Solid-state characterization

Powders are masses of solid particles or granules surrotmded by air (or other fluid) and it is the solid plus fluid combination that significantly affects the bulk properties of the powder. It is perhaps the most complicating characteristic because the amotmt of fluid can be highly variable. 

Find lonizabie Functional Group - Preparation of Various Salt Forms -pKa Determination - Selection of Appropriate Counterions 

Powders are probably the least predictable of all materials in relation to flow ability because of the large number of factors that can change their rheological properties. Physical characteristics of the particles, such as size, shape, angularity, size variability, and hardness will all affect flow properties. External factors, such as humidity, conveying environment, vibration, and perhaps most importantly, aeration, will compotmd the problem. The more common variables would include  

Powder or particle variables o particle size o size distribution o shape o surface texture o cohesivity o surface coating o particle interaction o wear or attrition characteristic o propensity to electrostatic charge o hardness o stiffness o strength o fracture toughness 

External factors influencing powder behavior o flow rate 

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Based on voltammetry and solid-state characterization results. Pettier and Maurin [175] defined the electrochemical conditions leading to the formation of smooth crystalline deposits of CuInSe2 and also of the related binary compounds... 

Solid state characterization studies of the previously mentioned polymorphic systems [26-34] all utilize IR as a means to differentiate the various crystal modifications. In some cases, the observation of variations in IR absorption intensities has led to conclusions regarding intramolecular hydrogen bonding [26]. For other systems, fairly complete IR spectral band assignment has allowed for determination of structure for the polymorphic system. In one study [29], DSC-IR was used to identify the polymorphs and determine simultaneously the correlation between thermal events and structural changes. 

In this section, discussion of physicochemical profiling is limited to solubility, permeability, drug stability, and limited solid-state characterization (as we will see in Section 3.4, there are other physical-mechanical properties that must also be considered). For convenience, methods available for physicochemical profiling are discussed under the following categories computational tools (sometimes referred to as in silico tools), HTS methods, and in-depth physicochemical profiling.16... 

Tang, H., Pintauro, P. N., Guo, Q. and O Connor, S. 1999. Polyphosphazene membranes. ni. Solid-state characterization and properties of sulfonated poly[bis(3-methylphenoxy)phosphazene]. Journal of Applied Polymer Science 71 387-399. 

J.M. Chalmers and G. Dent, Vibrational spectroscopic methods in pharmaceutical solid-state characterization. Polymorphism, 95-138 (2006). 

The thermochemical characteristics of l,3,5-trinitro-l,3,5-triazepane, such as energies of dissociation of N-NOz bonds, enthalpies of formation, vaporization, and combustion, as well as enthalpy of formation of amine radicals, have been determined <2004MI92>. The rate constants of initial monomolecular stages of thermal decomposition in the solid phase were measured for its furazano-fused analog 20 <1999RCB1250> and the ratio of the rate constants of decomposition in the melt and solid states, characterizing the reaction retardation in the crystal lattice, was determined. The kinetics of the thermal decomposition of 20 has also been studied <1995MI885>. 

Mura, P, Bettinetti, G. P, Cirri, M., Maestrelli, F., Sorrenti, M., and Catenacci, L. 2005. Solid-state characterization and dissolution properties of naproxen-arginine-hydroxyptjbtnylelodextrin ternary system. 

Vippagunta, S. R., K. A. Maul, S. Tallavajhala, and D. J. W. Grant. 2002. Solid-state characterization of nifedipine solid dispersion nt J Pharm236 111-123. 

Vippagunta, S.R., et al., Solid-state characterization of nifedipine solid disperbibni, Pharm,... 

The solid-state characterization of the bifunctional radical [4,4 -(5-cyanobenzene)-l,3-bis(l,2,3,5-diselenadiazolyl)] 28 has been studied <1993CM820>. The crystal structure consists of stacks of diradicals running parallel to radical dimerization up and down the stack generates a zigzag arrangement, as seen in the related 1,3-phenylene structures. Along the stacking axis the mean intradimer Se-Se contact is 3.23 A, while the mean interdimer Se—Se distance is 3.91 A. 

Decatungstate, in the form of a lipophilic tetrabutilamonium salt ((n-C4H9N)4 W10O32), has been homogeneously dispersed in porous membranes made of PVDF (PVDF-W10). Solid-state characterization techniques confirmed that catalyst structure and spectroscopic properties of decatungstate have been preserved once immobilized within the membranes [42-44]. 

