Thau-Ming Cham - Academia.edu (original) (raw)

Papers by Thau-Ming Cham

Research paper thumbnail of Southern Taiwan Findings from the Institute for Safe Medication Practices Medication Safety Self Assessment for Hospitals Survey

Objective: Using the Institute for Safe Medication Practices (ISMP(superscript ®)) Medication Saf... more Objective: Using the Institute for Safe Medication Practices (ISMP(superscript ®)) Medication Safety Self Assessment(superscript ®) for Hospitals 2004 edition, we surveyed hospital medication use processes in southern Taiwan. The results can be used for healthcare quality improvement and related policy establishment in the future. Materials and Methods: Based on the current practice model in Taiwan, we translated and modified ISMP(superscript ®) Medication Safety Self Assessment(superscript®) for Hospitals 2004 edition. The self assessment survey is divided into 10 domains, 20 core characteristics and 235 items. Surveys were distributed to all hospitals in three counties of southern Taiwan. Results: Out of a total of 63 hospitals in southern Taiwan, 53 hospitals completed the survey (completion rate 84%) and 10 hospitals declined to participate. The 53 participating hospitals scored highest in domains related to environmental factors, workflow and staffing patterns (65.48%). Scores ...

Research paper thumbnail of Statistical Optimization of Novel Traditional Chinese Medicine (Liu-Wei-Di-Huang-Wan) Pellets Prepared by Extrusion-Spheronization Method

Traditional Chinese Medicine (TCM) has received broader attention recently, but the applications ... more Traditional Chinese Medicine (TCM) has received broader attention recently, but the applications are limited due to the lack of more complete study of their pharmaceutical properties. TCM often consists of numerous ingredients and generally involves a complicated manufacturing process, but studies on the interaction of the active ingredients and excipients are rare. In this study, the development of a novel dosage form of a widely utilized TCM (Liu-Wei-Di-Huang-Wan, LWDHW) was investigated. Firstly, Differential Scanning Calorimetry (DSC) was used to study the incompatibility between the active ingredients of LWDHW and three excipients commonly used in the manufacturing of TCM products. Secondly, a novel pellet dosage form of LWDHW was prepared using the extrusion-spheronization method, and L16 (2^15) orthogonal experimental design method was applied to perform an overall investigation of different variables. The frequently used excipient, hydroxypropyl methylcellulose (HPMC), was c...

Research paper thumbnail of Simultaneous analysis of ten components in patch preparation of Wan-Yin-Gau by high performance liquid chromatography

Journal of Food and Drug Analysis, 2020

Simultaneous analysis of ten components in patch preparation of Simultaneous analysis of ten comp... more Simultaneous analysis of ten components in patch preparation of Simultaneous analysis of ten components in patch preparation of Wan-Yin-Gau by high performance liquid chromatography Wan-Yin-Gau by high performance liquid chromatography

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

International Journal of Pharmaceutics, 1996

Nifedipine-loaded albumin microspheres were prepared by a chemical cross-linking method to develo... more Nifedipine-loaded albumin microspheres were prepared by a chemical cross-linking method to develop a sustainedrelease form. The qualities of the nifedipine-loaded albumin microsphere products were affected by several variables. In this study, the effects on the percentage of nifedipine incorporated into albumin microspheres of four different variables (i.e. drug/albumin ratio, amount of glutaraldehyde, amount of sodium dodecyl sulfate and stirring speed) at two levels were studied according to a factorial design of experiments.

Research paper thumbnail of Effects of different manufacturing methods on pharmaceutical properties and release kinetic models of ketoprofen sustained-release microparticles

African Journal of Pharmacy and Pharmacology, Dec 8, 2012

Extrusion-spheronization and the fluid bed method are valuable commonly applied methods in microp... more Extrusion-spheronization and the fluid bed method are valuable commonly applied methods in microparticle production. However, the characteristics of resultants prepared by these two methods have seldom been compared. The aim of this study was to investigate differences in pharmaceutical properties and release kinetics of sustained-release ketoprofen microparticles prepared by different manufacturing processes. Microparticles prepared by extrusion-spheronization displayed slower release rate resulting in increased diffusion path of the drug, a behavior distinct for microparticles with less Surelease ®. The effects of manufacturing method on release rate was also significant for microparticles with less Surelease ® compared to microparticles with more Surelease ®. The release profiles of coated microparticles fitted well to the Higuchi's release model, but in cases of microparticles with larger Surelease ® coating, the trend was towards a zero-order release model. These findings are valuable for comprehending the differences among different preparation processes and for choosing the optimal manufacturing method of sustained-release microparticles.

