Residual Moisture Content Research Articles

Model development and prediction of particle size distribution, density and friability of a comilling operation in a continuous pharmaceutical manufacturing process

The comilling process plays an important role in solid oral dosage manufacturing. In this process, the granulated products are comminuted to the required size distribution through collisions created from a rotating impeller. In addition to predicting particle size distribution, there is a need to predict other critical quality attributes (CQAs) such as bulk density and tapped density, as these impact tablet compaction behavior. A comprehensive modeling approach to predict the CQAs is needed to aid continuous process modeling in order to simulate interaction with the tablet press operation. In the current work, a full factorial experiment design is implemented to understand the influence of granule strength, impeller speed and residual moisture content on the CQAs. A population balance modeling approach is applied to predict milled particle size distribution and a partial least squares modeling approach is used to predict bulk and tapped density of the milled granule product. Good agreement between predicted and experimental CQAs is achieved. An R2 value of 0.9787 and 0.7633 is obtained when fitting the mean particle diameters of the milled product and the time required to mill the granulated material respectively.

Feasibility study for the development of a certified reference material of nitrofuran metabolites in chicken breast muscle from incurred samples

Certified reference materials (CRM) provide measurements of quality and metrological traceability relative to the International System of Units (SI). The results of a feasibility study for the development of an incurred CRM for the mass fraction of nitrofuran metabolites in chicken muscles are presented in this work. A small-scale batch of material was produced from freeze-dried chicken breast muscles containing residues of 3-amino-2-oxazolidinone (AOZ) and 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ) metabolites after the controlled in vivo administration of furazolidone and furaltadone antibiotics. A small-scale batch from a blank matrix, without the metabolites, was also produced. The granulometry, stability of residual moisture content, effect of the treatment by irradiation at 3 kGy, 5 kGy and 7 kGy, and degree of inhomogeneity of the property values and residual moisture were evaluated. All statistical approaches for homogeneity and stability assessments were performed based on the principles of ISO Guide 35:2006.

Heat tracer test in a riparian zone: Laboratory experiments and numerical modelling

The use of water temperature as a tracer has been widely utilized for characterizing the dynamics of water flow and heat transport in riparian zones. By using experimental approaches, we investigated the effects of water temperature, hydraulic head, and heat radiation on water flow and thermal dynamics in riparian zones through sand tank experiments, which simulate the dynamics of water flow and heat transport in riparian zones. Water of low temperature was pumped into the sand tank, and changes of temperature at different locations of the sand tank were measured. Temperature data was examined for three different water temperatures (4.0 °C, 6.0 °C, and 9.5 °C), two different hydraulic heads (25 cm and 45 cm), and two different radiation temperatures (no radiation and 22 °C). The thermal dynamic variation pattern in different types of water temperatures, hydraulic heads, and radiation combinations, was also analyzed using a HYDRUS-2D model. The temperature sensors, located near the inlet infiltration boundary, required a shorter time to reach the steady state, because the temperature declined more rapidly near the inlet. The effect of lateral inflow on the temperature gradient was obvious. The temperature gradient in the horizontal direction gradually decreased, and the vertical temperature gradient gradually increased. In the initial stage of infiltration, the temperature gradient in the horizontal direction was larger than the temperature gradient in the vertical direction, however, as time goes on, the temperature gradient in the vertical direction was larger than the temperature gradient in the horizontal direction. In addition, the horizontal temperature gradient of the top sand layer was less affected by the water temperature. The closer the temperature observation point of the same horizontal section was to the infiltration boundary, the higher the rate of temperature difference changes. Comparison of the predicted and observed thermal dynamics variation of the 2-D sand tank shows good agreement, indicating that the major mechanism for water flow and thermal dynamics variation was hydraulic head. The sensitivity analysis results illustrate that the model was most sensitive to hydraulic head (H), followed by Van Genuchten parameter (α), permeability coefficient (Ks), water temperature (T), Van Genuchten parameter (n), residual moisture content (θr), and saturated moisture content (θs). The variation of each parameter was linear with the change of temperature field. Parameters which were positively related to the temperature field were T, α, θr and θs, which means the parameter value becomes larger as the temperature becomes larger, and vice versa. The parameters which were negatively related to the temperature field were H, Ks and n.

