Displaying publications 1 - 20 of 42 in total

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  1. da Silva-Junio AG, Frias IAM, Lima-Neto RG, Migliolo L, E Silva PS, Oliveira MDL, et al.
    J Pharm Biomed Anal, 2022 Jul 15;216:114788.
    PMID: 35525110 DOI: 10.1016/j.jpba.2022.114788
    Bacterial and fungal infections are challenging due to their low susceptibility and resistance to antimicrobial drugs. For this reason, antimicrobial peptides (AMP) emerge as excellent alternatives to overcome these problems. At the same time, their active insertion into the cell wall of microorganisms can be availed for biorecognition applications in biosensing platforms. Temporin-PTA (T-PTA) is an AMP found in the skin secretions of the Malaysian fire frog Hylarana picturata, which presents antibacterial activity against MRSA, Escherichia coli, and Bacillus subtilis. In this work, T-PTA was explored as an innovative sensing layer aiming for the electrochemical differentiation of Klebsiella pneumoniae, Acinetobacter baumannii, Bacillus subtilis, Enterococcus faecalis, Candida albicans, and C. tropicalis based on the structural differences of their membranes. The biosensor was analyzed through electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). In this approach, the different structural features of each microorganism resulted in different adherence degrees and, therefore, different electrochemical responses. The transducing layer was fabricated by the self-assembling of a 4-mercaptobenzoic acid (MBA) monolayer and gold-capped magnetic nanoparticles (Fe3O4@Au) implemented to improve the electrical signal of the biointeraction. We found that each interaction, expressed in variations of electron transfer resistance and anodic peak current, demonstrated a singular response from which the platform can discriminate all different microorganisms. We found expressive sensitivity towards Gram-negative species, especially K. pneumoniae. A detection limit of 101 CFU.mL-1 and a linear range of 101 to 105 CFU.mL-1 were obtained. The T-PTA biosensor platform is a promising and effective tool for microbial identification.
  2. Zahed FM, Hatamluyi B, Lorestani F, Es'haghi Z
    J Pharm Biomed Anal, 2018 Nov 30;161:12-19.
    PMID: 30142492 DOI: 10.1016/j.jpba.2018.08.004
    A highly efficient electrochemical sensor for the analysis of anticancer drug 5-fluorouracil (5-FU), is fabricated based on silver nanoparticles-polyaniline nanotube (AgNPs@PANINTs). AgNPs@PANINTs nanocomposite has been synthesized by a simple one-step method. Synthesized AgNPs@PANINTs nanocomposite was studied by Fourier transform infrared spectrometry, Scanning Electron Microscopy and Energy Dispersive X-ray. The fabricated PANINTs@AgNPs PGE was applied to the electrochemical sensing of 5-FU. Cyclic voltammetry and differential pulse voltammetry experiments illustrated high electro activity for the AgNPs@PANINTs nanocomposite. The study was explored using the Taguchi experimental design method. Electrochemical measurements using differential pulse voltammetry showed a wide linear relationship between 5-FU concentration and peak height within the range 1.0-300.0 μM with a low detection limit (0.06 μM). Also, the fabricated sensor showed excellent selectivity in the presence of two anticancer drugs and a number of other interfering compounds. The as-prepared sensor showed to be a promising device for a simple, rapid, and direct analysis of 5-FU.
  3. Yuen KH, Choy WP, Tan HY, Wong JW, Yap SP
    J Pharm Biomed Anal, 2001 Feb;24(4):715-9.
    PMID: 11272330
    A simple high-performance liquid chromatographic method was developed for the determination of omeprazole in human plasma. Omeprazole and the internal standard, chloramphenicol, were extracted from alkalinized plasma samples using dichloromethane. The mobile phase was 0.05 M Na2HPO4-ACN (65:35, v/v) adjusted to pH 6.5. Analysis was run at a flow rate of 1.0 ml/min at a detection wavelength of 302 nm. The method was specific and sensitive with a detection limit of 2.5 ng/ml at a signal-to-noise ratio of 4:1. The limit of quantification was set at 5 ng/ml. The calibration curve was linear over a concentration range of 5-1280 ng/ml. Mean recovery value of the extraction procedure was about 96%, while the within and between day coefficient of variation and percent error values of the assay method were all less than 14%.
  4. Venkatesh G, Ramanathan S, Mansor SM, Nair NK, Sattar MA, Croft SL, et al.
    J Pharm Biomed Anal, 2007 Mar 12;43(4):1546-51.
