Histomorphometrical analysis of bone formed after maxillary sinus floor augmentation by grafting with a combination of autogenous bone and demineralized freeze-dried bone allograft or hydroxyapatite

Background: Maxillary sinus floor augmentation procedures are currently the treatment of choice when the alveolar crest of the posterior maxilla is insufficient for dental implant anchorage. This procedure aims to obtain enough bone with biomaterial association with the autogenous bone graft to create volume and allow osteo conduction. The objective of this study was to histologically and histometrically evaluate the bone formed after maxillary sinus floor augmentation by grafting with a combination of autogenous bone, from the symphyseal area mixed with DFDBA or hydroxyapatite.Methods: Ten biopsies were taken from 10 patients 10 months after sinus floor augmentation using a combination of 50% autogenous bone plus 50% dernineralized freeze-dried bone allograft (DFDBA group) or 50% autogenous bone plus 50% hydroxyapatite (HA group). Routine histological processing and staining with hernatoxylin and eosin and Masson's trichrome were performed.Results: the histomorphometrical analysis indicated good regenerative results in both groups for the bone tissue mean in the grafted area (50.46 +/- 16.29% for the DFDBA group and 46.79 +/- 8.56% for the HA group). Histological evaluation revealed the presence of mature bone with compact and cancellous areas in both groups. The inflammatory infiltrate was on average nonsignificant and of mononuclear prevalence. Some biopsies showed blocks of the biomaterial in the medullary spaces close to the bone wall, with absence of osteogenic activity.Conclusions: the results indicated that both DFDBA and HA associated with an autogenous bone graft were biocompatible and promoted osteoconduction, acting as a matrix for bone formation. However, both materials were still present after 10 months.

Sorption isotherm, glass transitions and state diagram for freeze-dried plum skin and pulp

Differential scanning calorimetry (DSC) was used to determine phase transitions of freeze-dried plums. Samples at low and intermediate moisture contents, were conditioned by adsorption at various water activities (0.11≤a w≤0.90) at 25°C, whereas in the high moisture content region (a w>0.90) samples were obtained by direct water addition, with the resulting sorption isotherm being well described by the Guggenheim-Anderson-deBoer (GAB) model. Freeze-dried samples of separated plum skin and pulp were also analysed. At a w≤0.75, two glass transitions were visible, with the glass transition temperature (T g) decreasing with increasing a w due to the water plasticising effect. The first T g was attributed to the matrix formed by sugars and water. The second one, less visible and less plasticised by water, was probably due to macromolecules of the fruit pulp. The Gordon-Taylor model represented satisfactorily the matrix glass transition curve for a w≤0.90. In the higher moisture content range T g remained practically constant around T g′ (-57.5°C). Analysis of the glass transition curve and the sorption isotherm indicated that stability at a temperature of 25°C, would be attained by freeze dried plum at a water activity of 0.04, corresponding to a moisture content of 12.9% (dry basis). © 2006 SAGE Publications.

In vitro evaluation of demineralized freeze-dried bone allograft in combination with enamel matrix derivative

BACKGROUND Preclinical and clinical studies suggest that a combination of enamel matrix derivative (EMD) with demineralized freeze-dried bone allograft (DFDBA) may improve periodontal wound healing and regeneration. To date, no single study has characterized the effects of this combination on in vitro cell behavior. The aim of this study is to test the ability of EMD to adsorb to the surface of DFDBA particles and determine the effect of EMD coating on downstream cellular pathways such as adhesion, proliferation, and differentiation of primary human osteoblasts and periodontal ligament (PDL) cells. METHODS DFDBA particles were precoated with EMD or human blood and analyzed for protein adsorption patterns via scanning electron microscopy. Cell attachment and proliferation were quantified using a commercial assay. Cell differentiation was analyzed using real-time polymerase chain reaction for genes encoding Runx2, alkaline phosphatase, osteocalcin, and collagen 1α1, and mineralization was assessed using alizarinred staining. RESULTS Analysis of cell attachment revealed no significant differences among control, blood-coated, and EMD-coated DFDBA particles. EMD significantly increased cell proliferation at 3 and 5 days after seeding for both osteoblasts and PDL cells compared to control and blood-coated samples. Moreover, there were significantly higher messenger ribonucleic acid levels of osteogenic differentiation markers, including collagen 1α1, alkaline phosphatase, and osteocalcin, in osteoblasts and PDL cells cultured on EMD-coated DFDBA particles at 3, 7, and 14 days. CONCLUSION The results suggest that the addition of EMD to DFDBA particles may influence periodontal regeneration by stimulating PDL cell and osteoblast proliferation and differentiation.

