Pharmacodynamic and pharmacokinetic properties of the combined preparation of levothyroxine plus sustained- release liothyronine; a randomized controlled clinical trial.

BACKGROUND: Understanding pharmacokinetics (PK) and pharmacodynamics (PD) of the sustained-release liothyronine (SR-T3) is of paramount importance to design therapeutic regimens that are able to simulate normal thyroid hormone secretion while avoiding excursions in the T3 serum concentration. Here, we designed a parallel randomized clinical trial to characterize the PK and PD of the combined preparations of LT4 + SR-T3 in hypothyroid patients. METHODS: Radioiodine-treated hypothyroid patients over 20 years of age, who attained euthyroidism with LT4 monotherapy were recruited from the Endocrine Clinic in Tehran. The patients were allocated to two intervention groups of group A: 9 µg SR-T3 plus 68.5 µg LT4 (ratio 1:7.5) and group B: 12 µg SR-T3 plus 60 µg LT4 (ratio 1:5), and a control group with LT4 monotherapy. For PD study, thyroid hormone profile was evaluated at 8 and 12 weeks intervals after intervention. To assess PK properties of SR-T3, T3-Cmax, T3-Tmax and AUC0 - 24 were calculated at the last visit. RESULTS: Serum T4 and FT4 concentrations decreased in the intervention groups after 3 months. No significant difference was observed in serum T3 and FT3 concentrations before and after intervention. Serum T3/T4 ratio increased significantly in the intervention groups after intervention, with the highest increase in group B from 8.6 ± 2.03 at baseline to 12.2 ± 1.6. Comparison of trial groups at follow-up showed no differences in serum TSH, T4, T3 and T3/T4 concentrations among different groups. During 24 h, minimal variation in serum T3 concentration was observed in group B with mean ∆T3 of 15.4 ± 10.5 ng/dl. T3-Tmax, T3-Cmax and AUC0 - 24 in the combined sustained-release preparation were 4.38 ± 1.1 h., 101.0 ± 5.7 ng/dl and 2257 ± 110 ng.h/L, respectively which were significantly different from the control group. CONCLUSION: Combined treatment with a single dose of SR-T3 plus LT4 is associated with increased serum T3/T4 ratio and minimal excursions in serum T3 concentration during 24 h; however, it was not significantly different from the control group. To incorporate sustained-release T3 in the management of hypothyroidism, a higher ratio of SR-T3 to LT4 than that of the previously recommended by the international organizations is suggested. IRCT REGISTRATION NUMBER: IRCT20100922004794N13. https://www.irct.ir/search/result?query=IRCT20100922004794N13 . Registration date: 08/12/2021.

Brinzolamide-loaded nanoemulsions: ex vivo transcorneal permeation, cell viability and ocular irritation tests.

The aim of this study was to investigate the corneal penetration of brinzolamide (BZ) nanoemulsions (NEs) and evaluate their in vitro and ex vivo irritancy potential. Twelve BZ NEs were prepared by the spontaneous emulsification method and ex vivo permeability studies were conducted using excised bovine corneas fixed onto Franz diffusion cells. To confirm the safety of the formulations for ophthalmic use, preparations were examined for potential ocular irritancy using a cell viability assay on retinal cells, the Hen's Egg Test-Chorio-Allantoic Membrane (HET-CAM) and the bovine corneal opacity-permeability (BCOP) test. Seven BZ NEs exhibited superior penetration across isolated bovine cornea compared to the marketed BZ suspension. The half maximal inhibitory concentration (IC50) values of various surfactants and oils determined using the sulforhodamine B cell viability assay on retinal cells showed that Transcutol P, Cremophor RH40 and Triacetin were the least toxic excipients and may be safely used in the eye at various concentrations. HET-CAM and BCOP tests revealed that NE6B and NE4C did not result in any irritation and were thus considered safe for ocular use. Our finding suggests that optimized NEs can be a safe and effective vehicle for ocular delivery of BZ.

Physicochemical, Stress Degradation Evaluation and Pharmacokinetic Study of AZGH101; a New Synthesized COX2 Inhibitor after I.V. and Oral Administration in Male and Female Rats.

