Displaying publications 1 - 20 of 99 in total

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  1. Gopalan Y, Shuaib IL, Magosso E, Ansari MA, Abu Bakar MR, Wong JW, et al.
    Stroke, 2014 May;45(5):1422-8.
    PMID: 24699052 DOI: 10.1161/STROKEAHA.113.004449
    Previous cell-based and animal studies showed mixed tocotrienols are neuroprotective, but the effect is yet to be proven in humans. Thus, the present study aimed to evaluate the protective activity of mixed tocotrienols in humans with white matter lesions (WMLs). WMLs are regarded as manifestations of cerebral small vessel disease, reflecting varying degrees of neurodegeneration and tissue damage with potential as a surrogate end point in clinical trials.
  2. Magosso E, Ansari MA, Gopalan Y, Shuaib IL, Wong JW, Khan NA, et al.
    Nutr J, 2013;12(1):166.
    PMID: 24373555 DOI: 10.1186/1475-2891-12-166
    Nonalcoholic fatty liver disease (NAFLD) is one of the commonest liver disorders. Obesity, insulin resistance, lipid peroxidation and oxidative stress have been identified amongst the possible hits leading to the onset and progression of this disease. Nutritional evaluation of NAFLD patients showed a lower-than-recommended intake of vitamin E. Vitamin E is a family of 8 isoforms, 4 tocopherols and 4 tocotrienols. Alpha-tocopherol has been widely investigated in liver diseases, whereas no previous clinical trial has investigated tocotrienols for NAFLD. Aim of the study was to determine the effects of mixed tocotrienols, in normalising the hepatic echogenic response in hypercholesterolaemic patients with ultrasound-proven NAFLD.
  3. Lim R, Liong ML, Khan NA, Yuen KH
    J Sex Marital Ther, 2017 Feb 17;43(2):142-146.
    PMID: 26836418 DOI: 10.1080/0092623X.2016.1141817
    There is currently no published information on the validity and reliability of the Golombok Rust Inventory of Sexual Satisfaction in the Asian population, specifically in patients with stress urinary incontinence, which limits its use in this region. Our study aimed to evaluate the psychometric properties of this questionnaire in the Malaysian population. Ten couples were recruited for the pilot testing. The agreement between the English and Chinese or Malay versions were tested using the intraclass correlation coefficients, with results of more than 0.80 for all subscales and overall scores indicating good agreement. Sixty-six couples were included in the subsequent phase. The following data are presented in the order of English, Chinese, and Malay. Cronbach's alphas for the male total score were 0.82, 0.88, and 0.95. For the female total score, Cronbach's alphas were 0.76, 0.78, and 0.88. Intraclass correlation coefficients for the male total score were 0.93, 0.94, and 0.99, while intraclass correlation coefficients for the female total score were 0.89, 0.86, and 0.88. In conclusion, the English, Chinese, and Malay versions each proved to be valid and reliable in our Malaysian population.
  4. Lim R, Liong ML, Leong WS, Khan NA, Yuen KH
    J Urol, 2016 07;196(1):153-8.
    PMID: 26812304 DOI: 10.1016/j.juro.2016.01.090
    PURPOSE: Studies of the effects of stress urinary incontinence on the sexual function of couples are scarce. We prospectively evaluated couple sexual function and the relationship between sexual function and quality of life. We also compared quality of life in females with vs without stress urinary incontinence.

    MATERIALS AND METHODS: Sexually active females at least 21 years old with or without stress urinary incontinence and their partners were recruited for study. To assess sexual function the couples completed GRISS (Golombok Rust Inventory of Sexual Satisfaction) and a 1-item question on overall sexual experience, "Over the past 4 weeks, how satisfied have you been with your overall sexual life?" Additionally, females completed ICIQ-LUTSqol (International Consultation on Incontinence Questionnaire-Lower Urinary Tract Symptoms Quality of Life) to assess quality of life.

