The effect of moisture on the physical characteristics of ranitidine hydrochloride tablets prepared by different binders and techniques

The effect of moisture on the physical properties of ranitidine hydrochloride tablets prepared by direct-compression and by wet-granulation method using PVP or EC as binders was studied. Tablets adsorped moisture at 50 and 75 % RH (relative humidity) but lost moisture at 30% RH. Except storage at 75% RH, however, tablet volumes did not change significantly during the test period. Moisture sorption caused a decrease in strength of tablets except low humidity (30% RH). Also, the disintegration time of tablets showed a decrease at all conditions except 30% RH. Furthermore, generally dissolution profiles of tablets prepared by direct-compression and by ethyl cellulose remained unchanged. Changes in the binder type in the tablet formulations changed the water uptake properties and also the physical properties of tablets. Directly-compressed tablets were much susceptible to change caused by humidity than tablets prepared by wet-granulation.     

The influence of drug-excipient and drug-polymer interactions on butt adhesive strength of ranitidine hydrochloride film-coated tablets

The influence of fillers and polymeric films on adhesive strength of hydroxypropyl methylcellulose (HPMC) and Eudragit E100® films coated on ranitidine HCl tablets containing either spray-dried rice starch (SDRS) or lactose monohydrate as fillers after storage at 45°C/75% RH for four weeks was investigated by the use of butt adhesion technique. The adhesive strength of film-coated tablets of fillers without drug was found to slightly decrease after storage. In contrast, the adhesive strength of drug-containing film-coated tablets significantly reduced, the degree of which was higher for Eudragit E100® than HPMC. Physicochemical characterization by employing differential scanning calorimetry (DSC) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) revealed that the drug was obviously incompatible with lactose and possibly mild interaction with Eudragit E100® was suggested. The results indicated that the adhesive strength of film-coated tablets would be affected not only by the drug-excipient interaction, but also by the drug-polymeric film interaction.     

The effect of moisture on the physical and mechanical integrity of epoxies

The effect of specific combinations of moisture, heat, and stress on the physical structure, failure modes, and tensile mechanical properties of diaminodiphenyl sulphone (DDS)-cured tetraglycidyl 4,4diaminodiphenyl methane (TGDDM) epoxies [TGDDM-DDS (27 wt% DDS)] are reported. Sorbed moisture plasticizes TGDDM-DDS epoxies and deteriorates their mechanical properties in the range 23 to 150° C. Studies of the initiation cavity and mirror regions of the fracture topographies of these epoxies indicate that sorbed moisture enhances the craze initiation and propagation processes. The effect of tensile stress-level, applied for 1 h on dry epoxies, on the subsequent moisture sorption characteristics of the epoxies was also investigated. Such studies indicate that the initial stages of failure that involve both dilatational craze propagation and subsequent crack propagation enhance the accessibility of moisture to sorption sites within the epoxy to a greater extent than in the latter stages of failure which involve crack propagation alone. The amount of moisture sorbed by TGDDM-DDS epoxies is enhanced by 1.6 wt% after exposure to a 150° C thermal spike, as a result of moisture-induced free volume increases in the epoxies that involve rotational—isomeric population changes.Research sponsored in part by the McDonnell Douglas Independent Research and Development Program and in part by the Air Force Office of Scientific Research/AFSC, United States Air Force, under Contract No. F44620-76-C-0075. The United States Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation hereon.     

Effect of moisture content,temperature and exposure time on the physical stability of chitosan powder and tablets

Context: Chitosan does not rank highly regarding its employment as tablet filler due to certain limitations. Undesirable properties that limit its utilization as excipient in solid dosage forms include its hydration propensity that negatively affects tablet stability, strength and disintegration.

Objective: The objective of this study was to investigate the physical stability of chitosan powder, mixtures, granules and tablets under accelerated conditions such as elevated temperatures and humidity over different periods of time.