Research paper thumbnail of Compression behavior and tensile strength of heat-treated polyethylene glycols

International Journal of Pharmaceutics, 1995

Abstract The compression behavior and tensile strength of five heat-treated polyethylene glycol (... more Abstract The compression behavior and tensile strength of five heat-treated polyethylene glycol (PEG) powders of different average molecular weights were determined. Compacts were prepared at various compression pressures using three different size fractions. The compression behavior of the compacts was analyzed according to the Kawakita, Cooper-Eaton and Heckel methods, respectively, and their compression parameters were calculated. Compared to the other polymers, PEG 4000 underwent greater densification during compression. The yield pressure from the slope of the Cooper-Eaton plot was lowest for PEG 4000. The yield pressure determined via the Heckel method was found to be proportional to the molecular weight of the PEG. These polymers obey a Heckel relationship at lower pressures (not exceeding 80 MN/m 2 ) and exhibit a behavior similar to those of fatty acid powders. The specific surface area of the compacts decreased with increasing compression pressure. The change in specific surface area of compacts compressed at pressures greater than 80 MN/m 2 was only very slight. This indicates that the surface of the compacts melts at such pressures. At pressures above 26.53 MN/m 2 , PEG 10 000 compacts had superior tensile strength compared to the other polymers.

Research paper thumbnail of HPLC Determination of Lansoprazole and Method Application for the Formulation Development of Enteric-coated Lansoprazole Pellets

Journal of the Chinese Chemical Society, 2015

The aim of this study was to develop a validated HPLC method for the determination of lansoprazol... more The aim of this study was to develop a validated HPLC method for the determination of lansoprazole in dissolution medium and pellets. For the formulation development, we investigated the role of 2hydroxypropyl-b-cyclodextrin (HPbCD) on the dissolution of enteric-coated pellets of lansoprazole prepared by the solution layering technique using a fluid bed coater. Dissolution results demonstrated the coating using Acryl-Eze protected the formulations from releasing lansoprazole in acid medium for the first 2 h, and the addition of HPbCD improved the dissolution performance by 189%, compared with the group without HPbCD. The DSC analysis displaced an absence of the endothermic peak for the lyophilized products lansoprazole and HPbCD, and FTIR analysis demonstrated the band broadening, shifting or disappearance compared to the spectra of the physical mixture, which indicated the formation of the inclusion complex between lansoprazole and HPbCD. This study has developed a validated HPLC method to measure lansoprazole in test media and pellets, which was applied successfully to the formulation development of enteric-coated pellets.

Research paper thumbnail of Preparation, physicochemical characterization, and antioxidant effects of quercetin nanoparticles

International Journal of Pharmaceutics, 2008

ABSTRACT The purpose of this study was to develop quercetin-loaded nanoparticles (QUEN) by a nano... more ABSTRACT The purpose of this study was to develop quercetin-loaded nanoparticles (QUEN) by a nanoprecipitation technique with Eudragit E (EE) and polyvinyl alcohol (PVA) as carriers, and to evaluate the antioxidant effects of quercetin (QU) and of its nanoparticles. The novel QUEN systems were characterized by particle size and morphology, yield and encapsulation efficiency, differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), (1)H nuclear magnetic resonance ((1)H NMR), and dissolution study. It was observed that the weight ratio of QU:EE:PVA at 1:10:10 carried a particle size of <85 nm, a particle distribution with polydispersity index <0.3, and its yield and encapsulation efficiency were over 99%. The results from XRD and DSC of the QUEN showed that the crystal of the drug might be converted to an amorphous state. The FT-IR and (1)H NMR demonstrated that QU formed intermolecular hydrogen bonding with carriers. The release of the drug from the QUEN was 74-fold higher compared with the pure drug. In addition, the antioxidant activity of the QUEN was more effective than pure QU on DPPH scavenging, anti-superoxide formation, superoxide anion scavenging, and anti-lipid peroxidation.

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

Journal of Chromatography B: Biomedical Sciences and Applications, 1996

A sensitive procedure consisting of a pre-and post-microbore column reactor sequence of a LC-elec... more 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 was found to be 5 fmol//~l (50 fmol/10 /zl). 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.

Research paper thumbnail of Magnetically Directed Targeting Aggregation of Radiolabelled Ferrite Nanoparticles

Journal of Nanomaterials, 2011

Ferrite magnetic nanoparticles (Fe3O4or iron (II,III) oxide; 15–25 nm of diameter) were developed... more Ferrite magnetic nanoparticles (Fe3O4or iron (II,III) oxide; 15–25 nm of diameter) were developed. These magnetic nanoparticles are a potential vehicle for magnetically induced target aggregation in living animals. In this preliminary study, the radiochemical purity for the radiolabeled magnetic nanoparticles was examined, and the possibility of the magnetically induced targeting of the radio-nanoparticles was evaluated. Our results showed that radiolabeled ferrite nanoparticles can be used as magnetic targeting agents with high labeling efficiency and stability. These particles can be distributed within living animals via intravenous injection, and the biodistribution of the particles can be potentially controlled by external magnetism. These evaluations will be the groundwork for the future development of delivery techniques for radiopharmaceuticals through external magnetic control.

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

International Journal of Pharmaceutics, 1996

Nifedipine-loaded albumin microspheres were prepared by a chemical cross-linking method to develo... more 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.

