Devitrification of amorphous celecoxib

The purpose of this research was to analyze the devitrification of amorphous celecoxib (CEL) in the presence of different stressors (temperature, pressure, and/or humidity) encountered during processing of solid dosage forms. Amorphous CEL was prepared in situ in the analytical instruments, as well as in laboratory, by quench-cooling of melt process, and analyzed by dynamic mechanical thermal analysis, differential scanning calorimetry, microscopy, and Fourier-transform infrared spectroscopy. Amorphous CEL prepared in situ in the analytical instruments was resistant to crystallization under the influence of temperature and/or pressure, because of its protection from the external environment during preparation. These samples exhibited structural relaxation during annealing at 25°C/0% relative humidity (RH) for 16 hours. Generation of amorphous CEL in the laboratory resulted in partially crystalline samples, because of exposure to environmental temperature and humidity, resulting in incomplete vitrification. Subjection to thermal stress favored crystallization of amorphous CEL into metastable polymorphic forms, which were not obtained by solvent recrystallization approach. Temperature and humidity were identified as the major factors promoting devitrification of amorphous CEL, leading to loss of solubility advantage. Exposure to International Conference on Harmonization-specified accelerated stability storage conditions (40°C/75% RH) resulted in complete devitrification of amorphous CEL within 15 days. The phase-transformation process of amorphous CEL along the temperature scale was examined visually, as well as spectrally. This propensity for devitrification of amorphous CEL seemed to depend on the strength of differential molecular interactions between the amorphous and crystalline form.     

Physicochemical stability of cimetidine amorphous forms estimated by isothermal microcalorimetry

The effect of humidity on the physicochemical properties of amorphous forms of cimetidine was investigated using differential scanning calorimetry, isothermal microcalorimetry, and x-ray diffraction analysis. Amorphous forms were obtained by the melting (amorphous form M [AM]) and the cotton candy (amorphous form C [AC]) methods. Thermal behaviors of AM and AC with or without seed crystals were measured using an isothermal microcalorimeter under various conditions of relative humidity (RH) and temperature, respectively. The crystallization kinetics of amorphous solids was analyzed based on 10 kinds of solid-state reaction models. AM transformed into form A at 11% RH, 50°C but transformed into a mixture of form A and monohydrate at 51% and 75% RH at 25°C. The mean crystallization times (MCTs) of the heat flow curve of AM and AC at 11% RH, 50°C were 47.82 and 32.00 hours, respectively, but at 11% RH, 25°C both were more than 4320 hours. In contrast, AC transformed into form A under all storage conditions. The MCTs of AC at 51% and 75% RH were 29.61 and 11.81 hours, respectively; whereas the MCTs of AM were 46.79 and 15.52 hours, respectively. The crystallization of amorphous solids followed the three-dimensional growth of nuclei (Avrami equation) with an induction period (IP). The IP for AM at 11% RH, 50°C was more than 2 times that for AC, but the difference in the crystal growth rate constant (CR) between AC and AM was within 10%. The IP for AM at 75% RH, 25°C was reduced to only 10% of the IP at 51% RH with increasing humidity, but the CR did not change significantly. In contrast, the IP for AC was slightly reduced at 75% RH compared with 51% RH, but the CR was about 5 times greater. At 75% RH, 25°C, the IP and CR of AM were about one-fourth the values of AC. This result suggests that the crystallization process consists of an initial stage during which the nuclei are formed and a final stage of growth.     

Monitoring Phase Transformations in Intact Tablets of Trehalose by FT-Raman Spectroscopy

The purpose of this study is to monitor phase transformations in intact trehalose tablets using FT-Raman spectroscopy. Tablets of trehalose dihydrate, amorphous trehalose (obtained by freeze-drying aqueous trehalose solutions), and anhydrous trehalose (β-trehalose) were prepared. The tablets were exposed to different conditions [11% and 0% RH (60°C); 75% RH (25°C)] and monitored periodically over 96 h using Raman spectroscopy. Within 96 h of storage, the following phase transformations were observed: (1) trehalose dihydrate → β-trehalose (11% RH, 60°C), (2) trehalose dihydrate → α-trehalose (0% RH, 60°C), (3) β-trehalose → trehalose dihydrate (75% RH, 25°C), and (4) amorphous trehalose → trehalose dihydrate (75% RH, 25°C). FT-Raman spectroscopy was a useful technique to identify the solid form and monitor multiple-phase transformations in intact trehalose tablets stored at different conditions.     