Methods: Selected physico-chemical properties of pure chitosan powder, physical mixtures of chitosan with Kollidon® VA64 (BASF, Ludwigshafen, Germany), chitosan granules, as well as tablets were evaluated under conditions of elevated humidity and temperature.

Results and discussion: The physical stability of chitosan tablets exhibited sensitivity towards varying exposure conditions. It was furthermore evident that the presence of moisture (sorbed water) had a marked influence on the physical stability of chitosan powder and tablets. It was evident that the presence of Kollidon® VA64 as well as the method of inclusion of this binder influenced the properties of chitosan tablets. The physical stability of chitosan powder deteriorated to a greater extent compared to that of the chitosan tablets, which were subjected to the same conditions.

Conclusion: It is recommended that tablets containing chitosan should be stored at a temperature not exceeding 25?°C as well as at a relatively low humidity (<60%) to prevent deterioration of physical properties. Direct compression of chitosan granules which contained 5%w/w Kollidon® VA64 produced the best formulation in terms of physical stability at the different conditions.     

Mechanical properties of amorphous alloy compacts prepared by different consolidation techniques

Amorphous alloy compacts of Fe₇₈B₁₃Si₉ prepared by three different techniques (explosive consolidation, high hydrostatic pressure consolidation and warm extrusion) were deformed in compression between 573 and 723 K at a strain rate ranging from 8.3×10^–5–4.2×10^–4s^–1. Explosively consolidated compacts had high strength ranging from 1.9–2.5 GPa below 623 K and could be plastically deformed to a strain of more than 50% at 673 K while preserving the amorphous state. Amorphous alloy compacts prepared by high hydrostatic pressure consolidation showed lower compressive strength. Those produced by warm extrusion were anisotropic in strength, the highest strength being as high as 2.74 GPa. It was also found that the geometry of the starting powders had a profound effect on the strength of the product compacts. Compacts prepared from flaky powders were stronger than those prepared from spherical ones. It is concluded that the mechanical properties of the amorphous alloy compacts depend on the consolidation technique, powder geometry and surface conditions of the powders, especially existence of oxide films.     

取向对PLD法制备BiFeO3薄膜性能的影响

以快速等离子烧结法(SPS)制备的BiFeO3块体为靶材,用激光脉冲沉积(PLD)法在不同衬底上制备了BiFeO3(100)/LaNiO3(100)/Si(100)、BiFeO3(111)/LaNiO3(111)/SrTiO3(111)、BiFeO3(110)/Pt/TiO2/SiO2/Si、BiFeO3(110)LaNiO3(110)/Pt/TiO2/SiO2/Si不同择优取向的薄膜,并对薄膜进行了XRD和SEM分析。X射线衍射结果表明,BiFeO3薄膜外延沉积在导电层衬底上,并且它们具有相同的高度取向。SEM分析表明,薄膜上的晶粒是柱状形态,表面光滑致密且颗粒分布非常均匀,晶粒的边界和尺寸也能被清晰地观察到。通过铁电铁磁性能研究,BiFeO3(111)择优取向性能最佳。SrTiO3衬底上(111)取向的BiFeO3薄膜铁电剩余极化值达到了30.3μC/cm2,漏电流为1.0×10-3 A/cm2,饱和磁化强度为20.0kA/m。     

The effect of pH,buffer capacity and ionic strength on quetiapine fumarate release from matrix tablets prepared using two different polymeric blends

