We prepared the isosorbide-5-mononitrate pulsatile controlled-release pellets (PCRP) and studied the influencing factors in vitro. The isosorbide-5-mononitrate (5-ISMN) pellets prepared by extrusion-spheronization technology were coated with swelling material as the inner coating swelling layer, and with ethylcellulose aqueous dispersion as the outer coating controlled layer. The influences of the coating materials of the swelling layer, the coating levels of the swelling layer and controlled layer,and the pH values of the media on the release of 5-ISMN from PCRP were investigated. The drug release from the pellets was pulsatile. The ISMN-5-PCRP, with a lag time of 5 h and more than 80% released within the following 1.5 h,were prepared by using the low-substituted hydroxypropyl cellulose as the inner swelling layer with 15% (weight) in coating thickness, and the ethylcellulose aqueous dispersion as the outer controlling layer with 13% (weight) in coating thickness.
Capsules ; Cellulose ; analogs & derivatives ; chemistry ; Delayed-Action Preparations ; chemical synthesis ; Drug Carriers ; chemistry ; Hypromellose Derivatives ; Isosorbide Dinitrate ; administration & dosage ; analogs & derivatives ; chemistry ; Methylcellulose ; analogs & derivatives ; chemistry

Membrane separation, as an efficient and green technology, has found more and more research and development reports in the separation and purification of the effective parts and components of traditional Chinese medicine. The basic principle and mechanism was first described in this paper, and the applicability and technological advantage was analyzed accordingly. Then, the separation performance of commonly employed membrane materials including polymeric materials such as polysulfones, cellulose acetate, polyacrylonitrile as well as inorganic materials was compared out and the application examples were presented. Finally, the major considerations in choosing the membrane materials were tentatively listed, including the physical and chemical stability, the flux and selectivity, membrane fouling, and pretreatment of membrane surface.
Acrylic Resins ; Cellulose ; analogs & derivatives ; Drugs, Chinese Herbal ; isolation & purification ; Membranes, Artificial ; Polymers ; Technology, Pharmaceutical ; instrumentation ; methods

Curcumin-ethyl-cellulose (EC) sustained-release composite particles were prepared by using supercritical CO2 anti-solvent technology. With drug loading and yield of inclusion complex as evaluation indexes, on the basis of single factor tests, orthogonal experimental design was used to optimize the preparation process of curcumin-EC sustained-release composite particles. The experiments such as drug loading, yield, particle size distribution, electron microscope analysis (SEM) , infrared spectrum (IR), differential scanning calorimetry (DSC) and in vitro dissolution were used to analyze the optimal process combination. The orthogonal experimental optimization process conditions were set as follows: crystallization temperature 45 degrees C, crystallization pressure 10 MPa, curcumin concentration 8 g x L(-1), solvent flow rate 0.9 mL x min(-1), and CO2 velocity 4 L x min(-1). Under the optimal conditions, the average drug loading and yield of curcumin-EC sustained-release composite particles were 33.01% and 83.97%, and the average particle size of the particles was 20.632 μm. IR and DSC analysis showed that curcumin might complex with EC. The experiments of in vitro dissolution showed that curcumin-EC composite particles had good sustained-release effect. Curcumin-EC sustained-release composite particles can be prepared by supercritical CO2 anti-solvent technology.
Carbon Dioxide ; chemistry ; Cellulose ; administration & dosage ; analogs & derivatives ; chemistry ; Curcumin ; administration & dosage ; chemistry ; Delayed-Action Preparations ; Solubility ; Solvents ; Technology, Pharmaceutical

The effect of hemodialysis on the mechanical behavior of a cellulosic Hemophane ME-IOH and one Polysulfone type hollow fibers was investigated. Mechanical tests showed that the deformation of polysulfone type of hollow fibers is entirely different than that of the other dialyser for the samples used and unused in hemodialysis. All the samples exposed to the dialysis showed decreased in ductility. Fracture surface studies proved that there was some alignment on the fracture surface. XRD and DSC experiments revealed structural changes had occurred.
*Biocompatible Materials ; Biomechanics ; *Cellulose/*analogs & derivatives ; Materials Testing ; *Membranes, Artificial ; Microscopy, Electron, Scanning ; *Polymers ; Renal Dialysis/*instrumentation ; *Sulfones ; Surface Properties

AIMTo prepare dilitazem hydrochloride delayed-onset, sustained release tablet, which can not only provide the delay in release start, but also the constant release rate after a lag time. To analyze release mechanism and investigate the effect of outershell compositions on release behavior.

