Thau-Ming Cham

Effect of particle size on the available surface area of nifedipine from nifedipine-polyethylene glycol 6000 solid dispersions

Solid dispersions containing 5%, 10%, 20%, 30% and 50% of nifedipine were prepared with polyethylene glycol (PEG) 6000 as carrier, respectively, by the fusion method. Drug release from four different size fractions of nifedipine-polyethylene glycol 6000 solid dispersions were examined. The probability parameters of Weibull distribution or log-normal distribution could be obtained from linear regression of the dissolution data. The effects of particle size on the dissolution rate of nifedipine were evaluated in terms of the time course of the available surface area (S(t)). The X-ray diffraction patterns showed that nifedipine was dispersed homogeneously in an amorphous state in the solid dispersions with nifedipine concentration up to 10%. The initial values and faster rate of decrease of S(t) during the dissolution process were markedly enhanced in the solid dispersions with lower contents of nifedipine (5% and 10%) due to the formation of high energy metastable (amorphous) states of the drug and differences in the particle sizes had little effect on the values of the available surface area and the dissolution of the drug. Values of available surface area were particle size dependent for the solid dispersions with higher contents of nifedipine (20%, 30% and 50%) and the rate of decrease of S(t) was enhanced as the particle size reduced.

Nattokinase decreases plasma levels of fibrinogen, factor VII, and factor VIII in human subjects

Nattokinase, a serine proteinase from Bacillus subtilis, is considered to be one of the most active functional ingredients found in natto. In this study, we hypothesized that nattokinase could reduce certain factors of blood clotting and lipids that are associated with an increase risk for cardiovascular disease (CVD). Thus, an open-label, self-controlled clinical trial was conducted on subjects of the following groups: healthy volunteers (Healthy Group), patients with cardiovascular risk factors (Cardiovascular Group), and patients undergoing dialysis (Dialysis Group). All subjects ingested 2 capsules of nattokinase (2000 fibrinolysis units per capsule) daily orally for 2 months. The laboratory measurements were performed on the screening visit and, subsequently, regularly after the initiation of the study. The intent-to-treat analysis was performed on all 45 enrolled subjects. By use of mixed model analysis, a significant time effect, but not group effect, was observed in the change from baseline of fibrinogen (P = .003), factor VII (P < .001), and factor VIII (P < .001), suggesting that the plasma levels of the 3 coagulation factors continuously declined during intake; also, the extents of decrease were similar between groups. After 2 months of administration, fibrinogen, factor VII, and factor VIII decreased 9%, 14%, and 17%, respectively, for the Healthy Group; 7%, 13%, and 19%, respectively, for the Cardiovascular Group; and 10%, 7%, and 19%, respectively, for the Dialysis Group, whereas blood lipids were unaffected by nattokinase. No significant changes of uric acid or notable adverse events were observed in any of the subjects. In summary, this study showed that oral administration of nattokinase could be considered as a CVD nutraceutical by decreasing plasma levels of fibrinogen, factor VII, and factor VIII.

Determination of acetylcholine by on-line microdialysis coupled with pre- and post-microbore column enzyme reactors with electrochemical detection

A sensitive procedure consisting of a pre- and post-microbore column reactor sequence of a LC-electrochemical detection system coupled with on-line microdialysis system is described in the present study to measure endogenous acetylcholine concentration in freely moving rats. The pre-column packed, with immobilized choline oxidase and catalase, was used to remove choline, whereas the post-column, packed with immobilized acetylcholine oxidase and choline oxidase, was used to measure acetylcholine selectively. The detection limit of acetylcholine oxidase and choline oxidase, was used to measure acetylcholine selectively. The detection limit of acetylcholine was found to be 5 fmol/microliter (50 fmol/10 microliters). The usefulness of the described methodology was evaluated by examining the change in the striatal acetylcholine concentration of freely moving rats after physostigmine (0.5 mg/kg, s.c.) administration.

Isolation of new esters from the stems of Cinnamomum reticulatum Hay

The stems of Cinnamomum reticulatum Hay (Lauraceae) were extracted with hexane and chloroform successively. A series of new esters, including a mixture of 4-hydroxy-3-methoxyphenethyl derivatives (1–5), along with two butanolides, isoobtusilactone A (6) and obtusilactone A (7), two amides, N-trans-feruloylmethoxytyramine (8) and N-cis-feruloyl-methoxytyramine (9), three benzenoids, p-hydroxybenzoic acid (10), syringic acid (11) and vanillic acid (12), one lignan, (+)-syringaresinol (13) and one steroid, β-sitostenone (14), were isolated. The structures of the new esters were elucidated by chemical and physical evidence.

Preparation and in-vitro evaluation of nifedipine loaded albumin microspheres cross-linked by different glutaraldehyde concentrations

Nifedipine-loaded albumin microspheres were prepared by a chemical cross-linking method to develop a sustained release form. The effects of cross-linking agent (glutaraldehyde) on the percentage of drug loading, biodegradability of albumin microspheres and drug release kinetics were investigated in this study. Moreover, the kinetics of nifedipine released from different albumin microspheres were analysed using four different theoretical models, that is, zero order, first order, planar matrix and spherical matrix model. Albumin microspheres prepared with different amounts of glutaraldehyde indicated different release kinetics. Increasing the glutaraldehyde concentration decreased the release rate of nifedipine from albumin microspheres as a result of formation of greater structural strength and more tightly texture. Besides, albumin microspheres gave an adequate fit to either zero order or spherical matrix model, depending on the extent of cross-linking reaction.

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

Antibacterial Properties of Chinese Herbal Medicines against Nosocomial Antibiotic Resistant Strains of Pseudomonas aeruginosa in Taiwan

330 billion to US

Formulation Design of a Highly Hygroscopic Drug (Pyridostigmine Bromide) for its Hygroscopic Character Improvement and Investigation of In Vitro/In Vivo Dissolution Properties

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

Development of nifedipine-loaded albumin microspheres using a statistical factorial design

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.

Secondary prophylaxis treatment versus on-demand treatment for patients with severe haemophilia A: comparisons of cost and outcomes in Taiwan.

Pseudomonas aeruginosa is well-recognized as a nosocomial pathogen, which exhibits inherent drug resistance. In this study, the antibacterial activity of ethanol extracts of 58 Chinese herbal medicines used in Taiwan were tested against 89 nosocomial antibiotic resistant strains of Pseudomonas aeruginosa. The results gathered by the disc diffusion method showed that 26 out of the 58 herbal extracts exhibited antibacterial activity. Among the 26 herbal extracts, 10 extracts showed broad-spectrum antibacterial activities and were selected for further antibacterial property assay. The minimum inhibitory concentrations (MIC) of the active partition fractions ranged from 0.25 to 11.0 mg/L. The presence of flavonoid compounds in the active fractions of test herbal extracts was observed by the TLC-bioautography. The results from the time-kill assay revealed that most of the herbal extracts completely killed the test organisms within 4 hours. Exposure of the test strains to a sub-MIC level of the herbal extracts for 10 consecutive subcultures did not induce resistance to the active components. A combination of the active herbal fractions with antibiotics showed that one of the herbal medicines, the hexane fraction of Ramulus Cinnamomi, possessed a synergistic effect with tetracycline, gentamycin, and streptomycin. In conclusion, the tested Chinese medical herbs have the potential to be developed into natural antibiotics. This is the first evaluation for screening large amounts of medical plants against nosocomial antibiotic resistant bacteria in Taiwan.