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Optimization of acetic acid production from synthesis gas by chemolithotrophic bacterium--Clostridium aceticum using statistical approach

Sim JH, Kamaruddin AH

Bioresour Technol, 2008 May;99(8):2724-35.
PMID: 17697778

Efforts in optimizing reducing agents, cysteine-HCl.H2O and sodium sulfide in order to attain satisfactory responses during acetic acid fermentation have been carried out in this study. Cysteine-HCl.H2O each with five concentrations (0.00-0.50 g/L) was optimized one at a time and followed by sodium sulfide component (0.00-0.50 g/L). Response surface methodology (RSM) was used to determine the optimum concentrations of cysteine-HCl.H2O and sodium sulfide. The statistical analysis showed that the amount of cells produced and efficiency in CO conversion were not affected by sodium sulfide concentration. However, sodium sulfide is required as it does influence the acetic acid production. The optimum reducing agents for acetic acid fermentation was at 0.30 g/L cysteine-HCl.H2O and sodium sulfide respectively and when operated for 60 h cultivation time resulted in 1.28 g/L acetic acid production and 100% CO conversion.

Matched MeSH terms: Freeze Drying
Fulltext Safety Evaluation of Oral Toxicity of Carica papaya Linn. Leaves: A Subchronic Toxicity Study in Sprague Dawley Rats

Ismail Z, Halim SZ, Abdullah NR, Afzan A, Abdul Rashid BA, Jantan I

Evid Based Complement Alternat Med, 2014;2014:741470.
PMID: 25530788 DOI: 10.1155/2014/741470

The subchronic toxicity effect of the leaf extract of Carica papaya Linn. in Sprague Dawley (SD) rats was investigated in this study. The extract was prepared by dissolving the freeze dried extract of the leaves in distilled water and was administered orally to SD rats (consisted of 10 rats/sex/group) at 0 (control), 0.01, 0.14, and 2 g/kg body weight (BW) for 13 weeks. General observation, mortality, and food and water intake were monitored throughout the experimental period. Hematological and biochemical parameters, relative organ weights, and histopathological changes were evaluated. The study showed that leaf extract when administered for 13 weeks did not cause any mortality and abnormalities of behavior or changes in body weight as well as food and water intake. There were no significant differences observed in hematology parameters between treatment and control groups; however significant differences were seen in biochemistry values, for example, LDH, creatinine, total protein, and albumin. However, these changes were not associated with histopathological changes. In conclusion, the results suggested that daily oral administration of rats with C. papaya leaf extract for 13 weeks at a dose up to fourteen times the levels employed in traditional medicine practice did not cause any significant toxic effect.

Matched MeSH terms: Freeze Drying
Amplification of ST50 gene using dry-reagent-based polymerase chain reaction for the detection of Salmonella typhi

Aziah I, Ravichandran M, Ismail A

Diagn Microbiol Infect Dis, 2007 Dec;59(4):373-7.
PMID: 17964105

Conventional polymerase chain reaction (PCR) testing requires many pipetting steps and has to be transported and stored in cold chain. To overcome these limitations, we designed a ready-to-use PCR test for Salmonella typhi using PCR reagents, primers against the ST50 gene of S. typhi, a built-in internal amplification control (IAC), and gel loading dye mixed and freeze-dried in a single tube. The 2-step dry-reagent-based assay was used to amplify a 1238-bp target gene and an 810-bp IAC gene from 73 BACTEC blood culture broths (33 true positives for S. typhi and 40 true negatives for non-S. typhi). The sensitivity, specificity, positive predictive value, and negative predictive value of the PCR assay were 87.9%, 100%, 100%, and 90.9%, respectively. We suggest that this rapid 2-step PCR test could be used for the rapid diagnosis of typhoid fever.

Matched MeSH terms: Freeze Drying/methods*
Effect of different drying methods on the morphology, crystallinity, swelling ability and tensile properties of nata de coco

Norhayati Pa'e, Nur Idayu Abd Hamid, Norzieana Khairuddin, Khairul Azly Zahan, Kok FS, Bazlul Mobin Siddique, et al.

Sains Malaysiana, 2014;43:767-773.