METHODSThe delayed-onset, sustained release tablets were prepared by dry-compression coated technology. The release profiles of uncoated cores and presscoated tablets were compared. Two parameters, time-lag (Tlag) and release rate (k), were used to evaluate the influence of factors, such as the amount of hydroxypropylmethylcellulose (HPMC) and poly-vinyl-pyrrolidinone (PVP) K30, the viscosity of ethylcellulose (EC) and HPMC, and the compression load on diltazam hydrochloride (DIL) release. Higuchi equation and Peppa's equation were used to analyze release mechanism.

RESULTSWith the increase of HPMC amount or HPMC viscosity, Tlag was prolonged and k was decreased; With the increase of PVP K30 amount, Tlag was shortened and k was increased; EC viscosity and compression load above certain degree showed no effect on DIL release.

CONCLUSIONThe drug release from delayed-release tablet is controlled by erosion mechanism, Tlag is determined by the erosion rate of outer-shell.

Cellulose ; chemistry ; Delayed-Action Preparations ; Diltiazem ; administration & dosage ; Lactose ; analogs & derivatives ; chemistry ; Methylcellulose ; analogs & derivatives ; chemistry ; Oxazines ; Polyvinyls ; chemistry ; Pyrrolidinones ; chemistry ; Tablets ; administration & dosage ; chemistry ; Technology, Pharmaceutical ; Viscosity

In this work a system which consists of chitosan (CS) microcores entrapped within enteric polymer is presented. Vitamin D2, used as a model drug, was efficiently entrapped within CS microcores using spray-drying and then microencapsulated into ethylic cellulose(EC). The morphology and release properties of microcapsules were tested. The influential factors of preparation conditions included molecular weight of chitosan, concentration of chitosan solution, concentration of acetic acid, loading of vitamin D2 were discussed. The results of in vitro release studies showed that the microcapsules prepared in this article could realize sustained release in intestine.
Capsules ; Cellulose ; analogs & derivatives ; pharmacology ; Chitin ; analogs & derivatives ; pharmacology ; Chitosan ; Delayed-Action Preparations ; Drug Compounding ; Drug Delivery Systems ; Ergocalciferols ; pharmacology ; In Vitro Techniques

Adsorption ; Adult ; Aged ; Bilirubin ; blood ; isolation & purification ; Cellulose ; analogs & derivatives ; chemistry ; Female ; Humans ; Jaundice, Obstructive ; therapy ; Male ; Membranes, Artificial ; Middle Aged ; Polyethyleneimine ; chemistry ; Serum Albumin ; analysis

OBJECTIVEElectrolytic detachable coils (EDC) have been the main embolic materials for intracranial aneurysms. Liquid aneurysmal embolic materials represented by cellulose acetate polymer (CAP) are still in controversy. In this research, the embolization results and pathological reactions after embolization of canine aneurysmal models with EDC or CAP were observed and compared.

METHODSThe canine aneurysmal models constructed by anastomosis of venous pouches were randomly grouped. The aneurysms were respectively occluded with CAP and electrolytic detachable coils that was named by Wu electrolytic detachable coil (WEDC) and made by us. Angiogram follow-ups were performed at 24-hour, 2-week, and 2-month after embolization. The occluded aneurysms were dissected in each stage for light microscopic, electron microscopic, and histochemical research.

