Displaying publications 41 - 60 of 193 in total

Abstract:
Sort:
  1. Population pharmacokinetic modelling of tramadol with application of the NPEM algorithms
    Gan SH, Ismail R, Wan Adnan WA, Zulmi W, Jelliffe RW
    J Clin Pharm Ther, 2004 Oct;29(5):455-63.
    PMID: 15482390
    Although the kinetic behaviour of tramadol has been described, the present study is the first to our knowledge, to report specifically on the population pharmacokinetic modelling of tramadol hydrochloride.
  2. Fulltext Physicochemical and antioxidant properties of Malaysian honeys produced by Apis cerana, Apis dorsata and Apis mellifera
    Moniruzzaman M, Khalil MI, Sulaiman SA, Gan SH
    BMC Complement Altern Med, 2013;13:43.
    PMID: 23433009 DOI: 10.1186/1472-6882-13-43
    The aim of the present study was to evaluate the physicochemical and antioxidant properties of Malaysian monofloral honey samples-acacia, pineapple and borneo honey-and compare them with tualang honey. Acacia and pineapple honey are produced by Apis mellifera bees while borneo and tualang honey are produced by Apis cerana and Apis dorsata bees, respectively.
  3. Antiphospholipid Antibody-Mediated Thrombotic Mechanisms in Antiphospholipid Syndrome: Towards Pathophysiology-Based Treatment
    Islam MA, Alam F, Sasongko TH, Gan SH
    Curr Pharm Des, 2016;22(28):4451-69.
    PMID: 27229722
    Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by a persistently high titer of antiphospholipid antibodies (aPLs). In addition to pregnancy morbidity, arterial and/or venous thrombosis is another clinical feature of APS. Regardless of the type of APS, the thrombi formed by the induction of aPLs can lead to deep vein thrombosis, pulmonary embolism, myocardial infarction, stroke and gangrene. Although the concept of APS was introduced approximately 32 years ago, its thrombogenic pathophysiology is still unclear. Therefore, patients are treated with anticoagulant and/or antiplatelet regimens just as in other thrombotic disorders even though the thrombotic pathophysiology is mainly aPLs-mediated. In this review, we provided an update of the cellular, auto-immune and genetic factors known to play important roles in the generation of thrombi. Current successful regimens are also outlined along with potential emerging treatment strategies that may lead to the optimum management of thrombotic APS patients.
  4. Fulltext Lack of Association between the Serotonin Transporter (5-HTT) and Serotonin Receptor (5-HT2A) Gene Polymorphisms with Smoking Behavior among Malaysian Malays
    Rozak NI, Ahmad I, Gan SH, Abu Bakar R
    Sci Pharm, 2014 07 18;82(3):631-42.
    PMID: 25853073 DOI: 10.3797/scipharm.1406-01
    An insertion/deletion polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) and a polymorphism (rs6313) in the serotonin 2A receptor gene (5-HT2A) have previously been linked to smoking behavior. The objective of this study was to determine the possible association of the 5-HTTLPR and 5-HT2A gene polymorphisms with smoking behavior within a population of Malaysian male smokers (n=248) and non-smokers (n=248). The 5-HTTLPR genotypes were determined using the polymerase chain reaction (PCR) and were classified as short (S) alleles or long (L) alleles. The 5HT2A genotypes were determined using PCR-restriction fragment length polymorphisms (PCR-RFLP). No significant differences in the distribution frequencies of the alleles were found between the smokers and the non-smokers for the 5-HTTLPR polymorphism (x(2) = 0.72, P>0.05) or the 5HT2A polymorphism (x(2) = 0.73, P>0.05). This is the first study conducted on Malaysian Malay males regarding the association of 5-HTTLPR and 5HT2A polymorphisms and smoking behavior. However, the genes were not found to be associated with smoking behavior in our population.
