Effectiveness of antiresorptive medications in women on long-term dialysis after hip fracture: A population-based cohort study.

There is no clear evidence how effective the antiresorptive (AR) drugs alendronate and raloxifene are at reducing risk of second hip fracture and mortality in dialysis populations. The purpose of this study was to compare the risk of hospitalization for second hip fracture and risk of mortality between AR user and non-user groups in Taiwanese women on long-term dialysis with hip fractures. We conducted a retrospective cohort study using Taiwan National Health Insurance Research Datasets. Long-term dialysis women older than 50 years with newly diagnosed hip fractures and new to AR therapy from 2005 to 2011 were recruited. The patients were divided into AR users and non-users and matched by propensity score. We used Cox Proportional Hazards models to assess association of AR with risks of second hip fracture and mortality. Totally, 1,079 dialysis patients were included, and after matching, we were left with 74 AR users and 74 non-users. AR users did not show a significant reduction in the incidence of second hip fracture compared with non-users (adjusted Hazard Ratio (HR): 0.91, 95% CI: 0.30-2.76), and alendronate users exhibited higher risk of second hip fracture compared with raloxifene users (adjusted HR: 2.80, 95% CI: 0.42-18.79). In addition, AR users were found to have significantly lower 1- and 2-year mortality rates than the non-users (1- year: adjusted HR 0.25, 95% CI, 0.07-0.90; 2-year: 0.35, 95%CI: 0.17-0.72). AR treatment did not significantly improve the risk of second hip fracture but significantly reduce mortality in older women on dialysis. Further clinical trials on effectiveness of AR medications for dialysis populations should be warranted.

Medication adherence to oral anticancer drugs: systematic review.

Many studies have demonstrated that non-adherence to oral anticancer drugs (OACDs) has challenged treatment efficacy. Otherwise, few validated tools exist to measure patients' adherence to medication regimen in clinical practice. To synthesize previous studies on adherence by cancer patients taking OACDs, especially in targeted therapy, a systematic search of several electronic databases was conducted. We analyzed existing scales' contents for various cancer patients and outcomes of studies assessing adherence. However, a well-validated scale designed particularly for OACD adherence is still lacking. Most adherence scales used in the studies reviewed contain items focused on measuring patients' medication-taking behavior more than their barriers to medication compliance and beliefs. However, non-adherence to OACDs is a complex phenomenon, and drug-taking barriers and patient beliefs significantly affect patients' non-adherence. To understand the key drivers and predisposing factors for non-adherence, we need to develop a well-validated, multidimensional scale.

Quantitative analysis of insulin in total parenteral nutrition bag in Taiwan.

Regular insulin can reduce hyperglycemia when directly added to total parenteral nutrition (TPN) solutions. Insulin is not routinely added to all TPN solutions. For patients who require insulin prior to the initiation of TPN supplement, one-third to one-half of the usual total daily dose can be added to the TPN bag as regular human insulin. However, an incorrect dose or an interaction between insulin and the TPN bag material may affect blood sugar control in clinical practice. Therefore, it is important to quantitatively determine the final dose of insulin in the TPN bag. High performance liquid chromatography is a very powerful technique for determining the purity of proteins. The goal of this study was to use high-performance liquid chromatography to perform quantitative analysis of insulin in a TPN bag. The analysis was performed under different light conditions (UV, fluorescent, and darkness) and different temperatures (25°C and 2-8°C). The results show that adsorption of insulin on an ethylene vinyl acetate TPN bag is significantly higher than that on glass. Based on the results, it is evident that regular insulin should be administered separately from TPN to reduce cost and eliminate wasteful disposal of TPN solutions.

Trace analysis of acetylcholinesterase inhibitors with antipsychotic drugs for Alzheimer's disease by capillary electrophoresis with on column field-amplified sample injection.