Research paper thumbnail of An investigation of acetylcholine released in skeletal muscle and protein unbound drug released in blood based on the pyridostigmine bromide (pretreatment drug) sustained-release pellets by microdialysis technique in the rabbit model

Neuroscience Letters, 2007

Pyridostigmine bromide (PB) is a reversible acetylcholinesterase inhibitor that has been used as ... more Pyridostigmine bromide (PB) is a reversible acetylcholinesterase inhibitor that has been used as a pretreatment drug for "Soman" nerve gas poisoning in combat to increase survival. The once-daily PB-sustained-release (SR) pellets were developed by extrusion-spheronization and fluid-bed methods in our laboratory, which was followed by zero-order release mechanism. The results showed that the released concentration of acetylcholine (ACh) in skeletal muscle and the released concentration of protein unbound drug in blood were determined by microdialysis technique to have significant differences (P < 0.05) among the three dosage forms (IV injection, commercial IR tablets and the PB-SR pellet). The released concentrations of ACh and protein unbound drug for PB-SR pellets were slower than IV injection and commercial IR tablets; this phenomenon indicating that the retention period of drug efficacy in vivo for PB-SR pellet was longer than the others, that is to say, the PB-SR pellets provided with SR effect in vivo as well. We believe that once-daily administered PB-SR pellets would improve limitations of post-exposure antidotes, decrease the frequency of administration and enhance the retention period of drug efficacy in vivo for personnel exposed to contamination situations in wars or terrorist attacks in the future.

Research paper thumbnail of Effectiveness of Implementation of a New Drug Storage Label and Error-Reducing Process on the Accuracy of Drug Dispensing

Journal of Medical Systems, 2010

This study evaluated the effectiveness of implementation of an improved storage label and an erro... more This study evaluated the effectiveness of implementation of an improved storage label and an error-reducing process on the incidence of drug-dispensing errors. A total of 27 pharmacists (11 male and 16 female) were included. Questionnaires were distributed to pharmacists to measure their degree of satisfaction with the format and content of the labels. The questionnaires were completed before and one month after implementation of new label. Pharmacists were also requested to follow a new error-reducing dispensing process by circling the following items on the new storage label: drug name, appearance, packaging, dose, and formulation. The pharmacists&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; degrees of satisfaction increased significantly after implementation of the new label with respect to these questionnaire items: all label format items, edition appropriateness, use of capital fonts to distinguish similar drug names, reminder images to help with drug differentiation, and complete label information. The outpatient monthly drug-dispensing error rate was significantly decreased.

Research paper thumbnail of Nanoparticles formulation of Cuscuta chinensis prevents acetaminophen-induced hepatotoxicity in rats

Food and Chemical Toxicology, 2008

Cuscuta chinensis is a commonly used traditional Chinese medicine to nourish the liver and kidney... more Cuscuta chinensis is a commonly used traditional Chinese medicine to nourish the liver and kidney. Due to the poor water solubility of its major constituents such as flavonoids and lignans, its absorption upon oral administration could be limited. The purpose of the present study was to use the nanosuspension method to prepare C. chinensis nanoparticles (CN), and to compare the hepatoprotective and antioxidant effects of C. chinensis ethanolic extract (CE) and CN on acetaminophen-induced hepatotoxicity in rats. An oral dose of CE at 125 and 250 mg/kg and CN at 25 and 50mg/kg showed a significant hepatoprotective effect relatively to the same extent (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05) by reducing levels of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase. These biochemical assessments were supported by rat hepatic biopsy examinations. In addition, the antioxidant activities of CE and CN both significantly increased superoxide dismutase, catalase, glutathione peroxidase, and reduced malondialdehyde (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). Moreover, the results also indicated that the hepatoprotective and antioxidant effects of 50 mg/kg CN was effectively better than 125 mg/kg CE (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05), and an oral dose of CN that is five times as less as CE could exhibit similar levels of outcomes. In conclusion, we suggest that the nanoparticles system can be applied to overcome other water poorly soluble herbal medicines and furthermore to decrease the treatment dosage.

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

Drug Development and Industrial Pharmacy, 2007

Pyridostigmine bromide (PB) sustained-release (SR) pellets were developed by extrusion-spheroniza... more Pyridostigmine bromide (PB) sustained-release (SR) pellets were developed by extrusion-spheronization and fluid-bed methods using Taguchi experimental and 2(3) full factorial design. In vitro studies, the 2(3) full factorial design was utilized to search for the optimal SR pellets with specific release rate at different time intervals (release percent of 2, 6, 12, and 24 hr were 6.24, 33.48, 75.18, and 95.26%, respectively) which followed a zero-order mechanism (n=0.93). The results of moisture absorption by Karl Fischer has shown the optimum SR pellets at 25 degrees C/60% RH, 30 degrees C/65% RH, and 40 degrees C/75% RH chambers from 1 hr-4 weeks, attributing that the moisture absorption was not significantly increased. In the in vivo study, the results of the bioavailability data showed the Tmax (from 0.65+/-0.082 hr-4.82+/-2.12 hr) and AUC0-30 hr (from 734.88+/-230.68 ng/mL.hr-1454.86+/-319.28 ng/mL.hr) were prolonged and increased, as well as Cmax (from 251.87+/-27.51 ng/mL-115.08+/-14.87 ng/mL) was decreased for optimum SR-PB pellets when compared with commercial immediate-release (IR) tablets. Furthermore, a good linear regression relationship (r=0.9943) was observed between the fraction dissolution and fraction absorption for the optimum SR pellets. In this study, the formulation design not only improved the hygroscopic character of PB but also achieved the SR effect.