Nata de coco or bacterial cellulose produced by Acetobacter xylinum is a unique type of biocellulose. It contains more than 90% of water. Dried nata was preferred compared to wet form since it is more convenient and portable with stable properties. Therefore, drying process is necessary in order to produce dried nata de coco. Drying method is a key factor that influenced the properties of dried nata de coco produced. The aim of this study was to investigate the effect of different drying methods on morphology, crystallinity, swelling ability and tensile strength of dried nata de coco. Nata de coco samples were dried using three physical drying methods such as oven, tray dryer or freeze dryer until it achieved 3-5% moisture content. Obviously, the three drying techniques produced web-like structured nata de coco and quite similar crystallinity which was in range between 87 and 89%. Freeze dried sample showed the largest swelling capacity and tensile strength which was found to be 148 MPa. Different drying method gave different properties of nata de coco. Therefore, the present work proposed the most suitable drying method can be utilized based on the properties of end product needed.

Matched MeSH terms: Freeze Drying
Fulltext Lyophilised Platelet-Rich Fibrin: Physical and Biological Characterisation

Ngah NA, Dias GJ, Tong DC, Mohd Noor SNF, Ratnayake J, Cooper PR, et al.

Molecules, 2021 Nov 25;26(23).
PMID: 34885714 DOI: 10.3390/molecules26237131

BACKGROUND: Platelet-rich fibrin (PRF) has gained popularity in craniofacial surgery, as it provides an excellent reservoir of autologous growth factors (GFs) that are essential for bone regeneration. However, the low elastic modulus, short-term clinical application, poor storage potential and limitations in emergency therapy use restrict its more widespread clinical application. This study fabricates lyophilised PRF (Ly-PRF), evaluates its physical and biological properties, and explores its application for craniofacial tissue engineering purposes.
MATERIAL AND METHODS: A lyophilisation method was applied, and the outcome was evaluated and compared with traditionally prepared PRF. We investigated how lyophilisation affected PRF's physical characteristics and biological properties by determining: (1) the physical and morphological architecture of Ly-PRF using SEM, and (2) the kinetic release of PDGF-AB using ELISA.
RESULTS: Ly-PRF exhibited a dense and homogeneous interconnected 3D fibrin network. Moreover, clusters of morphologically consistent cells of platelets and leukocytes were apparent within Ly-PRF, along with evidence of PDGF-AB release in accordance with previously reports.
CONCLUSIONS: The protocol established in this study for Ly-PRF preparation demonstrated versatility, and provides a biomaterial with growth factor release for potential use as a craniofacial bioscaffold.

Matched MeSH terms: Freeze Drying
Effects of freeze-dried Mitsuokella jalaludinii culture and Natuphos(®) phytase supplementation on the performance and nutrient utilisation of broiler chickens

Lan G, Abdullah N, Jalaludin S, Ho YW

J Sci Food Agric, 2012 Jan 30;92(2):266-73.
PMID: 21796639 DOI: 10.1002/jsfa.4570

Phytate-bound phosphorus (P) in poultry diets is poorly available to chickens. Hence exogenous phytase is often added to their diets. Mitsuokella jalaludinii is a rumen bacterial species that produces high phytase activity. In this study the effects of freeze-dried active M. jalaludinii culture (FD-AMJC) and Natuphos(®) phytase (phytase N) supplementations on the growth performance and nutrient utilisation of broiler chickens fed a low-available P (aP) diet were evaluated.

Matched MeSH terms: Freeze Drying
Enhancement of viability of a probiotic Lactobacillus strain for poultry during freeze-drying and storage using the response surface methodology

Khoramnia A, Abdullah N, Liew SL, Sieo CC, Ramasamy K, Ho YW

Anim Sci J, 2011 Feb;82(1):127-35.
PMID: 21269371 DOI: 10.1111/j.1740-0929.2010.00804.x