Nonsteroidal anti-inflammatory drugs (NSAIDs) act mainly via inhibition of prostaglandins synthesis by inhibition of cyclooxygenase (COX) isoenzymes (COX-1 and COX-2). Selective COX-2 inhibitors which are also known as coxibs provide the main therapeutic effects of NSAIDs. Zarghi et al. reported 6-benzoyl-2-(4-(methylsulfonyl) phenyl) quinoline-4-carboxylic acid (AZGH101) as a novel derivative of ketoprofen with improved selectivity index (COX-1/COX-2 inhibitory potency) in comparison with ketoprofen. In this study, the log P and stability of AZGH101 were evaluated and the pharmacokinetic characteristics of this compound were investigated following intravenous (10 mg/kg), and oral administration (20 mg/kg), to Wistar rats. As the data demonstrated, the AZGH101was classified as lipid soluble compound and had suitable stability according to forced degradation protocol ICH guideline for new drug substance. This derivative absorbs, distributes, and eliminates similar in both sexes. The AUC 0-∞, absolute bioavailability, Cl, and Vd were not different in both sexes. According to the obtained data, the AZGH101 does not have a sex dependent pharmacokinetic in Wistar rats.

Pharmacokinetics and Biodistribution of Pegylated Methotrexate after IV Administration to Mice.

The efficacy of methotrexate (MTX) as an antimetabolite chemotherapeutic agent highly depends on its blood circulation half-life. In our previous study, different conjugates of MTX (MTX-PEG) were synthesized, their physicochemical properties were investigated and MTX-PEG5000 was finally selected as optimum drug-conjugate for further investigations. In the current work, first the stability of MTX-PEG5000 was studied at 37 °C and the results indicated its high stability in plasma (T1/2 = 144 h) and a relatively rapid degradation in tissue homogenate (T1/2 = 24 h). The study of protein binding pointed out that the conjugate was highly protein-bound (95%). The results of pharmacokinetic studies in mice indicated that MTX-PEG5000 had longer plasma distribution and elimination half-lives compared to free MTX (T1/2 α 9.16 min for MTX-PEG5000 versus 2.45 min for MTX and T1/2 ß 88.44 for MTX-PEG5000 versus 24.33 min for MTX). Pharmacokinetic parameters also showed higher area under the curve (AUC) of conjugate compared to parent drug (12.33 mg.mL-1.min for MTX-PEG5000 versus 2.64 mg.mL-1.min for MTX). The biodistribution studies demonstrated that MTX-PEG5000 did not highly accumulate in liver and intestine and had a mild and balanced distribution to other organs. Also, the conjugate was measurable in tissues up to 48 h after injection and was detected in the brain, suggesting the possibility of delivering drug to brain tumors.

Formulation Development and Evaluation of the Therapeutic Efficacy of Brinzolamide Containing Nanoemulsions.

Brinzolamide (BZ) is an intraocular pressure reducing agent with low bioavailability. The purpose of the present study was to overcome this issue by development of BZ containing nanoemulsions (NEs) as an ocular drug delivery system with desirable therapeutic efficacy. Brinzolamide NEs were prepared by the spontaneous emulsification method. Based on initial release studies, twelve formulations with the slowest release characteristics were subjected to further physicochemical investigations such as particle size, polydispersity index, pH, refractive index, osmolality and viscosity. The therapeutic efficacy of these formulations was assessed by measuring the intraocular pressure after instillation of the prepared NEs in normotensive albino rabbit eyes. Nanoemulsions with suitable physicochemical properties exhibited high formulation stability under different conditions. more over biological evaluations indicated that using lower drug concentrations in NE formulations (0.4%) had a similar or even better pharmacodynamic effect compared to the commercial suspension with a higher drug concentration (1%). Our findings suggest that NEs could be effectively used as carriers for enhancing the bioavailability of topically applied ophthalmic drugs.

Physicochemical, Stress Degradation Evaluation and Pharmacokinetic Study of AZGH102, a New Synthesized COX2 Inhibitors after I.V. and Oral Administration in Male and Female Rats.