Research paper thumbnail of Evaluation of Defatted Soybean Flakes as a Tablet Excipient Part I. As a Disintegrant

Drug Development and Industrial Pharmacy, 1988

AbstractOriental people have been using soybeans as a protein foodstuff for centuries. At present... more AbstractOriental people have been using soybeans as a protein foodstuff for centuries. At present soybeans have become a major source of edible oil, and the meal provides an important source of protein for animal feeds. In the present study, the dehulled, and defatted soybean flakes were investigated as a possible tablet excipient.Four different samples (sieve fraction 150-180 um), namely samples A, B, C, and D were prepared from dehulled, defatted soybean flakes and their physical characteristics were determined subsequently. Compacts of these four substances and their binary mixtures with dicalcium phosphate dihydrate in four different ratios were also prepared at seven different compression pressures.The changes in density of the compacts under compression were 1 2 interpreted using the Heckel plots 1, 2 The crushing strength and disintegration time of the subsequent compacts were also determined. Great differences in the disintegrating properties between the four soybean samples were noticed.Samples A...

Research paper thumbnail of Comparison of the Solubility and Dissolution Rate Between Gliclazide Solid Complex and Its Nanospheres

Drug Development and Industrial Pharmacy, 2007

The solid complex of gliclazide and beta-cyclodextrin was prepared by neutralization method and t... more The solid complex of gliclazide and beta-cyclodextrin was prepared by neutralization method and the precipitation solvent evaporation method was used to prepare gliclazide nanospheres. Fourier-transform infrared spectroscopy and differential scanning calorimetry were used to examine whether gliclazide solid complex and gliclazide nanospheres were successfully formed in this study. The dissolution rate of gliclazide from its nanospheres was faster than its solid complex and pure drug. The morphology of particles for nanospheres showed no crystal character of gliclazide. In summary, the results indicate that nanotechnology provides better effects in solubility and dissolution rate of gliclazide than neutralization method.

Research paper thumbnail of Evaluation of Era-Tab as a Direct Compression Excipient

Drug Development and Industrial Pharmacy, 1997

ABSTRACT

Research paper thumbnail of Microencapsulation of extract containing shikonin using gelatin–acacia coacervation method: A formaldehyde-free approach

Colloids and Surfaces B: Biointerfaces, 2007

The application of microcapsule for pharmaceutical dosage form for various drugs has received con... more The application of microcapsule for pharmaceutical dosage form for various drugs has received considerable attention in recent years due to its multiple advantages. The most frequently used crosslinking agent formaldehyde in the gelatin-acacia microencapsulation process was altered by glycerol in this study. The effect of various parameters such as the concentration of surfactant, concentration of gelatin and continuous phase pH condition on the microcapsule particle size distribution was experimentally investigated. It was shown that the optimum concentration for surfactant/oil ratio is 1/10 and gelatin/oil ratio is 1/5 in the pH condition of approximately 4-6 for the coacervation process. Results obtained from microscopy observation revealed that one core microcapsule prepared by 6% glycerol was no different from formaldehyde. Hence, glycerol was demonstrated to be a good potential non-toxic crosslinking material for the applications of encapsulated extract containing shikonin.

Research paper thumbnail of A new butanolide from the leaves of Cinnamomum reticulatum

Chemistry of Natural Compounds, 2011

A new butanolide, isoreticulide ((4R,3E)-4-hydroxy-5-methylene-3-octadecylidenedihydrofuran-2-one... more A new butanolide, isoreticulide ((4R,3E)-4-hydroxy-5-methylene-3-octadecylidenedihydrofuran-2-one) (1), along with nine compounds including one sesquiterpenoid, (3-methoxy-5H-9,11dioxabenzo[3,4]cyclohepta[1,2-f])inden-7-yl)-methanol (2); six benzenoids, p-hydroxybenzoic acid (3), p-hydroxybenzaldehyde (4), protocatechuic acid (5), ferulic acid (6), trans-methyl p-coumarate (7), and p-dihydrocoumaric acid (8), and two amides, N-trans-feruloyltyramine (9) and dihydroferuloyltyramine (10), were isolated from the leaves of Cinnamomum reticulatum Hayata (Lauraceae). These compounds were characterized and identified by physical and spectral evidence.