Conditioned Medium of Demineralized Freeze-Dried Bone Activates Gene Expression in Periodontal Fibroblasts in Vitro.

BACKGROUND: Demineralized bone matrix (DBM) is used for the treatment of osseous defects. Conditioned medium from native bone chips can activate transforming growth factor (TGF)-β signaling in mesenchymal cells. The aim of the study was to determine whether processing of native bone into DBM affects the activity of the conditioned medium. METHODS: Porcine cortical bone blocks were subjected to defatting, different concentrations of hydrochloric acid and various temperatures. DBM was lyophilized, ground, and placed into culture medium. Human gingiva and periodontal fibroblasts were exposed to the respective conditioned medium (DBCM). Changes in the expression of TGF-β target genes were determined. RESULTS: DBCM altered the expression of TGF-β target genes, e.g., adrenomedullin, pentraxin 3, KN Motif And Ankyrin Repeat Domains 4, interleukin 11, NADPH oxidase 4, and BTB (POZ) Domain Containing 11, by at least five-fold. The response was observed in fibroblasts from both sources. Defatting lowered the activity of DBCM. The TGF-β receptor type I kinase inhibitor SB431542, but not the inhibitor of bone morphogenetic protein receptor dorsomorphin, blocked the effects of DBCM on gene expression. Moreover, conditioned medium obtained from commercial human DBM modulated the expression of TGF-β target genes. CONCLUSION: The findings suggest that the conditioned medium from demineralized bone matrix can activate TGF-β signaling in oral fibroblasts. KEYWORDS: TGF-beta superfamily proteins; bone; bone substitutes; bone transplantation; conditioned media; freeze drying

Formulation and process engineering of freeze-dried orally disintegrating tablets

Orally disintegrating tablets (ODTs) which are also referred to as orodispersible and fast disintegrating tablets, are solid oral dosage forms which upon placing on the tongue, disperse/disintegrate rapidly before being swallowed as a suspension or solution. ODTs are therefore easier and more convenient to administer than conventional tablets and are particularly beneficial for paediatric and geriatric patients, who generally have difficulty swallowing their medication. The work presented in this thesis involved the formulation and process development of ODTs, prepared using freeze-drying. Gelatin is one of the principal excipients used in the formulation of freeze-dried ODTs. One of the studies presented in this thesis investigated the potential modification of the properties of this excipient, in order to improve the performance of the tablets. As gelatin is derived from animal sources, a number of ethical issues surround its use as an excipient in pharmaceutical preparations. This was one of the motivations, Methocel™ and Kollicoat® IR were evaluated as binders as alternative materials to gelatin. Polyox™ was also evaluated as a binder together with its potential uses as a viscosity increasing and mucoadhesive agent to increase the retention of tablets in the mouth to encourage pre-gastric absorption of active pharmaceutical ingredients (APIs). The in vitro oral retention of freeze-dried ODT formulations was one property which was assessed in a design of experiments – factorial design study, which was carried out to further understand the role that formulation excipients have on the properties of the tablets. Finally, the novel approach of incorporating polymeric nanoparticles in freeze-dried ODTs was investigated, to study if the release profile of APIs could be modified, which could improve their therapeutic effect. The results from these studies demonstrated that the properties of gelatin-based formulations can be modified by adjusting pH and ionic strength. Adjustment of formulation pH has shown to significantly reduce tablet disintegration time. Evaluating Methocel™, in particular low viscosity grades, and Kollicoat® IR as binders has shown that these polymers can form tablets of satisfactory hardness and disintegration time. Investigating Polyox™ as an excipient in freeze-dried ODT formulations revealed that low viscosity grades appear suitable as binders whilst higher viscosity grades could potentially be utilised as viscosity increasing and mucoadhesive agents. The design of experiments – factorial design study revealed the influence of individual excipients in a formulation mix on resultant tablet properties and in vitro oral retention of APIs. Novel methods have been developed, which allows the incorporation of polymeric nanoparticles in situ in freeze-dried ODT formulations, which allows the modification of the release profile of APIs.

