A rapid liquid chromatography/tandem mass spectrometry method for simultaneous determination of levodopa, carbidopa, entacapone and their six related compounds in film-coated tablets.

RATIONALE: A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed and validated to determine levodopa, carbidopa, entacapone, and corresponding six related substances - levodopa impurity B, levodopa impurity C, methyldopa, methylcarbidopa, entacapone impurity C, and entacapone impurity A - in film-coated tablets for the first time. METHODS: Chromatographic separation was achieved with a gradient elution by using a C18 column, a mobile phase containing 0.5% formic acid in water and 0.5% formic acid in methanol. The mobile phase flow rate was 0.5 mL min-1 . The UV detector was set at 280 nm and the triple quadrupole mass spectrometer was used in multiple reaction monitoring (MRM) mode. RESULTS: The limit of detection (LOD) and limit of quantification (LOQ) results were 1.3 and 3.94 ng mL-1 for levodopa impurity B; 5.26 and 15.9 ng mL-1 for levodopa impurity C; 0.833 and 2.53 ng mL-1 for methyldopa; 3.31 and 10.0 ng mL-1 for methylcarbidopa; 1.67 and 5.06 ng mL-1 for entacapone impurity C; and 0.61 and 1.86 ng mL-1 for entacapone impurity A. CONCLUSIONS: The method was rapid, linear, accurate, and reproducible. The LC/MS/MS method that was developed to determine the related substances and assay of levodopa, carbidopa, and entacapone can be used to evaluate the quality of regular samples in the pharmaceutical industry. It can be also used to test the stability of samples.

The impact of klotho gene polymorphisms on urinary tract stone disease.

OBJECTIVES: To investigate the effect of klotho gene and ß-glucuronidase activity on stone formation in patients with urinary tract stone disease (UTSD). METHODS: A total of 103 patients with UTSD and 102 controls with no specific urolithiasis history were enrolled into the study. G395A and C1818T polymorphisms of klotho gene were analyzed with PCR method. Serum levels of calcium and phosphorus and 24-h urine levels of ß-glucuronidase activity, calcium and phosphorus levels were measured biochemically. RESULTS: A total of 103 of patients were male (50.2 %) and 102 were female (49.8 %) (p 0.945). Twenty-four-hour urine levels of calcium were significantly higher in UTSD group, whereas no difference was observed in phosphorus levels (p < 0.001, p 0.074, respectively). As for the G395A polymorphism, type of GG was significantly higher in the patient group compared to the controls (p = 0.02), while GA genotype was significantly higher in the controls (p = 0.001). There was no significant difference in F352V and C1818T polymorphism between the patient and control groups. ß-glucuronidase activity was slightly lower in the patient group without significance (p 0.932).When patients with GG genotype and the rest were compared, there were no significant difference in all parameters. CONCLUSIONS: Any polymorphism altering the function of klotho gene may result with stone formation. We found that there are more GG sequences of G395A gene in patients with UTSD. That may be a polymorphism of klotho gene which results with stone formation. Further studies with more patients should be accomplished which are combining the genetic and epigenetic factors associated with urolithiasis and klotho gene to enlighten the etiology of this disease.

Simultaneous UPLC Assay for Oxitropium Bromide and Formoterol Fumarate Dihydrate in Pressurized Metered Dose Inhaler Products for Chronic Obstructive Pulmonary Disease.

BACKROUND: Oxitropium bromide (OB) and formoterol fumarate dihydrate (FFD) are inhaler molecules that are widely used in the treatment of chronic lung diseases. OBJECTIVE: The goal of this work was to create a reversed phase-ultra performance liquid chromatography (RP-UPLC) technique for assay and identification of OB and FFD, as well as identification and estimate of its associated compounds in pressurized metered dose inhaler product (pMDI). METHOD: Separation of oxitropium and formoterol peaks were enhanced on a C18 (50 × 2.1 mm × 1.7 µm) UPLC column with ethylene-bridged-hybrid technology, The mobile phase consists of buffer (0.07 M KH2PO4) and acetonitrile (80:20, v/v). The detector wavelength of 210 nm, flow rate of pump 0.6 mL/min, and oven temperature for column were set at 25°C. The injection volume was 10 µL. The method run time was 2 min. The mobile phase was used as the solvent. RESULTS: Retention times (RTs) were 0.5 min for OB and 1.0 min for FFD. The assay analysis was linear range for all analytes within the range for concentrations 0.03-14.8 µg/mL of OB, 0.01-0.88 µg/mL of FFD. LOD values and LOQ values 0.009 and 0.026 µg/mL for OB and 0.003 and 0.009 µg/mL for FFD, respectively. Recoveries were obtained at 96.3% for OB and 97.2% for FFD. Precisions values were (as RSD, %) ≤1.5%. CONCLUSIONS: With the UPLC method developed and validated according to the current ICH guidelines, it is possible to simultaneously detect OB and FFD of assay analysis in pMDI products accurately, precisely and selectively, independent of the matrix effect. HIGHLIGHTS: The present method is the first method in the literature based on the UPLC method for this purpose. The UPLC method is a time-saving method, it provides a faster and cheaper technique than the high performance liquid chromatography (HPLC) method.

