Changes in Structural and Rheological Properties of Guar Gum Particles in Fluidized-Bed Agglomeration: Effect of Sucrose Binder Concentration

Fluidized-bed agglomeration (FBA) is known to modify the structure and rheology of food powders. In this study, guar gum (GG) powders with various concentrations of sucrose binder (0%, 10%, 20%, or 30%) were subjected to fluidized-bed agglomeration. Subsequently, changes in the characteristics of the GG powders were evaluated by using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), particle size distribution (PSD) analysis, and rheological and dispersibility measurements. SEM images and FTIR spectra revealed surface morphology changes and structural modification, respectively, in the original GG powder after FBA, although the changes observed in FTIR spectra were only slightly dependent on sucrose concentration at low concentrations (0–20%). XRD patterns confirmed that the crystallinity of the GG powder was affected by FBA, but not greatly so by binder concentration. The PSD results showed that the GG particle size was increased by FBA and there was a clear relationship between sucrose concentration (10–30%) and mean particle size. The rheological behavior and dispersibility of GG (properties that are known to be affected by the structure of a powder) were also influenced by sucrose concentration. To sum up, FBA and the concentration of sucrose binder used can serve as factors for modifying GG powder.

Prediction of quality attributes (mechanical strength, disintegration behavior and drug release) of tablets on the basis of characteristics of granules prepared by high shear wet granulation

High shear wet granulation is commonly applied technique for commercial manufacturing of tablets. Granulation process for tablets manufacturing is generally optimized by hit and trial which involves preparation of granules under different processing parameters, compression of granules and evaluation of the resultant tablets; and adjustment is made in granulation process on the basis of characteristics of tablets. Objective of the study was to optimize the process of high shear wet granulation and prediction of characteristics of tablets on the basis of properties of granules. Atenolol granules were prepared by high shear wet granulation method, using aqueous solution of polyvinyl pyrrolidone (PVP k-30) as binder. Concentration of binder solution and granulation time were taken as process variables, both studied at three levels. Different combinations of process variables were determined by Design Expert software. Granules were evaluated for different parameters on the basis of SeDeM-ODT (Sediment Delivery Model-Oro Dispersible Tablets) expert system. Granules from all the trials were compressed using round (10.5 mm) flat faced punches at compression weight of 250 mg/tablet. Tablets were evaluated of different quality control parameters as per USP. Results showed that both the process variables had positive effect on mechanical strength of tablets and negative effect on disintegration and dissolution rate. Granule prepared with highest level of binder concentration (15%) and highest granulation time (60 sec) resulted in tablets with highest crushing strength (11.8 kg), specific crushing strength (0.328 kg/mm2), tensile strength (0.208 kg/mm2), lowest value of friability (0.19%) and highest disintegration time (10.9 min), as predicted from granules characteristics on the basis of SeDeM-ODT expert system. Drug release from Trial-13 (processed under highest level of both process parameters) was also lower than rest of the trials. It is concluded from the study that quality characteristics of tablets can be predicted from granules characteristics using SeDeM-ODT expert system. Furthermore, SeDeM-ODT expert system can also be used for optimization of the process of high shear wet granulation.

Formulation Development and Evaluation of Multiple Unit Pellet System of Tamsulosin Hydrochloride