    PMID: 17157469
    A simple, sensitive and specific reversed phase high performance liquid chromatographic (RP-HPLC) method with UV detection at 251 nm was developed for simultaneous quantitation of buparvaquone (BPQ), atenolol, propranolol, quinidine and verapamil. The method was applicable in rat in situ intestinal permeability study to assess intestinal permeability of BPQ, a promising lead compound for Leishmania donovani infections. The method was validated on a C-4 column with mobile phase comprising ammonium acetate buffer (0.02 M, pH 3.5) and acetonitrile in the ratio of 30:70 (v/v) at a flow rate of 1.0 ml/min. The retention times for atenolol, quinidine, propranolol, verapamil and BPQ were 4.30, 5.96, 6.55, 7.98 and 8.54 min, respectively. The calibration curves were linear (correlation coefficient > or =0.996) in the selected range of each analyte. The method is specific and sensitive with limit of quantitation of 15 microg/ml for atenolol, 0.8 microg/ml for quinidine, 5 microg/ml for propranolol, 10 microg/ml for verapamil and 200 ng/ml for BPQ. The validated method was found to be accurate and precise in the working calibration range. Stability studies were carried out at different storage conditions and all the analytes were found to be stable. This method is simple, reliable and can be routinely used for accurate permeability characterization.
  5. Tham SY, Agatonovic-Kustrin S
    J Pharm Biomed Anal, 2002 May 15;28(3-4):581-90.
    PMID: 12008137
    Quantitative structure-retention relationship(QSRR) method was used to model reversed-phase high-performance liquid chromatography (RP-HPLC) separation of 18 selected amino acids. Retention data for phenylthiocarbamyl (PTC) amino acids derivatives were obtained using gradient elution on ODS column with mobile phase of varying acetonitrile, acetate buffer and containing 0.5 ml/l of triethylamine (TEA). Molecular structure of each amino acid was encoded with 36 calculated molecular descriptors. The correlation between the molecular descriptors and the retention time of the compounds in the calibration set was established using the genetic neural network method. A genetic algorithm (GA) was used to select important molecular descriptors and supervised artificial neural network (ANN) was used to correlate mobile phase composition and selected descriptors with the experimentally derived retention times. Retention time values were used as the network's output and calculated molecular descriptors and mobile phase composition as the inputs. The best model with five input descriptors was chosen, and the significance of the selected descriptors for amino acid separation was examined. Results confirmed the dominant role of the organic modifier in such chromatographic systems in addition to lipophilicity (log P) and molecular size and shape (topological indices) of investigated solutes.
  6. Teoh XY, Goh CF, Aminu N, Chan SY
    J Pharm Biomed Anal, 2021 Jan 05;192:113631.
    PMID: 33011581 DOI: 10.1016/j.jpba.2020.113631
    Atovaquone (ATQ) is a poorly soluble drug. Therefore, formulating ATQ into its supersaturated state through solid dispersion for bioavailability enhancement can be of great value. However, due to fast crystallising properties of ATQ, the quantification of ATQ in a supersaturated solid dispersion system can be complicated. Therefore, in pursuit of accurate quantification of such sample, a simple HPLC analytical method utilising a C18 column (250 × 4.6 mm ID, 5 μm) for the quantitation of ATQ has been developed and validated. Atovaquone elution using the proposed method demonstrated a retention time around 7.6 min with good linearity (R2 > 0.999). The system suitability is also detailed with the tailing factor at 1.365 ± 0.002. The addition of solubilising agent as sample treatment step aided in ensuring the accurate quantitation of the fast crystallising ATQ. The developed HPLC quantitation method has been successfully employed in the analysis of ATQ from solid dispersion samples in in vitro dissolution as well as ex vivo permeation studies for formulation development.
  7. Saleem H, Htar TT, Naidu R, Ahmad I, Zengin G, Ahmad M, et al.
    J Pharm Biomed Anal, 2019 Mar 20;166:128-138.