Effects of the evolutions of coal properties during nitrogen and MTE drying processes on the spontaneous combustion behavior of Zhaotong lignite

Compared to nitrogen drying process, the mechanical thermal expression (MTE) drying process, a typical non-evaporation drying process with great potential in large-scale application, results in significantly different changes in characteristics of lignite such as pore structures, mineral matters contents and particle size. In this study, the effects of the evolutions of coal properties during nitrogen and MTE drying process on the spontaneous combustion behavior of Zhaotong lignite were systematically investigated. The samples were treated by nitrogen and MTE drying process to desired residual moisture contents, and the changes in pore structures, mineral matters and particle size of samples were analyzed. The test of spontaneous combustion behavior of the sample was carried out by wire basket method. It was found that the removal of water from lignite resulted in the decrease of crossing point temperature (CPT) indicating the promotion of spontaneous combustion susceptibility. The stabilization of pore structures by MTE process which inhibited the transform of macropores into smaller pores, resulted in a lower CPT compared to nitrogen dried samples with the same residual moisture content. The removal of mineral matters from lignite by MTE process also contributed to the decrease of CPT. The effect of particle size in a wide range (from <0.2 mm to 10–20 mm) on CPT was also studied. The CPT increased with the enlargement of particle size above the critical diameter, due to the less exposition of internal surface area and inhibited the oxygen diffusion to internal particle surface which inhibited the oxidation reactions. The inhibition on the spontaneous combustion of dried lignite by the MTE process was deprived from the large size of its products.

Experimental study on the effects of drying methods on the stabilities of lignite

Abstract The drying processes are always applied prior to the transportation or utilization of lignite, and result in notable changes in the stabilities of lignite. In this paper, the study on the effects of nitrogen and MTE drying process on the physico-chemical properties and stabilities of Zhaotong lignite was carried out. The briquettes produced by MTE drying in this study were 150 mm in dimension, and so had a much larger particle size than nitrogen-dried samples. Nitrogen adsorption, mercury intrusion porosimetry and scanning electron microscopy all suggested that drying was accompanied by the transformation of larger pores into smaller ones. Compared to nitrogen drying, the pore structures could be stabilized by the MTE process. The soluble salts were removed during MTE drying which resulted in the decrease in ash and the concentrations of some of the major metals. The removal of water enhanced the hydrophilicity of nitrogen dried samples, but did not affect the hydrophilicity of MTE dried samples. The moisture holding capacity of MTE dried samples reduced faster than nitrogen dried samples with the decrease of residual moisture content. The moisture readsorption processes of MTE dried samples were strongly inhibited due to the much larger particle size of sample produced by MTE drying than nitrogen drying. The susceptibility to spontaneous combustion, indicated by cross point temperature and self-heating tests, of nitrogen and MTE dried samples increased with the decrease of residual moisture content. The MTE dried samples are more liable to spontaneous combustion than nitrogen dried samples with the same residual moisture and particle size. However, the larger particle size of the MTE product made it more stable with respect to spontaneous combustion and also moisture readsorption.

Predictive Evaluation of Pharmaceutical Properties of Ulinastatin-Containing Vaginal Suppositories as a Hospital Preparation by Near-Infrared Spectroscopy.