A simple and sensitive capillary zone electrophoresis (CZE) with UV detection (214 nm) was developed and validated for the simultaneous determination of the acetylcholinesterase inhibitors (AChEI), donepezil, and rivastigmine, with antipsychotic drugs in plasma. A sample pretreatment by liquid-liquid extraction and subsequent quantification by CZE with field-amplified sample injection (FASI) was used. The optimum separation for these analytes was achieved in <20 min at 25 °C with a fused-silica capillary column of 60.2 cm × 50 µm I.D. (effective length 50 cm) and a run buffer containing 120 mM phosphate (pH 4.0) with 0.1 % γ-cyclodextrin, 40 % methanol (MeOH), and 0.02 % polyvinyl alcohol as a dynamic coating to reduce analytes' interaction with the capillary wall. Using phenformin as an internal standard (40.0 ng/mL), the linear ranges of the proposed method for the simultaneous determination of donepezil, rivastigmine, aripiprazole, quetiapine, risperidone, clozapine, ziprasidone, and trazodone were over the range 4.0-80.0 ng/mL, and olanzapine was over the range 1.0-20.0 ng/mL. The method was applied for concentrations monitoring of AChEIs and antipsychotic drugs in ten Alzheimer's disease patients with behavioral and psychological symptoms of dementia after oral administration of the commercial products.

Reliability of 95% confidence interval revealed by expected quality-of-life scores: an example of nasopharyngeal carcinoma patients after radiotherapy using EORTC QLQ-C 30.

BACKGROUND: Many researchers use observed questionnaire scores to evaluate score reliability and to make conclusions and inferences regarding quality-of-life outcomes. The amount of false alarms from medical diagnoses that would be avoided if observed scores were substituted with expected scores is interesting, and understanding these differences is important for the care of cancer patients. Using expected scores to estimate the reliability of 95% confidence intervals (CIs) is rarely reported in published papers. We investigated the reliability of patient responses to a quality-of-life questionnaire and made recommendations for future studies of the quality of life of patients. METHODS: A total of 115 patients completed the EORTC core questionnaire QLQ-C30 (version 3) after radiotherapy. The observed response scores, assumed to be one-dimensional, were summed and transformed into expected scores using the Rasch rating scale model with WINSTEPS software. A series of simulations was performed using a unified bootstrap procedure after manipulating scenarios with different questionnaire lengths and patient numbers to estimate the reliability at 95% confidence intervals. Skewness analyses of the 95% CIs were compared to detect different effects between groups according to the two data sets of observed and expected response scores. RESULTS: We found that (1) it is necessary to report CIs for reliability and skewness coefficients in papers; (2) data derived from expected response scores are preferable to making inferences; and (3) visual representations displaying the 95% CIs of skewness values applied to item-by-item analyses can provide a useful interpretation of quality-of-life outcomes. CONCLUSION: Reliability coefficients can be reported with 95% CIs by statistical software to evaluate the internal consistency of respondent scores on questionnaire items. The SPSS syntax procedures for estimating the reliability of the 95% CI, expected score generation and visual skewness analyses are demonstrated in this study. We recommend that effect sizes such as a 95% CI be reported along with p values reporting significant differences in quality-of-life studies.

Trends of benzodiazepine prescribing and the risk of hip fracture in elderly patients in Taiwan: A population-based study.