Research paper thumbnail of Southern Taiwan Findings from the Institute for Safe Medication Practices Medication Safety Self Assessment for Hospitals Survey

Objective: Using the Institute for Safe Medication Practices (ISMP(superscript ®)) Medication Saf... more Objective: Using the Institute for Safe Medication Practices (ISMP(superscript ®)) Medication Safety Self Assessment(superscript ®) for Hospitals 2004 edition, we surveyed hospital medication use processes in southern Taiwan. The results can be used for healthcare quality improvement and related policy establishment in the future. Materials and Methods: Based on the current practice model in Taiwan, we translated and modified ISMP(superscript ®) Medication Safety Self Assessment(superscript®) for Hospitals 2004 edition. The self assessment survey is divided into 10 domains, 20 core characteristics and 235 items. Surveys were distributed to all hospitals in three counties of southern Taiwan. Results: Out of a total of 63 hospitals in southern Taiwan, 53 hospitals completed the survey (completion rate 84%) and 10 hospitals declined to participate. The 53 participating hospitals scored highest in domains related to environmental factors, workflow and staffing patterns (65.48%). Scores ...

Research paper thumbnail of Statistical Optimization of Novel Traditional Chinese Medicine (Liu-Wei-Di-Huang-Wan) Pellets Prepared by Extrusion-Spheronization Method

Traditional Chinese Medicine (TCM) has received broader attention recently, but the applications ... more Traditional Chinese Medicine (TCM) has received broader attention recently, but the applications are limited due to the lack of more complete study of their pharmaceutical properties. TCM often consists of numerous ingredients and generally involves a complicated manufacturing process, but studies on the interaction of the active ingredients and excipients are rare. In this study, the development of a novel dosage form of a widely utilized TCM (Liu-Wei-Di-Huang-Wan, LWDHW) was investigated. Firstly, Differential Scanning Calorimetry (DSC) was used to study the incompatibility between the active ingredients of LWDHW and three excipients commonly used in the manufacturing of TCM products. Secondly, a novel pellet dosage form of LWDHW was prepared using the extrusion-spheronization method, and L16 (2^15) orthogonal experimental design method was applied to perform an overall investigation of different variables. The frequently used excipient, hydroxypropyl methylcellulose (HPMC), was c...

Research paper thumbnail of Simultaneous analysis of ten components in patch preparation of Wan-Yin-Gau by high performance liquid chromatography

Journal of Food and Drug Analysis, 2020

Simultaneous analysis of ten components in patch preparation of Simultaneous analysis of ten comp... more Simultaneous analysis of ten components in patch preparation of Simultaneous analysis of ten components in patch preparation of Wan-Yin-Gau by high performance liquid chromatography Wan-Yin-Gau by high performance liquid chromatography

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

International Journal of Pharmaceutics, 1996

Nifedipine-loaded albumin microspheres were prepared by a chemical cross-linking method to develo... more Nifedipine-loaded albumin microspheres were prepared by a chemical cross-linking method to develop a sustainedrelease form. The qualities of the nifedipine-loaded albumin microsphere products were affected by several variables. In this study, the effects on the percentage of nifedipine incorporated into albumin microspheres of four different variables (i.e. drug/albumin ratio, amount of glutaraldehyde, amount of sodium dodecyl sulfate and stirring speed) at two levels were studied according to a factorial design of experiments.

Research paper thumbnail of Effects of different manufacturing methods on pharmaceutical properties and release kinetic models of ketoprofen sustained-release microparticles

African Journal of Pharmacy and Pharmacology, Dec 8, 2012

Extrusion-spheronization and the fluid bed method are valuable commonly applied methods in microp... more Extrusion-spheronization and the fluid bed method are valuable commonly applied methods in microparticle production. However, the characteristics of resultants prepared by these two methods have seldom been compared. The aim of this study was to investigate differences in pharmaceutical properties and release kinetics of sustained-release ketoprofen microparticles prepared by different manufacturing processes. Microparticles prepared by extrusion-spheronization displayed slower release rate resulting in increased diffusion path of the drug, a behavior distinct for microparticles with less Surelease ®. The effects of manufacturing method on release rate was also significant for microparticles with less Surelease ® compared to microparticles with more Surelease ®. The release profiles of coated microparticles fitted well to the Higuchi's release model, but in cases of microparticles with larger Surelease ® coating, the trend was towards a zero-order release model. These findings are valuable for comprehending the differences among different preparation processes and for choosing the optimal manufacturing method of sustained-release microparticles.

