SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Drying

141

Flower pollen is collected by honeybee foragers, adhered on their rear legs and transported into the hives in the form of pellets. Once in the hives, bee pollen is moisturised with nectar and bee mouth secretions and due to enzymatically modifications it becomes the so-called bee-bread, the protein reservoir of young bees. Bee pollen can be artificially removed from bee legs and collected by using specific systems, the bee pollen traps. Bee pollen is commercialized for human consumption as fresh product and after freezing or drying. Although bee pollen is nowadays largely consumed in developed countries, as food or food supplement according to local legislation, little is known on its safety related to microbiological hazards. In this work, we aimed to characterize for the first time the microbiological profile of Italian bee pollen in fresh, frozen and dried form collected along an entire harvesting season. Moreover, monthly microbiological analyses were performed on frozen (storage at -18°C) and dried (storage at room temperature) bee pollen over a 4 months period. Further aim of this work was the evaluation of the possible impact on production level of three different traps used for pollen collection. Our results on microbial contamination of fresh and frozen bee pollen show that a more comprehensive microbiological risk assessment of bee pollen is required. On the other side, dried pollen showed very low microbial contamination and no pathogen survived after the drying process and during storage.

Concepts: Bacteria, Microbiology, Honey bee, Beekeeping, Drying, Flower, Honey, Apidae

140

Patchouli is used as an incense material and essential oil. The characteristic odor of patchouli leaves results from the drying process used in their production; however, there have to date been no reports on the changes in the odor of patchouli leaves during the drying process. We investigated the aroma profile of dried patchouli leaves using the hexane extracts of fresh and dried patchouli leaves. We focused on the presence or absence of the constituents of the fresh and dried extracts, and the differences in the content of the common constituents. Fourteen constituents were identified as characteristic of dried patchouli extract odor by gas chromatography-olfactometry analysis. The structures of seven of the 14 constituents were determined by gas chromatography-mass spectrometry (α-patchoulene, seychellene, humulene, α-bulnesene, isoaromadendrene epoxide, caryophyllene oxide, and patchouli alcohol). The aroma profile of the essential oil obtained from the dried patchouli leaves was clearly different from that of dried patchouli. The aroma profile of the essential oil was investigated by a similar method. We identified 12 compounds as important odor constituents. The structures of nine of the 12 constituents were determined by gas chromatographymass spectrometry (cis-thujopsene, caryophyllene, α-guaiene, α-patchoulene, seychellene, α-bulnesene, isoaromadendrene epoxide, patchouli alcohol, and corymbolone). Comparing the odors and constituents demonstrated that the aroma profile of patchouli depends on the manufacturing process.

Concepts: Olfaction, Drying, Perfume, Odor, Essential oil, Aroma compound, Aromatherapy, Patchouli

27

BACKGROUND: Intraabdominal peritoneal onlay polypropylene (PP) mesh repair of incisional hernia has the potential risk of adhesions, bowel obstructions, and intestinal fistulae. Fresh or cryopreserved human amniotic membrane (HAM) has been tested as an antiadherent layer in animals, with excellent outcomes. However, it has disadvantages: it is difficult to handle, and it is expensive to store. Another processing method is available: drying in a laminar flow hood and gamma irradiation. Because this method impairs the membrane’s cell viability, it may affect its antiadherent properties. However, such properties may also result from the collagen matrix and its basement membrane, which remain after drying. The aim of the present study was to asses dried irradiated HAM in adhesion prophylaxis in rats. METHODS: Twenty-four female rats were randomized into two groups. In the first group (control group), PP meshes were placed in the intraabdominal space, and in the second group (treatment group), PP meshes coated with HAM were used. Animals were killed on day 30 after surgery. Adhesions and parietal prosthetic incorporation were assessed macroscopically and expressed as the average percentage of the covered area. The portion of the abdominal wall was then resected for histological testing. RESULTS: The treatment group had a significantly higher percentage of adhesions and parietal incorporation compared with the control group (p = 0.003). Histological testing showed a higher inflammatory response in the treatment group, with an intense foreign body reaction. CONCLUSIONS: Dried irradiated HAM does not prevent adhesion formation in intraabdominal peritoneal onlay PP mesh repair in rats. Any use of this biomaterial in adhesion prophylaxis must be undertaken respecting graft cell viability as much as possible.