Temperature preferences of the mite, Alaskozetes antarcticus, and the collembolan, Cryptopygus antarcticus from the maritime Antarctic

Abstract. The thermal preferences of Alaskozetes antarcticus (Acari, Cryptostigmata) and Cryptopygus antarcticus (Collembola, Isotomidae) were investigated over 6 h within a temperature gradient (?3 to +13 °C), under 100% relative humidity (RH) conditions. After 10 days of acclimation at ?2 or +11 °C, individual supercooling points (SCP) and thermopreferences were assessed, and compared with animals maintained for 10 days under fluctuating field conditions (?6 to +7 °C). Acclimation at ?2 °C lowered the mean SCP of both A. antarcticus (?24.2 ± 9.1) and C. antarcticus (?14.7 ± 7.7) compared to field samples (?19.0 ± 9.0 and ?10.7 ± 5.2, respectively). Acclimation at +11 °C increased A. antarcticus mean SCP values (?13.0 ± 8.5) relative to field samples, whereas those of C. antarcticus again decreased (?16.7 ± 9.1). Mites acclimated under field conditions or at +11 °C selected temperatures between ?3 and +1 °C. After acclimation at ?2 °C, both species preferred +1 to +5 °C. Cryptopygus antarcticus maintained under field conditions preferred +5 to +9 °C, whereas individuals acclimated at +11 °C selected +9 to +13 °C. For A. antarcticus, thermopreference was not influenced by its cold hardened state. The distribution of field specimens was further assessed within two combined temperature and humidity gradient systems: (i) 0–3 °C/12% RH, 3–6 °C/33% RH, 6–9 °C/75% RH and 9–12 °C/100% RH and (ii) 0–3 °C/100% RH, 3–6 °C/75% RH, 6–9 °C/33% RH and 9–12 °C/12% RH. In gradient (i), C. antarcticus distributed homogeneously, but, in gradient (ii), C. antarcticus preferred 0–3 °C/100% RH. Alaskozetes antarcticus selected temperatures between 0 and +6 °C regardless of RH conditions. Cryptopygus antarcticus appears better able than A. antarcticus to opportunistically utilize developmentally favourable thermal microclimates, when moisture availability is not restricted. The distribution of A. antarcticus appears more influenced by temperature, especially during regular freeze‐thaw transitions, when this species may select low temperature microhabitats to maintain a cold‐hardened state.     

Effect of temperature and relative humidity on the rate of development,fecundity and life table parameters of the red spider mite Oligonychus mangiferus (Rahman and Sapra) (Acari: Tetranychidae)

Studies on biology of Oligonychus mangiferus (Rahman and Sapra) at combination of eight constant temperatures and relative humidities (RHs) viz., 7.0°C with 85% RH, 10°C with 80% RH, 15.0°C with 75% RH, 23.0°C with 70% RH, 31.0°C with 65% RH, 34.0°C with 65% RH, 36.0°C with 60% RH and 40.0°C with 55% RH revealed that the optimal condition for the development of these mites are 15.0–31.0°C and 65–75% RH. The highest temperature and the lowest RH accelerated the rate of development and induced more reproduction of O. mangiferus. Its population also multiplied 30.81 times in a generation time of 27.36 days at 31.0°C and 65% RH, while the same population only increased 7.46 times in a generation time of 48.07 days at 15.0°C and 75% RH. Fecundity was highest at 31.0°C and 65% RH with 46.43 eggs per female. The highest intrinsic rate of natural increase was observed at 31.0°C as 0.125 per day.     