RESULTSThe effect of embolization was significantly better with WEDC than that with CAP (chi2 = 5. 56, P < 0.05). Post-embolized complications such as aneurysm rupture and stenosis of parent arteries could only be found in CAP group. Pathological research showed that CAP mass could packed the aneurysms more densely than coils. Acute chemical damage of aneurysmal wall and inflammatory cell infiltration was prominently found in early stage after CAP-embolization. Organization of thrombus inside aneurysms and formation of endothelial tissue over the orifices of aneurysmal necks could be found in both groups 2 months after embolization. But parts of coils might be exposed outside endothelial layer.

CONCLUSIONSEDC are still the most safe, efficient, and reliable instruments to embolize aneurysm. CAP should be improved further to solve the problem of strong chemical corrosion and difficulty in control before it is widely used.

Animals ; Biocompatible Materials ; Cellulose ; analogs & derivatives ; Dogs ; Embolization, Therapeutic ; instrumentation ; methods ; Female ; Follow-Up Studies ; Intracranial Aneurysm ; therapy ; Male ; Random Allocation ; Tungsten

The aim of this work was to investigate guar gum/ethylcellulose mix coated pellets for potential colon-specific drug delivery. The coated pellets, containing 5-fluorouracil as a model drug, were prepared in a fluidized bed coater by spraying the aqueous/ethanol dispersion mixture of guar gum and ethylcellulose. The lag time of drug release and release rate were adjustable by changing the ratio of guar gum to ethylcellulose and coat weight gain. In order to find the optimal coating formulation that was able to achieve drug targeting to the colon, the effect of two independent variables (the ratio of guar gum to ethylcellulose and the coat weight gain) on drug release characteristics was studied using 3 x 4 factorial design and response surface methodology. Results indicated that drug release rate decreased as the proportion of ethylcellulose in the hybrid coat and the coat weight gain increased. When the ratio of guar gum to ethylcellulose was kept in the range of 0.2 to 0.7, and the coat weight gain in the range of 250% to 500%, the coated pellets can keep intact for about 5 h in upper gastrointestine and achieve colon-specific drug delivery. The pellets prepared under optimal conditions resulted in delayed-release sigmoidal patterns with T(5%) (time for 5% drug release) of 5.1 - 7.8 h and T(90%) (time for 90% drug release) of 9.8 - 16.3 h. Further more, drug release was accelerated and T(90%) of the optimum formulation pellets decreased to 9.0 - 14.5 h in pH 6.5 phosphate buffer with hydrolase. It is concluded that mixed coating of guar gum and ethylcellulose is able to provide protection of the drug load in the upper gastrointestinal tract, while allowing enzymatic breakdown of the hybrid coat to release the drug load in the colon.
Cellulose ; administration & dosage ; analogs & derivatives ; Colon ; metabolism ; Drug Delivery Systems ; Fluorouracil ; administration & dosage ; chemistry ; Galactans ; administration & dosage ; Mannans ; administration & dosage ; Plant Gums ; administration & dosage

AIMTo study sandwiched osmotic pump tablet for delivering water-insoluble drug for 24 hours.

METHODSSandwiched osmotic pump tablet was prepared using nifedipine as the model drug. The effects of various formulation variables and orifice size on drug release were studied. The mechanical properties of cellulose acetate membrane were also investigated.

RESULTSPolyethylene oxide of drug layer and potassium chloride of push layer showed marked positive effects on drug release. In the range of 0.50 mm to 1.40 mm, orifice size hardly affects drug release. Cellulose acetate membrane is strong enough to assure the integrity of osmotic pump tablet and could sustain an internal pressure ranging from 0.34 MPa to 2.85 MPa.

CONCLUSIONSandwiched osmotic pump tablet can deliver water-insoluble drug constantly for 24 hours. Release media and agitation rate scarcely affect drug release. Compared with the commercialized push-pull osmotic pump tablet, sandwiched osmotic pump tablet is easy in preparation with exempting identification of drug layer before drilling.

Cellulose ; analogs & derivatives ; chemistry ; Delayed-Action Preparations ; Drug Carriers ; Nifedipine ; administration & dosage ; Osmosis ; Polyethylene Glycols ; chemistry ; Potassium Chloride ; chemistry ; Solubility ; Tablets ; Technology, Pharmaceutical ; methods