  5. Correlation of tramadol pharmacokinetics and CYP2D6*10 genotype in Malaysian subjects
    Gan SH, Ismail R, Wan Adnan WA, Wan Z
    J Pharm Biomed Anal, 2002 Sep 05;30(2):189-195.
    PMID: 12191703
    The aim of the present study is to investigate the influence of the CYP2D6*10 allele on the disposition of tramadol hydrochloride in Malaysian subjects. A single dose of 100 mg tramadol was given intravenously to 30 healthy orthopaedic patients undergoing various elective surgeries. After having obtained written informed consents, patients were genotyped for CYP2D6*10: the most common CYP2D6 allele among Asians by means of allele-specific polymerase chain reaction. The presence of other mutations (CYP2D6*1, *3, *4, *5, *9 and *17) was also investigated. Tramadol was extracted from 1 ml serum with an n-hexane: ethylacetate combination (4:1) after alkalinisation with ammonia (pH 10.6). Serum concentrations were measured by means of high-performance liquid chromatography. The pharmacokinetics of tramadol was studied during the 24 h after the dose. As among other Asians, the allele frequency for CYP2D6*10 among Malaysians was high (0.43). Subjects who were homozygous for CYP2D6*10 had significantly (P=0.046) longer mean serum half-life of tramadol than subjects of the normal or the heterozygous group (Kruskal-Wallis test). When patients were screened for the presence of other alleles, the pharmacokinetic parameter values were better explained. CYP2D6 activity may play a main role in determining tramadol pharmacokinetics. The CYP2D6*10 allele particularly was associated with higher serum levels of tramadol compared with the CYP2D6*1 allele. However, genotyping for CYP2D6*10 alone is not sufficient to explain tramadol disposition.
  6. Autoimmune disease and cancer comorbidity: Current understandings of immune-mediated pathogenesis and treatment
    Islam MA, Kamal MA, Gan SH, Alam F
    Semin Cancer Biol, 2020 08;64:iii-iv.
    PMID: 31589922 DOI: 10.1016/j.semcancer.2019.10.001
  7. Fulltext Anti-hepatitis A seroprevalence among chronic viral hepatitis patients in Kelantan, Malaysia
    Ahmad F, Hamzah NA, Mustaffa N, Gan SH
    World J Gastroenterol, 2011 Sep 28;17(36):4130-4.
    PMID: 22039329 DOI: 10.3748/wjg.v17.i36.4130
    To determine the seroprevalence of anti-hepatitis A virus (HAV) antibodies in patients with chronic liver disease (CLD) and to justify the need for hepatitis A vaccination.
  8. Fulltext Characterization and Evaluation of Bone-Derived Nanoparticles as a Novel pH-Responsive Carrier for Delivery of Doxorubicin into Breast Cancer Cells
    Haque ST, Islam RA, Gan SH, Chowdhury EH
    Int J Mol Sci, 2020 Sep 14;21(18).
    PMID: 32937817 DOI: 10.3390/ijms21186721
    Background: The limitations of conventional treatment modalities in cancer, especially in breast cancer, facilitated the necessity for developing a safer drug delivery system (DDS). Inorganic nano-carriers based on calcium phosphates such as hydroxyapatite (HA) and carbonate apatite (CA) have gained attention due to their biocompatibility, reduced toxicity, and improved therapeutic efficacy. Methods: In this study, the potential of goose bone ash (GBA), a natural derivative of HA or CA, was exploited as a pH-responsive carrier to successfully deliver doxorubicin (DOX), an anthracycline drug into breast cancer cells (e.g., MCF-7 and MDA-MB-231 cells). GBA in either pristine form or in suspension was characterized in terms of size, morphology, functional groups, cellular internalization, cytotoxicity, pH-responsive drug (DOX) release, and protein corona analysis. Results: The pH-responsive drug release study demonstrated