Modifying the Release Properties of Eudragit® L30D

Abstract

The influence of various additives, namely, PEG, mannitol, and HPMCP 50 incorporated with Eudragit® L30D on drug release from pellets was investigated. Cores of a water soluble drug were prepared by the powder layering technique using the CF Granulator (CF 360) and coating was accomplished utilizing the Glatt GPCG3 machine. Drug release from pellets coated with Eudragit® L30D was found to be influenced by the type and the level of the additive incorporated with the copolymer. At pH 1.5, PEG, regardless of the molecular weight, did not have any significant effect on drug release. At pH 5.5, however, PEG significantly decreased drug release from coated pellets, and the decrease was more pronounced as the molecular weight of PEG was increased. Release of the drug from pellets coated with Eudragit® L30D containing mannitol was found to be dependent on mannitol concentration at pH 1.5, 3.5 and 4.5 but independent of mannitol concentration at pH 5.5. The release of drug through Eudragit® L30D:HPMCP 50 films was found to be dependent on the ratio of the polymers.     

Ketoprofen Spray-dried Microspheres Based on Eudragit® RS and RL: Study of the Manufacturing Parameters

The preparation of ketoprofen spray-dried microspheres can be affected by the long drug recrystallization time. Polymer type and drug–polymer ratio as well as manufacturing parameters affect the preparation. The purpose of this work was to evaluate the possibility to obtain ketoprofen spray-dried microspheres using the Eudragit® RS and RL; the influence of the spray-drying parameters on morphology, dimension, and physical stability of microspheres was studied. Ketoprofen microspheres based on Eudragit® blend can be prepared by spray-drying and the nebulization parameters do not influence significantly particle properties; nevertheless, they can be affected by drying and storage methods. No effect of the container material is found.     

Study of Iron-based Surface Composite Materials

new surface infiltrating composite technique has been developed to obtain metal and ceramic composite layer on the surface of metal by traditional casting method. It has been shown that with the new method, a composite layer with a thickness of 2-5 mm can be obtained. The ceramic particulates distribute uniformly in the matrix. The composite layer is very favorable to wear resistance and thermal resistance situations     

Physicochemical Characterization of Solid Dispersions of Indomethacin with PEG 6000, Myrj 52, Lactose,Sorbitol, Dextrin,and Eudragit® E100

The purpose of this study was to prepare and characterize solid dispersions of indomethacin with polyethylene glycol (PEG) 6000, Myrj 52, Eudragit® E100, and different carbohydrates such as lactose, mannitol, sorbitol, and dextrin. Indomethacin is a class II substance according to the Biopharmaceutics Classification System. It is a poorly water soluble antirheumatic agent. The goal was to investigate whether the solid dispersion can improve the dissolution properties of indomethacin. The solid dispersions were prepared by three different methods depending on the type of carrier. The evaluation of the properties of the dispersions was performed using solubility measurements, dissolution studies, Fourier‐transform infrared spectroscopy, and x‐ray powder diffractometery. The results indicate that lactose, mannitol, sorbitol, and especially Myrj 52 are suitable carriers to enhance the in vitro dissolution rate of indomethacin at pH 7.2. Eudragit E100, Myrj 52, and mannitol increase the dissolution properties at pH 1.2. The data from the x‐ray diffraction showed that the drug was still detectable in its solid state in all solid dispersions except solid dispersions with dextrin and high amounts of mannitol. However, the results from infrared spectroscopy together with those from x‐ray diffraction showed well‐defined drug–carrier interactions for dextrin coevaporates.     

Controlled release formulation of ranitidine-containing montmorillonite and Eudragit® E-100

Aim: The objective of this work was to illustrate the suitability of montmorillonite (MMT) as a drug delivery carrier, by developing a new clay–drug composite of ranitidine hydrochloride (RT) intercalated in MMT. Methods: The MMT–RT composite was prepared by ion-exchange process. X-ray diffraction and Fourier transform infrared spectra were employed to confirm the intercalation of RT in the MMT interlayers. The prepared MMT–RT hybrid was coated with cationic polymer Eudragit® E-100 by oil-in-water solvent evaporation method. The release processes of RT from MMT–RT and MMT–RT/Eudragit® E-100 were monitored under in vitro condition in the gastric fluid. Results: X-ray diffraction and Fourier transform infrared spectra analysis indicated the intercalation of RT molecules within the clay lattice. The in vitro release studies showed that MMT–RT released RT in a controlled manner. In the case of MMT–RT/Eudragit® E-100, both the release rate and the release percentages noticeably increased in the presence of Eudragit® E-100, because of its effective exchange with intercalated RT molecules. The release kinetics followed parabolic diffusion mechanism. Conclusion: MMT has great potential as a drug delivery carrier with various scenarios. The dosage of the MMT–RT/Eudragit® E-100 can be in the tablet form. The hybrid material and polymer-coated hybrids are microparticles.     