An examination of the moisture sorption characteristics of commercial magnesium stearate

The objective of this study was to characterize the moisture sorption of magnesium stearate and the morphological changes, if any, resulting from moisture sorption. Six samples of commercial magnesium stearate USP were examined. Moisture sorption isotherms were obtained at 25°C and 5% to 98% relative humidity (RH) using a moisture balance. Changes in crystal form resulting from moisture sorption were determined by x-ray diffraction. There were differences in the shape of the isotherm, reversibility of moisture uptake, and shape of the hysteresis loop in the isotherms of crystalline and amorphous magnesium stearates. The isotherm of crystalline magnesium stearate was almost parallel to the pressure axis until and RH of ∼80%. The isotherm of the amorphous sample was characterized by continuous uptake of water over the entire range of RH. Exposure of amorphous magnesium stearate to RH greater than 70% resulted in the formation of the trihydrate. The trihydrate was converted into the anhydrous form when heated to a temperature of 100°C to 105°C. The trihydrate could be generated by exposing the anhydrate to RH higher than 70%.     

Effects of water vapor absorption on the physical and chemical stability of amorphous sodium indomethacin

This study reports on the effects that water absorbed into amorphous sodium indomethacin (NaIMC) can have on simultaneous tendencies to crystallize to its trihydrate form and to undergo base-catalyzed hydrolysis because of the plasticizing effects of water on molecular mobility. Measurement of water vapor absorption at 30°C and powder x-ray diffraction patterns as a function of relative humidity (RH) reveal that upon exposure to 21% RH, NaIMC does not crystallize over a 2-month period. Measurements of the glass transition temperature as a function of such exposure reveals a change in T _g from 121°C, dry, to 53°C at 21% RH, such that T _g at 21% RH is ≈13°C above the highest storage temperature of 40°C used in the study. At 56% RH and higher, however, crystallization to the trihydrate occurs rapidly; although over the 2-month period, crystallization was never complete. Assessment of chemical degradation by high-performance liquid chromatography analysis revealed significant instability at 21% RH; whereas at higher RH, the extent of chemical degradation was reduced, reflecting the greater crystallization to the more chemically stable crystalline form. It is concluded that when amorphous forms of salts occur in solid dosage forms, the simultaneous effects of enhanced water vapor sorption on crystallization and chemical degradation must be considered, particularly when assessing solid-state chemical degradation at higher temperatures and RH (eg, 40°C 75% RH).     

Effect of temperature on the survival and infectivity of <Emphasis Type="Italic">Pseudotheraptus devastans</Emphasis> vector

The aim of this study was to investigate under a controlled environment, the effect of temperature on the survival and infectivity of Pseudotheraptus devastans Distant, a cassava anthracnose disease vector. The insect P. devastans was collected from young cassava (Manihot esculenta Crantz) field plots, at the International Institute of Tropical Agriculture, (IITA), Ibadan, Nigeria. A mixture of the different developmental stages of eggs, first to fifth instar nymphs, and adults, were incubated in controlled environment chambers, under various constant temperatures of: 15, 17, 22, 25, 27, 30, and 35°C. Relative humidity at different temperature conditions were recorded and maintained at 90%, 85%, 80%, 75%, 70%, 65%, and 60%, respectively. A significant increase in insect survival was observed between 22 and 27°C temperature conditions while a significant decrease in survival was observed at 15°C and above 30°C. Lesion number, lesion diameter and infectivity among the insect stages varied as a function of temperature and relative humidity. Infectivity was highest at 22–25°C maintained at 75–80% RH and lowest at 15°C and above 30°C maintained respectively, at 65% RH and 90% RH. There was considerable low vector infectivity due to low survival of the insects at extreme temperatures.     

