The effect of dehydration conditions on the functionality of anhydrous amorphous raffinose.

The purpose of this investigation is to study the effect of dehydration conditions of raffinose pentahydrate (RF.5H2O) on the physical properties and functionality of the resulting material. Crystalline RF.

Theoretical and experimental considerations on the enthalpic relaxation of organic glasses using differential scanning calorimetry.

The enthalpy relaxation of amorphous salicin, used as model organic glass of pharmaceutical relevance, was investigated using a combination of DSC measurements and theoretical simulations. The combined approach makes it possible to discern between the effect of the glass forming properties of the material and the effects of the thermal history and experimental conditions. The approach also facilitates an unambiguous definition of the time scale of the experiment, such that objective comparison among relaxation time and glass transition temperature values can be made.

Elucidating raw material variability--importance of surface properties and functionality in pharmaceutical powders.

The purpose of this study is to illustrate, with a controlled example, the influence of raw material variability on the excipient's functionality during processing. Soluble starch was used as model raw material to investigate the effect of variability on its compaction properties. Soluble starch used in pharmaceutical applications has undergone a purification procedure including washing steps.

Calorimetric study and modeling of molecular mobility in amorphous organic pharmaceutical compounds using a modified Adam-Gibbs approach.

The purpose of this study is to provide a quantitative characterization of the thermal behavior of amorphous organic pharmaceutical compounds across their glass transition temperature, and to assess their molecular mobility as a function of temperature and time by combining theoretical simulations with experimental measurements using differential scanning calorimetry. A computational approach built on the Boltzmann superposition principle of nonexponential decay and the Adam-Gibbs theory of entropic-dependent structural relaxation is presented. The heat capacities of the crystalline and amorphous forms are incorporated into the simulation in order to accurately assess the entropic fictive temperature as functions of temperature and time under any arbitrary set of experimental conditions.

Time-dependence of molecular mobility during structural relaxation and its impact on organic amorphous solids: an investigation based on a calorimetric approach.

Purpose: To develop a calorimetry-based model for estimating the time-dependence of molecular mobility during the isothermal relaxation of amorphous organic compounds below their glass transition temperature (Tg).

Methods: The time-dependent enthalpy relaxation times of amorphous sorbitol, indomethacin, trehalose and sucrose were estimated based on the nonlinear Adam-Gibbs equation. Fragility was determined from the scanning rate dependence of Tg.

Gene delivery to dendritic cells facilitated by a tumor necrosis factor alpha-competing peptide.

Efficient gene delivery systems tailor-designed for dendritic cells (DCs) would allow the possibility of therapeutic manipulation of a wide spectrum of immune functions. Toward achieving this goal, we have identified a novel heptameric peptide (YTYQGKL) that functions as a localization moiety to mediate gene transfer in murine DCs. The sequence was identified by screening a phage display library against a DC cell line (JAWSII) using mouse TNFalpha as the eluting ligand.

A cationic peptide consists of ornithine and histidine repeats augments gene transfer in dendritic cells.

Condensing the plasmid with high molecular weight cationic polymers such as poly-L-lysine (PLL) and poly-L-ornithine (PLO) can enhance antigen-specific immunity generated from genetic vaccination with naked DNA encoding antigens. While these high molecular weight polymers are clearly effective in transfection experiments, clinical applications are limited by their physical heterogeneity and toxicity. Three chemically defined low molecular weight cationic peptides, K(16), K(10)H(6), and O(10)H(6), were examined in the context of DNA binding, toxicity, and efficiency of gene transfer in dendritic cells (DC).