Yahdiana Harahap

Simultaneous quantification of losartan and active metabolite in human plasma by liquid chromatography-tandem mass spectrometry using irbesartan as internal standard.

A simple and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method employing electronspray ionization was developed and validated for quantification of losartan and its carboxylic acid metabolite in human plasma using irbesartan as internal standard (IS). Following a simple pretreatment procedure, the analytes were separated using a gradient mobile phase on reverse phase C18 column. Selected reaction monitoring was specific for losartan, losartan acid and irbesartan. The method validation demonstrated the specificity, lower limit of quantification, accuracy and precision of measurements. The assay exhibited a linear dynamic range of 2.0-400 ng/mL for losartan and 1.85-370 ng/mL for losartan acid. A run time of 3.5 min for each sample made it possible to analyze more than 200 samples per day. The validated method has been successfully used to analyze human plasma samples for application in bioavailability/bioequivalence studies.

Comparative bioavailability of two dexamethasone tablet formulations in Indonesian healthy volunteers

AIM To compare the bioavailability of two dexamethasone (CAS 50-02-2) tablet formulations -- 4 mg Dexmethsone tablets as test formulation and 4 mg tablets of the originator product as reference formulation. METHODS The study was conducted according to an open-label, randomized two-way crossover design with a one-week washout period. Twenty-four volunteers received a single dose of two tablets of the two different dexamethasone formulations. Blood samples for pharmacokinetic profiling were taken up to 24 h after drug administration in fasting condition. Plasma concentrations of dexamethasone were determined with a validated HPLC method using an ultraviolet detector. Pharmacokinetic parameters were calculated from observed plasma concentration-time profiles. RESULT The mean AUC0-t, AUC0-infinity, and Cmax were 501.61 ng x h/ml, 518.88 ng x h/ ml and 98.02 ng/ml, respectively for the test formulation and 507.10 ng x h/ml, 525.20 ng x h/ml and 97.82 ng/ml, respectively, for the reference formulation. The median Tmax, for both formulations was 0.75 h. Plasma elimination half-lives (t1/2) were 3.44 h (test) and 3.38 h (reference). The point estimates and 90% confidence intervals (CI) for AUC0-t, AUC0-infinity and Cmax were 98.92% (94.62-103.41%), 98.80% (94.51-103.28%) and 100.20% (91.43-109.81%), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration guidelines. CONCLUSION These results indicate that the two formulations of dexamethasone are bioequivalent and thus may be prescribed interchangeably.

Bioequivalence of ciprofloxacin tablet formulations assessed in Indonesian volunteers.

AIM Determination of the bioequivalence of two ciprofloxacin tablet formulations (test formulation manufactured by Novell Pharmaceutical Laboratories, Indonesia, reference formulation from Quimica Farmaceutica Bayer, Spain). SUBJECTS AND METHODS 24 healthy volunteers received each of the two ciprofloxacin formulations at a dose of 500 mg in a 2-way crossover design. Blood samples were obtained prior to dosing and at 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10, 12 and24h after drug administration. Plasma concentrations of ciprofloxacin were monitored using high-performance liquid chromatography over a period of 24 h after administration. The pharmacokinetics parameter AUC0-24h, AUC0-infinity and Cmax were tested for bioequivalence after log-transformation of data and ratios of tmax were evaluated non-parametrically. RESULTS The point estimates and 90% confidence intervals for AUC0-24h, AUC0-infinity and Cmax were 97.55% (92.71 - 102.6%), 97.63% (92.90 - 102.59%) and 95.84% (89.95 - 102.10%), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration guidelines. CONCLUSION These results indicate that two medications of ciprofloxacin are bioequivalent and, thus, may be prescribed interchangeably.

Comparative bioavailability of two irbesartan/hydrochlorothiazide tablet formulations in Indonesian healthy subjects.

AIM The bioavailability of two 300 mg irbesartan (CAS 138402-11-6)/12.5 mg hydrochlorothiazide (CAS 58-93-5) tablet formulations was compared, using Co-Ir-vell tablets as test formulation and the originator product as reference formulation. METHODS Twenty-four subjects were included in this single-dose, open-label, randomized two-way crossover study following an overnight fasting. A two-week wash-out period was applied. Blood samples were drawn up to 48 h following drug administrations. Irbesartan and hydrochlorothiazide plasma concentrations were determined by liquid chromatography-tandem mass spectrometry method with TurboIonSpray mode. Pharmacokinetic parameters AUC(0-t), AUC(0-infinity), Cmax and t were determined and used for bioequivalence evaluation after log-transformation, whereas t max ratios were evaluated non-parametrically. RESULTS The estimated point and 90% confidence intervals (CI) for AUC(0-t), AUC(0-infinity), Cmax and t for irbesartan were 97.74% (85.40-111.86%), 96.36% (83.25-111.55%), 103.30% (90.65-117.71%), 92.38% (82.68-103.21%) and for hydrochlorothiazide, 106.30% (97.72-115.63%), 106.28% (98.14-115.10%), 108.01% (95.48-122.18%), 105.52% (96.70-115.14%), respectively. CONCLUSION These results indicated that the two formulations of irbesartan/hydrochlorothiazide were bioequivalent; therefore they may be prescribed interchangeably.