Influence of Temperature and Relative Humidity on Germinability of Mucor piriformis Spores

Studies were conducted to determine the influence of temperature and relative humidity (RH) on germinability and viability of Mucor piriformis spores. Spores did not survive when stored at 35 °C and their survival rate decreased rapidly at 30 °C; however, spores remained viable for more than 1 year at 0 °C. RH also significantly affected spore viability. Spores held at 26 °C and 100% RH no longer germinated after 35 days, while those held at 75 or 90% RH germinated for 65 days. At 20 °C, RH had little effect on spore germinability. The effect of temperature and RH on percentage spore germination also varied. At all temperatures studied, spore viability decreased more rapidly with time at 100% RH than at 75 or 90% RH. The least favorable, temperature-humidity combination, 30 °C and 100% RH, decreased spore germination from 100% to less than 1% in 14 days.     

Studies on the stability of salvianolic acid B as potential drug material

Introduction – Salvianolic acid B (Sal B) is one of the major water‐soluble compounds isolated from the roots of Salvia miltiorrhiza, which is widely used as a traditional Chinese medicine. Although much research on the general stability of Sal B has been undertaken and reported, there is still a need for further study of the stability required as a potential drug material. Objective – To study the stability of Sal B in the solid state and in normal saline (NS) solution during storage, as required in the ICH guidelines (2003) and Chinese Pharmacopoeia (2005). Methodology – Sal B stability was analysed using the high‐performance liquid chromatography (HPLC) method described in the Chinese Pharmacopoeia. HPLC coupled with time‐of‐flight mass spectrometry (HPLC‐TOFMS) was applied for the separation and identification of the degradation products of Sal B. Results – In the solid state, Sal B packaged in aluminium foil bags was stable for 6 months under ‘accelerated conditions’ (40°C, 75% relative humidity, RH). However, solid Sal B degradation was observed under open exposure to stress conditions of high temperature (60°C) or high humidity (92.5 or 75% RH). In NS solution, Sal B underwent severe degradation under accelerated conditions. Through HPLC‐TOFMS, nine degradation products were identified and the possible degradation pathway was deduced. Conclusion – The results demonstrate that the potential drug material Sal B could be used in a solid formulation, but is not suitable for use as a liquid formulation. Copyright © 2011 John Wiley & Sons, Ltd.     

Stability of Benzocaine Formulated in Commercial Oral Disintegrating Tablet Platforms

Pharmaceutical excipients contain reactive groups and impurities due to manufacturing processes that can cause decomposition of active drug compounds. The aim of this investigation was to determine if commercially available oral disintegrating tablet (ODT) platforms induce active pharmaceutical ingredient (API) degradation. Benzocaine was selected as the model API due to known degradation through ester and primary amino groups. Benzocaine was either compressed at a constant pressure, 20 kN, or at pressure necessary to produce a set hardness, i.e., where a series of tablets were produced at different compression forces until an average hardness of approximately 100 N was achieved. Tablets were then stored for 6 months under International Conference on Harmonization recommended conditions, 25°C and 60% relative humidity (RH), or under accelerated conditions, 40°C and 75% RH. Benzocaine degradation was monitored by liquid chromatography–mass spectrometry. Regardless of the ODT platform, no degradation of benzocaine was observed in tablets that were kept for 6 months at 25°C and 60% RH. After storage for 30 days under accelerated conditions, benzocaine degradation was observed in a single platform. Qualitative differences in ODT platform behavior were observed in physical appearance of the tablets after storage under different temperature and humidity conditions.     

Susceptibility of the cigarette beetle Lasioderma serricorne (Coleoptera: Anobiidae) to hypoxia