A rotatable central composite design (CCD) was used to study the effect of cryoprotectants (skim milk, sucrose and lactose) on the survival rate of a probiotic Lactobacillus strain, L. reuteri C10, for poultry, during freeze-drying and storage. Using response surface methodology, a quadratic polynomial equation was obtained for response value by multiple regression analyses: Y = 8.59546-0.01038 X(1)-0.09382 X(2)-0.07771 X(3)-0.054861 X(1)(2)-0.04603 X(3)(2)-0.10938 X(1)X(2). Based on the model predicted, sucrose exerted the strongest effect on the survival rate. At various combinations of cryoprotectants, the viability loss of the cells after freeze-drying was reduced from 1.65 log colony forming units (CFU)/mL to 0.26-0.66 log CFU/mL. The estimated optimum combination for enhancing the survival rate of L. reuteri C10 was 19.5% skim milk, 1% sucrose and 9% lactose. Verification experiments confirmed the validity of the predicted model. The storage life of freeze-dried L. reuteri C10 was markedly improved when cryoprotectants were used. At optimum combination of the cryoprotectants, the survival rates of freeze-dried L. reuteri C10 stored at 4°C and 30°C for 6 months were 96.4% and 73.8%, respectively. Total viability loss of cells which were not protected by cryoprotectants occurred after 12 and 8 weeks of storage at 4°C and 30°C, respectively.

Matched MeSH terms: Freeze Drying*
Fulltext Effect of freeze-drying on the antioxidant compounds and antioxidant activity of selected tropical fruits

Shofian NM, Hamid AA, Osman A, Saari N, Anwar F, Dek MS, et al.

Int J Mol Sci, 2011;12(7):4678-92.
PMID: 21845104 DOI: 10.3390/ijms12074678

The effects of freeze-drying on antioxidant compounds and antioxidant activity of five tropical fruits, namely starfruit (Averrhoa carambola L.), mango (Mangifera indica L.), papaya (Carica papaya L.), muskmelon (Cucumis melo L.), and watermelon Citruluss lanatus (Thunb.) were investigated. Significant (p < 0.05) differences, for the amounts of total phenolic compounds (TPC), were found between the fresh and freeze-dried fruit samples, except muskmelon. There was no significant (p > 0.05) change, however, observed in the ascorbic acid content of the fresh and freeze-dried fruits. Similarly, freeze-drying did not exert any considerable effect on β-carotene concentration of fruits, except for mango and watermelon, where significantly (p < 0.05) higher levels were detected in the fresh samples. The results of DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging and reducing power assays revealed that fresh samples of starfruit and mango had relatively higher antioxidant activity. In case of linoleic acid peroxidation inhibition measurement, a significant (p < 0.05) but random variation was recorded between the fresh and freeze-dried fruits. Overall, in comparison to β-carotene and ascorbic acid, a good correlation was established between the result of TPC and antioxidant assays, indicating that phenolics might have been the dominant compounds contributing towards the antioxidant activity of the fruits tested.

Matched MeSH terms: Freeze Drying
The use of freeze-dry bovine pericardium (FDBP) in diaphragmatic herniorrhaphy in dogs

Loqman MY, Wong CM, Hair-Bejo M, Zuki AB, Hafeez YM

Med J Malaysia, 2004 May;59 Suppl B:113-4.
PMID: 15468844

A study was conducted to investigate the effectiveness of freeze-dried bovine pericardium (FDBP) as a biomaterial in diaphragmatic herniorrhapy in dogs. Eight adult dogs were randomly selected and divided into two equal groups. In FDBP group, a diaphragmatic defect was induced and repaired with an identical size of FDBP. In the control group, a diaphragmatic wall was incised at three-side border creating a flap and sutured. Grossly, only mild intrathoracic adhesion was observed for most of the animals, and no herniation occured. Microscopically, the biomaterial incorporated into the host's tissue by ingrowth of young muscle fiber and massive new blood vessel formation in between the fibrous tissue.

Matched MeSH terms: Freeze Drying
Effect of steam sterilisation on lipophilic nutrient stability in a chloroplast-rich fraction (CRF) recovered from postharvest, pea vine field residue (haulm)

Wattanakul J, Syamila M, Briars R, Ayed C, Price R, Darwish R, et al.

Food Chem, 2021 Jan 01;334:127589.
PMID: 32707366 DOI: 10.1016/j.foodchem.2020.127589

Postharvest, pea vine field residue (haulm) was steam-sterilised and then juiced; a chloroplast-rich fraction (CRF) was recovered from the juice by centrifugation. The stability of selected nutrients (β-carotene, lutein, and α-tocopherol) in the freeze-dried CRF material was measured over 84 days; the impact of temperature (-20 °C, 4 °C, 25 °C and 40 °C), light and air on nutrient stability was established. All three nutrients were stable at -20 °C and 4 °C in the presence or absence of air; this stability was lost at higher temperatures in the presence of air. The extent and rate of nutrient breakdown significantly increased when the CRF samples were exposed to light. β-Carotene appeared to be more susceptible to degradation than lutein and α-tocopherol at 40 °C in the presence of air, but when CRF was exposed to light all three nutrients measured were significantly broken down during storage at 25 °C or 40 °C, whether exposed to air or not.