the prompt release of DOX from GBA through its disintegration in acidic pH (5.5-6.5), which mimics the pH of the endosomal and lysosomal compartments as well as the stability of GBA in physiological pH (pH 7.5). The result of DOX binding with GBA indicated an increment in binding affinity with increasing concentrations of DOX. Cell viability and cytotoxicity analysis showed no innate toxicity of GBA particles. Both qualitative and quantitative cellular uptake analysis in both cell lines displayed an enhanced cellular internalization of DOX-loaded GBA compared to free DOX molecules. The protein corona spontaneously formed on the surface of GBA particles exhibited its affinity toward transport proteins, structural proteins, and a few other selective proteins. The adsorption of transport proteins could extend the circulation half-life in biological environment and increase the accumulation of the drug-loaded NPs through the enhanced permeability and retention (EPR) effect at the tumor site. Conclusion: These findings highlight the potential of GBA as a DDS to successfully deliver therapeutics into breast cancer cells.
  9. Updates on Managing Type 2 Diabetes Mellitus with Natural Products: Towards Antidiabetic Drug Development
    Alam F, Islam MA, Kamal MA, Gan SH
    Curr Med Chem, 2018;25(39):5395-5431.
    PMID: 27528060 DOI: 10.2174/0929867323666160813222436
    Over the years, natural products have shown success as antidiabetics in in vitro, in vivo studies and clinical trials. Because natural product-derived drugs are more affordable and effective with fewer side-effects compared to conventional therapies, pharmaceutical research is increasingly leaning towards the discovery of new antidiabetic drugs from natural products targeting pathways or components associated with type 2 diabetes mellitus (T2DM) pathophysiology. However, the drug discovery process is very lengthy and costly with significant challenges. Therefore, various techniques are currently being developed for the preclinical research phase of drug discovery with the aim of drug development with less time and efforts from natural products. In this review, we have provided an update on natural products including fruits, vegetables, spices, nuts, beverages and mushrooms with potential antidiabetic activities from in vivo, in vitro and clinical studies. Synergistic interactions between natural products and antidiabetic drugs, and potential antidiabetic active compounds from natural products are also documented to pave the way for combination treatment and new drug discovery, respectively. Additionally, a brief idea of the drug discovery process along with the challenges that arise during drug development from natural products and the methods to conquer those challenges are discussed to create a more convenient future drug discovery process.
  10. Fulltext Impact of CYP3A4*18 and CYP3A5*3 Polymorphisms on Imatinib Mesylate Response Among Chronic Myeloid Leukemia Patients in Malaysia
    Maddin N, Husin A, Gan SH, Aziz BA, Ankathil R
    Oncol Ther, 2016;4(2):303-314.
    PMID: 28261657 DOI: 10.1007/s40487-016-0035-x
    INTRODUCTION: Imatinib mesylate (IM), a selective inhibitor of the BCR-ABL tyrosine kinase, is a well-established first-line treatment for chronic myeloid leukemia (CML). IM is metabolized mainly by cytochrome P450 (CYP) in the liver, specifically the CYP3A4 and CYP3A5 enzymes. Polymorphisms in these genes can alter the enzyme activity of IM and may affect its response. In this study, the impact of two single-nucleotide polymorphisms (SNPs), CYP3A5*3 (6986A>G) and CYP3A4*18 (878T>C), on IM treatment response in CML patients (n = 270; 139 IM resistant and 131 IM good responders) was investigated.