Leising, R.A., W.C. Thiebolt, and E.S. Takeuchi. 1994. Solid-state characterization of reduced silver vanadium oxide from the Li/SVO discharge reaction. Inorg. Chem. 33 5733-5740. 

Giron, D., Goldbrown, Ch., Mutz, M., Pfeffer, S., Piechon, Ph., and Schwab, Ph. (2002), Solid-state characterization of pharmaceutical hydrates, J. Therm. Anal. Calor., 68, 453 165. 

The present studies provide a new oxidative route to carbocations and the first solid state characterization of the previously reported and CBr3 ... 

Vega, C., Kim, E.H.J., Chen, X.D., and Roos, Y.H. (2005). Solid-state characterization of spray-dried ice cream mixes. Coll. Surf. B Biointerfaces, 45, 66-75. 

Nitrides can be obtained by decomposition of the azides, but thermolysis of the pentahalides with ammonium salts appears more general. Recent synthetic pathways involve the cleavage of N2 or decarboxylation of a Nb isocyanate." The solid-state characterization of the [M2NXio] anions shows a linear symmetrical M=N=M bridge. Neutral halide nitrides are polymeric. Heterometallic nitrides based on a comer-shared double cube NbTieNg core (27) have been described (equation 14). ... 

Polymorphism is an ability of the drug substance to form crystals with different molecular arrangements giving distinct crystal species with different physical properties such as solubility, hygroscopicity, compressibility, and others. This phenomenon is well known within pharmaceutical companies. The reader can find additional information in references 47 and 48. The determination of possible polymorphic transition and existence of thermodynamically unstable forms during preformulation stage of drug development is important. Typical methods used for solid-state characterization of polymorphism are DSC,... 

X. Chen, M. Carillo, R. C. Haltiwanger, and P. Bradley, Solid state characterization of mometazone furoate anhydrous and monohydrate forms, J. Pharm. Sci. 94 (2005), 2496-2509. 

The majority of characterization techniques discussed thus far have been surface-related, with some capable of analyzing sub-surface depths through in situ ion etching. This final section will focus briefly on a selection of common bulk techniques that may be used to characterize as-synthesized materials such as polymers, ceramics, etc. More details on these and other techniques not discussed herein may be found in the Further Reading section at the end of this chapter. In particular, these additional resources, as well as countless others online, will highlight solid-state characterization techniques such as ... 

Chan, H.-K. Gonda, 1. Solid state characterization of spray-dried powders of recombinant human deoxyribonuclease (rhDNase). J. Pharm. Sci. 1998, 87, 647-654. 

Vitez, I.M. Newman, A.W. Davidovich, M. Kiesnowski, C. The evolution of hot stage microscopy to aid solid-state characterizations of pharmaceutical solids. Thermochim. Acta 1998, 324, 187-196. 

Most solid-state characterization studies investigate the starting material and the freeze-dried end product. It will be useful and relevant to study alterations in the solid state during the different stages of the freeze-drying process, and this is enabled by low temperature XRD. The physical characterization of the phases at... 

Study of the modification of solid surfaces requires, preferably, surface sensitive methods. Spectroscopic techniques, for example X-ray photoelectron spectroscopy (XPS) and FTIR spectroscopy are excellent tools for gathering information on the chemical surface composition and the kind and number of functional surface groups. The fact that the carbon and nitrogen containing organic phase is only introduced during the adsorption procedure and locally fixed on the outside of the particles allows the use of established methods for polymer and solid-state characterization, particularly NMR and solid-state NMR spectroscopy (e.g. 13C CP MAS NMR). 

Hydroboration of coordinated alkenes has been achieved with the phosphine-stabilized olefin complexes, (775-C5H5)2Zr(772-CH2=CHR)(PPh2Me) (R = H, 78 Et, 79 Ph, 80), upon addition of the Lewis-acidic borane, HB(C6F5)2 (Equation (5)).37,65 Solid-state characterization indicates a weak interaction between the formally positively charged zirconium center and the carbon adjacent to the borate anion. This interaction is maintained in solution, as an upheld shifted 13C NMR resonance is observed for this carbon, which is in agreement with previous reports of metal-carbon interactions of this type. 

Thermodynamic Solubility Assays with Solid-State Characterization... 

More recently in discovery there has been a trend toward developing high-throughput thermodynamic solubility assays, which incorporate a solid-state assessment at the end of the period of agitation. This assessment aids interpretation of the solubility data and is an important consideration when relating the solubility data to molecular structure. Solid-state characterization methods include the use of PLM [16], microscopic analysis [34], PXRD [32, 33], and Raman microscopy [22]. With all these... 

Tests concerned with solid-state characterization... 

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