Coxibs such as celecoxib, rofecoxib, and valdecoxib are introduced as selective COX-2 inhibitors to the market. It has been reported that inhibition of COX-2 beside traditional effects of NSAIDs, reduces the risk of colorectal, breast and lung cancers and also slow the progress of Alzheimer's disease. Zarghi et al. reported 8-benzoyl-2-(4-(methylsulfonyl)phenyl)quinoline-4-carboxylic acid (AZGH 102) as a novel compound with similar IC50 to celecoxib besides improved selectivity index (COX-1/COX-2 inhibitory potency) in comparison with celecoxib. In this study, the physicochemical properties of AZGH 102 such as solubility, log P, and stability were evaluated and the pharmacokinetic characteristics of this compound following intravenous (10 mg/Kg), and oral administration (20 mg/Kg), to male and female Wistar rats were investigated. As the data demonstrated, the AZGH 102 classified as lipophil compound and had suitable stability. This derivative absorbs and distributes faster in female than in male. The AUC 0-∞, absolute bioavailability, Cl and Vd were different in both sexes. According to the obtained data, the AZGH 102 has a sex dependent pharmacokinetic in Wistar rats.

An investigation into the ability of alendronate ion pairs to increase oral absorption.

The purpose of this study is to increase oral absorption of the highly charged drug alendronate using an ion pair strategy. Ion pairing is a formulation approach in drug delivery that is performed to improve the lipophilicity of ionized drugs. Cationic counter ions, such as arginine, phenazopyridine, hyoscine and pyridostigmine, were selected to enhance the lipophilicity and permeability of alendronate. Data obtained from quasi-equilibrium analysis were used to calculate the binding constant and intrinsic partition coefficient of ion pairs in an octanol/water system. The results of the partitioning study in an octanol/water system were confirmed using in vitro transport models with PAMPA and Caco-2 monolayer assays. Two counter ions, phenazopyridine and arginine, substantially increased the partition coefficient of alendronate by up to 1.15 and 0.73 units, respectively, in the octanol/water system. Binding constants of 117M-1 for alendronate-arginine and 90M-1 for alendronate-phenazopyridine ion pairs were obtained using quasi equilibrium analysis. Arginine and phenazopyridine enhanced the apparent permeability of alendronate by 14- and 26-fold in the PAMPA model and 6.5- and 4.4-fold across caco-2 cell monolayers, respectively. Based on this study, the lipophilicity and permeability of alendronate across lipophilic membranes was increased by suitable counter ions and could be used to establish a new formulation to increase the oral absorption of alendronate.

Development and Validation of an HPLC Method for Determination of Amifostine and/or Its Metabolite (WR-1065) In Human Plasma Using OPA Derivatization and UV Detection.

A rapid, sensitive and reproducible HPLC method was developed and validated for the analysis of amifostine (AMF) and/or its metabolite, WR-1065 in human plasma. The method involves the alkylation of free sulfydryl group with iodoacetic acid followed by derivatization of the drug and its metabolite with o-phthaldialdehyde (OPA) and UVdetection at 340 nm. The derivatized AMF and WR-1065 were eluted in less than 11 min, and in the case of the metabolite with no interferences from the endogenous plasma peaks. Cystein was used as the internal standard. Analysis was carried out on a Eurosphere Performance (RP-18e, 100 × 4.6 mm) analytical column. The mobile phase was a mixture of methanol and phosphate buffer 0.03 M pH = 2.7 at a ratio of 40: 60v/v, respectively, with a flow rate of 1.5 mLmin(-1). Limit of detection was 0.5 µgmL(-1). The method involved a simple extraction procedure for AMF and/or its metabolite and analytical recovery was 90 ± 0.9%.The calibration curve was linear over the concentration range of 1-200 µgmL(-1). The coefficients of variation for intra-day and inter-day assays were less than 10%.

Occurrence of deoxynivalenol in foods for human consumption from tehran, iran.

The occurrence of deoxynivalenol (DON) in retail foods in Tehran (Iran) was determined using high-performance liquid chromatography technique and immunoaffinity column as the clean-up step. A method was validated for analysis of DON in rice, bread, puffed corn snack and wheat flour. The average recoveries and precision (RSD) for DON in different foods ranged 84.2-93.1% and 2.9-12.0%, respectively. A survey of DON was performed on the 72 samples of rice, bread, puffed corn snack, and wheat flour collected from Tehran retail market. The data showed that 10 samples (13.9%) out of 72 samples were contaminated with DON with the maximum level of 368.7 ng/g. The samples had contamination level lower than the maximum tolerated level of DON in foods in Iran. The total intake of DON was under the provisional maximum tolerable daily intake set for DON by the JECFA.

Development of a combined solution formulation of atropine sulfate and obidoxime chloride for autoinjector and evaluation of its stability.