STM Study on the Surface Relief and Mechanism of Bainite Transformation

Scanning tunneling microscopy (STM ) has been first employed to study the surface relief accompanying bainite transformation in a Fe-2.17C-12.18Cr-0.31Si-0.26Mn (wt pct) steel. With the exclusive vertical resolution of STM, we observed that the surface relief associated with bainite is a group of surface reliefs related to subplates, subunits and sub-subunits. As a whole, the relief group is in a tent shape, not of invariant plane strain (IPS) type, which is obviously different from that of martensite, and implying that bainite is not formed by shear mechanism. The fine structure of bainite in Fe-1.0C-4Cr-2.0Si (wt pct) alloy has also been studied with STM and TEM. It is found that the bainite plate is composed of subplates, subunits and sub-subunits. On the basis of the fine structure inside a bainitic ferrite plate observed under STM, a sympathetic-ledgewise mechanism of bainite formation is proposed     

Preparation and Evaluation of Eudragit® Acrylic Resin for Controlled Drug Release of Pseudoephedrine Hydrochloride

Abstract

The preparation of a sustained release dosage form for pseudoephedrine hydrochloride was evaluated. Beadlets (PS) containing pseudoephedrine hydrochloride were prepared by spraying a slurry of pseudoephedrine hydrochloride, Eudragit® S-100, dibutyl sebacate and alcohol onto non-pariel seeds via the Wurster column process. The oven-dried PS beadlets were coated with different levels of Eudragit® RS (poorly water permeable) and Eudragit® S-100 (enteric resin). In-vitro dissolution     

Phenomenological Anisotropic Study of Surface Finish in Pack Rolling

A phenomenological anisotropic model has been presented for the surface roughness modeling of pack rolling. The model is an assembly of grains in different orientations and sizes. The grain size is assumed to be in log-normal distribution. To model the macro anisotropic mechanical behavior of the grains induced by the slip deformation, the grains are assumed as isolated anisotropic units. The units have different mechanic behavior, and depend on the crystallographic orientations and the external loading as well as the interaction of the adjunctive grains. In the paper, the material properties of the grains are assumed as uniform distributions. The roughness of the contact surfaces depends on the distribution types and the scatters of the distributions. It is found that the initial roughness of the contact surfaces has a little influence on the surface roughness when the rolling deformation is large. The comparison between the phenomenological model and crystallographic model shows that the phenomenological model can also give out a reasonable result, while it only takes much less CPU time. The agreement between the single sheet model and the pack rolling model shows that in a certain degree the pack rolling model can be replaced by the single sheet model to decrease the CPU time.     

Effect of Ageing on Progesterone-Polyoxyethylene Glycol 6000 Dispersions. X – Ray Study

Abstract

Progesterone solid dispersions in polyoxyéthylene glycol 6000 were prepared by fusion method in order to improve the progesterone wettability and solubility in aqueous body fluids. Its crystalline state after fusion was determined by radiocrystallography on the pure drug and on the solidified melts. It has been established that a slow cooling speed of the melt induced the stable polymorph emergence in the solidified melt (α form). Moreover, X-ray diffraction patterns investigation showed a good physical stability of the preparations after one year storage at room temperature.     

Investigation of the physical–mechanical properties of Eudragit® RS PO/RL PO and their mixtures with common pharmaceutical excipients

Ammonio methacrylate copolymers Eudragit^® RS PO and Eudragit® RL PO have found widespread use as key components in various types of extended release solid dosage forms. The deformation behavior of neat polymers and binary mixes was evaluated using Heckel Analysis, strain rate sensitivity, work of compaction and elastic recovery index. Additionally, the compact forming ability of neat materials and binary mixes were evaluated by analyzing their tabletability, compressibility and compactibility profiles. The Heckel analysis of both polymers exhibited a speed-sensitive deformation behavior typical to plastic materials. The yield values of the binary mixes of the polymers with microcrystalline cellulose revealed a linear relationship with the weight fractions of individual components. The yield values of binary mixes of both the polymers with dibasic calcium phosphate exhibited slight negative deviations from linearity. Both polymers exhibited axial relaxation after ejection typical of viscoelastic materials, as measured by the elastic recovery index values. The work of compaction and the elastic recovery index values of the binary mixtures were found to be linearly related to the weight fractions of the individual components thus, confirming ideal mixing behavior based on the composition. Addition of microcrystalline cellulose to both polymers significantly improved their tabletability and compactibility. The tensile strengths of the compacts prepared with neat materials and binary mixes with microcrystalline cellulose, dibasic calcium phosphate and lactose were the function of their solid fraction and independent of the tableting speeds tested; thus, validating compactibility as a reliable parameter in predicting acceptable tablet properties.     