Abstract Objective. The aim of this study was to explore the trends of prescribing potentially inappropriate benzodiazepine use (PIBU) and the risk of fractures in an elderly population in Taiwan. Methods. Retrospective administrative database analysis was conducted. Outpatient claim data were retrieved from the Longitudinal Health Insurance Database (LHID) between 2000 and 2003, which contains all inpatient and outpatient medical claims of approximately 23 million patients in Taiwan. All patients with the diagnosis of hip fractures (ICD codes) were identified from the database. The inappropriate use for the elderly was defined as a prescription with the dose of short- and long-acting BZD according to the 2003 version of Beers' criteria. Multiple logistic regressions were used to determine the association of PIBU with fractures. Results. A total of 62,023 elderly patients aged ≧65 years were retrieved from the database. The proportion of elderly patients taking short-and long-acting benzodiazepines declined significantly from 28.1 to 25% and 19.5 to 14.5% from 2000 to 2003, respectively (P<0.001). After adjustment for age, sex, co-morbidity, other medications in one prescription and all of the covariates, the risk of hip fractures (∼50%) was still statistically significant (adjusted OR in the four years studied: 1.57, 1.38, 1.68, 1.45) for elderly patients taking benzodiazepines in Taiwan. Conclusion. These findings suggest that the inappropriate use of benzodiazepine may be associated with the risk of fractures. Physicians should prescribe benzodiazepines appropriately for the elderly to minimize the risk of hip fractures.

Validation of a shortened Taiwanese version of an asthma quality-of-life questionnaire by Rasch model.

The purpose of this study was to assess the one-dimensionality, item fit, redundancy, and differential item functioning (DIF) of a Taiwanese version of the Asthma Quality of Life Questionnaire (TAQLQ) using Rasch model and to examine the test-retest reliability, validity of a simplified version of the TAQLQ and the original AQLQ. The design of this study was a two-time assessment on a 1-month interval. A total of 143 asthmatic outpatients were requested to administer the original 7-point 32-item TAQLQ questionnaires at the first visit and the 5-point 27-item TAQLQ questionnaires at the second visit. Two versions of the questionnaire were analyzed by using the Rasch model (Rasch G, Probabilistic Models for Some Intelligence and Attainment Tests, Chicago: University of Chicago Press, 1992) to determine the difference in validity and reliability between the original 32-item and the shortened 27-item TAQLQ scales with different categories responded. The analyzed data show that 5 items in the original 32-item AQLQ are not fitting to the Rasch model's expectations. The shortened 27-item TAQLQ was created by removing the misfit and redundant items. The reliability of the shortened 27-item TAQLQ is greater than the original 32-item AQLQ. The quality of life for asthma patients could be improved and stratified into five strata by summed raw scores of 61, 89, 106, and 120. The cutoff thresholds of averaged raw scores are 2.3, 3.3, 3.9, and 4.4. The simplified 5-point 27-item TAQLQ holds better validity and higher reliability than the original 7-point 32-item TAQLQ. Assessment of the quality of life using an abbreviated 5-point 27-item TAQLQ could be applied to Taiwanese asthma patients who are less educated in southern Taiwan than those in the northern part of Taiwan.

Cost-effectiveness of trastuzumab as adjuvant therapy for early breast cancer: a systematic review.

OBJECTIVE: To identify published, original, cost-effectiveness analyses presenting cost/quality-adjusted life year (QALY) ratios for trastuzumab used as an adjuvant treatment for HER2-positive early breast cancer and to evaluate the quality of reporting the favorable cost-effectiveness ratios. DATA SOURCES: The terms trastuzumab adjuvant therapy, cost-effectiveness, quality-adjusted, QALY, and early breast cancer were searched in MEDLINE, PubMed, Embase, and CancerLit, as well as in Cochrane economic evaluation and reference lists from 1998 to June 2008. Only English-language publications were eligible. STUDY SELECTION AND DATA EXTRACTION: All published studies examining cost-effectiveness outcomes on the basis of modeling or clinical trials were included. Cost-effectiveness analysis that measured health effects in units other than QALY, life year gained, neoadjuvant data, reviews, and comments were excluded. Each study was assessed independently by 2 trained reviewers. DATA SYNTHESIS: Thirteen of the 239 articles identified met the inclusion criteria, with 23 cost-effectiveness ratios pertaining to treatment of early breast cancer. These ratios ranged from $5020/QALY to $134,610/QALY. Most studies reported favorable cost-effectiveness values (ie, below $50,000/QALY). About 84.6% were conducted using a Markov model based on data from clinical trials and 15.3% were analyzed by other economic or cost models; 84.6% reported sensitivity analysis, 11 studies (84.6%) clearly described a justification of selecting study design, and only 15.3% noted study limitations. All studies mentioned their perspective; 92.3% did not show the funding source. Methods of reporting costs, effectiveness, and time-horizons for disease states varied significantly. Nine (69.2%) studies used a discount rate of 3%, 3 studies used a discount rate of 5%, and 1 study used 3.5%. The mean quality of the studies was 4.43. CONCLUSIONS: Most studies presenting the frequently proposed threshold of QALY suggest that trastuzumab may be cost-effective for treatment of early breast cancer in a 1-year treatment regimen.