Atropine (AT) and oximes, alone or in combination, have been proven greatly valuable therapeutics in the treatment of organophosphates intoxications. An injectable mixture of AT and obidoxime (OB) was formulated for the administration by automatic self-injector. The aqueous single dose solution contained 275 mg obidoxime chloride and 2.5 mg atropine sulfate per 1 mL (220 mg and 2 mg per 0.8 effective dose, respectively). The final solution was sterilized by filtration through a 0.22 µm pore size filter. This more concentrated solution allowed to use a smaller size and lighter weight cartridge. Quality control tests, including assay of the two major compounds were performed separately, using reversed-phase HPLC methods. Besides, the stability test was carried out according to ICH guideline for the accelerated test. The obtained results showed that the proposed formulation is stable over a period of 2 years after preparation.

Rapid high performance liquid chromatographic method for determination of clarithromycin in human plasma using amperometric detection: application in pharmacokinetic and bioequivalence studies.

A rapid, sensitive and reproducible HPLC method using amperometric detector was developed and validated for the analysis of clarithromycin in human plasma. The separation was achieved on a monolithic silica column (MZ- C8 125×4.0 mm) using acetonitrile-methanol-potassium dihydrogen phosphate buffer (40:6:54,v/v), with pH of 7.5, as the mobile phase at a flow rate of 1.5 mL/min. The assay enables the measurement of clarithromycin for therapeutic drug monitoring with a minimum quantification limit of 20 ng/mL. The method involves simple, protein precipitation procedure and analytical recovery was complete. The calibration curve was linear over the concentration range of 0.1-6 µg/mL. The coefficients of variation for inter-day and intra-day assay were found to be less than 6%. This method was used in bioequivalency and pharmacokinetic studies of the test (generic) product 2 × 500 mg clarithromycin tablets, with respect to the reference product.

Analysis of aflatoxin b1 in Iranian foods using HPLC and a monolithic column and estimation of its dietary intake.

A high performance liquid chromatographic method was developed for determination of aflatoxin B1 (AFB1) in foods using a monolithic column with sample clean up on an immunoaffinity column. The method was validated for analysis of AFB1 in rice, bread, puffed corn snack, wheat flour and peanut samples. The average recoveries for AFB1 in different foods ranged from 94.4 to 102.5% with the coefficient of variation lower than 10% for all foods. Limit of detection was 0.01 ng/g. A survey of AFB1 was performed on 90 samples collected from Tehran retail market in June 2005. The results showed that none of the bread and wheat flour samples were contaminated with AFB1. The mean AFB1 levels in rice, puffed corn snack and peanut samples were 4.17, 0.11, and 1.97 ng/g, respectively. The level of contamination of 3 samples (one rice sample and two peanuts samples) to AFB1 was found to be higher than 5 ng/g. Although all food samples had mean concentration of AFB1 below the maximum tolerated level in Iran, the mean intake of AFB1 from rice was estimated 3.49 times higher than the guidance value of 1 ng AFB1/Kg body weight/day. Therefore, it is strongly recommended to monitor AFB1 in foods, especially in rice, in Iran. This is the first study on exposure assessment of Iranian population to AFB1.

Dissolution rate enhancement of clarithromycin using ternary ground mixtures: nanocrystal formation.

Clarithromycin (CLA), a broad-spectrum macrolide, is a poorly soluble drug with dissolution rate limited absorption. The aim of this investigation was to prepare CLA nanoparticles from a ternary ground mixture in the presence of sodium lauryl sulfate (SLS) and polyvinyl pyrrolidone (PVP) as co-grinding water-soluble compounds, in order to improve the drug dissolution rate. Different weight ratios of CLA: SLS: PVP were ground in a dry process by planetary ball mill using different grinding ball size. Following the dissolution rate study, physical properties of the best dissolved co-ground formulation was studied. The accelerated stability studies were also conducted on the co-ground formulation. The results revealed that the dissolution rate of ternary ground mixtures was much higher than that of the intact drug (p < 0.001). Decreasing the grinding ball size and weight with the same rotation speed resulted in particles with decreased dissolution. On the other hand, increasing the PVP concentration in the formulations reduced the drug dissolution. Dissolution efficiencies (DE10 and DE30) for the best dissolved formulation, which consisted of the equal ratio of each co-ground component, were 8.7 and 5 folds higher than the untreated CLA, respectively. This formulation formed nanocrystals with enhanced solubility after dispersing in water. X-ray diffraction, differential scanning calorimetry and infrared spectrophotometry confirmed no chemical interaction and phase transition during the process. Accelerated stability studies confirmed that the co-ground mixture almost remained unchanged in terms of dissolution rate, drug assay and particle size after exposing in stability conditions for three months.