Matched MeSH terms: Freeze Drying
Development of a novel ionic liquid-curcumin complex to enhance its solubility, stability, and activity

Chowdhury MR, Moshikur RM, Wakabayashi R, Tahara Y, Kamiya N, Moniruzzaman M, et al.

Chem Commun (Camb), 2019 Jun 11.
PMID: 31184357 DOI: 10.1039/c9cc02812a

We report a one-step emulsification and rapid freeze-drying process to develop a curcumin-ionic liquid (CCM-IL) complex that could be readily dispersed in water with a significantly enhanced solubility of ∼8 mg mL-1 and half-life (t1/2) of ∼260 min compared with free CCM (solubility ∼30 nM and t1/2 ∼ 20 min). This process using an IL consisting of a long chain carbon backbone as a surfactant, may provide an alternative way of enhancing the solubility of poorly water-soluble drugs.

Matched MeSH terms: Freeze Drying
Fulltext Physicochemical Characterization, Molecular Docking, and In Vitro Dissolution of Glimepiride-Captisol Inclusion Complexes

Pal A, Roy S, Kumar A, Mahmood S, Khodapanah N, Thomas S, et al.

ACS Omega, 2020 Aug 18;5(32):19968-19977.
PMID: 32832751 DOI: 10.1021/acsomega.0c01228

This present study investigated the effect of Captisol, a chemically modified cyclodextrin, on the in vitro dissolution of glimepiride. We prepared glimepiride-Captisol complexes of different mass ratios (1:1, 1:2, and 1:3 w/w) by a physical mixing or freeze-drying technique, and found that complexation with Captisol enhanced the water solubility of glimepiride. Molecular docking and dynamic simulation predicted complex formation; at the same time, Fourier transform infrared spectroscopy, differential scanning calorimetry, powder X-ray diffractometry, and scanning electron microscope indicated molecular interactions that support complexation. We also found that an inclusion complex was better than a physical mixture in enhancing the complexation of glimepiride with Captisol and enhancing water solubility. Phase solubility study of the glimepiride-Captisol complex showed an AL-type profile, implying the formation of a 1:1 inclusion complex. The study also revealed that pH influenced the stability of the complex because the stability constant of the glimepiride-Captisol complex was higher in distilled water of pH ∼6.0 than in phosphate buffer of pH 7.2.

Matched MeSH terms: Freeze Drying
Effect of processing methods on xylitol-starch base co-processed adjuvant for orally disintegrating tablet application

Bin LK, Helaluddin ABM, Islam Sarker MZ, Mandal UK, Gaurav A

Pak J Pharm Sci, 2020 Mar;33(2):551-559.
PMID: 32276897

Orally disintegrating tablet (ODT) is a friendly dosage form that requires no access to water and serves as a solution to non-compliance. There are many co-processed adjuvants available in the market. However, there is no single product possesses all the ideal characteristics such as good compressibility, fast disintegration and good palatability for ODT application. The aim of this research was to produce a xylitol-starch base co-processed adjuvant which is suitable for ODT application. Two processing methods namely wet granulation and freeze drying were used to compare the characteristics of co-processed adjuvant comprising of xylitol, starch and crospovidone XL-10 mixed at various ratios. The co-processed excipients were compressed into ODT and physically characterized for powder flow, particle size, hardness, thickness, weight, friability, in-vitro disintegration time and in-situ disintegration time, lubricant sensitivity, dilution potential, Fourier transform infrared spectroscopy, scanning electronic microscopy and x-ray diffraction analysis. Formulation F6 was selected as the optimum formulation due to the fastest in-vitro (135.33±11.52 s) and in-situ disintegration time (88.67±13.56s) among all the formulations (p<0.05). Increase in starch component decreases disintegration time of ODT. The powder flow fell under the category of fair flow. Generally, it was observed that freeze drying method produced smaller particle size granules compared to wet granulation method. ODT produced from freeze drying method had shorter disintegration time compared to ODT from wet granulation batch. In conclusion, a novel co-processed excipient comprised of xylitol, starch and crospovidone XL-10, produced using freeze drying method with fast disintegration time, good compressibility and palatability was developed and characterized. The co-processed excipient is suitable for ODT application.

