A reversed-phase high-performance liquid chromatographic method is described for the determination of betaxolol in human aqueous humour. Betaxolol and the internal standard metoprolol were extracted with cyclohexane and separated on a reversed-phase column (Luna C(18), 250 x 4.6 mm, 5 microm) with a mobile phase containing acetonitrile-phosphate buffer (40:60, v/v) at a flow-rate of 0.8 ml/min. The column effluent was monitored with a fluorescence detector at 227 nm (excitation) and 301 nm (emission). The retention times for metoprolol and betaxolol were 3.55 and 5.63 min, respectively. The recovery from aqueous humour was found to be 71.6% for betaxolol at 1.25 microg/ml. The within-day and day-to-day accuracy values were in the range of 96.17-105.2% for betaxolol at 0.1, 4 and 12 microg/ml (n=6), within-day and day-to-day precision values were less than 10% for betaxolol at the concentrations given above. The detection limit corresponding to the signal-to-noise ratio of 3:1 was 15 ng/ml. The presented method was suitable for measuring betaxolol levels in human aqueous humour samples obtained from patients after topical administration.

BACKGROUND/AIMS: Recent reports indicate that an individual's iron status might affect the response rate achieved with Interferon therapy for the treatment of chronic viral hepatitis.METHODOLOGY: Forty individuals, 29 men and 11 women, with chronic viral hepatitis B, who had elevated serum ferritin levels, were randomized to receive either Interferon (IFN) 5 MU TIW SQ for 6 months alone (n=21) or Interferon in combination with repetitive cycles of desferrioxamine infused at a dose of 80mg/kg per cycle (n=19) over 3 consecutive days in an effort to reduce their metabolically active iron pool during the course of IFN treatment. These cycles were continued until a serum ferritin level of less than 250 ng/ml (normal values <220 ng/ml) was achieved. Additionally, all desferrioxamine treated subjects were placed on a low iron containing diet. An interferon response was defined as normalization of the serum ALT and seroconversion from eAg positive to eAb positive. All other responses were defined as failures.RESULTS: The mean ages of the subjects in the 2 groups were 39+/-6 and 38+/-5 years. The initial serum ALT levels were 150+/-27 and 151+/-13 IU/l. The hepatic iron concentrations were 916+/-29 and 896+/-15 mu g/g/dry liver weight. The serum ferritin levels were 386+/-12 and 393+/-18 ng/ml. None of these values differed significantly between the 2 treatment groups. The desferrioxamine treated group consisted of 14 men and 5 women. This group experienced a reduction in their serum ferritin to a level of 237+/-13 ng/ml as a result of the desferrioxamine treatment (p<0.05). Additionally, a reduction in their hepatic iron concentration, to a level 766+/-29 mu g/g/dry liver weight, occurred with treatment (p<0.05). Twelve of the 19 (63%) desferrioxamine-treated subjects and 8 of the 21 (38%) control subjects experienced a normalization of their serum ALT levels with treatment (p<0.05). Thirteen of 19 (68%) of the desferrioxamine-treated subjects but only 8 of 21(38%) of the IFN alone treated group seroconverted to anti-e positive (p<0.05). Moreover, a greater improvement in the hepatic histologic score and rate of HBV-DNA loss occurred in the desferrioxamine-treated group.CONCLUSIONS: Based upon these data, it can be concluded that desferrioxamine infusion to achieve a normal serum ferritin level enhances the likelihood of an individual with chronic hepatitis B responding to IFN therapy. The precise mechanism responsible for this phenomenon is not clear, but would appear to be due to a reduction in the hepatic free iron pool as reflected by sequential changes in the serum ferritin and hepatic iron concentrations.

Clenbuterol which is mostly used as an anabolic agent. It is also used for treatment of asthma. Clenbuterol was analysed from urine by using gas chromatography-mass spectrometry. GC-MS parameters were determined. Timolol was used as an internal standard. Extraction and derivatisation procedure of clenbuterol from urine were developed. Clenbuterol was extracted by using diethylether/ter-butanol (4:1; v:v) and pH 12 K2CO3/KHCO3 (3:2; w:w) buffer. MSTFA/NH4I (1 ml/10 mg) mixture was used for derivatization of clenbuterol. Selected ions of clenbuterol-bis-TMS were m/z: 405, 337, 336, 335, 300, and 227. Extraction yield and minimum detection limit of clenbuterol from urine were identified. Extraction yield was 94.30% and minimum detection was found 0.02 ng ml(-1) urine. It has been concluded that the GC-MS method is sensitive, accurate, precise, and reproducible for analysing of clenbuterol from urine.

