To investigate the influence of machine operating variables on formulations derived from lactose types in capsule filling: part 2

Abstract

This study is the second in a series that examines the characterizing and selection of suitable grades of lactose for capsule formulation development. Based upon the previous study, four grades were selected for further study. The effects of drug load and operational variables on formulations derived from these four lactose types were evaluated for physicochemical and mechanical attributes of plugs and their capsules on an instrumented dosing-disc capsule filling machine (H&H KFM/3) using acetaminophen as a model, highly soluble and poorly compressible drug. The results obtained were as follows: (1) flowability reduced upon increasing drug load; (2) powder bed height (PBH) and compression force (CF) had positive significant effect on plug weight (p?<?0.05); (3) ejection force was positively and significantly correlated with increasing speed and CF (p?<?0.05); (4) AL capsule plugs had the highest plug crushing force which was followed by DCL15; (5) the crushing strength of plugs made from DCL11 increased with increasing acetaminophen concentration; (6) higher CF had a significant negative impact on acetaminophen release at 15?min time point (p?<?0.05); (7) at 10% and 40% drug load, formulations containing AL showed the quickest drug release; and (8) increased drug load had a significant negative impact on the release rate at 15 and 45?min time points (p?<?0.05). Overall, the results from this study provides information on risk based assessment of filler selection based on drug load and the range of machine operating variables which will help in defining criteria for meeting key quality attributes for capsule formulation development.     

Highly Efficient Osmotic Energy Harvesting in Charged Boron-Nitride-Nanopore Membranes

Recent studies of the high energy-conversion efficiency of the nanofluidic platform have revealed the enormous potential for efficient exploitation of electrokinetic phenomena in nanoporous membranes for clean-energy harvesting from salinity gradients. Here, nanofluidic reverse electrodialysis (NF-RED) consisting of vertically aligned boron-nitride-nanopore (VA-BNNP) membranes is presented, which can efficiently harness osmotic power. The power density of the VA-BNNP reaches up to 105 W m⁻², which is several orders of magnitude higher than in other nanopores with similar pore sizes, leading to 165 mW m⁻² of net power density (i.e., power per membrane area). Low-pressure chemical vapor deposition technology is employed to uniformly deposit a thin BN layer within 1D anodized alumina pores to prepare a macroscopic VA-BNNP membrane with a high nanopore density, ≈10⁸ pores cm⁻². These membranes can resolve fundamental questions regarding the ion mobility, liquid transport, and power generation in highly charged nanopores. It is shown that the transference number in the VA-BNNP is almost constant over the entire salt concentration range, which is different from other nanopore systems. Moreover, it is also demonstrated that the BN deposition on the nanopore channels can significantly enhance the diffusio-osmosis velocity by two orders of magnitude at a high salinity gradient, resulting in a huge increase in power density.     

Low cycle fatigue behaviour of modified and conventional superalloy Inconel 718 at 650°C

The present investigation deals with the study and comparison of low cycle fatigue (LCF) behavior of modified IN 718 alloy with higher Al+Ti/Nb and Al/Ti ratios of 0.458 and 0.870, with that of conventional IN 718 alloy with corresponding ratios of 0.294 and 0.50 respectively. LCF tests were carried out in total strain control mode at total strain amplitudes (Δɛ_t/2) from ±0.625% to ±1.0%, in fully reversed loading (R= −1) at 650°C. The modified alloy was found to exhibit better LCF resistance than the conventional alloy.     

Uniaxial compression and combined compression‐and‐shear response of amorphous polycarbonate at high loading rates

We present results of a study conducted to better understand the yield and flow response of amorphous poly(bisphenol A carbonate), PC‐Lexan® (PC), under uniaxial compression and combined compression‐and‐shear impact loading. A split Hopkinson pressure bar (SHPB) is utilized to obtain nearly adiabatic uniaxial compression response of the PC in the strain‐rate range of 1000–2000 s^?1. Since temperature is expected to play an important role in governing the dynamic response of PC, nearly isothermal SHPB tests are also conducted and compared with the adiabatic response. In order to investigate the coupling of shear behavior and dilatation in PC at high loading rates, combined compression‐and‐shear plate impact experiments are conducted at strain‐rates in the range of 10⁵–10⁶ s^?1. In addition, novel plate impact experiments are conducted to better understand the evolution of the shearing resistance of PC in response to sudden alterations (drop) in hydrostatic pressure under extremely high shearing rates. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Liquid Phase Oxidation of p-Cresol over Cobalt Saponite

Liquid phase oxidation of p-cresol was carried out over a Co-saponite catalyst in a temperature and pressure range of 333–393 K and 20–827 kPa, respectively in n-propanol. Co-saponites with varying cobalt content (5–30%) were prepared and screened among which 13% Co-saponite gave the highest conversion of 92% of p-cresol with 92% selectivity to p-hydroxybenzaldehyde without formation of any non-oxidation products.     