The susceptibility of the cigarette beetle Lasioderma serricorne (F.) to hypoxia was examined at three different oxygen concentrations (0.5?C0.8, 1.0?C1.3, and 2.0?C2.3?%) and four different temperature/humidity (RH) conditions: 30?°C/75?% RH, 25?°C/75?% RH, 20?°C/43?% RH, and 15?°C/43?% RH. The influence of humidity on mortality was also examined at three humidity levels (21, 43, and 75?% RH) at 1.0?C1.3?% oxygen (O₂) and 25?°C. Our results revealed that adult beetles were the most tolerant at 2.0?C2.3?% O₂ and that the larvae were the most tolerant at O₂ levels <1.0?C1.3?%. Mortality increased with increasing temperatures and decreasing O₂ concentrations. At 30?°C, 75?% RH, and 0.5?C0.8?% O₂, the 99?% lethality (LT₉₉) of larvae was 6.9?days; however, it increased to 20?days when the temperature was decreased to 25?°C or when O₂ levels were increased to 1.0?C1.3?%. Humidity also influenced mortality of both larval and adult beetles. LT₉₉ values for larvae at 25?°C and 1.0?C1.3?% O₂ were 24.0, 44.6, and 50.2?days at 21, 43, and 75?% RH, respectively. Results of this study indicate that a controlled atmosphere (CA) with reduced oxygen levels (<0.5?C0.8?% O₂) represents an effective measure for disinfesting stored tobacco as an alternative to conventional phosphine fumigation at temperatures >30?°C.     

Studies on Prolonged Storage of Beauveria bassiana Conidia: Effects of Temperature and Relative Humidity on Conidial Viability and Virulence against Chickpea Borer,Helicoverpa armigera

Unformulated conidia of Beauveria bassiana were stored at five different temperatures (0°, 10°, 20°, 30° and 40°C) at six different relative humidities (RH) (0, 33, 53, 75, 85 and 98%). Conidial viabilities and virulence against third instar larvae of Helicoverpa armigera were determined over a 24‐month period. Conidia survived longest at lower temperatures (0–20°C) and lower RH levels (0–53% RH). At higher temperatures (30–40°C) conidia did not survive. When the temperature was decreased from 30°C to 0°C, at nearly all RH levels the longevity of conidia increased. Conidia remained virulent for third instar larvae of H. armigera under favourable storage conditions for 24 months.     

Stability study of stavudine-loaded O-palmitoyl-anchored carbohydrate-coated liposomes

The purpose of this study was to evaluate the physicochemical stability of carbohydrate-anchored liposomes. In the present study, carbohydrate (galactose, fucose, and mannose) was palmitoylated and anchored on the surface of positively charged liposomes (PL). The stabilities of plain neutral liposomes (NL), PL, and O-palmitoyl carbohydrate-anchored liposomes were determined. The effects of storage conditions (4°C±2°C, 25°C±2°C/60%±5% relative humidity [RH], or 40°C±2°C/75%±5% RH for a period of 10, 20, and 30 days) were observed on the vesicle size, shape, zeta potential, drug content, and in vitro ligand agglutination assay by keeping the liposomal formulations in sealed ambercolored vials (10-mL capacity) after flushing with nitrogen. The stability of liposomal formulations was found to be temperature dependent. All the liposomal formulations were found to be stable at 4°C±2°C up to 1 month. Storage at 25°C±2°C/60%±5% RH and 40°C±2°C/75%±5% RH adversely affected uncoated liposomal formulations. Carbohydrate coating of the liposomes could enhance the stability of liposomes at 25°C±2°C/60%±5% RH and 40°C±2°C/75%±5% RH. Published: May 18, 2007     

Influence of Formulation and Processing Factors on Stability of Levothyroxine Sodium Pentahydrate