    PMID: 30640043 DOI: 10.1016/j.jpba.2019.01.007
    In this study, different solvent extracts (methanol, dichloromethane and n-hexane) from aerial and stem parts of Buxus papillosa C.K. Schneid (Buxaceae) were investigated for a panoply of bioassays. Biological profiles were established by determining antioxidant and enzyme inhibition profiles. Toxicity was tested using MTT cell viability assay on five different human cancer cell lines i.e, MCF-7, MDA-MB-231, CaSki, DU-145 and SW-480. For chemical fingerprinting, total bioactive contents and UHPLC-MS secondary metabolites profile were determined. Generally, both aerial and stem methanol extracts had highest total bioactive contents, radical scavenging and reducing power potential. DCM and n-hexane extracts were found to be most active for total antioxidant and metal chelating activity. The UHPLC-MS analysis of methanol extracts revealed the presence of several phenolic, flavonoid, alkaloid, saponin and depsipeptide derivatives. All the extracts were significantly active against butyrylcholinesterase, whereas moderate inhibition was observed for acetylcholinesterase, α-glucosidase and urease. Similarly, a considerable level of cytotoxicity was observed against all the tested cell lines with IC50 values ranging from 26 to 225.9 μg/mL. Aerial methanol and stem n-hexane extracts were found to be most cytotoxic. Principal component analysis was also performed to find any possible correlation between biological activities and total bioactive contents. On the basis of our findings, B. papillosa may be considered as promising source of bioactive molecules.
  8. Saleem H, Zengin G, Ahmad I, Lee JTB, Htar TT, Mahomoodally FM, et al.
    J Pharm Biomed Anal, 2019 Jun 05;170:132-138.
    PMID: 30921647 DOI: 10.1016/j.jpba.2019.03.027
    The current research work was conducted in order to probe into the biochemical and toxicological characterisation of methanol and dichloromethane (DCM) extracts of Bougainvillea glabra (Choisy.) aerial parts. Biological fingerprints were assessed for in vitro antioxidant, key enzyme inhibitory and cytotoxicity potential. Total bioactive contents were determined spectrophotometrically and the secondary metabolite components of methanol extract was assessed by UHPLC mass spectrometric analysis. The antioxidant capabilities were evaluated via six different in vitro antioxidant assays namely DPPH, ABTS (free radical scavenging), FRAP, CUPRAC (reducing antioxidant power), phosphomolybdenum (total antioxidant capacity) and ferrous chelating activity. Inhibition potential against key enzymes urease, α-glucosidase and cholinesterases were also determined. Methanol extract exhibited higher phenolic (24.01 mg GAE/g extract) as well as flavonoid (41.51 mg QE/g extract) contents. Phytochemical profiling of methanol extract identified a total of twenty secondary metabolites and the major compounds belonged to flavonoids, phenolics and alkaloid derivatives. The findings of antioxidant assays revealed the methanol extract to exhibit stronger antioxidant (except phosphomolybdenum) activities. Similarly, the methanol extract showed highest butyrylcholinesterase and urease inhibition. The DCM extract was most active for phosphomolybdenum and α-glucosidase inhibition assays. Moreover, both extracts exhibited significant cytotoxic potential against five (MCF-7, MDA-MB-231, CaSki, DU-145, and SW-480) human carcinoma cell lines with half maximal inhibitory concentration values of 22.09 to 257.2 μg/mL. Results from the present study highlighted the potential of B. glabra aerial extracts to be further explored in an endeavour to discover novel phytotherapeutics as well as functional ingredients.
  9. Saisahas K, Soleh A, Promsuwan K, Phonchai A, Mohamed Sadiq NS, Teoh WK, et al.
    J Pharm Biomed Anal, 2021 Feb 08;198:113958.
    PMID: 33662759 DOI: 10.1016/j.jpba.2021.113958
    A portable electrochemical sensor was developed to determine xylazine in spiked beverages by adsorptive stripping voltammetry (AdSV). The sensor was based on a graphene nanoplatelets-modified screen-printed carbon electrode (GNPs/SPCE). The electrochemical behavior of xylazine at the GNPs/SPCE was an adsorption-controlled irreversible oxidation reaction. The loading of graphene nanoplatelets (GNPs) on the modified SPCE, electrolyte pH, and AdSV accumulation potential and time were optimized. Under optimal conditions, the GNPs/SPCE provided high sensitivity, linear ranges of 0.4-6.0 mg L-1 (r = 0.997) and 6.0-80.0 mg L-1 (r = 0.998) with a detection limit of 0.1 mg L-1 and a quantitation limit of 0.4 mg L-1. Repeatability was good. The accuracy of the proposed sensor was investigated by spiking six beverage samples at 1.0, 5.0, and 10.0 mg L-1. The recoveries from this method ranged from 80.8 ± 0.2-108.1 ± 0.3 %, indicating the good accuracy of the developed sensor. This portable electrochemical sensor can be used to screen for xylazine in beverage samples as evidence in cases of sexual assault or robbery.