The objective of this study was to investigate the effect of the different physiological parameters of the gastrointestinal (GI) fluid (pH, buffer capacity, and ionic strength) on the in vitro release of the weakly basic BCS class II drug quetiapine fumarate (QF) from two once-a-day matrix tablet formulations (F1 and F2) developed as potential generic equivalents to Seroquel^® XR. F1 tablets were prepared using blends of high and low viscosity grades of hydroxypropyl methylcellulose (HPMC K4M and K100LV, respectively), while F2 tablets were prepared from HPMC K4M and PEGylated glyceryl behenate (Compritol^® HD5 ATO). The two formulations attained release profiles of QF over 24?h similar to that of Seroquel^® XR using the dissolution medium published by the Food and Drug Administration (FDA). A series of solubility and in vitro dissolution studies was then carried out using media that simulate the gastric and intestinal fluids and cover the physiological pH, buffer capacity and ionic strength range of the GIT. Solubility studies revealed that QF exhibits a typical weak base pH-dependent solubility profile and that the solubility of QF increases with increasing the buffer capacity and ionic strength of the media. The release profiles of QF from F1, F2 and Seroquel^® XR tablets were found to be influenced by the pH, buffer capacity and ionic strength of the dissolution media to varying degrees. Results highlight the importance of studying the physiological variables along the GIT in designing controlled release formulations for more predictive in vitro–in vivo correlations.     

Differences in characteristics of pellets prepared by different pelletization methods

Pellets are currently a very popular dosage form for oral application. They can be prepared by several pelletization techniques. Extrusion/spheronization, commonly used in the pharmaceutical industry, and modern agglomeration in a rotoprocessor were the methods chosen for pellet preparation in our study. Theophylline (in 10% to 65% concentration) was the model drug, lactose monohydrate was used as filler, microcrystalline cellulose Avicel® PH 101 was thespheronization enhancer, and the wetting agent was purified water. Both techniques led to the formation of pellets of appropriate shape and mechanical properties. Pellets of a higher density, hardness, lower friability, and slightly slower dissolution profiles were obtained by extrusion/spheronization. This method of pelletization also led to production of particles with narrower size distribution and bigger yield of pellets with the requested size.     

The effect of Sn concentration on some physical properties of zinc oxide films prepared by ultrasonic spray pyrolysis

The effect of Sn concentration on zinc oxide (ZnO) film properties has been investigated by depositing films with various Sn concentrations in the solution (Sn/Sn + Zn ratio from 0 to 50 at%) at a substrate temperature of 350°C by ultrasonic spray pyrolysis (USP) technique. The deposited films were characterized for their electrical, structural, morphological and elemental properties using current-voltage and conductivity-temperature measurements, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. Electrical investigations showed that the resistivity of ZnO films decreases for lower Sn concentration (at 10%) and then increases for higher Sn concentration (at 30–50%). Also, depending on the increasing Sn concentration, energies of donor-like traps for ZnO films decreased and activation energy of donors for ZnO films increased. The XRD patterns showed that the as-deposited films have polycrystalline structure and the crystalline nature of the films was deteriorated with increasing Sn concentration and a shift to amorphous structure was seen. The effect of Sn concentration was to increase the surface roughening and change considerably the morphologies of ZnO films. The most homogenous surface was seen in ZnO films. EDS results showed that all elements in the starting solutions were in the solid films and Zn element is more dominant than Sn on the surfaces. After all investigations, it was determined that Sn incorporation dramatically modifies the properties of ZnO films. ZnO and ZnO:Sn (10 at%) films have a low resistivity and high transparency in the visible range and may be used as window material and antireflecting coating in solar cells while the other films may be used in gas sensors where high conductivity is unnecessary.     

Mechanical characteristics of optical coatings prepared by various techniques: a comparative study

Good performance of optical coatings depends on the appropriate combination of optical and mechanical properties. Therefore, successful applications require good understanding of the relationship between optical microstructural and mechanical characteristics and film stability. In addition, there is a lack of standard mechanical tests that allow one to compare film properties measured in different laboratories. We give an overview of the methodology of mechanical measurements suitable for optical coatings; this includes depth-sensing indentation, scratch resistance, friction, abrasion and wear testing, and stress and adhesion evaluation. We used the techniques mentioned above in the same laboratory to systematically compare the mechanical behavior of frequently used high- and low-index materials, namely, TiO2, Ta2O5, and SiO2, prepared by different complementary techniques. They include ion-beam-assisted deposition by electron-beam evaporation, magnetron sputtering, dual-ion-beam sputtering, plasma-enhanced chemical-vapor deposition, and filtered cathodic arc deposition. The mechanical properties are correlated with the film microstructure that is inherently related to energetic conditions during film growth.     