    METHODS: Genotyping of CYP3A4*18 and CYP3A5*3 was performed using the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) technique. The association between allelic variants and treatment response was assessed by means of odds ratio (OR) with 95% confidence intervals calculated by logistic regression.

    RESULTS: Our results indicated that CML patients carrying the heterozygous (AG) and homozygous variant (GG) genotype of CYP3A5*3 were associated with a significantly lower risk of acquiring resistance with OR 0.171; 95% CI: 0.090-0.324, p 

  11. Immune-mediated Pathogenesis and Therapies for Inflammatory Autoimmune Diseases
    Islam MA, Kamal MA, Md Zulfiker AH, Gan SH
    Curr Pharm Des, 2019;25(27):2907-2908.
    PMID: 31621552 DOI: 10.2174/138161282527191007151037
  12. Metabolic Control of Type 2 Diabetes by Targeting the GLUT4 Glucose Transporter: Intervention Approaches
    Alam F, Islam MA, Khalil MI, Gan SH
    Curr Pharm Des, 2016;22(20):3034-49.
    PMID: 26951104 DOI: 10.2174/1381612822666160307145801
    Type 2 diabetes mellitus (T2DM), the most common form of diabetes, is characterized by insulin resistance in the hepatic and peripheral tissues. Glucose transporter 4 (GLUT4) plays a major role in the pathophysiology of T2DM. Its defective expression or translocation to the peripheral cell plasma membrane in T2DM patients hinders the entrance of glucose into the cell for energy production. In addition to suitable drugs, an appropriate diet and/or exercise can be implemented to target the increase in GLUT4 expression, GLUT4 concentrations and GLUT4 translocation to the cell surface when managing the glucose metabolism of T2DM patients. In this review, we discussed successful intervention strategies that were individually administered or coupled with diet and/or exercise and affected the expression and translocation of GLUT4 in T2DM while reducing the excess glucose load from the blood. Additionally, some potentially good synthetic and natural compounds, which can activate the insulin-independent GLUT4 signaling pathways for the efficient management of T2DM, are highlighted as possible targets or emerging alternative sources for future anti-diabetic drug development.
  13. Type 2 Diabetes Mellitus and Alzheimer's Disease: Bridging the Pathophysiology and Management
    Alam F, Islam MA, Sasongko TH, Gan SH
    Curr Pharm Des, 2016;22(28):4430-42.
    PMID: 27229721 DOI: 10.2174/1381612822666160527160236
    Although type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) are two independent diseases, evidences from epidemiological, pathophysiological and animal studies have indicated a close pathophysiological relationship between these diseases. Due to the pathophysiological similarity of T2DM and AD, which includes insulin resistance and deficiency, protein aggregation, oxidative stress, inflammation, autophagocytosis and advanced glycation end products; AD is often referred to as "type 3 diabetes". In addition to the targeted regimens usually used for treating T2DM and AD individually, currently, anti-diabetic drugs are successfully used to reduce the cognitive decline in AD patients. Therefore, if a common pathophysiology of T2DM and AD could be clearly determined, both diseases could be managed more efficiently, possibly by shared pharmacotherapy in addition to understanding the broader spectrum of preventive strategies. The aim of this review is to discuss the pathophysiological bridge between T2DM and AD to lay the foundation for the future treatment strategies in the management of both diseases.
  14. VKORC1 and CYP2C9 genotypic data-based dose prediction alone does not accurately predict warfarin dose requirements in some Malaysian patients
    Chua YA, Abdullah WZ, Yusof Z, Gan SH
    Turk J Med Sci, 2015;45(4):913-8.
    PMID: 26422867
    BACKGROUND/AIM: VKORC1 and CYP2C9 genetic polymorphisms may not accurately predict warfarin dose requirements. We evaluated an existing warfarin dosing algorithm developed for Malaysian patients that was based only on VKORC1 and CYP2C9 genes.

    MATERIALS AND METHODS: Five Malay patients receiving warfarin maintenance therapy were investigated for their CYP2C9*2, CYP2C9*3, and VKORC1-1639G>A genotypes and their vitamin K-dependent (VKD) clotting factor activities. The records of their daily warfarin doses and international normalized ratio (INR) 2 years prior to and after the measurement of VKD clotting factors activities were acquired. The mean warfarin doses were compared with predicted warfarin doses calculated from a genotypic-based dosing model developed for Asians.

    RESULTS: A patient with the VKORC1-1639 GA genotype, who was supposed to have higher dose requirements, had a lower mean warfarin dose similar to those having the VKORC1-1639 AA genotype. This discrepancy may be due to the coadministration of celecoxib, which has the potential to decrease warfarins metabolism. Not all patients' predicted mean warfarin doses based on a previously developed dosing algorithm for Asians were similar to the actual mean warfarin dose, with the worst predicted dose being 54.34% higher than the required warfarin dose.

    CONCLUSION: Multiple clinical factors can significantly change the actual required dose from the predicted dose from time to time. The additions of other dynamic variables, especially INR, VKD clotting factors, and concomitant drug use, into the dosing model are important in order to improve its accuracy.