  10. Ruzilawati AB, Wahab MS, Imran A, Ismail Z, Gan SH
    J Pharm Biomed Anal, 2007 Apr 11;43(5):1831-5.
    PMID: 17240100
    In this study, the development and validation of a high-performance liquid chromatography (HPLC) assay for determination of repaglinide concentration in human plasma for pharmacokinetic studies is described. Plasma samples containing repaglinide and an internal standard, indomethacin were extracted with ethylacetate at pH 7.4. The recovery of repaglinide was 92%+/-55.31. Chromatographic separations were performed on Purospher STAR C-18 analytical column (4.8 mm x 150 mm; 5 microm particle size). The mobile phase composed of acetonitrile-ammonium formate (pH 2.7; 0.01 M) (60:40, v/v). The flow rate was 1 ml/min. The retention time for repaglinide and indomethacin were approximately 6.2 and 5.3 min, respectively. Calibration curves of repaglinide were linear in the concentration range of 20-200 ng/ml in plasma. The limits of detection and quantification were 10 ng/ml and 20 ng/ml, respectively. The inter-day precision was from 5.21 to 11.84% and the intra-day precision ranged from 3.90 to 6.67%. The inter-day accuracy ranged 89.95 to 105.75% and intra-day accuracy ranged from 92.37 to 104.66%. This method was applied to determine repaglinide concentration in human plasma samples for a pharmacokinetic study.
  11. Roslan A, Said DS, Sulaiman N, Mohd Ghani KA, Nurdin A
    J Pharm Biomed Anal, 2023 Nov 30;236:115729.
    PMID: 37778199 DOI: 10.1016/j.jpba.2023.115729
    Studies reveal that alterations in membrane protein (MP) patterns are associated with underlying drug resistance to chemotherapy. Therefore, the tryptic-digested MPs from the bladder cancer cell line were subjected to global proteomics using LC-MS/MS to identify the highly expressed potential MPs in bladder cancer cells. Our findings revealed the identification of MP biomarkers, CD147, and caveolin-1. Immunocytochemistry analysis confirmed the presence of CD147 on the cell membrane, while caveolin-1 showed positive signals without apparent staining on the membrane, suggesting its existence in multiple locations. Western blot analysis confirmed the higher expression of CD147 in non-invasive (RT 112) and metastatic (UM-UC-13) bladder cancer cells compared to invasive bladder cancer cells (5637 and J82), suggesting its potential as an MP biomarker for both of the former subtypes. The identified MPs could be used as drug therapy targets aimed at improving drug sensitivity and enhancing treatment outcomes in bladder cancer patients. SIGNIFICANCE: Identification of the membrane proteins associated with bladder cancer recurrence is crucial to understanding the mechanisms underlying the drug resistance to chemotherapy.
  12. Romero Rocamora C, Ramasamy K, Meng Lim S, Majeed ABA, Agatonovic-Kustrin S
    J Pharm Biomed Anal, 2020 Jan 30;178:112909.
    PMID: 31618702 DOI: 10.1016/j.jpba.2019.112909
    A high-performance thin-layer chromatography (HPTLC) method combined with effect-directed-analysis (EDA) was developed to screen the antioxidant, neuroprotective and antidiabetic effects in essential oils derived from lavender flower, lemon myrtle, oregano, peppermint, sage, and rosemary leaves (Lamiaceae family). HPTLC hyphenated with microchemical (DPPH•, p-anisaldehyde, and ferric chloride) derivatizations, was used to evaluate antioxidant activity, presence of phytosterols and terpenoids, and polyphenolic content, while the combination with biochemical (α-amylase and acetylcholine esterase (AChE) enzymatic) derivatizations was used to asses α-amylase and AChE inhibitory activities. The superior antioxidant activity of oregano leaf extract is attributed to the presence of high levels of aromatic compounds, like polyphenolic acids. The strongest α-amylase inhibition was observed in lemon myrtle and rosemary plus extracts due to the presence of monoterpenes. Rosemary and sage extracts exhibit the highest AChE inhibition activity, with 1 μL essential oils being more potent than the recommended daily dose of donepezil. This superior neuroprotection was attributed to the presences of di- and triterpenes that displayed strong AChE inhibition and antioxidant potential in DPPH• free radical assay. Antioxidant activity was related to phenolic content (R = 0.49), while α-amylase inhibitory activity was positively related to antioxidant activity (R = 0.20) and terpenoid/sterol content (R = 0.31). AChE inhibitory activity was correlated (R = 0.80) to the combined effect of phenolics and terpenoids. Thus, the superior AChE inhibitory and neuroprotection potential of rosemary and sage essential oils could be attributed to joint effects of main phenolic and terpene constituents. The hyphenated HPTLC method provided rapid bioanalytical profiling of highly complex essential oil samples.