The aim of current work was to grow extended release multiple unit pellets of Tamsulosin Hydrochloride, is an alpha-blocker, used for the healing of the symptoms of a prostate gland condition called BPH (benign prostatic hyperplasia) by extrusion- spheronization (E/S) and solution/suspension layering (S/S) method. In the Extrusion-Spheronization, A ratio of 75:25, 67:33, 64:36 Tamsulosin Hydrochloride and Microcrystalline cellulose were mixed for making drug pellets and extended release (ER) coating was performed in fluidized bed processor (FBP) by solution/suspension layering with Ethyl cellulose (aqueous. dispersion, 4 cps and 7 cps) and Hypromellose (5cps) with different ratios % weight buildups accordingly. In the Solution/suspension layering (S/S) method, Tamsulosin Hydrochloride drug pellets were prepared by layering onto MCC spheres in FBP. These drug pellets were further coated for extended release with HPMC, 5cps and EC, 7cps. In drug coating stage, drug and different binder (Hypromellose, 5 cps) concentrations 8, 10, 12, 14 mg/unit were coated onto the cores for optimization of binder concentration. The weight of MCC spheres were optimized for further formulations. For all the drug coated pellets, ER coating was given with EC, 7cps and HPMC, 5 cps at a coating level of 8% weight by weight. In the extrusion- spheronization (E/S) Optimization of Drug pellets: Among the trials TD3 (Tamsulosin HCl and MCC) showed good mechanical strength with better yield due to increased MCC concentration. Optimization of Extended Release Coating: Optimized TD3 drug pellets were coated with ER coating using water insoluble polymer (Aq.EC 25% dispersion/ EC, 4cps/ EC, 7cps) and water soluble polymer (HPMC, 5cps). Among these polymers, extended release coating was optimized (TD3E14) with the combination of EC, 7cps and HPMC, 5cps at 8% weight build up. In the Solution/Suspension layering: Optimization of binder concentration in drug coating stage: HPMC, 5cps with 12 mg/unit for TF7 was optimized based on %yield. Optimization of MCC spheres in drug coating stage in formulation of ER pellets with different weight drug pellets: The weight of MCC spheres (160, 170, 180, 190 mg/unit) used in the drug coating stage with binder HPMC, 5cps (12 mg/unit). These drug pellets were given with ER coating at 8% weight buildup by using EC, 7cps and HPMC, 5cps. Among these trials, TF7E7 was optimized. Based on the investigations of the present study, conclusions was. formulating low dose, high soluble, BCS class I drug- Tamsulosin Hydrochloride ER formulation by extrusion-spheronization showed flexibility for batch processing and cost effectiveness while solution/suspension layering was process feasible but time consuming due to high drug loading.

Statistically Quantifying the Uncertainty in Strength of Marine Clay Stabilized by a Type of Portland-Fly Ash Cement

This study deals with the variation in strength of clays stabilized by a special binder—the CEM II/B-V type of Portland-fly ash cement. Two sources of uncertainties were examined, that is, the uncertainty in cement fraction in the binder, and the nonuniformity in binder concentration resulted from the process of mixing binder slurry with in situ clays. These two uncertainties were quantitatively described as two random variables, and the analyses were conducted through the Monte Carlo simulation method. Results indicate that the strength is insensitive to the cement fraction in the binder but is sensitive to the binder concentration; the variation of the latter even results in an amplified variation of strength. The variation of binder concentration is proposed to be linked up with the variation of strength through the operational parameter of blade rotation number. By doing so, the results could benefit designers in quality control prior to the construction of soil stabilization.

CNT-Based Solar Thermal Coatings: Absorptance vs. Emittance

A novel approach for fabricating selective absorbing coatings based on carbon nanotubes (CNTs) for mid-temperature solar–thermal application is presented. The developed formulations are dispersions of CNTs in water or solvents. Being coated on stainless steel (SS) by spraying, these formulations provide good characteristics of solar absorptance. The effect of CNT concentration and the type of the binder and its ratios to the CNT were investigated. Coatings based on water dispersions give higher adsorption, but solvent-based coatings enable achieving lower emittance. Interestingly, the binder was found to be responsible for the high emittance, yet, it is essential for obtaining good adhesion to the SS substrate. The best performance of the coatings requires adjusting the concentration of the CNTs and their ratio to the binder to obtain the highest absorptance with excellent adhesion; high absorptance is obtained at high CNT concentration, while good adhesion requires a minimum ratio between the binder/CNT; however, increasing the binder concentration increases the emissivity. The best coatings have an absorptance of ca. 90% with an emittance of ca. 0.3 and excellent adhesion to stainless steel.