Prolonged release matrix tablet of pyridostigmine bromide: formulation and optimization using statistical methods.

The aim of this study was to design and optimize a prolonged release matrix formulation of pyridostigmine bromide, an effective drug in myasthenia gravis and poisoning with nerve gas, using hydrophilic - hydrophobic polymers via D-optimal experimental design. HPMC and carnauba wax as retarding agents as well as tricalcium phosphate were used in matrix formulation and considered as independent variables. Tablets were prepared by wet granulation technique and the percentage of drug released at 1 (Y(1)), 4 (Y(2)) and 8 (Y(3)) hours were considered as dependent variables (responses) in this investigation. These experimental responses were best fitted for the cubic, cubic and linear models, respectively. The optimal formulation obtained in this study, consisted of 12.8 % HPMC, 24.4 % carnauba wax and 26.7 % tricalcium phosphate, had a suitable prolonged release behavior followed by Higuchi model in which observed and predicted values were very close. The study revealed that D-optimal design could facilitate the optimization of prolonged release matrix tablet containing pyridostigmine bromide. Accelerated stability studies confirmed that the optimized formulation remains unchanged after exposing in stability conditions for six months.

Rapid high-performance liquid chromatographic method for determination of adefovir in plasma using UV detection: application to pharmacokinetic studies.

A rapid, sensitive and reproducible HPLC method was developed and validated for the analysis of adefovir (CAS 106941-25-7) in human plasma. The separation was achieved on a monolithic silica column (Chromolith Performance RP-18e, 100 x 4.6 mm) using acetonitrile-ammonium dihydrogen phosphate buffer (6:94, v/v), pH 5.2, as the mobile phase at a flow rate of 1.5 ml min(-1). The wavelength was set at 260 nm. The assay enables the measurement of adefovir for therapeutic drug monitoring with a minimum quantification limit of 1 ng ml(-1). The method involves a simple protein precipitation procedure. Analytical recovery was complete. The calibration curve was linear over the concentration range 1-40 ng ml(-1). The coefficients of variation for inter-day and intra-day assay were found to be less than 5%. The method was applied to the determination of adefovir in plasma from 12 subjects dosed with adefovir 2 x 10 mg tablets and pharmacokinetic parameters were evaluated.

Sensitive and rapid HPLC method for determination of memantine in human plasma using OPA derivatization and fluorescence detection: application to pharmacokinetic studies.

A rapid, sensitive and reproducible HPLC method was developed and validated for the analysis of memantine in human plasma after derivatization with o-phthaldialdehyde (OPA) and fluorescence detection. Amantadine was used as internal standard. The derivatized memantine and amantadine were eluted in less than 10 min with no interference from endogenous plasma peaks. The analysis was carried out on a monolithic silica column (Chromolith Performance RP-18e, 100Ã4.6 mm). The mobile phase was composed of a mixture of acetonitrile and 0.025 M phosphate buffer (50:50, v/v, pH=4.6) with a flow rate of 2.5 mLmin(â1). The excitation and emission wavelengths were set at 335 nm and 440 nm respectively. The assay enables the measurement of memantine for therapeutic drug monitoring with a lower quantification limit of 2 ngmL(â1). The method involves simple extraction procedure and analytical recovery was 82.8Â 0.9%. The calibration curve was linear over the concentration range 2â80 ngmL(â1). The coefficients of variation for inter-day and intra-day assay were found to be less than 8%. The method was successfully applied to pharmacokinetic studies in humans.

Synthesis and characterization of methotrexate polyethylene glycol esters as a drug delivery system.