Direct medical costs in patients with Alzheimer's disease in Taiwan: A population-based study.

BACKGROUND: Alzheimer's disease (AD) has the potential to become a major health concern and associated health care costs may become a significant economic burden on society. OBJECTIVE: The aim of this study was to estimate the direct medical costs attributable to AD in patients aged ≥60 years in Taiwan from 2000 through 2002 and to explore the correlation of these costs with patients' age and sex. METHODS: This study was based on the National Health Insurance Research Database of Taiwan's National Health Insurance (NHI) program. The NHI program insures >98% of the 23 million inhabitants of Taiwan. Detailed data were extracted from a random sample of 0.2% of inpatient and 5% of outpatient recipients with AD (International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code 331.0) who were aged ≥60 years and who received inpatient or outpatient services with claims from January 1, 2000, to December 31, 2002. Duplicate charges for a specific patient and diagnoses of other types of dementia were excluded from this study. RESULTS: A total of 69,780 patients were found to have a diagnosis of AD. The direct medical costs for outpatients were estimated at US $1.2 million in 2000, US $1.9 million in 2001, and US $2.3 million in 2002; the costs for inpatient care were estimated at US $670,000 in 2000, US $2.4 million in 2001, and US $3.2 million in 2002. The total direct medical costs were estimated at US $1.86 million in 2000, US $4.24 million in 2001, and US $5.48 million in 2002. The increase of total direct medical costs was not significantly correlated with patients' age or sex. CONCLUSIONS: From 2000 through 2002, the direct medical costs of AD increased annually in Taiwan among patients with AD aged ≥60 years. No significant correlation was found between increased total direct medical costs and sex or age. The cost estimate presented here has implications for future decision making about reallocating medical resources for treating AD in Taiwan.

Cost evaluation of adverse drug reactions in hospitalized patients in Taiwan: A prospective, descriptive, observational study.

BACKGROUND: Adverse drug reactions (AADRs) are a leading cause of morbidity and mortality. In the United States, ADR-related morbidity and mortality costs have been estimated at US $330 billion to US $1130 billion annually. OBJECTIVES: The aim of this study was to evaluate the incidence of ADRs in Taiwan, to identify the drug classes that are most commonly related to ADRs, and to determine the direct medical costs to hospitals associated with prolonged hospitalizations due to ADRs. METHODS: In this prospective, descriptive, observational study, patients who experienced ADRs during their hospitalization at a Taiwan teaching hospital or who were admitted due to an ADR from January 1, 2002, through December 31, 2004, were included in the study. The patients were identified actively by clinical pharmacists and passively by physicians and nurses who reported ADRs. The World Health Organization (WWHO) definition of ADR severity was adopted, and degrees of probability for each ADR were determined using the Naranjo algorithm. The direct medical costs incurred to the hospital in the treatment of ADRs that prolonged hospitalization were calculated (ie, costs of emergency department [ED] visits, intensive care unit visits, extra days of hospitalization, monitoring and laboratory studies, pharmacist dispensing fees, physician fees, room charges, ED charges). RESULTS: During the study period, 43 of the 142,295 hospitalized patients (00.03%)) were admitted because of an ADR. A total of 564 (00.40%)) of the hospitalized patients were verified to have ADRs. Three hundred eighteen of the patients (56.44%) with ADRs were male and the overall mean (SD) age was 66(2) years. The most common drug classes associated with the ADRs were antibiotics (219 patients [38.8% ]), analgesics (62 [11.0%]), and cardiovascular agents (56 [9.9%]). The systems most commonly involved in ADRs were cutaneous (296 patients [52.5%]), hematologic (61 [10.8%]), and cardiovascular (54 [9.66%]). The causes of the ADRs were anaphylactic (464 patients [82.3%]), drug overdose (78 [13.8%]), and drug-drug interactions (22 [3.9%]). Of the ADRs, 474 (884.0%) were idiosyncratic type B reactions (predictable). ADR-related costs, estimated at US $3489/ADR, were mostly due to prolonged length of stay. Based on the WHO definition, of the 564 ADRs, 330 (58.5%) and 40 (7.1%) were classified as moderate and severe, respectively. Two patients died of ADRs associated with allopurinol. CONCLUSION: In this hospital, 0.40% of patients were identified as having ADRs that were associated with high direct costs, mostly due to extended hospitalizations.