Effect of different binders and secondary carbides on NbC cermets

Due to the rapidly increasing price of tungsten carbide and the significant health risks associated with the wear products of WC-Co (Co₃O₄ and Wo₃), an alternative is required. Niobium carbide (NbC) is well suited as a cutting tool due to its high melting point and low solubility in iron. Compared to pure NbC, a complete substitution of WC to NbC-Co resulted in an increased toughness and strength. As alternative binders, nickel and iron-based binders were subsequently investigated. Although iron-based cermets would be an economical, low-cost alternative to NbC-Ni cermets, they showed a higher coefficient of friction and wear rate. So far, NbC-Ni cermets best met the requirements of high hardness and toughness. Various secondary carbides such as VC, Mo₂C, TiC, but also WC were added to further improve the hardness. Elemental analyses of NbC-Ni-MeC cermets (Me = metal) showed that the binder is a face-centered cubic solid solution, while the NbC phase is a solid solution of the type (Nb, Me)C.

     

Effect of formulation composition on the properties of controlled release tablets prepared by roller compaction

This study discusses the effect of formulation composition on the physical characteristics and drug release behavior of controlled-release formulations made by roller compaction. The authors used mixture experimental design to study the effect of formulation components using diclofenac sodium as the model drug substance and varying relative amounts of microcrystalline cellulose (Avicel), hydroxypropyl methylcellulose (HPMC), and glyceryl behenate (Compritol). Dissolution studies revealed very little variability in drug release. The t₇₀ values for the 13 formulations were found to vary between 260 and 550 min. A reduced cubic model was found to best fit the t₇₀ data and gave an adjusted r-square of 0.9406. Each of the linear terms, the interaction terms between Compritol and Avicel and between all three of the tested factors were found to be significant. The longest release times were observed for formulations having higher concentrations of HPMC or Compritol. Tablets with higher concentrations of Avicel showed reduced ability to retard the release of the drug from the tablet matrix. Crushing strength showed systematic dependence on the formulation factors and could be modeled using a reduced quadratic model. The crushing strength values were highest at high concentrations of Avicel, while tablets with a high level of Compritol showed the lowest values. A predicted optimum formulation was derived by a numerical, multiresponse optimization technique. The validity of the model for predicting physical attributes of the product was also verified by experiment. The observed responses from the calculated optimum formulation were in very close agreement with values predicted by the model. The utility of a mixture experimental design for selecting formulation components of a roller compacted product was demonstrated. These simple statistical tools can allow a formulator to rationally select levels of various components in a formulation, improve the quality of products, and develop more robust processes.     

Fast-disintegrating sublingual epinephrine tablets: effect of tablet dimensions on tablet characteristics

The purpose of this study was to evaluate the effect of changing dimensions on the hardness (H), disintegration time (DT), and wetting time (WT) of fast-disintegrating epinephrine tablets for sublingual administration as potential first aid treatment for anaphylaxis. Tablet formulations I and II, containing 0% and 10% epinephrine bitartrate, respectively, and weighing 150 mg were prepared by direct compression. Formulations were compressed at a range of forces using an 8/32' die with concave punches (CP); a 10/32' and an 11/32' die with CP and flat punches (FP). Tablet weight variation, content uniformity, thickness, H, DT, and WT were measured. The 8/32', 10/32', and 11/32' dies resulted in tablet thickness of ranges 0.25-0.19', 0.17-0.1', and 0.16-0.08', respectively. The DT and WT using the 8/32' die were相似文献   