On the use of damped updated FE model for dynamic design

Model updating techniques are used to update the finite element model of a structure, so that updated model predicts the dynamics of a structure more accurately. The application of such an updated model in dynamic design demands that it also predicts the effects of structural modifications with a reasonable accuracy. Most of the model updating techniques neglect damping and so these updated models cannot be used for predicting amplitudes of vibration at resonance and antiresonance frequencies. This paper deals with updating of the finite element model using the FRF data with damping identification using complex modal data and its subsequent use for predicting the effects of structure modifications. The updated model is obtained in two steps. In the first step, mass and stiffness matrices are updated using FRF-based model updating method. In the second step, damping is identified using updated mass and stiffness matrices, which are obtained in first step. Structural modifications in terms of mass and beam modifications are then introduced to evaluate the updated model for its usefulness in dynamic design.     

Reliability assessment of passive containment isolation system using APSRA methodology

In this paper, a methodology known as APSRA (Assessment of Passive System ReliAbility) has been employed for evaluation of the reliability of passive systems. The methodology has been applied to the passive containment isolation system (PCIS) of the Indian advanced heavy water reactor (AHWR). In the APSRA methodology, the passive system reliability evaluation is based on the failure probability of the system to carryout the desired function. The methodology first determines the operational characteristics of the system and the failure conditions by assigning a predetermined failure criterion. The failure surface is predicted using a best estimate code considering deviations of the operating parameters from their nominal states, which affect the PCIS performance. APSRA proposes to compare the code predictions with the test data to generate the uncertainties on the failure parameter prediction, which is later considered in the code for accurate prediction of failure surface of the system. Once the failure surface of the system is predicted, the cause of failure is examined through root diagnosis, which occurs mainly due to failure of mechanical components. The failure probability of these components is evaluated through a classical PSA treatment using the generic data. The reliability of the PCIS is evaluated from the probability of availability of the components for the success of the passive containment isolation system.     

Synthesis and Characterization of 1‐Azido‐2‐Nitro‐2‐Azapropane and 1‐Nitrotetrazolato‐2‐Nitro‐2‐Azapropane

1‐Azido‐2‐nitro‐2‐azapropane ( 1 ) was synthesized in high yield from 1‐chloro‐2‐nitro‐2‐azapropane and sodium azide. 1‐Nitrotetrazolato‐2‐nitro‐2‐azapropane ( 2 ) was synthesized in high yield from 1‐chloro‐2‐nitro‐2‐azapropane and silver nitrotetrazolate. The highly energetic new compounds ( 1 and 2 ) were characterized using vibrational (IR and Raman) and multinuclear NMR spectroscopy (¹H, ¹³C, ¹⁴N), elemental analysis and low‐temperature single crystal X‐ray diffraction. 1‐Azido‐2‐nitro‐2‐azapropane ( 1 ) represents a covalently bound liquid energetic material which contains both a nitramine unit and an azide group in the molecule. 1‐Nitrotetrazolato‐2‐nitro‐2‐azapropane ( 2 ) is a covalently bound room‐temperature stable solid which contains a nitramine group and a nitrotetrazolate ring unit in the molecule. Compounds 1 and 2 are hydrolytically stable at ambient conditions. The impact sensitivity of compound 1 is very high (<1 J) whereas compound 2 is less sensitive (<6 J).     

Effects of material microstructure on blunt projectile penetration of a nickel-based super alloy

Engine fan-blade containment systems, required in many aviation applications, are frequently manufactured from high-temperature superalloys, such as Inconel-718. As in many other applications, there is an incessant desire to maximize mechanical properties of the containment component while minimizing its weight. However, a thorough understanding of the impact behavior of the various heat treatments of these alloys in engine fan-blade containment applications does not currently exist. Due to this incomplete state of knowledge, a combined experimental–analytical investigation was conducted at CWRU in collaboration with researchers at NASA GRC. As a part of this investigation, thin plates of Inconel-718, in both annealed and precipitation hardened conditions were subjected to semi-quantitative high speed penetration tests. Dynamic compression and top hat shear localization tests using a split Hopkinson pressure bar were also conducted as part of a more fundamental assessment of this material. The measured dynamic material response in compression was used to develop a material model which adequately described the dynamic behavior of IN-718 in both the annealed and precipitation hardened states. Moreover, a transient large deformation thermo-elastic-viscoplastic finite element code is used to understand the local thermo-mechanical fields during impact in both the annealed and precipitation hardened microstructures. The results from these studies show that the annealed material demonstrated superior penetration resistance when compared with the hardened material. The annealed IN-718 absorbed more energy through multiple deformation modes and did not show any susceptibility to shear localization, which was in contrast to the precipitation hardened material. These results, therefore, suggest a precipitation hardened condition may not be optimal for impact energy absorption applications, such as, in engine fan-blade containment.