A vaginal suppository containing ulinastatin (UTI) was developed as a hospital pharmacy product from UTI injection solution and Witepsol® S-55. After mixing at 50°C for 0-8 h, UTI suppositories were prepared, which had good UTI content uniformity. Because 2% surfactant was contained in S-55, the UTI injection solution formed a water-in-oil type emulsion as a suppository base. The measured residual moisture content (loss on drying (LOD)) in the prepared vaginal suppositories decreased as the mixing time increased, but their hardness (hardness test (HT)) increased. Near (N) IR spectra of UTI suppositories were measured after mixing for 0-8 h. The best calibration models to predict the HT and LOD of the suppositories were determined based on the NIR spectra by the leave-one-out method in a partial least-squares regression analysis (PLS). The validation result indicated that PLS models for HT and LOD were obtained based on the spectra treated by a combination of smoothing and normalized, respectively, and the model consisted of three latent variables. The plots between the predicted and measured pharmaceutical properties (HT and LOD) based on the calibration data were superimposed with those of the external validation data. The developed NIR spectroscopy method was applied to the preparation process monitoring for UTI vaginal suppositories. In the prepared vaginal suppositories, the predicted LOD decreased as the mixing time increased, and the measured LOD values superimposed well with the predicted values. In contrast, the predicted HT increased as the mixing time increased, and the measured values superimposed with the predicted values.

Comparison of melibiose and trehalose as stabilising excipients for spray-dried β-galactosidase formulations

Spray-dried protein formulations commonly require stabilising excipients to prevent protein degradation during processing and storage, and trehalose has been commonly used. The purpose of this work was to evaluate melibiose in spray-dried protein formulations in comparison to trehalose. The protein-activity-preserving efficacy, process behaviour and storage stability were studied. Spray drying of β-galactosidase was carried out using different process temperature, drying air flow and feed liquid atomisation settings. Both melibiose and trehalose reduced protein activity loss during drying. A decrease in activities was observed when the process temperature exceeded a threshold temperature. During storage (30 days at 18% RH and 20 or 40 °C), the formulations dried below this threshold temperature showed no further activity loss, and the stabilising efficacy of the two disaccharides was equal. With higher process temperatures, the remaining protein activities after storage trended higher with melibiose formulations. All formulations remained amorphous. The powder yields of melibiose formulations were similar to trehalose. There was a difference in residual moisture contents, with melibiose formulations giving drier products. In conclusion, protein formulations with melibiose could be spray dried into amorphous powders that were physically stable, contained lower moisture contents and protected protein activity at least as well as trehalose formulations.

Development of a surface tension mediated technique for dry stabilization of mammalian cells.

Dry state preservation at ambient temperatures (lyopreservation) is a biomimetic alternative to low temperature stabilization (cryopreservation) of biological materials. Lyopreservation is hypothesized to rely upon the creation of a glassy environment, which is commonly observed in desiccation-tolerant organisms. Non-uniformities in dried samples have been indicated as one of the reasons for instability in storage outcome. The current study presents a simple, fast, and uniform surface tension based technique that can be implemented for lyopreservation of mammalian cells. The technique involves withdrawing cells attached to rigid substrates to be submerged in a solution of lyoprotectant and then withdrawing the samples at a specific rate to an inert environment. This creates a uniform thin film of desiccated lyoprotectant due to sudden change of surface tension. The residual moisture contents at different locations in the desiccated film was quantified using a spatially resolved Raman microspectroscopy technique. Post-desiccation cellular viability and growth are quantified using fluorescent microscopy and dye exclusion assays. Cellular injury following desiccation is evaluated by bioenergetic quantification of metabolic functions using extracellular flux analysis and by a Raman microspectroscopic analysis of change in membrane structure. The technique developed here addresses an important bottleneck of lyoprocessing which requires the fast and uniform desiccation of cellular samples.