Concepts: Food irradiation, Collagen, Bowel obstruction, Polypropylene, Drying, Abdomen, Irradiation, Laminar flow cabinet

27

The aim of this study was to develop a spray dried submicrometer powder formulation suitable for the excipient enhanced growth (EEG) application. Combination particles were prepared using the Buchi Nano spray dryer B-90. A number of spray drying and formulation variables were investigated with the aims of producing dry powder formulations that were readily dispersed upon aerosolization and maximizing the fraction of submicrometer particles. Albuterol sulfate, mannitol, L-leucine, and poloxamer 188 were selected as a model drug, hygroscopic excipient, dispersibility enhancer and surfactant, respectively. Formulations were assessed by scanning electron microscopy and aerosol performance following aerosolization using an Aerolizer® dry powder inhaler (DPI). In vitro drug deposition was studied using a realistic mouth-throat (MT) model. Based on the in vitro aerosolization results, the best performing submicrometer powder formulation consisted of albuterol sulfate, mannitol, L-leucine and poloxamer 188 in a ratio of 30:48:20:2, containing 0.5% solids in a water:ethanol (80:20% v/v) solution which was spray dried at 70°C. The submicrometer particle fraction (FPF(1μm/ED)) of this final formulation was 28.3% with more than 80% of the capsule contents being emitted during aerosolization. This formulation also showed 4.1% MT deposition. The developed combination formulation delivered a powder aerosol developed for the EEG application with high dispersion efficiency and low MT deposition from a convenient DPI device platform.

Concepts: Electron, Drying, Dosage forms, Spray drying, Nano spray dryer

27

PURPOSE: To develop spray dried mucoadhesive and pH-sensitive microspheres (MS) based on polymethacrylate salt intended for vaginal delivery of tenofovir (a model HIV microbicide) and assess their critical biological responses. METHODS: The formulation variables and process parameters are screened and optimized using a 2(4-1) fractional factorial design. The MS are characterized for size, zeta potential, yield, encapsulation efficiency, Carr’s index, drug loading, in vitro release, cytotoxicity, inflammatory responses and mucoadhesion. RESULTS: The optimal MS formulation has an average size of 4.73 μm, Zeta potential of -26.3 mV, 68.9% yield, encapsulation efficiency of 88.7%, Carr’s index of 28.3 and drug loading of 2% (w/w). The MS formulation can release 90% of its payload in the presence of simulated human semen. At a concentration of 1 mg/ml, the MS are noncytotoxic to vaginal endocervical/epithelial cells and Lactobacillus crispatus when compared to control media. There is also no statistically significant level of inflammatory cytokine (IL1-α, IL-1β, IL-6, IL-8, and IP-10) release triggered by MS. The mucoadhesive property of MS formulation is 2-fold higher than that of 1% HEC gel formulation. CONCLUSION: These data suggest the promise of using such MS as an alternative controlled microbicide delivery template by intravaginal route for HIV prevention.

Concepts: Childbirth, Sexual intercourse, Statistical significance, Colloid, Semen, Drying, Statistical theory, Pre-ejaculate

4

Graphene oxide (GO) has recently become an attractive building block for fabricating graphene-based functional materials. GO films and fibers have been prepared mainly by vacuum filtration and wet spinning. These materials exhibit relatively high Young’s moduli but low toughness and a high tendency to tear or break. Here, we report an alternative method, using bar coating and drying of water/GO dispersions, for preparing large area GO thin films (e.g. 800-1200 cm(2) or larger) with an outstanding mechanical behavior and excellent tear resistance. These dried films were subsequently scrolled to prepare GO fibers with extremely large elongation to fracture (up to 76 %), high toughness (up to 17 J/m(3)) and attractive macroscopic properties, such as uniform circular cross section, smooth surface, and great knotability. This method is simple and after thermal reduction of the GO material, it can render highly electrically conducting graphene-based fibers with values up to 416 S/cm at room temperature. In this context, GO fibers annealed at 2000 °C were also successfully used as electron field emitters operating at low turn on voltages of ca. 0.48 V/μm and high current densities (5.3 A/cm(2)). Robust GO fibers and large-area films with fascinating architectures and outstanding mechanical and electrical properties were prepared bar coating followed by dry film scrolling.

Concepts: Electric charge, Electricity, Fundamental physics concepts, Continuum mechanics, Graphene, Materials science, Drying, Film

2

We look at the drying process in a simple glass channel with dominant capillary effects as is the case in microfluidics. We find drying kinetics commonly observed for confined geometry, namely a constant period followed by a falling rate period. From visualization of the air/water interface with high resolution, we observe that the drying rate decreases without a drying front progression although this is the usually accepted mechanism for confined geometries. We show with FEM that in our specific geometry the falling rate period is due to changes in the shape of the air-water interface at the free surface where most evaporation occurs. Our simulations show that the sensitivity of the drying rate to the shape of the first air-water interface from the sample free surface implies that slight changes of the wetting or pinning conditions can significantly modify the drying rate.