Breads Fortified with Freeze-Dried Vegetables : Quality and Nutritional Attributes. Part II: Breads Not Containing Oil as an Ingredient

Acknowledgments: Funds for the study were provided by the Scottish Government's Rural and Environment Science and Analytical Services Division and conducted as part of the Scottish Government Strategic Research programme (Diet and Health Theme of the Food Land & People Programme). The authors are grateful to Phillip Morrice, Vivian Buchan, and Donna Henderson for helping with the nutritional analysis of the breads. The authors declare no conflicts of interest.

The preparation of a certified reference material of polar pesticides in freeze-dried water (CRM 606)

The preparation of a certified reference material of polar pesticides in freeze-dried water is described. The pesticides selected were atrazine, simazine, carbaryl, propanil, linuron, fenamiphos and permethrin which were added to 6000 litres of tap water at 50–80 μg · L–1 (200–320 μg · L–1 for permethrin) level in presence of NaCl (2.5 g · L–1) prior lyophilization. After the freeze-drying process the residue was rehomogenized, filled into amber glass bottles and stored at –20 °C, +4 °C and +20 °C. All pesticides were determined by HPLC/diode array detector, except permethrin which was determined by GC/ECD. The results obtained for atrazine, simazine, carbaryl, propanil, linuron and fenamiphos showed no within- or between-bottle inhomogeneity, however the material was non-homogeneous for permethrin and therefore this was withdrawn from further studies. With respect to the stability for over one year, all pesticides were stable at –20 °C. At +4 °C all pesticides were stable for at least 9 months and at +20 °C the stability was demonstrated only during the first month of storage. The content (mass fractions) of atrazine, simazine, carbaryl, propanil and linuron in freeze-dried water (CRM 606) was certified by an interlaboratory testing and a certification campaign.

Fingerprint profile by 1H RMN and chemometric analyses of freeze-dried Açaí berry pulp.

2016

Freeze-drying of ovalbumin loaded mesoporous silica nanoparticle vaccine formulation increases antigen stability under ambient conditions

Amino functionalised mesoporous silica nanoparticles (AM-41) have been identified as a promising vaccine delivery material. The capacity of AM-41 to stabilise vaccine components at ambient temperature (23–27 °C) was determined by adsorbing the model antigen ovalbumin (OVA) to AM-41 particles (OVA-41). The OVA-41 was successfully freeze-dried using the excipients 5% trehalose and 1% PEG8000. Both the immunological activity of OVA and the nanoparticle structure were maintained following two months storage at ambient temperature. The results of immunisation studies in mice with reconstituted OVA-41 demonstrated the induction of humoral and cell-meditated immune responses. The capacity of AM-41 particles to facilitate ambient storage of vaccine components without loss of immunological potency will underpin the further development of this promising vaccine delivery platform.

Modulated temperature differential scanning calorimetry and its application to freeze-drying

MTDSC is a software modification of the traditional DSC thermal analysis technique that allows more accurate determination of the glass transition as well as measurement of the endothermic relaxation that often accompanies the transition. The glass transition is an essential parameterboth of the original frozen solution and of the end product. Measurement of endothermic relaxation allows the determination of molecularrelaxation times in the freeze-dried product that may be useful in predicting the effect of formulation variables and storage conditions on physical stability.

Comparison between freeze and spray drying to obtain powder Rubrivivax gelatinosus biomass

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)