The evaluation of free influenza vaccination in health care workers in a medical center in Taiwan.

OBJECTIVE: To evaluate the outcome of free influenza vaccination for healthcare workers in Taiwan. METHOD: A retrospective observational study was conducted in a partially vaccinated sample of healthcare workers in a medical centre in the southern part of Taiwan. A convenience sample of 500 employees received a questionnaire. MAIN OUTCOME MEASURE: Incidence of influenza like- illness (ILI), rates of absenteeism and costs savings. RESULTS: A final number of 407 returned questionnaires could be evaluated. Forty respondents were not vaccinated. The incidence of ILI was lower in the vaccinated group than the nonvaccinated group (13.6 vs. 15%). Fever was the most frequently occurring ILI. Rate of absenteeism because of ILI in the non-vaccinated employees was higher than in the group of vaccinated employees. The costs per saved lost working day was US $36. CONCLUSION: Free influenza vaccination may cause reductions in incidence, absenteeism, and costs associated with ILI in healthcare workers in Taiwan.

Interaction between traditional Chinese medicine and Western medicine in rats--In-Chen-How and acetaminophen.

The purpose of this study is to evaluate the interaction effects of In-Chen-How (Artemisia capillaries Thunb.) on the pharmacokinetics of acetaminophen and on liver microsomal cytochrome P450 enzyme activity in rats. The rats were divided into control group (n = 8) without In-Chen-How and the pretreated group (n = 8) administered with In-Chen-How (approximately 1.0 mL x kg(-1), according to weight) for 5 consecutive days. Rats in the control group received water simultaneously. Each rat was then given acetaminophen. The pharmacokinetic parameters of acetaminophen of the two groups were significantly different. In the In-Chen-How pretreated group, the maximum concentration of acetaminophen and the area under the plasma concentration-time curve were reduced about 58.4%, 56.7% and 55.4%. To further explain the results, liver microsomal suspensions were obtained from rats that were randomly divided into control and In-Chen-How pretreated group. The levels of CYP1A2 and CYP2E1 in hepatic microsomal protein from pretreated group were increased as compared to that from the control group. It indicated that In-Chen-How can stimulate the activity of CYP isozymes. The changes in the pharmacokinetics of acetaminophen resulting from the administration of In-Chen-How are related to an increase in metabolic activity of CYP1A2 and CYP2E1.

Real-time dynamic monitoring of nonprotein-bound copper in the blood.