Methotrexate (MTX) is one of the most common anticancer drugs used for chemotherapy so far. However some problems such as high toxicity and short plasma half-life, have limited its use. To overcome these limitations, conjugation with polymers such as polyethylene glycol (PEG) is one the efficient approaches which has been attempted in recent years. The aim of the present study is to synthesize esters of MTX with PEGs of different molecular weights and to characterize their physicochemical properties. Polymeric esters (MTX-PEGs) of MTX with low, medium and high molecular weight PEGs (750 D, 5000 D and 35000 D, respectively) were synthesized using dicyclohexylcarbodiimide (DCC) as coupling agent and triethylamine (TEA) as catalyst. The purification was carried out using preparative TLC. Purified esters were characterized by UV, IR and (1)H-NMR spectroscopy methods and their thermal behavior was studied by differential scanning calorimetry (DSC). Also, an isocratic HPLC method with three mobile phase systems was set to determine the partition coefficient of the esters (log P). Gel permeation chromatography (GPC) was utilized for molecular weight determination of esters, which proved 1 : 1 conjugation of drug with each polymer. The stability and solubility of esters were determined in different pH values. The spectroscopy results indicated that esteric bond between MTX and PEGs were formed. The sharp endothermic peaks for MTX-PEGs were obtained in DSC which are similar to pure polymers, whilst a wide peak was observed for MTX. The values of log P for MTX-PEGs (+4.3, obtained by HPLC method) were remarkably different from log P of MTX (-1.4, obtained by shake-flask method). The stability results showed a pH range of 3-4 and an optimum polymer mw of 5000 for maximum stability of esters. A parabolic profile obtained from solubility studies that indicated the more solubility of MTX in alkaline condition (pH>5) and MTX-PEGs in acidic conditions (pH<5). Based on our results, it is concluded that MTX-PEGs were formed on an equimolar ratio of MTX and PEGs. The higher log P observed for the esters indicated dramatic physicochemical differences between MTX and its PEG conjugates and the higher stability and solubility in acidic medium showed a promising approach to improve the drug delivery of the conjugates, specially MTX-PEG5000 in the future.

Development and optimization of a sublingual tablet formulation for physostigmine salicylate.

This study is aimed to design and optimize a sublingual tablet formulation of physostigmine salicylate, an effective drug in Alzheimer's disease and nerve gas poisoning, by means of the D-optimal experimental design methodology. Polyvinyl pyrrolidone, lactose, starch 1500 and sodium starch glycolate were used in the formulations as independent variables. Tablets were prepared by the direct compression method and evaluated for their physical properties (tablet hardness, disintegration time and friability), which were regarded as responses in a D-optimal design. Due to the significance of the special cubic model for data fitted, compared to other models, it was used to examine the obtained results. Response surface plots were plotted to study the tablet properties and the optimized overlay plot was generated based on the results and targets considered for the responses. After verification of the optimum checkpoint formulations, an optimized formulation was chosen due to its desirable physical properties and closely observed and predicted values. Drug assay, content uniformity of the dosage unit, drug dissolution and accelerated stability studies were done on the optimum formulation as further experiments. All the obtained results complied with the requirements of a sublingual tablet formulation.

A rapid high-performance liquid chromatographic method for the determination of pantoprazole in plasma using UV detection. Application in pharmacokinetic studies.

A rapid, sensitive and reproducible HPLC method was developed and validated for the analysis of pantoprazole (CAS 102625-70-7) in human plasma. The separation was achieved on a monolithic silica column using acetonitrile-potassium dihydrogen phosphate buffer (25:75,v/v), pH 3.0, as the mobile phase at a flow rate of 1.5 ml min(-1). The wavelength was set at 290 nm. The assay enables the measurement of pantoprazole for therapeutic drug monitoring with a minimum quantification limit of 20 ng ml(-1). The method involves a simple protein precipitation procedure. Analyticil recovery was complete. The calibration curve was linear over the concentration range 20-3500 ng ml(-1) The coefficients of variation forthe inter-day and intra-day assay were found to be less than 7%.

Simultaneous determination of amoxicillin and clavulanic acid in human plasma by isocratic reversed-phase HPLC using UV detection.

A simple, rapid and sensitive isocratic reversed phase HPLC method with UV detection using internal standard has been developed and validated for simultaneous determination of amoxicillin and clavulanic acid in human plasma. The assay enables the measurement of amoxicillin and clavulanic acid for therapeutic drug monitoring with a minimum quantification limit of 15 and 30 ng ml(-1), respectively. The method involves simple, one-step extraction procedure and analytical recovery was complete. The separation was carried out in reversed-phase conditions using a Chromolith Performance (RP-18e, 100 mm x 4.6mm) column with an isocratic mobile phase consisting of 0.02 M disodium hydrogen phosphate buffer-methanol (96:4, v/v) adjusted to pH 3.0. The wavelength was set at 228 nm. The coefficients of variation for inter-day and intra-day assay were found to be less than 9.0%.