    RESULTS: For sexual function assessment 66 of 134 couples with (49.3%) and 95 of 176 without (54.0%) stress urinary incontinence were recruited. Females with stress urinary incontinence had lower overall sexual function, lower frequency of sexual intercourse, less satisfaction (each p <0.001) and higher avoidance behavior (p = 0.026). Partners of females with stress urinary incontinence had more problems with erectile dysfunction (p = 0.027), less satisfaction (p = 0.006) and lower frequency of sexual intercourse (p = 0.001) but no difference in overall GRISS score (p = 0.093). Couples with stress urinary incontinence had poorer overall sexual experience (p <0.05). Females with stress urinary incontinence had poorer quality of life than those without stress urinary incontinence (120 of 134, response rate 89.6% vs 145 of 176, response rate 82.4%, p <0.001). Sexual function and quality of life did not significantly correlate (r = 0.001, p = 0.997).

    CONCLUSIONS: Stress urinary incontinence in females is negatively associated not only with female quality of life and sexual function but also with partner sexual function.

  5. Lim R, Liong ML, Leong WS, Khan NA, Yuen KH
    Trials, 2015;16:279.
    PMID: 26093910 DOI: 10.1186/s13063-015-0803-1
    There is currently a lack of randomized, sham-controlled trials that are adequately powered, using validated outcomes, to allow for firm recommendations on the use of magnetic stimulation for stress urinary incontinence. We report a protocol of a multicenter, randomized, double-blind, sham-controlled parallel-group trial to evaluate the efficacy of magnetic stimulation for stress urinary incontinence.
  6. Billa N, Yuen KH
    AAPS PharmSciTech, 2000;1(4):E30.
    PMID: 14727895
    The purpose of this research was to study processing variables at the laboratory and pilot scales that can affect hydration rates of xanthan gum matrices containing diclofenac sodium and the rate of drug release. Tablets from the laboratory scale and pilot scale proceedings were made by wet granulation. Swelling indices of xanthan gum formulations prepared with different amounts of water were measured in water under a magnifying lens. Granules were thermally treated in an oven at 60 degrees C, 70 degrees C, and 80 degrees C to study the effects of elevated temperatures on drug release from xanthan gum matrices. Granules from the pilot scale formulations were bulkier compared to their laboratory scale counterparts, resulting in more porous, softer tablets. Drug release was linear from xanthan gum matrices prepared at the laboratory scale and pilot scales; however, release was faster from the pilot scales. Thermal treatment of the granules did not affect the swelling index and rate of drug release from tablets in both the pilot and laboratory scale proceedings. On the other hand, the release from both proceedings was affected by the amount of water used for granulation and the speed of the impeller during granulation. The data suggest that processing variables that affect the degree of wetness during granulation, such as increase in impeller speed and increase in amount of water used for granulation, also may affect the swelling index of xanthan gum matrices and therefore the rate of drug release.
  7. Lim R, Liong ML, Lim KK, Leong WS, Yuen KH
    Urology, 2019 Nov;133:91-95.
    PMID: 31415780 DOI: 10.1016/j.urology.2019.08.004
    OBJECTIVE: To estimate the minimum clinically important difference (MCID) of the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF) and the International Consultation on Incontinence Questionnaire-Lower Urinary Tract Symptoms Quality of Life (ICIQ-LUTSqol) using both anchor-based and distribution-based methods for women with stress urinary incontinence undergoing nonsurgical treatment.

    MATERIALS AND METHODS: Data from a randomized clinical trial evaluating efficacy of a nonsurgical intervention in women with stress urinary incontinence were used for analyses. The overall score of ICIQ-UI SF ranges from 0 to 21, with greater values indicating increased severity. The ICIQ-LUTSqol ranges from 19 to 76, with greater values indicating increased impact on quality of life. Instruments used in the anchor-based method were the Patient Global Impression of Improvement, patient satisfaction, 1-hour pad test and the incontinence episode frequency. The distribution-based method used an effect size of 0.5 standard deviation. Triangulation of findings was used to converge on a single value of MCID.