To obtain real-time dynamic changes of non-protein-bound copper in the blood, we have developed an online microdialysis sampling system coupled with a flow-injection graphite furnace-atomic absorption spectrometer (FI-GFAAS). The analytical performances of the online system such as linearity, limit of detection, precision, and spiked recoveries were validated. Before the in vivo experiments, the in vivo recovery was conducted. The levels of non-protein-bound Cu in the blood of living rabbits were evaluated before and after administering them with 5 mg/kg body weight of CuSO4 by the online microdialysis-FI-GFAAS system. The results showed that the average basal concentration of non-protein-bound Cu in the blood of living rabbits was 16.2 microg/L (n = 3). Furthermore, the levels of non-protein-bound Cu in the blood of living rabbits were observed after a long delay following intravenous injection of CuSO4. The non-protein-bound Cu reached the maximum value at 125 min after injection. Our present study might provide the in vivo, direct observation that different metals have their own binding characteristics with proteins when transported into the blood of living organisms.

Simultaneous determination of celecoxib, meloxicam, and rofecoxib using capillary electrophoresis with surfactant and application in drug formulations.

A simple and selective CE using surfactant with UV detection is described for the simultaneous determination of selective cyclooxygenase-2 inhibitors, celecoxib, meloxicam, and rofecoxib. The simultaneous analysis of celecoxib, meloxicam, and rofecoxib was performed in Tris buffer (10 mM; pH 11) with 60 mM sodium octane-sulfonate and 20% ACN as an anionic surfactant and organic modifier, respectively. Under this condition, good separation with high efficiency and the required short analysis time is achieved. The linear ranges of the method for the determination of celecoxib, meloxicam, and rofecoxib were over 5-100 microg/mL; the detection limits at 200 nm (S/N = 3; injection 3.45 kPa, 5 s) were 2, 1, and 1 microg/mL, respectively. The small amount of sample required and the expeditiousness of the procedure allow content uniformity to be determined in individual pharmaceutical products.

Determination of indomethacin in plasma by micellar electrokinetic chromatography with UV detection for premature infants with patent ducts arteriosus.

A simple and selective micellar electrokinetic chromatography (MEKC) is described for determination of indomethacin in plasma. Plasma proteins are precipitated by acetonitrile. An aliquot of supernatant was evaporated and reconstituted with Tris buffer for MEKC analysis. The separation of indomethacin was performed at 25 degrees C using a background electrolyte consisting of Tris buffer (30 mM; pH 8.0) with 100 mM sodium octanesulfonate (SOS) as an anionic surfactant. Under this condition, a good separation with high efficiency and short analysis time is achieved. Several parameters affecting the separation of indomethacin were studied, including pH and concentrations of the Tris buffer and SOS. The linear range of the method for the determination of indomethacin was over 0.3-10.0 microg/mL; the detection limit (signal-to-noise ratio=3; injection 0.5 psi 5s) was 0.1 microg/mL. The proposed method for determination of indomethacin in premature infants with patent ducts arteriosus has been demonstrated.

Simultaneous determination of cefepime and L-arginine by micellar electrokinetic chromatography and applications to commercial injections.

A simple micellar electrokinetic chromatography (MEKC) with UV detection is described for simultaneous analysis of cefepime and L-arginine. The determination of cefepime and L-arginine in pharmaceutical preparations was performed at 25degreesC using a background electrolyte consisting of Tris buffer with sodium dodecyl sulfate (SDS) as the electrolyte solution. Several parameters affecting the separation of the drugs were studied, including the pH and concentrations of the Tris buffer and SDS. Under optimal MEKC conditions, good separation with high efficiency and short analysis times is achieved. Using cefazolin as an internal standard, the linear ranges of the method for the determination of cefepime and L-arginine were over 5-100 microg/mL; the detection limits of cefepime (signal to noise ratio = 3; injection 3.45 kPa, 3 s) and L-arginine (signal to noise ratio = 3; injection 3.45 kPa, 3 s) were 2 microg/mL and 4 microg/ mL, respectively. Applicability of the proposed method for the determination of cefepime and L-arginine in commercial injections was demonstrated.

Trace analysis of zotepine and its active metabolite in plasma by capillary electrophoresis with solid phase extraction and head-column field-amplified sample stacking.