Research paper thumbnail of Compression behavior and tensile strength of heat-treated polyethylene glycols

International Journal of Pharmaceutics, 1995

Abstract The compression behavior and tensile strength of five heat-treated polyethylene glycol (... more Abstract The compression behavior and tensile strength of five heat-treated polyethylene glycol (PEG) powders of different average molecular weights were determined. Compacts were prepared at various compression pressures using three different size fractions. The compression behavior of the compacts was analyzed according to the Kawakita, Cooper-Eaton and Heckel methods, respectively, and their compression parameters were calculated. Compared to the other polymers, PEG 4000 underwent greater densification during compression. The yield pressure from the slope of the Cooper-Eaton plot was lowest for PEG 4000. The yield pressure determined via the Heckel method was found to be proportional to the molecular weight of the PEG. These polymers obey a Heckel relationship at lower pressures (not exceeding 80 MN/m 2 ) and exhibit a behavior similar to those of fatty acid powders. The specific surface area of the compacts decreased with increasing compression pressure. The change in specific surface area of compacts compressed at pressures greater than 80 MN/m 2 was only very slight. This indicates that the surface of the compacts melts at such pressures. At pressures above 26.53 MN/m 2 , PEG 10 000 compacts had superior tensile strength compared to the other polymers.

Research paper thumbnail of HPLC Determination of Lansoprazole and Method Application for the Formulation Development of Enteric-coated Lansoprazole Pellets

Journal of the Chinese Chemical Society, 2015

The aim of this study was to develop a validated HPLC method for the determination of lansoprazol... more The aim of this study was to develop a validated HPLC method for the determination of lansoprazole in dissolution medium and pellets. For the formulation development, we investigated the role of 2hydroxypropyl-b-cyclodextrin (HPbCD) on the dissolution of enteric-coated pellets of lansoprazole prepared by the solution layering technique using a fluid bed coater. Dissolution results demonstrated the coating using Acryl-Eze protected the formulations from releasing lansoprazole in acid medium for the first 2 h, and the addition of HPbCD improved the dissolution performance by 189%, compared with the group without HPbCD. The DSC analysis displaced an absence of the endothermic peak for the lyophilized products lansoprazole and HPbCD, and FTIR analysis demonstrated the band broadening, shifting or disappearance compared to the spectra of the physical mixture, which indicated the formation of the inclusion complex between lansoprazole and HPbCD. This study has developed a validated HPLC method to measure lansoprazole in test media and pellets, which was applied successfully to the formulation development of enteric-coated pellets.

Research paper thumbnail of Preparation, physicochemical characterization, and antioxidant effects of quercetin nanoparticles

International Journal of Pharmaceutics, 2008

ABSTRACT The purpose of this study was to develop quercetin-loaded nanoparticles (QUEN) by a nano... more ABSTRACT The purpose of this study was to develop quercetin-loaded nanoparticles (QUEN) by a nanoprecipitation technique with Eudragit E (EE) and polyvinyl alcohol (PVA) as carriers, and to evaluate the antioxidant effects of quercetin (QU) and of its nanoparticles. The novel QUEN systems were characterized by particle size and morphology, yield and encapsulation efficiency, differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), (1)H nuclear magnetic resonance ((1)H NMR), and dissolution study. It was observed that the weight ratio of QU:EE:PVA at 1:10:10 carried a particle size of &lt;85 nm, a particle distribution with polydispersity index &lt;0.3, and its yield and encapsulation efficiency were over 99%. The results from XRD and DSC of the QUEN showed that the crystal of the drug might be converted to an amorphous state. The FT-IR and (1)H NMR demonstrated that QU formed intermolecular hydrogen bonding with carriers. The release of the drug from the QUEN was 74-fold higher compared with the pure drug. In addition, the antioxidant activity of the QUEN was more effective than pure QU on DPPH scavenging, anti-superoxide formation, superoxide anion scavenging, and anti-lipid peroxidation.

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

Journal of Chromatography B: Biomedical Sciences and Applications, 1996

A sensitive procedure consisting of a pre-and post-microbore column reactor sequence of a LC-elec... more 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 was found to be 5 fmol//~l (50 fmol/10 /zl). 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.

Research paper thumbnail of Magnetically Directed Targeting Aggregation of Radiolabelled Ferrite Nanoparticles

Journal of Nanomaterials, 2011

Ferrite magnetic nanoparticles (Fe3O4or iron (II,III) oxide; 15–25 nm of diameter) were developed... more Ferrite magnetic nanoparticles (Fe3O4or iron (II,III) oxide; 15–25 nm of diameter) were developed. These magnetic nanoparticles are a potential vehicle for magnetically induced target aggregation in living animals. In this preliminary study, the radiochemical purity for the radiolabeled magnetic nanoparticles was examined, and the possibility of the magnetically induced targeting of the radio-nanoparticles was evaluated. Our results showed that radiolabeled ferrite nanoparticles can be used as magnetic targeting agents with high labeling efficiency and stability. These particles can be distributed within living animals via intravenous injection, and the biodistribution of the particles can be potentially controlled by external magnetism. These evaluations will be the groundwork for the future development of delivery techniques for radiopharmaceuticals through external magnetic control.

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

International Journal of Pharmaceutics, 1996

Nifedipine-loaded albumin microspheres were prepared by a chemical cross-linking method to develo... more 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.

