Physicochemical Characterization Techniques

Physicochemical characterization techniques are beginning to play a major role in the drug development process because they help us to understand the mechanism of drug delivery. Demonstration of this understanding is expected by the regulatory agencies and is usually an important component of the pharmaceutical development report. 

FIGURE I Polarized light micrograph of a granulation. Crystals of the API (see arrow) are visible within the matrix of the granulation. 

FIGURE 2 Chlorine mapping of a granulation containing a hydrochloride salt API. 

FIGURE 3 Scanning electron micrograph of a pellet at time zero of a dissolution. 

The molecules in a crystalline compound are ordered in a three-dimensional array called a lattice. When a collimated beam of X-rays is incident upon 

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A large number of analytical techniques and strategies have been developed to tackle modern speciation problems. There are four main approaches possible computational, direct species-specific detection, hybrid techniques, and physicochemical characterization techniques. 

Although a detailed description of the main physicochemical characterization techniques used in polymer characterization is clearly beyond the scope of this chapter, we have included specific details to be considered when such characterization is specifically for nanoparticles for the purpose of gene therapy. In such a situation we should take into consideration the following parameters and details ... 

TABLE 6 Analytical Techniques for Physicochemical Characterization of Proteins... 

JEV-loaded poly(lactide) (PLA) lamellar and PLG microspheres were successfully prepared with low-molecular-weight PLA by the precipitate method and with 6% w/v PLG in the organic phase, 10% w/v PVP, and 5% w/v NaCl in the continuous phase by using a w/o/w emulsion/solvent extraction technique, respectively [233], The JEV incorporation, physicochemical characterization data, and animal results obtained in this study may be relevant in optimizing the vaccine incorporation and delivery properties of these potential vaccine targeting carriers. 

The techniques listed in Table 3.4 are useful for the determination of purity and the presence of contaminating proteins. In addition to the physicochemical characterization and assays for bioactivity, the detection of undesirable biological activities arising from the protein product itself, and from contaminating proteins and other biomolecules is important, and is required by regulatory agencies. 

Equipment and Methods. The following equipment and techniques were used for the physicochemical characterization of the materials ... 

A definitive picture of the phase structure emerged and was made possible by the simultaneous development of powerful investigative techniques such as phase staining/electron micrography, low-angle X-ray diffraction, and GPC which were combined with conventional physicochemical characterizations of bulk, melt, and solution states of the block polymers. 

Samples of tridimensional microporous zinc phosphates with fully connected framework with structures type FAU and CZP have been prepared. The influence of some synthesis parameters on the nature of the crystalline phases obtained, such as crystallization time and temperature, concentration of the different reactives or pH, are discussed. Physicochemical characterization of the pure samples has been performed by different techniques ICP, XRD, C and P MAS-NMR, TG, TG-MS, in-situ thermal XRD analysis and SEM. These materials were tested in the Knoevenagel condensation of different esters and benzaldehyde. They have demonstrated a good selectivity and a higher activity than the basic zeolites previously described in the literature with these reactions. 

Several methods can be used to evaluate the hot-melt extruded products to distinguish among physical mixture of drug-carriers, solid solutions (molecularly dispersed), and solid dispersions, in which the drug is partly molecularly dispersed. An overview of the most common techniques used for the physicochemical characterization of hot-melt extruded formulations is provided in the following... 

Shah RM, Malherbe F, Eldridge D, Palombo EA, Harding IH. Physicochemical characterization of solid lipid nanoparticles (SLNs) prepared by a novel microemnlsion technique. Journal of Colloid and Interface Science. 2014 428(0) 286-294. 

A prerequisite for the development of optimized nanoparticles is precise characterization techniques. These are essential for quality control and are critical for application in biological setting. A thorough characterization of nanoparticle based therapeutics includes evaluation of physicochemical properties (size and morphology), assessment of biodistribution (absorption, distribution, metabolism and elimination) and safety studies (hemolysis. 

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