    RESULTS: At 12-month post-treatment, 106 (88.3%) participants completed the follow-up and were included in the analysis. Anchor-based MCIDs of the ICIQ-UI SF were between 3.4 and 4.4, while the distribution-based MCID was 1.7. Anchor-based MCIDs of the ICIQ-LUTSqol were between 4.8 and 6.9, while the distribution-based MCID was 5.2. Triangulation of findings showed that MCIDs of 4 for ICIQ-UI SF and 6 for ICIQ-LUTSqol were the most appropriate.

    CONCLUSION: For women undergoing nonsurgical treatments for incontinence, reductions of 4 and 6 points in ICIQ-UI SF and ICIQ-LUTSqol, respectively are perceived as clinically meaningful.

  8. Chang CT, Ang JY, Wong JM, Tan SS, Chin SK, Lim AB, et al.
    Med J Malaysia, 2020 05;75(3):286-291.
    PMID: 32467546
    AIM: This study is conducted to compare the pharmacokinetic profiles of two fixed dose combination of metformin/glibenclamide tablets (500mg/5 mg per tablet).

    MATERIALS AND METHODS: This is a single-center, single-dose, open-label, randomized, 2-treatment, 2-sequence and 2- period crossover study with a washout period of 7 days. All 28 adult male subjects were required to fast for at least 10 hours prior to drug administration and they were given access to water ad libitum during this period. Thirty minutes prior to dosing, all subjects were served with a standardized high-fat and high-calorie breakfast with a total calorie of 1000 kcal which was in accordance to the EMA Guideline on the Investigation of Bioequivalence. Subsequently, subjects were administered either the test or reference preparation with 240mL of plain water in the first trial period. During the second trial period, they received the alternate preparation. Plasma levels of glibenclamide and metformin were analysed separately using two different high performance liquid chromatography methods.

    RESULTS: The 90% confidence interval (CI) for the ratio of the AUC0-t, AUC0-∞, and Cmax of the test preparation over those of the reference preparation were 0.9693-1.0739, 0.9598- 1.0561 and 0.9220 - 1.0642 respectively. Throughout the study period, no serious drug reaction was observed. However, a total of 26 adverse events (AE)/side effects were reported, including 24 that were definitely related to the study drugs, namely giddiness (n=17), while diarrheoa (n=3), headache (n=2) and excessive hunger (n=2) were less commonly reported by the subjects.

    CONCLUSION: It can be concluded that the test preparation is bioequivalent to the reference preparation.