Stability of formulations over shelf-life is critical for having a quality product. Choice of excipients, manufacturing process, storage conditions, and packaging can either mitigate or enhance the degradation of the active pharmaceutical ingredient (API), affecting potency and/or stability. The purpose was to investigate the influence of processing and formulation factors on stability of levothyroxine (API). The API was stored at long-term (25°C/60%RH), accelerated (40°C/75%RH), and low-humidity (25°C/0%RH and 40°C/0%RH) conditions for 28 days. Effect of moisture loss was evaluated by drying it (room temperature, N₂) and placed at 25°C/0%RH and 40°C/0%RH. The API was incubated with various excipients (based on package insert of marketed tablets) in either 1:1, 1:10, or 1:100 ratios with 5% moisture at 60°C. Commonly used ratios for excipients were used. The equilibrium sorption data was collected on the API and excipients. The API was stable in solid state for the study duration under all conditions for both forms (potency between 90% and 110%). Excipients effect on stability varied and crospovidone, povidone, and sodium laurel sulfate (SLS) caused significant API degradation where deiodination and deamination occurred. Moisture sorption values were different across excipients. Crospovidone and povidone were hygroscopic whereas SLS showed deliquescence at high RH. The transient formulation procedures where temperature might go up or humidity might go down would not have major impact on the API stability. Excipients influence stability and if possible, those three should either be avoided or used in minimum quantity which could provide more stable tablet formulations with minimum potency loss throughout its shelf-life.     

Influence of Polymers on the Physical and Chemical Stability of Spray-dried Amorphous Solid Dispersion: Dipyridamole Degradation Induced by Enteric Polymers

Amorphous solid dispersions (ASDs) are inherently unstable because of high internal energy. Evaluating physical and chemical stability during the process and storage is essential. Numerous researches have demonstrated how polymers influence the drug precipitation and physical stability of ASDs, while the influence of polymers on the chemical stability of ASDs is often overlooked. Therefore, this study aimed to investigate the effect of polymers on the physical and chemical stability of spray-dried ASDs using dipyridamole (DP) as a model drug. Proper polymers were selected by assessing their abilities to inhibit drug recrystallization in supersaturated solutions. HPMC E5, Soluplus®, HPMCP-55, and HPMCAS-LP were shown to be effective stabilizers. The optimized formulations were further stored at a high temperature (60 °C) and high humidity (40 °C, 75% RH) for 2 months, and their physical and chemical stability was evaluated using polarizing optical microscopy, FTIR, HPLC, and mass spectrometry (MS). In general, crystallization was observed in all samples, which indicated the physical instability under stressed storage conditions. Also, it was noted that the polymers in ASDs rather than physical mixtures, induced a dramatic drug degradation after being exposed to a high temperature (HPMCP-55 >?80% and HPMCAS-LP >?50%) and high humidity (HPMCP-55 >?40% and HPMCAS-LP >?10%). The MS analysis further confirmed the degradation products, which might be generated from the reaction between dipyridamole and phthalic anhydride decomposed from HPMCP-55 and HPMCAS-LP. Overall, the exposure of ASDs to stressed conditions resulted in recrystallization and even the chemical degradation induced by polymers.     

The solution and solid state stability and excipient compatibility of parthenolide in feverfew

The objectives of this research were to evaluate the stability of parthenolide in feverfew solution state and powdered feverfew (solid state), and explore the compatibility between commonly used excipients and parthenolide in feverfew. Feverfew extract solution was diluted with different pH buffers to study the solution stability of parthenolide in feverfew. Powdered feverfew extract was stored under 40 degrees C/0% approximately 75% relative humidities (RH) or 31% RH/5~50 degrees C to study the influence of temperature and relative humidity on the stability of parthenolide in feverfew solid state. Binary mixtures of feverfew powered extract and different excipients were stored at 50 degrees C/ 75% RH for excipient compatibility evaluation. The degradation of parthenolide in feverfew solution appears to fit a typical first-order reaction. Parthenolide is comparatively stable when the environmental pH is in the range of 5 to 7, becoming unstable when pH is less than 3 or more than 7. Parthenolide degradation in feverfew in the solid state does not fit any obvious reaction model. Moisture content and temperature both play important roles affecting the degradation rate. After 6 months of storage, parthenolide in feverfew remains constant at 5 degrees C/31% RH. However, approximately 40% parthenolide in feverfew can be degraded if stored at 50 degrees C/31% RH. When the moisture changed from 0% to 75% RH, the degradation of parthenolide in feverfew increased from 18% to 32% after 6-month storage under 40 degrees C. Parthenolide in feverfew exhibits good compatibility with commonly used excipients under stressed conditions in a 3-week screening study.     