Agroecological integration of shade- and drought-tolerant food/feed crops for year-round productivity in banana-based systems under rain-fed conditions in Central Africa

Yield gaps in banana-based production systems have increased in the past two decades due to declining soil fertility, drought and biotic stresses. Sustainable, environmentally sound and economically viable strategies for intensification in these systems are urgently needed. Agroecological practices, such as the integration of shade- and drought-tolerant crops, nitrogen-fixing and cover crops could potentially improve soil fertility and moisture retention, reduce the weed burden, narrow yield gaps and increase overall plot/farm productivity in these systems. In Malaysia, leguminous crops like Pueraria phaseoloides, Calopogonium caeruleum and Centrosema pubescens are often cultivated as cover crops (to suppress weeds, and reduce moisture loss and soil erosion) in young rubber and oil palm plantations with low shade levels. Even in mature oil palm plantations with less than 30% light intensity, various shade-tolerant crops are grown, e.g., elephant foot yam, turmeric and arrow root. In humid tropical Africa, Colocasia (taro) and Xanthosoma (cocoyam) are reported to tolerate shade conditions and hence often planted under perennial banana/plantain plantations. Drought tolerance is a less common feature of most annual crops grown in the humid tropics. A few root and tuber crops (e.g., cassava, taro, yam and sweetpotato) remain in the field during the dry season in Central Africa and are then harvested according to household needs. This paper also reports on crops (Mucuna, lablab and chickpea) with potential for integration into banana-based systems during the dry season, if planted during the last month of the rainy season. These crops are reported to use the residual soil moisture content for continued growth during the dry season months. The paper concludes with detailed descriptions (from a literature review) on drought- and shade-tolerance characteristics of various crops which have long been integrated in Central African banana-based cropping systems, crops with a more recent cultivation history and crops with potential for system integration.

Performance Study of Fluidized Bed Dryer with Immersed Heater for Paddy Drying

This paper investigated the performance of fluidized bed dryer with immersed heater for paddy drying. The influence of drying temperature and the temperature of immersed heater on drying curve, thermal efficiency, and quality of paddy was investigated. The fixed operating conditions are drying time of 60 minutes, paddy weight of 200 grams and the air velocity of 0.4 m/s. The variables are drying temperature and the temperature immersed heater namely 50, 60, 70, 80, 90 (°C). The results show addition immersed heater will increase drying rates. No constant drying rate was found. Increasing the temperature will decrease the utilized energy. The thermal efficiency decreases with increasing temperature. The increasing temperature and use immersed heater will decrease the residual moisture content, increase damaged and yellow paddy grain, and increase red paddy grain.

Estimating the actual evapotranspiration and deep percolation in irrigated soils of a tropical floodplain, northwest Ethiopia

The deep percolation and actual evapotranspiration from flood irrigation in tropical floodplains were predicted using a numerical model, Hydrus-1D, and a bucket type water balance model. Field experiments were conducted on onion and maize crops grown from December 2015 to May 2016 in small irrigation schemes found in the Lake Tana floodplains of Ethiopia. Experimental fields were selected along a topographic transect to account for soil and groundwater variability. Irrigation volumes were measured using V-notches and irrigation depths (400–550 mm) were calculated, and daily groundwater levels were monitored manually from piezometers installed in the fields. The soil profiles were described at each field and physical properties (texture, FC, PWP, BD, and OM) were measured at each horizon which were used to derive model input parameters. Soil hydraulic properties (residual and saturated moisture content, saturated hydraulic conductivity, parameters related to: pore size distribution n, air entry α and pore connectivity l) were derived using KNN pedotransfer functions for tropical soils and fitted using Retention Curve Program for Unsaturated Soils, RETC. The seasonal actual evapotranspiration estimated by Hydrus and water balance models ranged from 320 to 360 mm for onion and from 400 to 470 mm for maize. The seasonal deep percolation estimated from both models was 12–41% of applied irrigation and with this flood irrigation management; the deep percolation is very high. Implementing precise irrigation and water saving practices that minimize deep percolation and unproductive excessive consumptive use are required to achieve the growing food demand with the available water. When less detailed information is available, the water balance model can be an alternative to predict deep percolation and actual evapotranspiration.

Effects of Cyclodextrins (β and γ) and l-Arginine on Stability and Functional Properties of Mucoadhesive Buccal Films Loaded with Omeprazole for Pediatric Patients.