  9. Yap SP, Julianto T, Wong JW, Yuen KH
    J Chromatogr B Biomed Sci Appl, 1999 Dec 10;735(2):279-83.
    PMID: 10670741
    A simple high-performance liquid chromatographic method using fluorescence detection was developed for the determination of vitamin E especially delta-, gamma- and alpha-tocotrienols in human plasma. The method entailed direct injection of plasma sample after deproteinization using a 3:2 mixture of acetonitrile-tetrahydrofuran. The mobile phase comprised 0.5% (v/v) of distilled water in methanol. Analyses were run at a flow-rate of 1.5 ml/min with the detector operating at an excitation wavelength of 296 nm and emission wavelength of 330 nm. This method is specific and sensitive, with a quantification limit of approximately 40, 34 and 16 ng/ml for alpha-, gamma- and delta-tocotrienol, respectively. The mean absolute recovery values were about 98% while the within-day and between-day relative standard deviation and percent error values of the assay method were all less than 12.0% for alpha-, gamma- and delta-tocotrienol. The calibration curve was linear over a concentration range of 40-2500, 30-4000 and 16-1000 ng/ml for alpha-, gamma- and delta-tocotrienol, respectively. Application of the method in a bioavailability study for determination of the above compounds was also demonstrated.
  10. Peh KK, Billa N, Yuen KH
    J Chromatogr B Biomed Sci Appl, 1997 Nov 07;701(1):140-5.
    PMID: 9389350
    A simple liquid chromatographic method using amperometric detection was developed for the determination of naltrexone in human plasma. Prior to analysis, naltrexone and the internal standard (naloxone) were extracted from plasma samples using a 9:1 mixture of chloroform and isopropyl alcohol. The mobile phase comprised 0.1 M disodium hydrogen orthophosphate (pH 3.5) and acetonitrile (85.5:14.5, v/v). Analysis was run at a flow-rate of 0.8 ml/min with the detector operating under oxidative mode at an applied potential of +0.95 V. The method is specific and sensitive with a detection limit of approximately 1 ng/ml at a signal-to-noise ratio of 3:1. Mean recovery value of the extraction procedure was about 93%, while the within day and between day coefficient of variation and percent error values of the assay method were all less than 10%. The calibration curve was linear over a concentration range of 1.5-100 ng/ml.
  11. Peh KK, Yuen KH
    J Chromatogr B Biomed Sci Appl, 1997 May 23;693(1):241-4.
    PMID: 9200543
    A simple high-performance liquid chromatographic method using fluorescence detection was developed for the determination of acyclovir in human plasma. The method entailed direct injection of the plasma sample after deproteination. It is both specific and sensitive with a detection limit of 30 ng/ml at a signal-to-noise ratio of 3:1, and is thus suitable for use in pharmacokinetic studies of acyclovir. The method had a mean absolute recovery of 96%, while the within-day and between-day coefficients of variation and percentages error were all less than 8%. The calibration curve was linear over a concentration range of 62.5-4000 ng/ml.
  12. Wong CF, Peh KK, Yuen KH
    J Chromatogr B Biomed Sci Appl, 1998 Oct 23;718(1):205-10.
    PMID: 9832378
    A simple high-performance liquid chromatographic method was developed for the determination of ranitidine in human plasma. Prior to analysis, ranitidine and the internal standard (metoprolol) were extracted from alkalinized plasma samples using dichloromethane. The mobile phase was 0.05 M potassium dihydrogenphosphate-acetonitrile (88:12, v/v) adjusted to pH 6.5. Analysis was run at a flow-rate of 1.3 ml/min and at a detection wavelength of 229 nm. The method is sensitive with a detection limit of 1 ng/ml at a signal-to-noise ratio of 3:1, while the quantification limit was set at 15 ng/ml. The calibration curve was linear over a concentration range of 15-2000 ng/ml. Mean recovery value of the extraction procedure was about 90%, while the within-day and between-day coefficients of variation and percent error values of the assay method were all less than 15%.
  13. Choy YW, Khan N, Yuen KH
    Int J Pharm, 2005 Aug 11;299(1-2):55-64.
    PMID: 15955645
    A polyglycolised glyceride carrier, Gelucire 50/13, was incorporated with paracetamol as a model drug, filled into hard gelatin capsules and stored at three different temperatures for various lengths of time. The resultant solidified matrix within the capsule was subjected to thermal analysis using differential scanning calorimetry (DSC) to ascertain its supramolecular structure. Polymorphic transformations towards more stable gelucire forms were observed upon aging the matrices, with samples stored at a temperature near the melting range of the lower temperature gelucire melting fraction showing the most profound changes. The increase in the rate of drug release from aged samples could be correlated to the alterations to the supramolecular structure of the gelucire. Accelerated drug release from aged samples could also be seen from in vivo studies using healthy human volunteers, although the extent of absorption was not affected. Therefore, even though the sustainability of release may be compromised by aging the gelucire matrices, the bioavailability of the incorporated drug is unlikely to be affected.
  14. Yuen KH
    Int J Pharm, 2010 Aug 16;395(1-2):9-16.
    PMID: 20478371 DOI: 10.1016/j.ijpharm.2010.04.045