β-blockers are generally determined using high-performance liquid chromatography (HPLC). Previous HPLC separations of β-blockers have often required a mobile phase containing three components; acetonitrile or methanol to control the retention; buffer to control the ionic strength and pH of the mobile phase; ion-pairing reagent to provide adequate retention of β-blockers or organic amines as masking agent to reduce peak tailing. Due to the complexity of the mobile phases employed, development of these assays can be a laborious process. Additionally, alkyl sulphonates and organic amines dramatically reduces the life-time reduction of silica based C18 columns. The results of this study demonstrated that the addition of tested alkyl sulphonates and organic amines is not essential for an adequate separation of β-blockers. In this study, we developed a simple HPLC method for the simultaneous separation of model β-blockers, atenolol, practolol, metoprolol, oxprenolol and propranolol. Atenolol, practolol, metoprolol, oxprenolol and propranolol adequately separated with high peak symmetries using a mobile phase consisted of methanol/acetonitrile/phosphate buffer (10 mM, pH 3.0) (15:15:70, v/v/v). By altering only the fraction of methanol with respect to acetonitrile, method development becomes a more efficient separation. Furthermore, atenolol, practolol, metoprolol, oxprenolol and propranolol can be detected up to 0.25, 5, 10, 50 and 10 ng ml−1. In this publication, we present the simultaneous separation of β-blockers having a wide range of polarity. It is proposed that this new mobile phase, consisting only acetonitrile, methanol and phosphate buffer can be used for the analysis of the several β-blockers presently in doping control analysis as well as others.

Unravelling the role of interferon (IFN) in the treatment of chronic hepatitis B compliance by many factors. Several mutant forms of hepatitis B virus (HBV) have recently been discovered; the most common of these is the precore mutant, characterized by hepatitis B e antigen (HBeAg) negativity and hepatitis B e antibody (HBeAb) positivity in an individual with an active HBV infection. The aim of this study was to compare the response rate to IFN therapy in patients with wild-type HBV infection and in individuals infected with the precore mutant. A second aim was to evaluate the role of an increased serum ferritin in terms of the IFN response rate in these two different types of HBV infection. IFN therapy was administered at a dose of 5 MU subcutaneously three times weekly for 6 months to 41 individuals with a chronic wild-type hepatitis B infection and 16 individuals with a precore mutant chronic HBV infection. An IFN response was defined as normalization of the serum alanine aminotransferase (ALT) level and an HBeAb to HBeAb seroconversion (in wild-type hepatitis infection), and a normalization of the serum ALT in individuals infected with a precore mutant infection. At entry, the two groups were matched for age, gender, serum ALT, serum iron, total iron binding capacity (TIBC), serum ferritin and liver histology. Forty-six per cent of the subjects with wild-type disease responded to IFN therapy. By contrast, only four of the 16 cases (25%) of the precore mutant cases responded (p < 0.05). Ferritin levels correlated well with the type of IFN response; as the serum ferritin level increased, the response rate to IFN declined. Hapatic infection caused by a precore HBV mutant is more resistant to IFN therapy than wild-type infection. The serum ferritin level appears to influence the type of IFN response achieved. Individuals with a serum ferritin level greater than 300 ng ml-1 failed to respond to IFN in 93% of the cases studied.

A differential pulse polarographic method was described for the determination of rutin that is obtained from Cruciata taurica (Pallas ex willd.) Ehrend s.I. Differential pulse polarograms of rutin show a distinct peak at -1.83 V (vs Ag, AgCl) at pH 6.00 Sorensen buffer. The total amount of flavonoids in Cruciata taurica (Pallas ex Wild) Ehrend.s.I. has been found to be 0.45% by using rutin as a standard.