Matched MeSH terms: Freeze Drying/methods
The effect of drying methods on the physicochemical and antioxidant properties of Bintangor orange (Citrus nobilis) powders

Phing PL, Abdullah A, Sin CL, Foong SCY

Acta Sci Pol Technol Aliment, 2022 2 18;21(1):111-122.
PMID: 35174693 DOI: 10.17306/J.AFS.0901

BACKGROUND: Bintangor oranges are a mandarin species that is abundant in vitamin C and beta-carotene. However, due to its short shelf life, the fresh fruit can be converted into powder form, which is comparatively more stable.
METHODS: This study compares the effects of spray drying, freeze drying, drum drying, vacuum oven drying, and convection oven drying on the physicochemical properties of Bintangor orange powder, including vitamin C and total carotenoid content. The physicochemical properties analyzed for the powders were color analysis, moisture content, water activity, hygroscopicity, degree of caking, wettability, flowability, water solubility index, and bulk density.
RESULTS: Our results showed that freeze dried and convection oven dried powders retained their color so that the powder was the same as the original puree. All powders used in this showed an acceptable moisture content level, with a range of 2.11–2.31%. Spray dried and drum dried powders had the lowest value of moisture content and water activity. Moreover, spray dried powders showed the lowest value in hygroscopicity and bulk density and took the shortest time to wet the powder. The highest solubility and flowability properties were 12.99%, 0.39 g/mL, 18.39 s, 96.08%, and 19.17°, respectively. However, the freeze drying method retained the highest value for both nutritional pigments of vitamin C and total carotenoid content, 18.31 mg/g and 91.32 μg/g, respectively.
CONCLUSIONS: Freeze drying is the most suitable drying method with favorable powder properties compared to spray drying, drum drying, vacuum oven drying and convection oven drying.

Matched MeSH terms: Freeze Drying
Development of various composition multicomponent chitosan/fish collagen/glycerin 3D porous scaffolds: Effect on morphology, mechanical strength, biostability and cytocompatibility

Ullah S, Zainol I, Chowdhury SR, Fauzi MB

Int J Biol Macromol, 2018 May;111:158-168.
PMID: 29305219 DOI: 10.1016/j.ijbiomac.2017.12.136

The various composition multicomponent chitosan/fish collagen/glycerin 3D porous scaffolds were developed and investigated the effect of various composition chitosan/fish collagen/glycerin on scaffolds morphology, mechanical strength, biostability and cytocompatibility. The scaffolds were fabricated via freeze-drying technique. The effects of various compositions consisting in 3D scaffolds were investigated via FT-IR analysis, porosity, swelling and mechanical tests, and effect on the morphology of scaffolds investigated microscopically. The biostability and cytocompatibility tests were used to explore the ability of scaffolds to use for tissue engineering application. The average pore sizes of scaffolds were in range of 100.73±27.62-116.01±52.06, porosity 71.72±3.46-91.17±2.42%, tensile modulus in dry environment 1.47±0.08-0.17±0.03MPa, tensile modulus in wet environment 0.32±0.03-0.14±0.04MPa and biodegradation rate (at day 30) 60.38±0.70-83.48±0.28%. In vitro culture of human fibroblasts and keratinocytes showed that the various composition multicomponent 3D scaffolds were good cytocompatibility however, the scaffolds contained high amount of fish collagen excellently facilitated cell proliferation and adhesion. It was found that the high amount fish collagen and glycerin scaffolds have high porosity, enough mechanical strength and biostability, and excellent cytocompatibility.