  13. Pariyani R, Ismail IS, Azam A, Khatib A, Abas F, Shaari K, et al.
    J Pharm Biomed Anal, 2017 Feb 20;135:20-30.
    PMID: 27987392 DOI: 10.1016/j.jpba.2016.12.010
    Orthosiphon stamineus (OS) is a popular medicinal herb used in traditional Chinese medicine as a diuretic agent and for renal system disorders. This study employed 1H NMR based metabolomics approach to investigate the possible protective activity of OS in cisplatin induced nephrotoxicity owing to its diuretic and antioxidant activities. Aqueous (OSAE) and 50% aqueous ethanolic (OSFE) extracts of OS leaves were orally administered at 400mg/kg BW doses to rats which were then intraperitoneally injected with cisplatin at 5mg/kg BW dose. The 1H NMR profile of the urine samples collected on day 5 after cisplatin administration were analyzed by multivariate pattern recognition techniques, whereby 19 marker metabolites suggestive in the involvement of TCA cycle, disturbed energy metabolism, altered gut microflora and BCAA metabolism pathways were identified. It was observed that OSFE caused significant changes (p<0.05) in the levels of 8 markers namely leucine, acetate, hippurate, lysine, valine, 2-oxoglutarate, 3-HBT and acetoacetate resulting in a moderate ameliorative effect, however, it did not completely protect from nephrotoxicity. OSAE did not demonstrate significant down regulatory effects on any markers, albeit, it potentiated the cisplatin nephrotoxicity by inducing significant increase in glucose, glycine, creatinine, citrate, TMAO, acetate and creatine levels. A Principal Component Analysis (PCA) of the 1H NMR spectra of OS extracts identified that OSFE had higher concentrations of the secondary metabolites such as caffeic acid, chlorogenic acid, protocatechuic acid and orthosiphol, among others. Whereas, OSAE was characterized by higher concentrations of acetate, lactate, succinic acid, valine and phosphatidylcholine. This research denotes the first comprehensive analysis to identify the effects of OS extracts on cisplatin nephrotoxicity.
  14. Muthudoss P, Kumar S, Ann EYC, Young KJ, Chi RLR, Allada R, et al.
    J Pharm Biomed Anal, 2022 Feb 20;210:114581.
    PMID: 35026592 DOI: 10.1016/j.jpba.2022.114581
    Particle size distribution (PSD), spatial location and particle cluster size of ingredients, polymorphism, compositional distribution of a pharmaceutical product are few of the most important attributes in establishing the drug release-controlling microstructural and solid state properties that would be used to (re)design or reproduce similar products. There are numerous solid-state techniques available for PSD analysis. Laser diffraction (LD) is mostly used to study PSD of raw materials. However, a constraint of LD is the interference between the active pharmaceutical ingredients (API) and excipients, where it is very challenging to measure API size in a tablet. X-ray powder diffraction (XRPD) is widely employed in establishing the polymorphism of API and excipients. This research examined a commercial osmotic tablet in terms of extracting solid state properties of API and functional excipient by Raman Imaging. Establishing repeatability, reproducibility, and sample representativeness when the samples are non-uniform and inhomogeneous necessitates multiple measurements. In such scenarios, when employing imaging-based techniques, it can be time-consuming and tedious. Advanced statistical methodologies are used to overcome these disadvantages and expedite the characterization process. Overall, this study demonstrates that Raman imaging can be employed as a non-invasive and effective offline method for assessing the solid-state characteristics of API and functional excipients in complex dosage forms like osmotic tablets.
  15. Mukhtar NH, Mamat NA, See HH
    J Pharm Biomed Anal, 2018 Sep 05;158:184-188.