    The human small intestine, with its enormous absorptive surface area, is invariably the principal site of drug absorption. Hence, the residence time of a dosage form in this part of the gut can have a great influence on the absorption of the contained drug. Various methods have been employed to monitor the gastrointestinal transit of pharmaceutical dosage forms, but the use of gamma-scintigraphy has superceded all the other methods. However, careful consideration of the time interval for image acquisition and proper analysis of the scintigraphic data are important for obtaining reliable results. Most studies reported the mean small intestinal transit time of various dosage forms to be about 3-4h, being closely similar to that of food and water. The value does not appear to be influenced by their physical state nor the presence of food, but the timing of food intake following administration of the dosage forms can influence the small intestinal transit time. While the mean small intestinal transit time is quite consistent among dosage forms and studies, individual values can vary widely. There are differing opinions regarding the effect of density and size of dosage forms on their small intestinal transit properties. Some common excipients employed in pharmaceutical formulations can affect the small intestinal transit and drug absorption. There is currently a lack of studies regarding the effects of excipients, as well as the timing of food intake on the small intestinal transit of dosage forms and drug absorption.
  15. Yap SP, Yuen KH
    Int J Pharm, 2004 Aug 20;281(1-2):67-78.
    PMID: 15288344
    A single dose comparative bioavailability study was conducted to evaluate the bioavailability of tocotrienols from two self-emulsifying formulations, one of which produced an emulsion that readily lipolysed under in vitro condition (SES-A), while the other produced a finer dispersion with negligible lipolysis (SES-B) in comparison with that of a non-self-emulsifying formulation in soya oil. The study was conducted according to a three-way crossover design using six healthy human volunteers. Statistically significant differences were observed between the logarithmic transformed peak plasma concentration (Cmax) and total area under the plasma concentration-time curve (AUC(0-infinity)) values of both SES-A and -B compared to NSES-C indicating that SES-A and -B achieved a higher extent of absorption compared to NSES-C. Moreover, the 90% confidence interval of the AUC(0-infinity) values of both SES-A and -B over those of NSES-C were between 2-3 suggesting an increase in bioavailability of about two-three times compared to NSES-C. Both SES-A and -B also achieved a faster onset of absorption. However, both SES-A and -B had comparable bioavailability, despite the fact that SES-B was able to form emulsions with smaller droplet size. Thus, it appeared that both droplet sizes as well as the rate and extent of lipolysis of the emulsion products formed were important for enhancing the bioavailability of the tocotrienols from the self-emulsifying systems.
  16. Wong JW, Yuen KH
    Int J Pharm, 2001 Oct 04;227(1-2):177-85.
    PMID: 11564552
    The bioavailability of beta- and gamma-cyclodextrin artemisinin complexes was evaluated in comparison with a normal commercially available preparation, Artemisinin 250. Twelve healthy male volunteers participated in the study conducted according to a three-way crossover design. The bioavailability was compared using the parameters, total area under the plasma level-time curve (AUC(0-infinity)), peak plasma concentration (C(max)), and time to reach peak plasma concentration (T(max)). A statistically significant difference was observed between the values of the complexes and Artemisinin 250 for the three parameters. However, no statistically significant difference was observed between the values of the beta- and gamma-cyclodextrin complexes. Moreover, the 90% confidence interval for the ratio of the AUC(0-infinity) values of the beta-cyclodextrin complex over those of Artemisinin 250 was estimated to be between 1.51-2.04, while that of C(max) was between 1.73-2.93. For the gamma-cyclodextrin complex, the respective intervals were 1.30-1.76 and 1.43-2.43. These findings indicated that the beta- and gamma-cyclodextrin complexes had a much higher rate and extent of bioavailability compared to Artemisinin 250. In addition, the absorption of artemisinin was observed to be poor and negligible when the preparations started to arrive in the colon. This could be attributed to poor dissolution of artemisinin in the semi-solid faecal matter in the lower part of the gastrointestinal tract.
  17. Jamaludin A, Mohamad M, Navaratnam V, Selliah K, Tan SC, Wernsdorfer WH, et al.
    Br J Clin Pharmacol, 1988 Feb;25(2):261-3.
    PMID: 3358888
    The hydrochloride, sulphate and ethylcarbonate salts of quinine were given in single oral doses (600 mg base equivalent) to nine healthy male subjects according to a cross-over design. No statistically significant differences were noted in the plasma drug concentration-time profiles although inter- and intra-subject variation in AUC, Cmax and tmax values was appreciable. The ethylcarbonate salt may be preferred for use in paediatric patients because of its neutral taste.
  18. Lim R, Liong ML, Lau YK, Yuen KH
    Neurourol Urodyn, 2017 02;36(2):438-442.
    PMID: 26693962 DOI: 10.1002/nau.22950
    AIMS: To enable the use of the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF) and ICIQ-Lower Urinary Tract Symptoms Quality of Life (ICIQ-LUTSqol) in Southeast Asia, we translated and subsequently evaluated their validity (content and discriminant validity), reliability (internal consistency and test-retest reliability), and responsiveness in female patients with stress urinary incontinence.