Omeprazole (OME) is employed for treating ulcer in children, but is unstable and exhibits first pass metabolism via the oral route. This study aimed to stabilize OME within mucoadhesive metolose (MET) films by combining cyclodextrins (CD) and l-arginine (l-arg) as stabilizing excipients and functionally characterizing for potential delivery via the buccal mucosa of paediatric patients. Polymeric solutions at a concentration of 1% w/w were obtained by dispersing the required weight of metolose in 20% v/v ethanol as solvent at a temperature of 40 °C using polyethylene glycol (PEG 400) (0.5% w/w) as plasticizer. The films were obtained by drying the resulting polymer solutions at in an oven at 40 °C. Textural (tensile and mucoadhesion) properties, physical form (differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy), residual moisture content (thermogravimetric analysis (TGA)) and surface morphology (scanning electron microscopy (SEM)) were investigated. Optimized formulations containing OME, CDs (β or γ) and l-arg (1:1:1) were selected to investigate the stabilization of the drug. The DSC, XRD, and FTIR showed possible molecular dispersion of OME in metolose film matrix. Plasticized MET films containing OME:βCD:l-arg 1:1:1 were optimum in terms of transparency and ease of handling and therefore further functionally characterized (hydration, mucoadhesion, in vitro drug dissolution and long term stability studies). The optimized formulation showed sustained drug release that was modelled by Korsmeyer–Peppas equation, while the OME showed stability under ambient temperature conditions for 28 days. The optimized OME loaded MET films stabilized with βCD and l-arg have potential for use as paediatric mucoadhesive buccal delivery system, which avoids degradation in the stomach acid as well as first pass metabolism in the liver.

Online measurement of moisture content, moisture distribution, and state of water in corn kernels during microwave vacuum drying using novel smart NMR/MRI detection system

ABSTRACTMoisture content is unevenly distributed and hard to measure when agricultural products are dried using microwave drying. A low-field nuclear magnetic resonance/imaging (NMR/MRI) and microwave vacuum drying (MVD) combination equipment was developed. The residual moisture content, distribution, and state of water (free, immobilized, and bound) in fresh corn kernels during MVD were quickly measured in real time. NMR results indicated that the amplitude of free and immobilized water decreased very rapidly at the early stage of MVD, while the amplitude of bound water experienced a similar rapid decrease at the last stage. MRI results indicated that the moisture content was always distributed unevenly during MVD, especially at the early stage. The moisture distribution tended to become uniform when drying progressed and the bound water became dominant. The residual moisture content of corn kernels and integral (total) amplitude of NMR were found to fit well with a linear model (R2 > 0.991, P < 0.01), which can be applied to predict the residual moisture content with error less than 0.01 g moisture/g solid during MVD. This work shows that an NMR/MRI smart detection system is capable of measuring and quantifying residual moisture content, moisture distribution, and state of water in foods online and in real time during drying.

Synthesis and characteristics of nanocrystalline Ni1−xCoxO/GDC powder as a methane reforming catalyst for SOFCs

This paper has described the application of nickel-doped catalytic constituents based on gadolinium-doped ceria (GDC) for fabrication of the solid-oxide fuel cell (SOFC) anode layer integrated with an in-situ methane-reforming layer (MRL). Nanocrystalline powders of Ni1−xCo3xO1+3×/GDC and Ni1−xCuxO/GDC with various compositions (x = 0.3, 0.5, 0.7) were synthesized using an ultrasound-assisted method followed by a thermal treatment to be applied for fabrication of the integrated MRL and the SOFC anode layer, respectively. Thermogravimetric analysis showed that the synthesized powders should be optimally calcined at 700°C to exhibit improved crystallinity and catalytic activity. The morphological analysis showed the formation of nanocrystalline powders with particle size ranging from 4 to 86nm that was confirmed by the crystal size analysis using XRD results. The elemental analysis by EDX indicated a successful distribution of the constituent ceramic and bimetallic phases after the addition of a sonication stage. The results of FT-IR and Raman spectroscopy confirmed lack of solvents residual after calcination that was in agreement with residual moisture content values obtained from TGA data. The fabricated anode-MRL bilayers had an adequate porosity (36.7%) and shrinkage (33.5%) after adding carbon particles as a pore former (at a loading fraction of 5.9wt%). The catalytic performance measurements of the MRL showed a methane conversion of 13% at maximum activity with a weight hour space velocity (WHSV) of 60L/gh that was mainly due to carbon deposition in the reaction condition.

