Dynamic mechanical thermal analysis of hypromellose 2910 free films

It is common practice to coat oral solid dosage forms with polymeric materials for controlled release purposes or for practical and aesthetic reasons. Good knowledge of thermo-mechanical film properties or their variation as a function of polymer grade, type and amount of additives or preparation method is of prime importance in developing solid dosage forms. This work focused on the dynamic mechanical thermal characteristics of free films of hypromellose 2910 (also known as HPMC), prepared using three grades of this polymer from two different manufacturers, in order to assess whether polymer chain length or origin affects the mechanical or thermo-mechanical properties of the final films. Hypromellose free films were obtained by casting their aqueous solutions prepared at a specific concentrations in order to obtain the same viscosity for each. The films were stored at room temperature until dried and then examined using a dynamic mechanical analyser. The results of the frequency scans showed no significant differences in the mechanical moduli E' and E" of the different samples when analysed at room temperature; however, the grade of the polymer affected material transitions during the heating process. Glass transition temperature, apparent activation energy and fragility parameters depended on polymer chain length, while the material brand showed little impact on film performance

High-Resolution Ultrasound Spectroscopy for the Determination of Phospholipid Transitions in Liposomal Dispersions

High-resolution ultrasound spectroscopy (HR-US) is a spectroscopic technique using ultrasound waves at high frequencies to investigate the structural properties of dispersed materials. This technique is able to monitor the variation of ultrasound parameters (sound speed and attenuation) due to the interaction of ultrasound waves with samples as a function of temperature and concentration. Despite being employed for the characterization of several colloidal systems, there is a lack in the literature regarding the comparison between the potential of HR-US for the determination of phospholipid thermal transitions and that of other common techniques both for loaded or unloaded liposomes. Thermal transitions of liposomes composed of pure phospholipids (dimyristoylphosphatidylcholine, DMPC; dipalmitoylphosphatidylcholine, DPPC and distearoylphosphatidylcholine, DSPC), cholesterol and their mixtures were investigated by HR-US in comparison to the most commonly employed microcalorimetry (mDSC) and dynamic light scattering (DLS). Moreover, tramadol hydrochloride, caffeine or miconazole nitrate as model drugs were loaded in DPPC liposomes to study the effect of their incorporation on thermal properties of a phospholipid bilayer. HR-US provided the determination of phospholipid sol-gel transition temperatures from both attenuation and sound speed that are comparable to those calculated by mDSC and DLS techniques for all analysed liposomal dispersions, both loaded and unloaded. Therefore, HR-US is proposed here as an alternative technique to determine the transition temperature of phospholipid membrane in liposomes

Thermosensitive self-assembling block copolymers as drug delivery systems

Self-assembling block copolymers (poloxamers, PEG/PLA and PEG/PLGA diblock and triblock copolymers, PEG/polycaprolactone, polyether modified poly(Acrylic Acid)) with large solubility difference between hydrophilic and hydrophobic moieties have the property of forming temperature dependent micellar aggregates and, after a further temperature increase, of gellifying due to micelle aggregation or packing. This property enables drugs to be mixed in the sol state at room temperature then the solution can be injected into a target tissue, forming a gel depot in-situ at body temperature with the goal of providing drug release control. The presence of micellar structures that give rise to thermoreversible gels, characterized by low toxicity and mucomimetic properties, makes this delivery system capable of solubilizing water-insoluble or poorly soluble drugs and of protecting labile molecules such as proteins and peptide drugs

Fabrication of green nanoinsecticides from agri-waste of corn silk and its larvicidal and antibiofilm properties

he corn silk (CS) is composed of the thread- like stigmas of female inflorescences of Zea mays L. and represents an important waste material from maize crop production that can be recycled in further applications. In this research, the CS was used for the bio-fabrication of Ag nanoparticles (AgNPs) that were evaluated against (I–V) larval instars and pupae of the mosquito vector Aedes aegypti. CS-AgNPs were characterized by UV-Vis spectroscopy, TEM, EDAX, XRD, FTIR, DLS, and zeta potential analysis. Z. mays extract analyzed by gas chro- matography mass spectrometry reveals 14 compounds. The larvicidal effectiveness of CS-fabricated AgNPs was 2.35 μg·mL−1 (I Instar) to 6.24 μg·mL−1 (pupae). The field application in water storage reservoirs of both CS extracts and CS-AgNPs (10 × LC50) led to a 68–69% reduction in larval density after 72 h post-treatment. Ecotoxicological impact of CS-fabricated AgNPs was evaluated on the pre- datory efficacy of Poecilia reticulata on all the larval instars and pupae of Ae. aegypti. Finally, CS-AgNPs were tested to elucidate its anti-biofilm attributes. The CS-AgNPs at 125 μg·mL−1 showed a biofilm inhibition of 90% on S. aureus and 79% on S. epidermidis. These results support the use of CS-AgNPs for futuristic green alternative to mosquito vector management

Toxicological profiles and surface properties at physiological pH of N-decanoyl amino acids

Meeting title: From Food to Pharma: the polyhedral nature of polymersPURPOSE: N-acyl amino acids based surfactants are an attractive class of anionic amphiphiles alternative to sulphate-based surfactants potentially employed as excipients in all pharmaceutical applications at which an anionic surfactant (eg. sodium dodecyl sulphate SDS) is needed (1, 2). The aim of this work is to correlate surface properties of N-decanoyl amino acids at physiological pH and their toxicological profile in order to explore the potential use of these surfactants for …postprin