Research paper thumbnail of An investigation of acetylcholine released in skeletal muscle and protein unbound drug released in blood based on the pyridostigmine bromide (pretreatment drug) sustained-release pellets by microdialysis technique in the rabbit model

Neuroscience Letters, 2007

Pyridostigmine bromide (PB) is a reversible acetylcholinesterase inhibitor that has been used as ... more Pyridostigmine bromide (PB) is a reversible acetylcholinesterase inhibitor that has been used as a pretreatment drug for "Soman" nerve gas poisoning in combat to increase survival. The once-daily PB-sustained-release (SR) pellets were developed by extrusion-spheronization and fluid-bed methods in our laboratory, which was followed by zero-order release mechanism. The results showed that the released concentration of acetylcholine (ACh) in skeletal muscle and the released concentration of protein unbound drug in blood were determined by microdialysis technique to have significant differences (P < 0.05) among the three dosage forms (IV injection, commercial IR tablets and the PB-SR pellet). The released concentrations of ACh and protein unbound drug for PB-SR pellets were slower than IV injection and commercial IR tablets; this phenomenon indicating that the retention period of drug efficacy in vivo for PB-SR pellet was longer than the others, that is to say, the PB-SR pellets provided with SR effect in vivo as well. We believe that once-daily administered PB-SR pellets would improve limitations of post-exposure antidotes, decrease the frequency of administration and enhance the retention period of drug efficacy in vivo for personnel exposed to contamination situations in wars or terrorist attacks in the future.

Research paper thumbnail of Effectiveness of Implementation of a New Drug Storage Label and Error-Reducing Process on the Accuracy of Drug Dispensing

Journal of Medical Systems, 2010

This study evaluated the effectiveness of implementation of an improved storage label and an erro... more This study evaluated the effectiveness of implementation of an improved storage label and an error-reducing process on the incidence of drug-dispensing errors. A total of 27 pharmacists (11 male and 16 female) were included. Questionnaires were distributed to pharmacists to measure their degree of satisfaction with the format and content of the labels. The questionnaires were completed before and one month after implementation of new label. Pharmacists were also requested to follow a new error-reducing dispensing process by circling the following items on the new storage label: drug name, appearance, packaging, dose, and formulation. The pharmacists&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; degrees of satisfaction increased significantly after implementation of the new label with respect to these questionnaire items: all label format items, edition appropriateness, use of capital fonts to distinguish similar drug names, reminder images to help with drug differentiation, and complete label information. The outpatient monthly drug-dispensing error rate was significantly decreased.

Research paper thumbnail of Nanoparticles formulation of Cuscuta chinensis prevents acetaminophen-induced hepatotoxicity in rats

Food and Chemical Toxicology, 2008

Cuscuta chinensis is a commonly used traditional Chinese medicine to nourish the liver and kidney... more Cuscuta chinensis is a commonly used traditional Chinese medicine to nourish the liver and kidney. Due to the poor water solubility of its major constituents such as flavonoids and lignans, its absorption upon oral administration could be limited. The purpose of the present study was to use the nanosuspension method to prepare C. chinensis nanoparticles (CN), and to compare the hepatoprotective and antioxidant effects of C. chinensis ethanolic extract (CE) and CN on acetaminophen-induced hepatotoxicity in rats. An oral dose of CE at 125 and 250 mg/kg and CN at 25 and 50mg/kg showed a significant hepatoprotective effect relatively to the same extent (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05) by reducing levels of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase. These biochemical assessments were supported by rat hepatic biopsy examinations. In addition, the antioxidant activities of CE and CN both significantly increased superoxide dismutase, catalase, glutathione peroxidase, and reduced malondialdehyde (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). Moreover, the results also indicated that the hepatoprotective and antioxidant effects of 50 mg/kg CN was effectively better than 125 mg/kg CE (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05), and an oral dose of CN that is five times as less as CE could exhibit similar levels of outcomes. In conclusion, we suggest that the nanoparticles system can be applied to overcome other water poorly soluble herbal medicines and furthermore to decrease the treatment dosage.

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

Drug Development and Industrial Pharmacy, 2007

Pyridostigmine bromide (PB) sustained-release (SR) pellets were developed by extrusion-spheroniza... more Pyridostigmine bromide (PB) sustained-release (SR) pellets were developed by extrusion-spheronization and fluid-bed methods using Taguchi experimental and 2(3) full factorial design. In vitro studies, the 2(3) full factorial design was utilized to search for the optimal SR pellets with specific release rate at different time intervals (release percent of 2, 6, 12, and 24 hr were 6.24, 33.48, 75.18, and 95.26%, respectively) which followed a zero-order mechanism (n=0.93). The results of moisture absorption by Karl Fischer has shown the optimum SR pellets at 25 degrees C/60% RH, 30 degrees C/65% RH, and 40 degrees C/75% RH chambers from 1 hr-4 weeks, attributing that the moisture absorption was not significantly increased. In the in vivo study, the results of the bioavailability data showed the Tmax (from 0.65+/-0.082 hr-4.82+/-2.12 hr) and AUC0-30 hr (from 734.88+/-230.68 ng/mL.hr-1454.86+/-319.28 ng/mL.hr) were prolonged and increased, as well as Cmax (from 251.87+/-27.51 ng/mL-115.08+/-14.87 ng/mL) was decreased for optimum SR-PB pellets when compared with commercial immediate-release (IR) tablets. Furthermore, a good linear regression relationship (r=0.9943) was observed between the fraction dissolution and fraction absorption for the optimum SR pellets. In this study, the formulation design not only improved the hygroscopic character of PB but also achieved the SR effect.