Matched MeSH terms: Freeze Drying
Fulltext Freeze-Dried Lopinavir-Loaded Nanostructured Lipid Carriers for Enhanced Cellular Uptake and Bioavailability: Statistical Optimization, in Vitro and in Vivo Evaluations

Khan AA, Mudassir J, Akhtar S, Murugaiyah V, Darwis Y

Pharmaceutics, 2019 Feb 25;11(2).
PMID: 30823545 DOI: 10.3390/pharmaceutics11020097

Nanostructured lipid carriers (NLCs) loaded with lopinavir (LPV) were prepared by the high-shear homogenization method. The LPV-NLCs formulations were freeze-dried using trehalose as a cryoprotectant. In vitro release studies in simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 6.8) showed a burst release. The optimized freeze-dried formulation (LPV-NLC-7-Tres) had a particle size (PS), polydispersity index (PdI), zeta potential (ZP) and % entrapment efficiency (%EE) of 286.8 ± 1.3 nm, 0.413 ± 0.017, -48.6 ± 0.89 mV and 88.31 ± 2.04%, respectively. The optimized formulation observed by transmission and scanning electron microscopes showed a spherical shape. Differential scanning calorimetry study revealed the absence of chemical interaction between the drug and lipids. In vitro cellular uptake study using Caco-2 cell line showed a higher LPV uptake from LPV-NLC-7-Tres formulation compared to the free LPV-suspension. The 6-month stability study showed a minimum rise of ~40 nm in PS, while no significant changes in PdI, ZP and drug content of the LPV-NLC-7-Tres formulation stored at 5 °C ± 3 °C. The bioavailability of LPV following oral administration of LPV-NLC-7-Tres in male Wistar rats was found 6.98-fold higher than the LPV-suspension. In conclusion, the nanostructure lipid carriers are potential carriers for improving the oral bioavailability of lopinavir.

Matched MeSH terms: Freeze Drying
Fulltext Antioxidant Activity, and Volatile and Phytosterol Contents of Strobilanthes crispus Dehydrated Using Conventional and Vacuum Microwave Drying Methods

Chua LYW, Chua BL, Figiel A, Chong CH, Wojdyło A, Szumny A, et al.

Molecules, 2019 04 09;24(7).
PMID: 30970652 DOI: 10.3390/molecules24071397

The preservation of active constituents in fresh herbs is affected by drying methods. An effective drying method for Strobilanthes crispus which is increasingly marketed as an important herbal tea remains to be reported. This study evaluated the effects of conventional and new drying technologies, namely vacuum microwave drying methods, on the antioxidant activity and yield of essential oil volatiles and phytosterols. These drying methods included convective drying (CD) at 40 °C, 50 °C, and 60 °C; vacuum microwave drying (VMD) at 6, 9, and 12 W/g; convective pre-drying and vacuum microwave finish drying (CPD-VMFD) at 50 °C and 9 W/g; and freeze-drying (FD). GC–MS revealed 33 volatiles, and 2-hexen-1-ol, 2-hexenal, 1-octen-3-ol, linalool, and benzaldehyde were major constituents. The compounds β-sitosterol and α-linolenic acid were the most abundant phytosterol and fatty acid, respectively, in fresh S. crispus. The highest phenolic content was achieved with CD at 60 °C. The highest antioxidant activity was obtained with CD at 40 °C and VMD at 9 W/g. On the contrary, the highest total volatiles and phytosterols were detected with CD at 50 °C and VMD at 9 W/g, respectively. This study showed that CD and VMD were effective in producing highly bioactive S. crispus. A suitable drying parameter level, irrespective of the drying method used, was an important influencing factor.

Matched MeSH terms: Freeze Drying
Effect of disaccharide-polyol systems on the thermal stability of freeze-dried Mycobacterium bovis

Tan YZ, Chong YQ, Khong E, Liew YK, Chieng N

Int J Pharm, 2019 Jul 20;566:400-409.
PMID: 31136777 DOI: 10.1016/j.ijpharm.2019.05.063

Live attenuated Mycobacterium bovis (M. bovis), marketed as Bacille Calmette-Guérin is the only FDA-approved vaccine against tuberculosis. The prerequisite of cold chain storage between 2 and 8 °C hinders the global vaccination effort. The study aims to investigate the effect of trehalose, sucrose and glycerol combinations in enhancing the stability of M. bovis. The bacilli were formulated in various ratios of trehalose-glycerol, sucrose-glycerol, trehalose-sucrose-glycerol systems (test samples) and sodium glutamate (control), freeze-dried and stored for 28 days at 4 °C, 25 °C and 37 °C. Bacteria viability at pre-, post-freeze-drying and after storage were quantified by its density in colony-forming unit per milliliter (CFU/mL) as obtained through the pour plate method. Formulations were characterized using differential scanning calorimetry. Structural collapsed cakes were found on all freeze-dried formulations because of the low Tg'. Comparing between binary and ternary formulations, trehalose-sucrose-glycerol was found to be a superior lyoprotectant. Upon storage, the viability of bacteria in disaccharide-polyol formulations was highest when stored at 4 °C followed by 25 °C. The lowest viability was found after storage at 37 °C. While the ternary disaccharide-polyol system may be used as a thermoprotectant up to 25 °C, sodium glutamate has a superior thermoprotective effect at temperature above 25 °C.