    PMID: 29883881 DOI: 10.1016/j.jpba.2018.05.044
    A sample pre-treatment method based on a dynamic mixed matrix membrane tip extraction followed by capillary electrophoresis with contactless conductivity detection (CE-C4D) was evaluated for the determination of tobramycin in human plasma. The extraction tip device consisted of a cellulose triacetate membrane tip wall immobilised with 15% (w/w) of hydrophilic lipophilic balance (HLB) nanoparticles as adsorbent. The extraction was performed dynamically by withdrawing/dispensing the plasma sample through the tip device followed by desorption into 20 μL of acidified aqueous solution at pH 3 prior to the CE-C4D analysis. Under the optimum conditions, the detection limit of the method for tobramycin was 10 ng/mL, with intraday and interday repeatability RSDs of 3.5% and 4.5%, respectively. Relative recoveries in spiked human plasma were 99.6%-99.9%. The developed approach was successfully demonstrated for the quantification of tobramycin in human plasma samples.
  16. Mokhtar SU, Chin ST, Kee CL, Low MY, Drummer OH, Marriott PJ
    J Pharm Biomed Anal, 2016 Mar 20;121:188-196.
    PMID: 26808068 DOI: 10.1016/j.jpba.2016.01.034
    Application of gas chromatography-triple quadrupole mass spectrometry for identification, confirmation and quantification of 6 phosphodiesterase-5 (PDE-5) inhibitors (sildenafil, dimethylsildenafil, homosildenafil, thiosildenafil, thiodimethylsildenafil and thiohomosildenafil) in dietary supplements was investigated. The MS was operated in multiple reaction monitoring mode, for better sensitivity and selectivity. In this manner, the method is adequate to reduce background noise with less interference from co-eluting compounds in the samples. Two different ionisation techniques, electron ionisation (EI) and chemical ionisation (CI), were studied and compared. The chromatographic separation was performed on a short 10 m non-polar capillary column without any derivatisation step. This permitted fast analysis for all analogues with retention time less than 11 min, for both techniques. Use of backflushing can aid method retention time reduction and improves column maintenance. Evaluation of method validation included limit of detection (LOD), lower limit of quantitation (LLOQ), linearity, precision and recovery were performed for both EI and CI techniques. The LOD obtained varied from 0.03 to 1.50 μg/g and the LLOQ ranged from 0.10 to 5.00 μg/g. Good calibration linearity was obtained for all analogues for both techniques, with correlation coefficients (r(2)) higher than 0.99. Mean recoveries of all analogues using CI show higher values (83.4-108.8%) than that of EI (61.9-91.1%). The intra- and inter-assay precisions were evaluated for all analogues at spiked concentration of 10 μg/g and the relative standard deviation was less than 15% for both methods. These methods were then successfully applied to dietary supplement samples without prior derivatisation, confirming that the samples were adulterated with sildenafil and/or its analogues.
  17. Mediani A, Abas F, Maulidiani M, Khatib A, Tan CP, Ismail IS, et al.
    J Pharm Biomed Anal, 2016 Sep 05;128:302-312.
    PMID: 27318080 DOI: 10.1016/j.jpba.2016.06.003
    Herbal medicine has been proven to be an effective therapy offering a variety of benefits, such as moderate reduction in hypoglycemia, in the treatment and prevention of obesity and diabetes. Phyllanthus niruri has been used as a treatment for diabetes mellitus. Herein, the induction of type 2 diabetes in Sprague-Dawley rats was achieved by a low dose of streptozotocin (STZ) (25mg/kgbw). Here, we evaluated the in vivo antidiabetic properties of two concentrations (250 and 500mg/kg bw) of P. niruri via metabolomics approach. The administration of 500mg/kgbw of P. niruri extract caused the metabolic disorders of obese diabetic rats to be improved towards the normal state. The extract also clearly decreased the serum glucose level and improved the lipid profile in obese diabetic rats. The results of this study may contribute towards better understanding the molecular mechanism of this medicinal plant in managing diabetes mellitus.
  18. Loh GOK, Wong EYL, Tan YTF, Wee HC, Ng RS, Lee CY, et al.
    J Pharm Biomed Anal, 2021 Feb 05;194:113758.