  15. Genetic polymorphisms of CYP3A4: CYP3A4*18 allele is found in five healthy Malaysian subjects
    Ruzilawati AB, Suhaimi AW, Gan SH
    Clin Chim Acta, 2007 Aug;383(1-2):158-62.
    PMID: 17601520 DOI: 10.1016/j.cca.2007.05.004
    BACKGROUND: Cytochrome P450 3A4 (CYP3A4) is the major cytochrome involved in metabolizing of >60% of all drugs used in humans. A number of allelic variations in CYP3A4 gene are known to affect catalytic activity including CYP3A4*4, CYP3A4*5 and CYP3A4*18. We investigated the frequencies of CYP3A4*4, CYP3A4*5 and CYP3A4*18 alleles in a Malaysian population. This will impact treatment of patients receiving drugs metabolized by these alleles.

    METHODS: The study was conducted in 121 healthy Malaysian volunteers. DNA was extracted from leucocytes and the 3 alleles were determined by PCR-RFLP. The PCR product was later digested with restriction enzymes BstMA I, BshV I and Hpa II.

    RESULTS: No mutations were detected for CYP3A4*4 and CYP3A4*5 alleles. The frequency of the CYP3A4*18 allele in the Malaysian population is 2.1%. All 5 subjects with CYP3A4*18 mutations were found to be heterozygous.

    CONCLUSION: The present study describes polymorphisms of CYP3A4 among Malaysian subjects. Clinical relevance of these genetic variants in these healthy volunteers is under investigation.
  16. Standard CYP2D6 genotyping procedures fail for the CYP2D6*5 and duplication alleles when hair roots are used as a source of DNA
    Gan SH, Ismail R, Wan Adnan WA, Wan Z
    Clin Chim Acta, 2003 Mar;329(1-2):61-8.
    PMID: 12589966 DOI: 10.1016/s0009-8981(03)00019-6
    BACKGROUND: Hair roots provide a useful alternative to blood as a source of DNA for genotyping. Besides simple and non-invasive collections, the DNA extraction step is also easy to perform and is fast. The aim of our study is to determine if hair roots can be used to genotype all of the common CYP2D6 alleles for routine screening purposes.

    METHOD: The study complies with the Declaration of Helsinki. After obtaining informed consents, both blood and hair samples were collected from 92 patients for genotyping of the CYP2D6 gene. PCR was used to detect the following mutations: CYP2D6*1, *3, *4, *5, *9, *10, *17 and duplication gene. The results were compared where hair roots and blood were used as templates for DNA respectively.

    RESULTS: When blood was used as a source of DNA for genotyping, all of the investigated CYP2D6 alleles were successfully amplified. However, with hair roots, the genes with the larger fragment sizes: CYP2D6*5 and the duplication gene could not be amplified and the bands of other alleles investigated were faint when visualized under UV light.