    METHODS: Permission was obtained to translate the English versions into Malay and subsequently validate them, and to validate the existing Chinese versions. The translated questionnaires were taken for pilot testing. Validation was carried out for the face/content and discriminant validity. Reliability was assessed for test-retest and internal consistency using Cronbach's alpha and intraclass correlation coefficient respectively. The responsiveness was calculated via effect size and standardized response mean.

    RESULTS: Ten patients were recruited for the pilot testing. The English and Chinese versions had "substantial" or "almost perfect" agreement as measured by weighted Kappa. 284 participants (139 patients with stress urinary incontinence and 145 healthy volunteers) were included in the subsequent phases. The ICIQ-UI SF and ICIQ-LUTSqol had good discriminant validity. The ICIQ-UI SF had moderate internal consistency although the ICIQ-LUTSqol had good internal consistency. Both questionnaires had high test-retest reliability. Responsiveness was established with a moderate to large effect size and a standardized response mean.

    CONCLUSIONS: The English, Chinese, and Malay versions each proved to be valid and reliable in our Malaysian population, thereby enabling more cross-cultural research in this region. Neurourol. Neurourol. Urodynam. 36:438-442, 2017. © 2015 Wiley Periodicals, Inc.

  19. Lim R, Lee SW, Tan PY, Liong ML, Yuen KH
    Neurourol Urodyn, 2015 Nov;34(8):713-22.
    PMID: 25251335 DOI: 10.1002/nau.22672
    To review whether patients with urinary incontinence (UI) treated with magnetic stimulation (MS) have a higher continence rate compared to sham.
  20. Lim R, Liong ML, Leong WS, Karim Khan NA, Yuen KH
    J Urol, 2017 05;197(5):1302-1308.
    PMID: 27871927 DOI: 10.1016/j.juro.2016.11.091
    PURPOSE: Despite significant differences in success rates between surgical and nonsurgical treatments for female stress urinary incontinence, a few cross-sectional surveys showed that most patients still prefer the latter. We evaluated the efficacy of the under studied nonsurgical treatment using pulsed magnetic stimulation for female stress urinary incontinence.

    MATERIALS AND METHODS: This randomized, double-blind, sham controlled study was performed in 120 female subjects at least 21 years old with stress urinary incontinence. Treatment involved pulsed magnetic stimulation for 2 sessions per week for 2 months (16 sessions). After 2 months, subjects could opt for 16 additional sessions regardless of initial randomization. The primary response criterion was a 5-point reduction in the ICIQ-UI SF (International Consultation on Incontinence Questionnaire for Urinary Incontinence-Short Form) score. Key secondary response criteria included objective and subjective cure, supplemented by other secondary criteria. Followups were performed at months 1, 2, 5, 8 and 14.

    RESULTS: At 2 months 45 of 60 subjects (75%) in the active arm vs 13 of 60 (21.7%) in the sham arm were treatment responders (p <0.001). After 2 months 24 subjects (40%) in the active arm and 41 (68%) in the sham arm elected additional active pulsed magnetic stimulation. At 14 months, subjects who received 32 sessions of active pulsed magnetic stimulation had the highest percentage of treatment responders (18 of 24 or 75.0%), followed by those who received 16 sessions (26 of 36 or 72.2% and 28 of 41 or 68.3%) and those who did not receive any active pulsed magnetic stimulation (4 of 19 or 21.1%) (p <0.001).

    CONCLUSIONS: The encouraging long-term response rates show that pulsed magnetic stimulation is an attractive nonsurgical alternative for patients who do not want to undergo surgery.

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