Comparative bioavailability of two cetirizine tablet formulations in Indonesian healthy volunteers.

AIM To compare the bioavailability of two cetirizine tablet (10 mg) formulations (ZyrtecA from UCB Pharma, Spain as a reference formulation and RyvelA from Novell Pharmaceutical Laboratories, Indonesia as a test formulation). MATERIAL AND METHODS The study was conducted according to an open, randomized, two-period crossover design with a 1-week washout period. Eighteen volunteers participated and all completed the study successfully. Blood samples were obtained prior to dosing and at 0.25, 0.5, 1, 2, 3, 5, 8, 12, 24 and 30 hours after drug administration. Plasma concentrations of cetirizine were monitored using high-performance liquid chromatography over a period of 30 hours after administration. The pharmacokinetics parameter AUC(0-30h), AUC(0-infinity) and C(max) were tested for bioequivalence after log-transformation of data and ratios of t(max) were evaluated non-parametrically. RESULT The point estimates and 90% confidence intervals for AUC(0-30h), AUC(0-infinity) and C(max) were 108.23% (101.90 â 114.95%), 108.11% (101.91 â 114.68%) and 99.71% (90.18 â 110.25%), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products an the US Food and Drug Administration guidelines. CONCLUSION These results indicate that two medications of cetirizine are bioequivalent and, thus, may be prescribed interchangeably.

Bioequivalence study of two rosuvastatin tablet formulations in healthy Indonesian subjects.

AIM To compare the bioavailability of two 40-mg Rosuvastatin tablet formulations. METHODS 24 subjects were included in this single-dose, open-label, randomized, two-way crossover study following an overnight fast. A 2-week wash out period was applied. Blood samples were drawn up to 72 hours following drug administrations. Rosuvastatin plasma concentrations were determined by liquid chromatography-tandem mass spectrometry method with TurboIon-Spray mode. Pharmacokinetic parameters AUC(0-t), AUC(0-∞), and Cmax were determined and used for bioequivalence evaluation after log-transformation, whereas tmax ratios were evaluated nonparametrically. RESULTS The estimated point and 90% confidence intervals (CI) for AUC(0-t), AUC(0-∞), and C(max) for rosuvastatin were 95.21% (87.56 - 103.53%), 95.76% (88.01 - 104.18%), and 99.33% (89.37 - 110.41%), respectively. CONCLUSION These results indicated that the two formulations of rosuvastatin were bioequivalent; therefore, they may be prescribed interchangeably.

Quantification of 6-Mercaptopurine and Its Metabolites in Patients with Acute Lympoblastic Leukemia Using Dried Blood Spots and UPLC-MS/MS

This research aimed to quantitatively bioanalyze 6-mercaptopurine (6-MP), 6-methylmercaptopurine (6-MMP), and 6-thioguanosine-5′-monophosphate (6-TGMP) in dried blood spots (DBS) prepared from a small volume of acute lymphoblastic leukemia (ALL) patients. Analytes on the DBS card were extracted using 90% methanol with 5-fluorouracil (5-FU) as an internal standard. Analytical separation was performed on a Waters Acquity® UPLC BEH AMIDA column of 1.7 μm (2.1 × 100 mm) with a mobile phase mixture of 0.2% formic acid in water and 0.1% formic acid in acetonitrile-methanol, with gradient elution and a flow rate of 0.2 mL/min. Mass detection of 6-MP, 6-MMP, 6-TGMP, and 5-FU showed m/z values of 153.09 > 119.09, 167.17 > 126.03, 380.16 > 168.00, and 129.09 > 42.05, respectively. This DBS method had a run time of 5 min and yielded a linear calibration curve over a range of 25.5–1020 ng/mL for 6-MP, 6-MMP, and 6-TGMP. Analyte analysis in 22 of 24 ALL patients showed that the measured value of 6-TGMP as an active metabolite was in the range of 29–429 pmol/8 × 108 erythrocytes. Five of 22 patients had concentrations in a therapeutic range, which indicates that the treatment is effective, while 17 of 24 patients had concentrations below the therapeutic range, which indicates that a treatment dose adjustment is needed. The measured value of 6-MMP, an inactive metabolite, was in the range of 28–499 pmol/8 × 108 erythrocytes, which includes concentrations below the hepatotoxic range. The method employed here can thus be effectively utilized to support therapeutic drug monitoring.