Poly(methyl methacrylate) salt as film forming material to design orodispersible films

This work aims to evaluate the possible use of a poly(sodium methacrylate, methyl methacrylate) (NaPMM2) plasticized by PEG400 in the design of orodispersible films (ODF). Placebo ODF prepared by solvent casting were intended to study the impact of the polymer/plasticizer ratio and residual moisture on disintegration time, stickiness and mechanical properties. The drug loading capacity was assessed using ketoprofen and paracetamol. Placebo ODF containing PEG400 in the 10–30% w/w range and 10–15% of residual moisture content were easy-to-handle, packed without failures and completely dissolved within 30 s.NaPMM2/PEG400 in 80/20 ratio allowed up to 70% of paracetamol loading, which appeared as the largest value described in literature. This ODF showed good mechanical properties and disintegration time. The same formulation loaded with 25% or 50% ketoprofen (pKa = 4.45) swelled without disintegrating, because of a partial protonation of NaPMM2, as verified by ATR-FTIR spectroscopy. However, the addition of 5% surfactants allowed the formulation of ODF containing 25% ketoprofen that disintegrated within one minute and guaranteed the complete drug dissolution within 5 min. All the presented data, discussed in the framework of information available on such copolymer, highlighted its versatility in the design of orodispersible dosage forms.

The Effects of Controlling the Residual Moisture Content in Oil Palm Fruits under Microwave Sterilization

The Effects of Controlling the Residual Moisture Content in Oil Palm Fruits under Microwave Sterilization

Study of the composition of cryoprotector and technological regime in liophilization of liposomes with oxaliplatinum

Lyophilization is one of the most prospective and technologically logical methods for preserving the structure of nanobiotechnological products. Liposomes with oxaliplatin were obtained, and a screening experiment was performed to select a cryoprotectant.Aim. The aim of the research is to obtain liposomes with oxaliplatin, determine the type of cryoprotectant and its quantity, study the parameters of lyophilisation to obtain the product with maximum encapsulation of oxaliplatin, with the save of the size of liposomes in the nano-diapason, and the optimum residual moisture content.Methods. Lyophilization was carried out in a Quarco lyophilizer (PRC). The liposomal form of oxaliplatin was obtained by the method of "passive" encapsulation in combination with the ion sorption method.Results. Lactose, sucrose, maltose and trehalose dihydrate were studied as cryoprotectants. As the most perspective, was chosen - trehalose dihydrate. The optimal concentration of trehalose dihydrate in the liposomal form of oxaliplatin was researched at 8 % by weight. Also was optimized the program of freeze-drying. Primary drying with a duration of 1740 minutes was not sufficient. When the program was increased for 300 min, up to 2040 min, the values of the loss of encapsulation rate of 8 %, from 65 % before drying, to 57 % after drying were obtained. This is a good indicator, which shows an effectiveness of cryoprotectant and a rational program of freeze-drying. The size of the liposomes after drying was 112 nm, the residual moisture content, measured by K. Fischer's method, was 2.3 %, which is within the scope of the target range.Conclusion. A technology for obtaining liposomes with encapsulated oxaliplatin has been proposed and screening studies have been carried out to determine the optimal cryoprotectant. It is proposed to use as a cryoprotector trehalose dihydrate as the most perspective. The effect of different content of trehalose dihydrate on the degree of encapsulation of oxaliplatin in liposomes was studied. It was found that the optimal cryoprotectant concentration in the preparation is 8 % (by mass).Technological parameters of the lyophilization process of liposomes with oxaliplatin have been developed: drying time and freezing temperature. The decrease in the incorporation of oxaliplatin into liposomes during lyophilisation did not exceed 8.0 % with a residual water content of about 2.3 %. The size of liposomes after lyophilization in the nanoscale is 112 nm