Formulation, in-vitro release and therapeutic effect of hydrogels based controlled release tablets of propranolol hydrochloride

Matrix based controlled release tablets of Propranolol Hydrochloride (PHCL) were formulated using hydroxy propyl methyl cellulose (HPMC), sodium carboxy methyl cellulose (sod. CMC) and their combinations. The in-vitro dissolution kinetics revealed a zero order release for selected drug, HPMC and sod. CMC combination. The selected formulation was evaluated in mongrel dog by recording the isoprenaline induced tachycardia and measuring the inhibition of tachycardia. The results showed the sustaining therapeutic effect of the formulation.     

The effect of surfactant on the structure and properties of ZnO films prepared by electrodeposition

The effect of surfactant on the formation, structure and properties of ZnO films synthesized by electrodeposition was studied in this work. It was carried out in an aqueous Zn(NO₃)₂ solution containing surfactant op-10 using cathodic galvanostatic method. The results showed that the additive surfactant effectively inhibited hydrogen evolution reaction on cathode surface, maintained stability of the solution pH and improved deposition rate of the films to two times. Grown ZnO films with uniform grain and smooth surface were observed by using atomic force microscopy. Optical characterizations indicated that average optical transmittance of such films was more than 80% in the visible wavelength range, and its optical band gap was near 3.21 eV.     

Formulation,in-vitro release and therapeutic effect of hydrogels based controlled release tablets of propranolol hydrochloride

Abstract

Matrix based controlled release tablets of Propranolol Hydrochloride (PHCL) were formulated using hydroxy propyl methyl cellulose (HPMC), sodium carboxy methyl cellulose (sod. CMC) and their combinations. The in-vitro dissolution kinetics revealed a zero order release for selected drug, HPMC and sod. CMC combination. The selected formulation was evaluated in mongrel dog by recording the isoprenaline induced tachycardia and measuring the inhibition of tachycardia. The results showed the sustaining therapeutic effect of the formulation.     

物理气相沉积薄膜应力产生机理的理论分析

在一维线性谐振子模型基础上,应用薛定谔方程分析了晶体中原子的概率分布;将晶体中原子的概率分布定义为原子云,解释了物理气相沉积法制备薄膜时残余应力产生的原因,建立了薄膜残余应力产生机理的理论模型.     

Latent structure analysis in the pharmaceutical process of tablets prepared by wet granulation

Background: Granule characteristics are some of the important intermediate qualities that determine tablet properties. However, the relationships between granule and tablet characteristics are poorly understood. The aim of this study was to elucidate relationships among formulation factors, granule characteristics, and tablet properties using a non-linear response surface method (RSM) incorporating a thin-plate spline interpolation (RSM-S) and a Bayesian network (BN).

Method: Tablets containing lactose (Lac), cornstarch (CS), and microcrystalline cellulose (MCC) were prepared by wet granulation. Ten formulations were prepared by an extreme vertices design. The angle of repose (Y₁), compressibility (Y₂), cohesion force (Y₃), internal friction angle (Y₄), and mean particle size (Y₅) were measured as granule characteristics. Tensile strength (TS) and disintegration time (DT) were measured as tablet properties.

Results: RSM-S results showed that TS increased with increasing amounts of MCC and Lac. DT decreased with increasing amounts of MCC and CS. The optimal BN models were predicted using four evaluation indices –Y₃ was shown to be the most important factor for TS, whereas Y₂, Y₃, and Y₄ were relatively important for predicting DT. Moreover, tablets with excellent tablet properties (i.e. high TS and low DT) were produced by relatively high Y₁, low Y₂, high Y₃, high Y₄, and middle Y₅ values, and resulted from the middle of MCC, middle-to-low CS, low Lac, and middle-to-low magnesium stearate (Mg-St) amounts.

Conclusion: The RSM-S and BN techniques are useful for revealing complex relationships among formulation factors, granule characteristics, and tablet properties.