A sensitive high-performance capillary zone electrophoresis (CZE) with head-column field-amplified sample stacking (FASS) in binary system has been developed for the simultaneous determination of zotepine and its active metabolite, norzotepine, in human plasma. The separation of zotepine and norzotepine was performed using a background electrolyte consisting of 50% ethylene glycol-borate buffer (20mM, pH 8.0) solution with 20% methanol as the running buffer and on-column detection at 200 nm. Under the optimal FASS-CZE condition, good separation with high efficiency and short analysis time is achieved. Several parameters affecting the separation and sensitivity of the drug were studied, including sample matrix, pH and concentrations of the borate buffer, ethylene glycol and methanol. Using clozapine as an internal standard, the linear ranges of the method for the determination of zotepine and norzotepine in human plasma were over 3-100 ng/mL; the detection limits of zotepine and norzotepine in plasma were 2 and 1 ng/mL, respectively. A sample pretreatment by means of solid-phase extraction (SPE) with subsequent quantitation by FASS-CZE was used. The application of the proposed method for determination of zotepine and norzotepine in plasma collected after oral administration of 125 mg zotepine in one schizophrenic patient was demonstrated.

Rapid and selective micellar electrokinetic chromatography for simultaneous determination of amikacin, kanamycin A, and tobramycin with UV detection and application in drug formulations.

A simple and selective micellar electrokinetic chromatography (MEKC) with UV detection is described for simultaneous determination of amikacin, tobramycin, and kanamycin A, performed in Tris buffer (180 mM; pH 9.1) with 300 mM sodium pentanesulfonate (SPS) as an anionic surfactant. Under this condition, good separation with high efficiency and the required short analysis time is achieved. The linear ranges of the method for the determination of amikacin, tobramycin, and kanamycin A were 0.1-0.5 mg / mL, 0.4-2.0 mg / mL, and 0.4-2.0 mg / mL, respectively; the detection limits (signal-to-noise ratio = 3; injection, 0.5 psi 5 s) were 0.08, 0.2, and 0.2 mg / mL, respectively. The small amount of sample required and the expeditiousness of the procedure allow content uniformity to be determined in individual commercial products.

Simultaneous determination of theophylline and dyphylline by micellar electrokinetic chromatography and application in drug formulations.

A simple micellar electrokinetic chromatography is described for well resolution of theophylline, dyphylline and caffeine. The separation was performed at 25 degrees C using a background electrolyte consisting of 10mM borate buffer at pH 9 and 40 mM sodium dodecyl sulfate (SDS) as running buffer. Under this condition, good separation with high efficiency and short analyses time required is achieved. Several parameters affecting the separation of the drugs were studied, including the pH and concentrations of the borate buffer and sodium dodecyl sulfate. Using caffeine as an internal standard (I.S.), the linear range of the method for the determination of theophylline and dyphylline was over 0.03-1 micromol ml(-1); the detection limit (signal-to-noise ratio 3; injection 0.3 psi, 3s) was 0.01 and 0.02 micromol ml(-1), respectively.

Highly sensitive analysis of iodide anion in seaweed as pentafluorophenoxyethyl derivative by capillary gas chromatography.

A simple and sensitive gas chromatography (GC) method is described for the trace analysis of iodide anion (iodide) in processed seaweed as an organic derivative. The method is based on the derivatization of aqueous iodide extracted from seaweed with 2-(pentafluorophenoxy)ethyl 2-(piperidino)ethanesulfonate in toluene using tetra-n-hexylammonium bromide as a phase-transfer catalyst. The resulting pentafluorophenoxyethyl iodide is highly responsive to an electron-capture detector (ECD) and was analyzed by GC-ECD, giving a low detection limit of approximately 2.7 nM (2.7 fmol/microL injected). Interferences of some common anions in the analysis of iodide were studied and proved to be minimal. Application of the method to the analysis of iodide in processed seaweed was performed.