Temperature and the hygropreference of the Arctic Collembolan Onychiurus arcticus and mite Lauroppia translamellata

The hygropreference of adult Onychiurus arcticus (Tullberg) was investigated over 2 h at 0, 10 and 20°C, along humidity gradients (12–98% RH) established using different salt solutions. At all temperatures O. arcticus preferred the highest humidity (98% RH). At 0 and 20°C, saturated conditions were preferred to 98% RH. The hygropreference of the mite Lauroppia translamellata (Willmann) was also assessed at 20°C, and no clear RH preference was observed. This species survived the loss of 24.9 ± 2.1% of its initial water content when held for 24 h at 20°C and 12% RH. A range of assays designed to eliminate the influence of thigmotactic behaviour and population clumping permit exclusion of these factors as being responsible for the observed results. The mean initial water content of O. arcticus samples (71.7 ± 10.9, 73.4 ± 4.0 and 73.8 ± 23.5% at 0, 10 and 20°C, respectively) did not differ significantly between temperatures, indicating that the results were not influenced by differences in initial hydrated state. The percentage water loss of individuals within the gradient increased with temperature, and differed significantly between regimes. The ecological significance of the observed humidity preferences are discussed.     

Core-shell encapsulation formulations to stabilize desiccated Bradyrhizobium against high environmental temperature and humidity

Engineered materials to improve the shelf-life of desiccated microbial strains are needed for cost-effective bioaugmentation strategies. High temperatures and humidity of legume-growing regions challenge long-term cell stabilization at the desiccated state. A thermostable xeroprotectant core and hydrophobic water vapour barrier shell encapsulation technique was developed to protect desiccated cells from the environment. A trehalose core matrix increased the stability of desiccated Bradyrhizobium by three orders of magnitude over 20 days at 32°C and 50% relative humidity (RH) compared to buffer alone; however, the improvement was not deemed sufficient for a shelf-stable bioproduct. We tested common additives (skim milk, albumin, gelatin and dextran) to increase the glass transition temperature of the desiccated product to provide further stabilization. Albumin increased the glass transition temperature of the trehalose-based core by 40°C and stabilized desiccated Bradyrhizobium for 4 months during storage at high temperature (32°C) and moderate humidity (50% RH) with only 1 log loss of viability. Although the albumin-trehalose core provided exceptional protection against high temperature, it was ineffective at higher humidity conditions (75%). We therefore incorporated a paraffin shell, which protected desiccated cells against 75% RH providing proof of concept that core and shell encapsulation is an effective strategy to stabilize desiccated cells.     

Effects of Temperature and Relative Humidity on Development,Reproduction, and Predation in Feltiella acarisuga (Vallot) (Diptera: Cecidomyiidae)

The predatory gall midge Feltiella acarisuga (Vallot) (Diptera: Cecidomyiidae) is a biological control agent for twospotted spider mites on greenhouse vegetable crops. Effects of temperature and relative humidity (RH) on development of immatures, reproduction, and prey capture were determined in order to confirm the suitability of F. acarisuga for use in greenhouses. Developmental time ranged from 10 days at 27°C to 34 days at 15°C. At 20°C, developmental time was significantly shorter at 96% RH than at 84% RH. There was very poor survival of immatures at 64% RH and none at 36%. Lifespan of adult females decreased with increasing temperature, but temperature had no significant effect on number of eggs laid. At 20°C, lifespan was longer at 84 and 96% RH than at 64 or 36% RH. The number of spider mites attacked by 3-day-old larvae over 8 h increased with increasing temperature from 15 to 27°C. The number of mites attacked also increased with increasing RH at 27°C. We conclude that F. acarisuga will complete its life cycle and reproduce under conditions typically found in vegetable greenhouses in northern temperate climates. However, extended periods of low RH (<60% RH) could reduce reproduction and survivorship sufficiently to impair the predator's action against spider mite populations.