-methyl-1,3,4-thiadiazol-2-yl)-thiazolidin-4-one (3f), 2-(3-fluorophenyl)-3-(5-methyl-1,3,4-thiadiazol-2- -yl)-thiazolidin-4-one (3b), and 2-(4-chlorophenyl)-3- -(5-methyl-1,3,4-thiadiazol-2-yl)-thiazolidin-4-one (3c) were found to be the most active derivatives with IC50 values of 46.34, 66.84, and 60.71 µmol L⁻¹, respectively. Antioxidant studies of all the synthesized compounds were carried out by diphenylpicrylhydrazyl (DPPH) assay. Among the compounds tested, 2-phenyl-3-(5-styryl- -1,3,4-thiadiazol-2-yl)-thiazolidin-4-one (3s) elicited superior antioxidant activity with IC50 of 161.93 µmol L⁻¹.

High-performance liquid chromatographic assay for ziprasidone in plasma samples: application to pharmacokinetic studies in rats.

Ziprasidone (ZRS) is among the various antipsychotic drugs indicated for treating schizophrenia. The determination of the pharmacokinetic behavior of this drug is of utmost importance in evaluating its bioavailability. The objectives of the present study are: (1) to develop and validate a sensitive, specific, accurate and precise reverse-phase high performance liquid chromatographic method for quantification of ZRS in the plasma of rats; and (2) to apply the developed method to study the pharmacokinetic profile of ZRS in rats after oral administration. The method uses a C18 (250.0 × 4.6 mm, 5 µm) column and ultraviolet detector with wavelength set at 210.0 nm. The mobile phase is acetonitrile-phosphate buffer (pH 3.6) 28:72% v/v at a flow rate of 1.0 mL/min. The internal standard (IS) is escitalopram. The extraction procedure for ZRS and IS from the biological matrix (plasma) employs liquid-liquid extraction technique using a mixture of methyl tert-butyl ether-dichloromethane (70:30% v/v). The results show good accuracy and precision over a linearity range of 20.0-3,000.0 ng/mL with r(2) ≥ 0.9986. The mean recoveries of ZRS and IS are 79.32 ± 1.16 and 84.10 ± 3.2%, respectively. The method has been successfully utilized to study the pharmacokinetic profile of ZRS in rats after oral administration.