King Faisal Specialist Hospital & Research Centre

About: King Faisal Specialist Hospital & Research Centre is a healthcare organization based out in Riyadh, Saudi Arabia. It is known for research contribution in the topics: Detection limit & High-performance liquid chromatography. The organization has 58 authors who have published 157 publications receiving 3527 citations.

Potentiometric, Enantioselective Electrode Responsive to Propranolol Enantiomers Based on a Lipophilic β‐Cyclodextrin

Abstract: Potentiometric, enantioselective electrodes responsive to R(+)‐ and S(−)‐propranolol were constructed, based on a lipophilic cyclodextrin, 2‐hydroxy‐3‐trimethylammoniopropyl‐β‐cyclodextrin as an ionophore. Different plasticizers, ortho‐nitrophenyl octyl ether (o‐NPOE) and bis(t‐butylphntyl) adipate (BBPA), and inner filling solutions were studied. Electrode A, prepared with O‐NPOE as a plasticizer, and 1.0 × 10−3 M R‐enantiomer solution as an inner filling solution, has a sensitivity of 59.1 mV decade−1, with a limit of detection, −log a = 4.92. Electrode B, prepared with BBPA as a plasticizer and 1.0 × 10−3 M NH4Cl as an inner filling solution, shows a sensitivity of 60.0 mV decade−1, with a limit of detection, −log a = 5.28. Inorganic cations (Na+, K+, Ca2+, Zn2+) and racemic and R‐sabutamol did not interfere with the measurement. The enantioselectivity coefficient (K± pot), determined in 1.0 × 10−3 M appropriate enantiomer solutions, was 0.20.

Phenotypic variation and allelic heterogeneity in young patients with Papillon-Lefèvre syndrome.

Abstract: Papillon-Lefevre syndrome is an autosomal recessive disorder characterized by palmoplantar hyperkeratosis and aggressive periodontitis. The aim of the study was to identify underlying cathepsin C mutations in 39 subjects with Papillon-Lefevre syndrome and to explore any phenotypic associations. Genotyping and mutation analyses were performed using standard molecular techniques, and dermatological and oral characteristics were assessed with a semiquantitative clinical score. Three genotypes were present at microsatellite marker D11S1780 and two underlying mutations were identified. The most common genotype (183/183) was associated with an 815G → C mutation in exon 6 resulting in an arginine to proline change at amino acid 272 (R272P). Patients with the 173/173 genotype revealed an exon 7 G300D mutation resulting in a glycine to aspartic acid change at amino acid 300. The mutation in a family with 189/189 genotype remained unknown. A significant difference in hyperkeratosis of the feet was found between the patients with mutations G300D and R272P (p <0.05), but not regarding hands or periodontal condition. Young girls displayed significantly less palmoplantar hyperkeratosis ( p <0.05) than young boys. In conclusion, considerable phenotypic heterogeneity was observed within the two cardinal mutations and in the 189/189 genotype.

Evaluation of some pyrazoloquinolines as inhibitors of herpes simplex virus type 1 replication.

Abstract: Three structurally related aminopyrazoloquinoline derivatives were evaluated for their antiviral activity against Herpes Simplex virus type 1. These compounds were examined for their in vitro antiviral activity by two different bioassays, namely; crystal violet staining and tetrazolium dye (MTS) measurement. The antiviral role of these compounds was confirmed by enumerating the infectious particles with plaque assay. The acute toxicity values of the biologically active compounds were determined prior to their screening as antiviral agents.

Rapid determination of methotrexate and 7-hydroxymethotrexate in serum and cerebrospinal fluid by radial compression liquid chromatography

Abstract: A rapid, specific and sensitive radial compression reverse phase liquid chromatographic method for the analysis of methotrexate and 7-hydroxymethotrexate in serum and cerebrospinal fluid is reported. A mobile phase consisting of acetonitrile-methanol-pH 3 phosphate (8:15:77) at 6 ml/min flow rate was employed. The U.V. detector was set at 317 nm, and folic acid was used as an internal standard. A rapid extraction of methotrexate and 7-hydroxymethotrexate was performed using Sep-Pak cartridges with high extraction efficiency for both compounds. Patients serum and cerebrospinal fluid samples were analyzed by the described method and the concentrations of methotrexate were compared to those obtained by an enzyme immunoassay. No interference from other metabolites or anticancer drugs in the described assay was observed.

Enantioselective determination of arotinolol in human plasma by HPLC using teicoplanin chiral stationary phase.

Abstract: A sensitive enantioselective high-performance liquid chromatography (HPLC) method was developed and validated to determine S-(+)- and R-(-)-arotinolol in human plasma. Baseline resolution was achieved by using teicoplanin macrocyclic antibiotic chiral stationary phase (CSP) known as Chirobiotic T with a polar organic mobile phase consisting of methanol:glacial acetic acid:triethylamine, 100:0.1:0.1, (v/v/v) at a fl ow rate of 0.8 mL/min and UV detection set at 317 nm. Human plasma was spiked with stock solution of arotinolol enantiomers and labetalol as the internal standard. The assay involved the use of liquid-liquid extraction procedure with ethyl ether under alkaline condition for human plasma sample prior to HPLC analysis. Recoveries for S-(+)- and R-(-)-arotinolol enantiomers were in the range 93-103% at 200-1400 ng/mL level. Intra-day and inter-day precision calculated as %RSD was in the ranges 1.3-3.4 and 1.9-4.5% for both enantiomers, respectively. Intra-day and inter-day accuracies calculated as percentage error were in the ranges 1.2-3.5 and 1.5-6.2% for both enantiomers, respectively. Linear calibration curves in the concentration range 100-1500 ng/mL for each enantiomer showed a correlation coefficient (r) of 0.9998. The limit of quantitation (LOQ) and limit of detection (LOD) for each enantiomer in human plasma were 100 and 50 ng/mL (S/N = 3), respectively.