Pharmaceutical evaluation of hospital-prepared, ulinastatin-containing vaginal suppositories

Ulinastatin (UTI) is a trypsin inhibitor derived from human urine. UTI has inhibitory activities against many enzymes, and is clinically effective and safe for the treatment of acute pancreatitis. Administration of UTI into the vagina is an effective treatment for threatened premature delivery. Traditional UTI-containing vaginal suppositories may have adverse effects on the stability and quality of UTI because of the properties of Witepsol® W-35. Therefore, we sought to develop UTI-containing vaginal suppositories with good UTI uniformity using a UTI injection solution and Witepsol® S-55. We investigated the influence of moisture content and hardness on the quality of UTI-containing vaginal suppositories. The residual moisture content of vaginal suppositories using S-55 decreased as mixing time increased. In addition, suppository hardness increased as mixing time increased because moisture content decreased. The water phase, which contains UTI, was dispersed uniformly by mixing for 5 h, and prepared vaginal suppositories had uniform UTI content. These results suggest that we can prepare UTI-containing vaginal suppositories with good quality control, and this will be beneficial for patients.

A step forward towards the development of stable freeze-dried liposomes: a quality by design approach (QbD)

This study highlights the advantages of using a Quality by Design (QbD) approach in order to gain a more comprehensive understanding of the freeze-drying process of pravastatin-loaded long-circulating liposomes (LCL-PRAV). Within the QbD paradigm, the present study aimed to establish the design space for the optimization of freeze-dried LCL-PRAV by means of Design of Experiment (DOE). The encapsulated solute retention (ESR), the average particle size, and zeta potential after freeze-drying, the residual moisture content, the macroscopic cake appearance, the glass transition temperature (Tg) of the freeze-dried cake, and the primary drying time were defined as critical quality attributes (CQAs) for the freeze-dried final product. Further on, the influence of lyoprotectant type, freezing rate, shelf temperature during primary drying, and the presence of an annealing step on the CQAs was investigated through a 21-run D-optimal experimental design. Three-dimensional response surfaces were generated to complete the statistical analysis and for a better understanding of the influence of variables and their interactions on the responses. The developed model was then used to build the design space for the freeze-dried liposomes, within which the product quality was assured and the process variability was minimized.

Classification of uncoated plywood based on moisture dynamics

Moisture has a significant influence on the mechanical and physical properties and on the biological durability of wood and wood based materials. As plywood is commonly used as a building material for outdoor applications knowledge regarding its moisture behaviour is of utmost importance. The aim of this research is to model water accumulation in plywood panels in terms of their basic characteristics and in-service moisture conditions. Therefore, moisture dynamics of 29 uncoated plywood types consisting of different wood species, adhesives and layering were evaluated using a simple laboratory water floating test and an outdoor continuous moisture measurement set-up. A significant correlation was found between laboratory and field test results. By means of regression analysis the material characteristics affecting the moisture dynamics of plywood were evaluated. The most influential parameters were wood species, glue type and thickness of the top veneer. Limit values for the water left in the plywood specimen after 72 h absorption and subsequent 72 h desorption, the residual moisture content (rm72), were calculated as to develop a classification tool for plywood. Based on such a classification tool some recommendations for uncoated plywood regarding end use and service life were drafted. Enhanced performance should be obtained by means of wood preservation or by reducing its residual moisture by applying a coating or by an optimal selection of adhesive, wood species and top veneer thickness.