    CONCLUSIONS: DNA extraction from hair roots and leucocytes yielded similar results but the DNA extracted from hair roots did not allow successful amplification of the longer genes such as the CYP2D6*5 and the duplication gene.
  17. Stereoselective method development and validation for determination of concentrations of amphetamine-type stimulants and metabolites in human urine using a simultaneous extraction-chiral derivatization approach
    Wan Raihana WA, Gan SH, Tan SC
    J Chromatogr B Analyt Technol Biomed Life Sci, 2011 Jan 1;879(1):8-16.
    PMID: 21147046 DOI: 10.1016/j.jchromb.2010.10.037
    Amphetamine-type stimulants (ATS) are a group of chiral amine drugs which are commonly abused for their sympathomimetic and stimulant properties. ATS are extensively metabolised by hepatic cytochrome P450 enzymes. As metabolism of ATS has been shown to be highly stereospecific, stereoselective analytical methods are essential for the quantitative determination of ATS concentrations for both in vivo and in vitro studies of ATS metabolism. This paper describes a new stereoselective method for the simultaneous determination of amphetamine (AM), methamphetamine (MA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), 4-hydroxy-3-methoxymethamphetamine (HMMA), 4-hydroxy-3-methoxyamphetamine (HMA), 3,4-hydroxymethamphetamine (HHMA) and 3,4-hydroxyamphetamine (HHA) in human urine samples validated according to the United States Food and Drug Administration guidelines. In this method, analytes are simultaneously extracted and derivatized with R-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride (R-MTPCl) as the chiral derivatization reagent. Following this, the analytes were subjected to a second derivatization with N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA) which targets the hydroxyl groups present in HMMA, HMA, HHMA and HHA. The derivatized analytes were separated and quantified using gas chromatography-mass spectrometry (GC-MS). The method was evaluated according to the established guidelines for specificity, linearity, precision, accuracy, recovery and stability using a five-day protocol. Intra-day precision ranged from 0.89 to 11.23% RSD whereas inter-day precision was between 1.03 and 12.95% RSD. Accuracy values for the analytes ranged from -5.29% to 13.75%. Limits of quantitation were 10 μg/L for AM, MA, MDMA, HMA and HMMA and 2μg/L for MDA, HMA and HHA. Recoveries and stability values were also within accepted values. The method was applied to authentic ATS-positive samples.
  18. Method development and validation of a high-performance liquid chromatographic method for tramadol in human plasma using liquid-liquid extraction
    Gan SH, Ismail R, Wan Adnan WA, Wan Z
    J Chromatogr B Analyt Technol Biomed Life Sci, 2002 May 25;772(1):123-9.
    PMID: 12016023
    An HPLC system using a simple liquid-liquid extraction and HPLC with UV detection has been validated to determine tramadol concentration in human plasma. The method developed was selective and linear for concentrations ranging from 10 to 2000 ng/ml with average recovery of 98.63%. The limit of quantitation (LOQ) was 10 ng/ml and the percentage recovery of the internal standard phenacetin was 76.51%. The intra-day accuracy ranged from 87.55 to 105.99% and the inter-day accuracy, 93.44 to 98.43% for tramadol. Good precision (5.32 and 6.67% for intra- and inter-day, respectively) was obtained at LOQ. The method has been applied to determine tramadol concentrations in human plasma samples for a pharmacokinetic study.
  19. Fulltext Honey, Propolis, and Royal Jelly: A Comprehensive Review of Their Biological Actions and Health Benefits
    Pasupuleti VR, Sammugam L, Ramesh N, Gan SH
    Oxid Med Cell Longev, 2017;2017:1259510.
    PMID: 28814983 DOI: 10.1155/2017/1259510
    BACKGROUND: There are several health benefits that honeybee products such as honey, propolis, and royal jelly claim toward various types of diseases in addition to being food.

    SCOPE AND APPROACH: In this paper, the effects of honey, propolis, and royal jelly on different metabolic diseases, cancers, and other diseases have been reviewed. The modes of actions of these products have also been illustrated for purposes of better understanding.

    KEY FINDINGS AND CONCLUSIONS: An overview of honey, propolis, and royal jelly and their biological potentials was highlighted. The potential health benefits of honey, such as microbial inhibition, wound healing, and its effects on other diseases, are described. Propolis has been reported to have various health benefits related to gastrointestinal disorders, allergies, and gynecological, oral, and dermatological problems. Royal jelly is well known for its protective effects on reproductive health, neurodegenerative disorders, wound healing, and aging. Nevertheless, the exact mechanisms of action of honey, propolis, and royal jelly on the abovementioned diseases and activities have not been not fully elucidated, and further research is warranted to explain their exact contributions.

  20. Fulltext Current practices, gaps, and opportunities on the role of clinical pharmacists in cancer pain management: Perspectives from Nepal
    Shrestha S, Gan SH, Paudyal V, Kc B, Sapkota S
    J Oncol Pharm Pract, 2023 Dec;29(8):2049-2056.
    PMID: 37847760 DOI: 10.1177/10781552231205025
    N/A.
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links