Summary An individual's iron status may affect the response rate achieved with the use of interferon (IFN) as therapy for chronic viral hepatitis. A total of 27 patients with chronic hepatitis B viral infection, who had elevated serum ferritin levels, were randomized to receive either IFN 5 MU, three times weekly by subcutaneous injection alone (n= 14) or in combination with cycles of deferoxamine at a dose of 80 mg kg‐1 per cycle (n= 13) administered over 3 consecutive days, to reduce their iron and maintain a serum ferritin level less than 250 ng ml‐1. All deferoxamine‐treated patients were on a low iron‐containing diet. An IFN response was defined as a normalization of the serum alanine aminotransferase (ALT) level and seroconversion from hepatitis B e antigen (HBeAg) positivity to hepatitis B e antibody (HBeAb) positivity. The deferoxamine‐treated group experienced a reduction in their serum ferritin level to 226 ± 73 ng ml‐1 as a result of the deferoxamine treatment. Six of the 13 (46%) deferoxamine‐treated patients and two of the 14 (14%) control patients normalized their ALT levels. Seven of the 13 (54%) deferoxamine but only 14% of the IFN‐treated group seroconverted to HBeAb positivity. A greater rate of histological improvement and loss of hepatitis B virus (HBV) DNA was seen in the deferoxamine‐treated group. Two of the deferoxamine‐treated patients were treated only once, two were treated twice, seven were treated three times and two were treated four times to achieve a ferritin level below 250 ng ml‐1.

Differential-pulse adsorptive stripping voltammetry was used to determine ceftriaxone in serum and aqueous humour samples. The method involved extraction of the ceftriaxone from serum samples with an Amberlite XAD-2 column followed by elution with methanol. The recovery was 97.6% with a relative standard deviation of 3.3% at a ceftriaxone concentration of 90.9 microg 1(-1). Peak currents of ceftriaxone were measured with a hanging mercury drop electrode at -0.78 V versus an Ag-AgCl reference electrode in pH 3.0 Britton-Robinson buffer. The calibration graph was linear from 0.02 to 1300 microg 1(-1). The method was applied to cataract cases and ceftriaxone levels were measured in aqueous humour and serum samples from patients who had received 1 or 2 g of ceftriaxone intravenously. Aqueous humour was added to the polarographic cell directly. The amounts of ceftriaxone in the aqueous humour and serum samples with respect to time were measured. The pharmacokinetic profiles for 1 and 2 g were compared.

In the present study, aluminum (Al) accumulation has been examined after aluminum loading in mice. The kidney, liver, and brain aluminum levels for mice that had been treated orally with aluminum hydroxide for 105 d and for the control group were determined using graphite furnace atomic absorption spectrophotometry (GFAAS) following an acid digestion. Matrix modifier consisted of 2% Triton X-100 and 2% Mg (NO3)2. Al loaded mice showed a significant increase in tissue aluminum levels, relative to the control group.

A new electroanalytical method was developed for the analysis of omeprazole. Various polarographic techniques and supporting electrolytes were examined. Best results were obtained with differential pulse polarography (DPP) in berate buffer (pH 9.0) solution. Linear response was observed from 2.0 x 10(-7) M to 2.0 x 10(-5) M. The peak potential was observed at -1.28 V (vs. Ag/AgCl). The developed method was applied to two different commercial hard gelatin capsules, containing enteric-coated granules, preparations. The relative standard deviations were found to be 3.04% (brand A) and 2.88% (brand B).

A method has been developed to analyze dithranol by using differential pulse polarography. The method developed was applied to a cream pharmaceutical preparation and compared with an official method. Electroanalytical studies show that a peak at -1.78 V vs. Ag/AgCl reference electrode in 0.05 M Et(4)NI solution can be used for the analysis of dithranol in the range of 0.2-6.5 ppb. A method for the analysis of dithranol has been applied to a cream pharmaceutical preparation after an extraction procedure. The liquid-liquid extraction has been accomplished by using chloroform. The recovery has been found to be 98% with a relative standard deviation of 2.70%.

Plasma chromium (Cr) levels were determined in 24 preterms and 18 full-term newborn infants. There was no statistically significant differences in plasma Cr levels between the preterm and full-term infants. Plasma Cr levels were similar in small-for-gestational-age infants and in infants with hypoglycemia compared with healthy infants.