Matched MeSH terms: Freeze Drying
Fulltext Lyophilized Amorphous Dispersion of Telmisartan in a Combined Carrier-Alkalizer System: Formulation Development and In Vivo Study

Al-Japairai KAS, Alkhalidi HM, Mahmood S, Almurisi SH, Doolaanea AA, Al-Sindi TA, et al.

ACS Omega, 2020 Dec 22;5(50):32466-32480.
PMID: 33376884 DOI: 10.1021/acsomega.0c04588

Telmisartan suffers from low oral bioavailability due to its poor water solubility. The research work presents a formulation of solid dispersed (SD) telmisartan formulation as a ternary mixture of a drug, a polymeric carrier (poly(vinylpyrrolidone) (PVP) K30), and an alkalizer (Na2CO3). The preparation method, which was lyophilization of an aqueous solution containing the ingredients, was free from any organic solvent. The developed SD formulations resulted in a significant improvement in in vitro dissolution (>90% drug dissolution in 15 min) compared to pure telmisartan. Solid-state characterization by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) studies indicated the conversion of crystalline telmisartan into an amorphous form. Fourier transform infrared (FTIR) spectroscopy revealed the drug-polymer interaction that was responsible for reducing the chances of recrystallization. A short-term stability study showed that selected SD formulations were stable in terms of in vitro dissolution and retained their amorphous structure in ambient and accelerated conditions over 2 months. Selected formulations (drug/PVP K30/Na2CO3 as 1:1:2 or 1:2:2 weight ratio) resulted in >2.48 times relative oral bioavailability compared to marketed formulations. It was considered that the incorporation of an alkalizer and a hydrophilic polymer, and amorphization of telmisartan by lyophilization, could enhance in vitro dissolution and improve oral bioavailability.

Matched MeSH terms: Freeze Drying
Fulltext Preliminary Study of In Vitro Three-Dimensional Skin Model Using an Ovine Collagen Type I Sponge Seeded with Co-Culture Skin Cells: Submerged versus Air-Liquid Interface Conditions

Fauzi MB, Rashidbenam Z, Bin Saim A, Binti Hj Idrus R

Polymers (Basel), 2020 Nov 25;12(12).
PMID: 33255581 DOI: 10.3390/polym12122784

Three-dimensional (3D) in vitro skin models have been widely used for cosmeceutical and pharmaceutical applications aiming to reduce animal use in experiment. This study investigate capability of ovine tendon collagen type I (OTC-I) sponge suitable platform for a 3D in vitro skin model using co-cultured skin cells (CC) containing human epidermal keratinocytes (HEK) and human dermal fibroblasts (HDF) under submerged (SM) and air-liquid interface (ALI) conditions. Briefly, the extracted OTC-I was freeze-dried and crosslinked with genipin (OTC-I_GNP) and carbodiimide (OTC-I_EDC). The gross appearance, physico-chemical characteristics, biocompatibility and growth profile of seeded skin cells were assessed. The light brown and white appearance for the OTC-I_GNP scaffold and other groups were observed, respectively. The OTC-I_GNP scaffold demonstrated the highest swelling ratio (~1885%) and water uptake (94.96 ± 0.14%). The Fourier transformation infrared demonstrated amide A, B and I, II and III which represent collagen type I. The microstructure of all fabricated sponges presented a similar surface roughness with the presence of visible collagen fibers and a heterogenous porous structure. The OTC-I_EDC scaffold was more toxic and showed the lowest cell attachment and proliferation as compared to other groups. The micrographic evaluation revealed that CC potentially formed the epidermal- and dermal-like layers in both SM and ALI that prominently observed with OTC-I_GNP compared to others. In conclusion, these results suggest that OTC_GNP could be used as a 3D in vitro skin model under ALI microenvironment.

Matched MeSH terms: Freeze Drying

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