Concepts: Scientific method, Observation, Computer graphics, Philosophy of science, Liquid, Surface tension, Drying, Evaporation

0

The aim was to explore the effects of non-polar and polar protic solvents composed of dichloromethane (DCM) and ethanol (EtOH) on the properties of felodipine (FLDP) and Soluplus in solutions, casting films and spray dried drug-rich or polymer-rich solid dispersions (SDs). Measurement of intrinsic viscosity and solubility indicated that FLDP and Soluplus were miscible. EtOH-DCM ranging from 20:80 to 50:50 induced the strongest molecular interactions for FLDP-Soluplus-solvents systems. Accordingly, the casting films and spray dried powders of FLDP and Soluplus were prepared using pure EtOH or DCM and their mixtures as solvents. PLM, DSC, FT-IR, in vitro dissolution tests, and stability have been conducted to characterize these films or spray dried powders. EtOH-DCM (50:50) showed δH2-3 MPa1/2higher than FLDP and Soluplus. It exhibited stronger inhibitory effects on phase separation and recrystallization of amorphous FLDP than pure DCM or EtOH in the drug-rich casting films, spray drying process and spray dried SDs exposure to 40oC/ RH75% for one month. Higher ratio of Soluplus may offset the effects of solvents on the dissolution and stability of polymer-rich SDs. In conclusion, combination of non-polar and polar protic solvents is of high potential for spray drying to optimize drug-rich SDs.

Concepts: Ethanol, Solubility, Acetic acid, Solvent, Chemical polarity, Drying, Tetrahydrofuran, Protic solvent

0

The coffee-ring effect, ubiquitously present in the drying process of aqueous droplets, impedes the performance of a myriad of applications involving precipitation of particle suspensions in evaporating liquids on solid surfaces, such as liquid biopsy combinational analysis, microarray fabrication, and ink-jet printing, to name a few. We invented the methodology of laser-induced differential evaporation to remove the coffee-ring effect. Without any additives to the liquid or any morphology modifications of the solid surface the liquid rests on, we have eliminated the coffee-ring effect by engineering the liquid evaporation profile with a CO2laser irradiating the apex of the droplets. The method of laser-induced differential evaporation transitions particle deposition patterns from coffee-ring patterns to central-peak patterns, bringing all particles (e.g. fluorescent double strand DNAs) in the droplet to a designated area of 100 μm diameter without leaving any stains outside. The technique also moves the drying process from the constant contact radius (CCR) mode to the constant contact angle (CCA) mode. Physical mechanisms of this method were experimentally studied by internal flow tracking and surface evaporation flux mapping, and theoretically investigated by development of an analytical model.

Concepts: Water, Liquid, Surface tension, Drop, Drying, Surface, Evaporation, Liquids

0

The worldwide switch to inactivated polio vaccines (IPV) is a key component of the overall strategy to achieve and maintain global polio eradication. To this end, new IPV vaccine delivery systems may enhance patient convenience and compliance. In this work, we examine NanopatchTM (a solid, polymer micro-projection array) which offers potential advantages over standard needle/syringe administration including intradermal delivery and reduced antigen doses. Using trivalent IPV (tIPV) and a purpose-built evaporative dry-down system, candidate tIPV formulations were developed to stabilize tIPV during the drying process and upon storage. Identifying conditions to minimize tIPV potency losses during rehydration and potency testing was a critical first step. Various classes and types of pharmaceutical excipients (∼50 total) were then evaluated to mitigate potency losses (measured through D-antigen ELISAs for IPV1, IPV2, and IPV3) during drying and storage. Various concentrations and combinations of stabilizing additives were optimized in terms of tIPV potency retention, and two candidate tIPV formulations containing a cyclodextrin and a reducing agent (e.g., glutathione), maintained ≥80% D-antigen potency during drying and subsequent storage for 4 weeks at 4˚C, and ≥60% potency for 3 weeks at room temperature with the majority of losses occurring within the first day of storage.

Concepts: Pharmacology, Vaccine, Poliomyelitis, Polio vaccine, Drying, Poliomyelitis eradication, OPV AIDS hypothesis, Poliovirus