Physicochemical and Functional Properties of Gelatin Extracted from Goat (Capra hircus) Skin Using the Partial Acid Hydrolysis Method

Gelatin is a high molecular weight polypeptide derived from the partial hydrolysis of collagen tissue of animals. The commonly used gelatin are gelatin that is derived from porcine and bovine. Porcine gelatin is absolutely forbidden for every Muslim, otherwise, bovine gelatin is halal (permitted, allowed). Unfortunately, the source of bovine gelatin is limited and relatively expensive, so that alternative sources in producing halal gelatin are still needed. One of the animals that have not been explored as a source of gelatin is goat. The objectives of this research were to extract and characterize the properties of gelatin from goat (Capra hircus) skin. In order to obtain gelatin from goatskin, the process begun by pre-treating goatskin with 4% hydrochloric acid for 24 h and extracting with distilled water at a temperature of 60 °C for 9 h. The physicochemical and functional properties of goat gelatin were evaluated. The results of the evaluation exhibited the following properties: moisture of 7.9%, ash content of 0.26%, pH of 4.96, fat content of 0.03%, protein content of 98.97%, sulfide content of 5.22 ppm, lead and copper were not detected, zinc content of 0.061 ppm, and the gel clarity of 56.4%. All of these physicochemical properties indicated that goatskin gelatin met the defined requirements of a good gelatin. The results of functional properties revealed that the emulsion activity index, foaming properties, and the gel strength are 57.42 m2/g, 152.67%, and 219.65 gbloom, respectively. Therefore, goatskin gelatin could be applied as emulsifying agent, foaming agent, and gelling agent in the food, pharmacy, and cosmetics product. This study showed goatskin gelatin had a high potential to be used as a gelatin alternative.

Pilot Study of Isoniazid Acetylation in Melanesian Healthy Subject from Indonesia

Objective: Isoniazid (INH) is metabolized by N-acetyl transferase-2 into acetyl isoniazid (Ac-INH). The acetylation rate is different in each ethnic, therefore it is very interesting to study of INH acetylation. The aims of this study were to synthesize Ac-INH and the produced Ac-INH was used as a working standard for the pilot study of INH acetylation in Melanesian healthy subjects from Indonesia. Methods: Ac-INH can be simply synthesized by acetylation reactions between INH and acetic anhydride. The synthesis results were characterized by organoleptic observation, purity test, UV-Vis spectrophotometry analysis, FTIR analysis, and mass spectrometry analysis. The pilot study of INH acetylation used high performance liquid chromatography to analyze the levels of INH and Ac-INH in blood of Melanesian healthy subjects. The acetylation rate of INH was determined by the ratio between Ac-INH and INH concentrations at 3 h after administration of INH. Results: The acetylation reaction to synthesize Ac-INH has been performed at temperature of 60°C for 30 min. The obtained Ac-INH had the same quality specifications with reference standard of Ac-INH. The average of ratio between of Ac-INH and INH concentrations was Conclusion: The obtained Ac-INH could be used for pilot study of INH acetylation by calculating the ratio of Ac-INH and INH concentrations in plasma subject. The subject has to be increased to represent the Melanesian population from Indonesia. Key words: Isoniazid, Acetyl isoniazid, Acetylation rate, Melanesia

Study on bioequivalence of beraprost in healthy volunteers by liquid chromatography with tandem mass spectrometry

Beraprost sodium is an oral prostacyclin analog that was first approved in 1992 (Japan) for the treatment of peripheral vascular disorders. It is administered orally as a tablet available in strength 20 μg. In this paper, we described a liquid chromatography tandem mass spectrometry method that was developed for the quantification of beraprost in human plasma with high sensitivity at picogram per milliliter concentration. The method had been validated in terms of selectivity, sensitivity, accuracy and precision, matrix effect, linearity, recovery and carry-over according to the Guideline on Bioanalytical Validation from the European Medicines Agency. The standard calibration curve for beraprost was 9.5-1419 pg/mL. This method has been applied successfully to a bioequivalence study with 60 μg of beraprost (three tablets) in 29 healthy volunteers. The results showed that the two formulations of beraprost are bioequivalent.