Design of meloxicam and lornoxicam transdermal patches: Preparation, physical characterization, ex vivo and in vivo studies.

Transdermal patches of meloxicam (MX) and lornoxicam (LX) were aimed to be prepared in order to overcome their side effects by oral application. The strategy was formulation of optimized films to prepare transdermal patches by determination of physical properties and investigation of drug-excipient compatibility. As the next step, in vitro drug release, assesment of anti-inflammatory effect on Wistar Albino rats, ex vivo skin penetration and investigation of factors on drug release from transdermal patches were studied. Hydroxypropyl methylcellulose (HPMC) was concluded to be suitable polymer for formulation of MX and LX transdermal films indicating pharmaceutical quality required. MX and LX transdermal patches gave satisfactory results regarding to the edema inhibition in the assessment of anti-inflammatory effect. MX was found out to be more effective compared to LX on relieving of edema and swelling. These results were supported by data obtained from ex vivo penetration experiments of drug through rat skin. Indicative parameters like log P, molecular weight and solubility constraint on penetration rate of drugs also indicated good skin penetration. Transdermal patches of MX and LX can be suggested to be used especially for the immediate treatment of inflammated area since it displays anti-inflammatory effect, soon.

Kinetic spectrophotometric determination of ciprofloxacin in a pharmaceutical preparation.

Two kinetic spectrophotometric methods were developed for determination of ciprofloxacin (CIP) in a pharmaceutical preparation. The methods are based on oxidation of CIP with potassium permanganate in alkaline media and measurement of the enhancement in the absorbance of manganate ion at 603 nm by spectrophotometry. The calibration graphs were constructed using the initial rate and fixed time methods. The linearity range for concentrations of CIP was found to be 4.0-20.0 microg/mL. The RSD values for intraday and interday precision were 0.05-0.50 and 0.07-0.63%, respectively. The procedures were applied successfully for determination of CIP in commercial tablets. The results compared well with those from a reference HPLC method. The proposed methods can be recommended for routine analysis of CIP in QC laboratories.

Clinical characteristics of inflammatory bowel disease in Turkey: a multicenter epidemiologic survey.

AIM: To investigate the epidemiologic and clinical characteristics of inflammatory bowel disease (IBD) patients in a large multicenter, countrywide, hospital-based study in Turkey. MATERIALS AND METHODS: Twelve centers uniformly distributed throughout Turkey reported through a questionnaire the new IBD cases between 2001 and 2003. The incidence of ulcerative colitis (UC) and Crohn's disease (CD) has been reported per 100,000 people. Epidemiologic features and clinical characteristics of both diseases were analyzed. RESULTS: During the study period, 661 patients of UC and 216 patients of CD were identified. The incidence in the referral population was 4.4/100,000 and 2.2/100,000 for UC and CD, respectively. The age of the patients showed the characteristic biphasic distribution with 2 peaks between 20 and 30 and 50 and 70 years. A male predominance was observed in both diseases. A history of smoking was detected in 15.5% of UC patients and 49.3% of patients with CD. Family history was positive in 4.4% in UC and 8.3% in CD patients. Concomitant amebiasis was observed in 17.3% of patients with UC and 1.3% of patients with CD. A history of appendectomy was reported in 15% of patients with CD and only 3% of patients with UC. Both extraintestinal and local complications were more frequent in CD patients, whereas arthritis was most common in both diseases. CONCLUSIONS: IBDs are frequently encountered in Turkey. IBD incidence is lower than North and West Europe but close to Middle East in our country. The majority of IBD cases are diagnosed in young people (20 to 40 y) with predominance in males. The rate of both intestinal and extraintestinal complications in our population was low when compared with the data reported in the literature. IBD and especially UC, can coexist with amebiasis or become manifest with amebic infestation. The presence of concomitant ameba may create confusion and cause dilemmas in the diagnosis and treatment of UC.

Determination of Zoledronic Acid and Its Related Substances by High Performance Liquid Chromatography with Evaporative Light Scattering Detection.

A method has been developed and validated for analysis of zoledronic acid (ZOL) and its related substances by ion-pair reversed-phase high performance liquid chromatography with evaporative light scattering detection (ELSD). Chromatographic separation was achieved with gradient elution by using a C18 column, mobile phase containing 12 mM ammonium acetate buffer and 35 mM n-pentylamine, whose pH value is 7.0, and 5% acetonitrile. The mobile-phase flow rate was 1.0 mL/min. The calibration plot was linear in the range from 0.4 mg/mL to 6.0 mg/mL for ZOL and from 6.25 µg/mL to 100 µg/mL for its related substances. ZOL and its related substances, namely imidazole-1-yl-acetic acid, phosphate, phosphite and degradation products did not interfere with each other. The method was rapid, linear, accurate and reproducible. The high performance liquid chromatographic method that has been developed to determine the related substances and assay of ZOL can be used simultaneously to evaluate the quality of regular samples. It can be also used to test the stability samples of ZOL.