The Corydalis alkaloids have been investigated by differential pulse polarography as part of our continuing study of alkaloids. In this study, the alkaloidal content of Corydalis solida (L.) subsp. solida was determined. The results were compared by their structure and reduction mechanism. Quantitative analysis illustrates that Corydalis alkaloids can be determined down to sub-ppm level using differential pulse polarography in Britton-Robinson buffer pH 10. The amount of the various alkaloids in Corydalis solida (L.) subsp. solida have been shown. It was concluded that the reduction process at the dropping mercury electrode was catalytic in nature.

A method has been developed to determine Ranitidine in stomach tissue of patients treated with this drug by using differential pulse adsorptive stripping voltammetry. A hanging mercury drop electrode was chosen as the working electrode. Extraction of ranitidine from the stomach tissue has been accomplished by using liquid-liquid extraction with chloroform. A peak at -0.56 V vs Ag/AgCl at Britton-Robinson buffer pH 2.3 has been taken for calibration curve which has been found linear in between 0.26 x 10(-10) M to 1.27 x 10(-5) M. Its precision was estimated by 10 successive measurements of 2 x 10(-7) M ranitidine. The relative standard deviation was 2.8 %. The percent recovery has been found as 81 %.

A number of studies have been carried out on the toxic effect of aluminium on bone mineralization and its relation to calcium and parathroid-hormone metabolism. Exposure to aluminium by the means of either diasylate or ingestion of aluminium hydroxide or both leads to its deposition in tissues, particularly in bone. This deposition blocks incorporation of calcium into osteoids, leading to the osteomalacia characteristic of aluminium-induced bone disease (Drucke 1980; Alfrey 1980; Cournot-Witmer et al 1981; Walker et al 1982; Mayor et al 1980; Cann et al 1979; Cannata et al 1983; Boyce et al 1982). Therefore, the effects of aluminium hydroxide loading on bone of mice were examined. Besides aluminium, the calcium level of the same bone samples were determined and aluminium/calcium ratios were evaluated in this study. The aluminium and calcium measurements have been performed by graphite furnace and flame atomic absorption spectrometry respectively.

A sensitive differential pulse polarographic method is described for the determination of some chalcones. The analysis was performed in Britton-Robinson buffer at pH 2.0. The reaction mechanism is based on the reduction of carboxyl group present on the chalcones. The detection limit found was 1.0x10(-8) M, and the response was found to be linear up to 2.9 x 10(-5)M with the relative standard deviation (of the 2.0x10(-5)M level) 2.66%.

Ceftriaxone is a member of the “third generation” of cephalosporin antibiotics which adsorbs strongly onto a mercury electrode. By using this phenomenon and by accumulating this compound at a static mercury dropping electrode prior to differential pulse voltammetric measurements, very high sensitivities can be readily achieved. The influence of several variables (including accumulation time, modulation amplitude, rest period, scan rate, and drop size) on the adsorptive stripping response has been evaluated. Peak currents were measured with a hanging mercury dropping electrode at −0.78 V versus an Ag/AgCl reference electrode in pH 3.0 Britton–Robinson buffer. The linear calibration range was 3.31 × 10−11 to 2.17 × 10−6 M.

In vitro effects of thyroxine on erythrocyte deformability and mechanical fragility were observed. Deformability of erythrocytes was improved in a dose dependent manner by thyroxine. Mechanical hemolysis was found to be lower if thyroxine was included in erythrocyte suspensions at concentrations close to the physiological levels (10(-9)M). These changes might be related to the alterations of intracellular calcium concentration, as in the erythrocyte suspensions containing 10(-9)M thyroxine, intracellular calcium concentration was found to be 30 times lower than the control suspensions which did not contain thyroxine. Thyroxine also reduced the mechanical hemolysis ratio in calcium loaded cells. These observations suggest that thyroxine might play some role in the regulation of the mechanical properties of erythrocytes which might be mediated via the effects on calcium metabolism.

Controlled interfacial accumulation of the benzodiazepine midazolam at a hanging mercury drop electrode provides the basis for a highly sensitive and accurate adsorptive stripping voltammetric procedure. The response was linear in the range 1.9 × 10−6− × 10−9 M when using a 120-s preconcentration at −0.45 V vs. Ag/AgCl in Britton-Robinson buffer of pH 5.00. In this range the relative standard deviation was between 1.21 and 1.62%. The applicability of the method to pharmaceutical preparations is discussed.