    PMID: 33248861 DOI: 10.1016/j.jpba.2020.113758
    A simple, rapid, sensitive, and reproducible LC-MS/MS method was developed for simultaneous quantification of flavoxate and 3-methyl-flavone-8-carboxylic (MFCA) in human plasma, using diphenhydramine HCl as internal standard (IS). The chromatographic separation was achieved using Agilent Poroshell 120 EC-C18 - Fast LC column (100 × 2.1mmID, 2.7 μm) fitted with UHPLC Guard Poroshell 120 EC-C18 (5 × 2.1 mmID, 2.7 μm). The mobile phase consisted of 0.1 % v/v formic acid and acetonitrile (30:70, v/v) run at a flow rate of 0.40 mL/min. The standard calibration curve was linear over the concentration range of 2.00 - 2,000.31 ng/mL and 240.00 - 24,000.04 ng/mL for flavoxate and MFCA. For flavoxate and MFCA, the within-run precision was 0.81-6.67 % and 1.68-4.37 %, while accuracy was 100.21-108.25 % and 103.99-110.28 %. The between-run precision was 2.01-9.14 % and 2.31-11.11 %, and accuracy was 96.09-103.33 % and 102.37-109.52 %. The extended run precision was 7.78-11.04 % and 2.22-3.33 %, while accuracy was 100.72-101.88 % and 102.34-105.60 %. Flavoxate and MFCA in plasma were stable 4 h at bench top (short term), 24 h in autosampler and instrumentation room (post-preparative), after 7 freeze-thaw cycles, and 89 days in the freezer. Both analytes and IS stock solutions were stable for 31 days when kept at room temperature (25 ± 4 °C) and refrigerated (2-8 °C). The validated method was successfully applied to a bioequivalence study of two flavoxate formulations involving 24 healthy volunteers.
  19. Lim SM, Agatonovic-Kustrin S, Lim FT, Ramasamy K
    J Pharm Biomed Anal, 2021 Jan 30;193:113702.
    PMID: 33160220 DOI: 10.1016/j.jpba.2020.113702
    Bioactive compounds from endophytic fungi exhibit diverse biological activities which include anticancer effect. Capitalising on the abundance of unexplored endophytes that reside within marine plants, this study assessed the anticancer potential of ethyl acetate endophytic fungal extracts (i.e. MBFT Tip 2.1, MBL 1.2, MBS 3.2, MKS 3 and MKS 3.1) derived from leaves, stem and fruits of marine plants that grow along Morib Beach, Malaysia. For identification of endophytic fungi, EF 4/ EF 3 and ITS 1/ ITS 4 PCR primer pairs were used to amplify the fungal 18S rDNA sequence and ITS region sequence, respectively. The resultant sequences were subjected to similarity search via the NCBI GenBank database. High-performance thin layer chromatography (HPTLC) hyphenated with bioassays was used to characterise the extracts in terms of their phytochemical profiles and bioactivity. Microchemical derivatisation was used to assess polyphenolic and phytosterol/ terpenoid content whereas biochemical derivatisation was used to establish antioxidant activities and α-amylase enzyme inhibition. The sulforhodamine B (SRB) assay was used to assess the anticancer effect of the extracts against HCT116 (a human colorectal cancer cell line). The present results indicated MBS 3.2 (Penicillium decumbens) as the most potent extract against HCT116 (IC50 = 0.16 μg/mL), approximately 3-times more potent than 5-flurouracil (IC50 = 0.46 μg/mL). Stepwise multiple regression method suggests that the anticancer effect of MBS 3.2 could be associated with high polyphenolic content and antioxidant potential. Nonlinear regression analysis confirmed that low to moderate α-amylase inhibition exhibits maximum anticancer activity. Current findings warrant further in-depth mechanistic studies.
  20. Lim CP, Quek SS, Peh KK
    J Pharm Biomed Anal, 2003 Feb 05;31(1):159-68.
    PMID: 12560060
    This paper investigates the use of a neural-network-based intelligent learning system for the prediction of drug release profiles. An experimental study in transdermal iontophoresis (TI) is employed to evaluate the applicability of a particular neural network (NN) model, i.e. the Gaussian mixture model (GMM), in modeling and predicting drug release profiles. A number of tests are systematically designed using the face-centered central composite design (CCD) approach to examine the effects of various process variables simultaneously during the iontophoresis process. The GMM is then applied to model and predict the drug release profiles based on the data samples collected from the experiments. The GMM results are compared with those from multiple regression models. In addition, the bootstrap method is used to assess the reliability of the network predictions by estimating confidence intervals associated with the results. The results demonstrate that the combination of the face-centered CCD and GMM can be employed as a useful intelligent tool for the prediction of time-series profiles in pharmaceutical and biomedical experiments.
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