A Study of the Ni-Cr-Zr System at 900°C

The phase equilibrium relations of the ternary Ni-Cr-Zr system at 900℃have been investigated by means of diffusion triple and electron probe microanalysis(EMPA) techniques.A series of tie lines and triangles have been determined, and the corresponding tentative isothermal section is presented based on the current information.     

A Study on the Reliability of a Large Vibration Machine

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Surface Tension Maximum of Liquid 3He—Experimental Study

The surface tension of liquid ³He was measured as a function of temperature by means of the capillary rise method. Suzuki et al. [Europhysics Lett. 5, 333 (1988)] reported that the surface tension was almost temperature independent below 120 mK. Here we have examined it with greater precision and found that it has a small maximum around 100 mK. The surface tension increased with temperature from 35 mK and had a maximum of about 3×10^–4 as a fraction of the surface tension at 0 K. It was found that the surface tension maximum can be attributed mainly to the T⁴ ln T variation which has been theoretically derived by Misawa on the basis of a local approximation for the entropy including Fermi liquid effect.     

Preparation and Characterization of Solid Dispersions of Dipyridamole with a Carrier “Copolyvidonum Plasdone®S-630”

Solid dispersions (SDs) of dipyridamole (DIP) with a novel carrier copolyvidonum Plasdone®S-630 (CoPVP) were developed by solvent evaporation method. The solid state of SDs of DIP with CoPVP (SDs CoPVP) was characterized by fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and polarizing microscopy, compared with that of SDs of DIP with polyvinylpyrrolidone Plasdone®K-29/32 (SDs PVP). FT-IR analysis demonstrated the presence of intermolecular hydrogen bonding between DIP and CoPVP or PVP in SDs. DSC and XRD studies indicated that DIP presented in amorphous state in both SDs CoPVP and SDs PVP at higher weight ratios. The dissolution property of SDs CoPVP was significantly improved in comparison of pure DIP and physical mixtures with CoPVP (PM CoPVP). Both SDs CoPVP and SDs PVP powder showed the favorable flowability. However, SDs CoPVP showed better compressibility than SDs PVP. The lower hydroscopicity of SDs CoPVP could be advantageous to the stability to SDs. This study proves the potential of CoPVP as a carrier in the formulations of SDs for poorly soluble drugs.     

Study on antibacterial effect of 45S5 Bioglass®

Previous studies have shown that bioactive glasses possessed antibacterial effect on common bacteria due to the high aqueous pH value caused by the bioactive glass dissolution. In the present study, the efficiency of the antibacterial effect of 45S5 Bioglass (45S5 BAG) against S. aureus, S. epidermidis and E. coli and its mechanism were investigated. The results showed that 45S5 BAG exhibited a strong antibacterial effect against the bacteria, and the sensitivity of gram-negative and gram-positive bacteria to Bioglass was different. Furthermore, a dose-dependent bacterial adhesion on 45S5 BAG particles and the formation of needle-like Bioglass debris were observed, which resulted in the damage of cell walls and inactivation of bacteria. The results suggested that both the high pH and bioglass debris on the surface of bacteria may be the possible mechanisms of the antibacterial effect of 45S5 BAG particulates.     

A Horizontality Adjusting Study of the Earth Drill＇s Platform

A horizontality adjusting system of the earth drill‘s platform is designed to deal with the operation difftculty of the platform which appeared while the earth drill is used. The proportional-impulse control to eliminate the over-adjustment and electricity-hydraulic-proportional control to drive the adjusting mechanism are adopted in the system. The control scheme and control algorithm are introduced in detail. The software flow chart is given.     

A Study on the Density of Agglomerates Prepared from Cork Waste

The density of black regranulate (BR) of cork and of black agglomerate (BA) and composite agglomerate(CA) prepared from such a waste by different methods was investigated.The preparation of the agglomerates was undertaken by controlling the specimen thickness for BA and the particle size for BR and the binder dosage for CA,The mass changes produced in the oven-drying treatment at 376.15 K of the agglomerates and in their subsequent stabilization under amibient conditions were also analyzed ,The density was determined by standard methods,For BR,the bulk density first decreased and then increased with decreasing particle size,It was much lower than the apparent density of the agglomeration products of cork ,Although to case of CA ,the density followed the same variation trends as for BR,Furthermore it increased significantly with the increase in resin dosage,This resulted in a noticaeable increase in the weight loss during the oven-drying and in a significant decrease in the degree of moisture adsorption during the stabilization period of the agglomerate.