Research paper thumbnail of Evaluation of Defatted Soybean Flakes as a Tablet Excipient Part I. As a Disintegrant

Drug Development and Industrial Pharmacy, 1988

AbstractOriental people have been using soybeans as a protein foodstuff for centuries. At present... more AbstractOriental people have been using soybeans as a protein foodstuff for centuries. At present soybeans have become a major source of edible oil, and the meal provides an important source of protein for animal feeds. In the present study, the dehulled, and defatted soybean flakes were investigated as a possible tablet excipient.Four different samples (sieve fraction 150-180 um), namely samples A, B, C, and D were prepared from dehulled, defatted soybean flakes and their physical characteristics were determined subsequently. Compacts of these four substances and their binary mixtures with dicalcium phosphate dihydrate in four different ratios were also prepared at seven different compression pressures.The changes in density of the compacts under compression were 1 2 interpreted using the Heckel plots 1, 2 The crushing strength and disintegration time of the subsequent compacts were also determined. Great differences in the disintegrating properties between the four soybean samples were noticed.Samples A...

Research paper thumbnail of Comparison of the Solubility and Dissolution Rate Between Gliclazide Solid Complex and Its Nanospheres

Drug Development and Industrial Pharmacy, 2007

The solid complex of gliclazide and beta-cyclodextrin was prepared by neutralization method and t... more The solid complex of gliclazide and beta-cyclodextrin was prepared by neutralization method and the precipitation solvent evaporation method was used to prepare gliclazide nanospheres. Fourier-transform infrared spectroscopy and differential scanning calorimetry were used to examine whether gliclazide solid complex and gliclazide nanospheres were successfully formed in this study. The dissolution rate of gliclazide from its nanospheres was faster than its solid complex and pure drug. The morphology of particles for nanospheres showed no crystal character of gliclazide. In summary, the results indicate that nanotechnology provides better effects in solubility and dissolution rate of gliclazide than neutralization method.

Research paper thumbnail of Evaluation of Era-Tab as a Direct Compression Excipient

Drug Development and Industrial Pharmacy, 1997

ABSTRACT

Research paper thumbnail of Microencapsulation of extract containing shikonin using gelatin–acacia coacervation method: A formaldehyde-free approach

Colloids and Surfaces B: Biointerfaces, 2007

The application of microcapsule for pharmaceutical dosage form for various drugs has received con... more The application of microcapsule for pharmaceutical dosage form for various drugs has received considerable attention in recent years due to its multiple advantages. The most frequently used crosslinking agent formaldehyde in the gelatin-acacia microencapsulation process was altered by glycerol in this study. The effect of various parameters such as the concentration of surfactant, concentration of gelatin and continuous phase pH condition on the microcapsule particle size distribution was experimentally investigated. It was shown that the optimum concentration for surfactant/oil ratio is 1/10 and gelatin/oil ratio is 1/5 in the pH condition of approximately 4-6 for the coacervation process. Results obtained from microscopy observation revealed that one core microcapsule prepared by 6% glycerol was no different from formaldehyde. Hence, glycerol was demonstrated to be a good potential non-toxic crosslinking material for the applications of encapsulated extract containing shikonin.

Research paper thumbnail of A new butanolide from the leaves of Cinnamomum reticulatum

Chemistry of Natural Compounds, 2011

A new butanolide, isoreticulide ((4R,3E)-4-hydroxy-5-methylene-3-octadecylidenedihydrofuran-2-one... more A new butanolide, isoreticulide ((4R,3E)-4-hydroxy-5-methylene-3-octadecylidenedihydrofuran-2-one) (1), along with nine compounds including one sesquiterpenoid, (3-methoxy-5H-9,11dioxabenzo[3,4]cyclohepta[1,2-f])inden-7-yl)-methanol (2); six benzenoids, p-hydroxybenzoic acid (3), p-hydroxybenzaldehyde (4), protocatechuic acid (5), ferulic acid (6), trans-methyl p-coumarate (7), and p-dihydrocoumaric acid (8), and two amides, N-trans-feruloyltyramine (9) and dihydroferuloyltyramine (10), were isolated from the leaves of Cinnamomum reticulatum Hayata (Lauraceae). These compounds were characterized and identified by physical and spectral evidence.