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Uro-Angiographic Contrast Agents—The Holy Grail
Published in Christoph de Haën, X-Ray Contrast Agent Technology, 2019
The success of diatrizoic acid-based contrast agents attracted further competitors to the field. A plethora of agents very similar in chemical structure and clinical performance, sometimes deprecatingly labeled me-too products, were developed. This generation of contrast agents was eventually to include in addition to diatrizoic acid salts, metrizoic acid salt128 [ISOPAQUE™, Nyegaard, patent priority 1961, marketed 1962], iothalamic acid meglumine salt (Figure 4.26, 16) [CONRAY™, Mallinckrodt, patent priority 1960 and 1961, marketed 1962], iodamide, sodium salt [UROMIRO™, Bracco, patent priority 1962, marketed 1968],129 and ioxitalamic acid meglumine or mixed meglumine/sodium salt [TÉLÉBRIX™, Guerbet, patent priority 1967, marketed 1970]. At the most widely used concentration of 300 mg(Iodine)/mL these pharmaceutical formulations had osmolalities around 1,600 mosmol/kg (Børdalen, Wang, and Holtermann 1970). They were distinguished by very modest differences in tolerability. Formulations based on these second-generation products, which beginning in the 1970s became referred to as ionic, or more precisely, as high-osmolal ionic contrast agents, dominated all major applications until the 1990s and to some extent are still used today, especially in the third world.
Single best answer (SBA)
Published in Tristan Barrett, Nadeem Shaida, Ashley Shaw, Adrian K. Dixon, Radiology for Undergraduate Finals and Foundation Years, 2018
Tristan Barrett, Nadeem Shaida, Ashley Shaw, Adrian K. Dixon
Gastromiro® (iopamidol) is a water-soluble non-ionic contrast agent and is safest to use if aspiration is a risk. Gastrografin® (diatrizoic acid) is a high-osmolality iodine containing contrast agent, it is contraindicated if there is a risk of aspiration as, being hyperosmolar, it will cause prompt pulmonary oedema: likewise it should always be used with caution in paediatric patients as its presence in the bowel may lead to dehydration. Urografin® is a derivitive of gastrografin® without added flavouring (making it unpalatable). Barium aspiration can lead to a chemical pneumonitis; water will not be visible under fluoroscopy.
Infrared Spectroscopy
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
A second approach uses canonical discriminant functions or canonical variables to classify substances. These, too, are linear combinations of the same wavelengths used in the classification functions. They are derived to maximize differences among the compounds such that they are orthogonal to each other. The first canonical variable contributes most to this discrimination, the second next most, and so on, until no further discrimination is obtained. Thus, each substance becomes a point in canonical space. Since the first two functions contain most of the discriminating power, two-dimensional plots of these functions can be most useful in viewing the data. A series of penicillins and diatrizoic acid (Figure 7) were thus treated, and the resulting plot is shown in Figure 8. One sees that amoxicillin and ampicillin are differentiated although they differ only by a phenol function. Likewise, potassium penicillin V and potassium penicillin G are distinguished although they differ only by an ether linkage. A second batch of potassium penicillin V, labeled pot pen V-2, is not distinguished from the first, as one would expect. Diatrizoic acid appears to be quite distinct from the penicillins, as one would expect. Identifications are made by measuring the NIR reflectance, calculating the values of the canonical variable, and determining if the resultant point is sufficiently close to the group to which it belongs. In the general case, where one may have more than two dimensions, one may calculate distances between points and test the assignment statistically. This combination of NIR and discriminant analysis (NIRDA) primises to permit rapid identification of materials in manufacturing plants, receiving departments, and in warehouses using little or no sample preparation and eliminating the need for spectral interpretation. It is difficult to do the approach justice in this space. Interested readers are referred to books on the subject by Lachenbruch [50] and Anderson [51].
Lung cancer: active therapeutic targeting and inhalational nanoproduct design
Published in Expert Opinion on Drug Delivery, 2018
Nasser Alhajj, Chin Fei Chee, Tin Wui Wong, Noorsaadah Abd Rahman, Noor Hayaty Abu Kasim, Paolo Colombo
In this approach, suspended nanoparticles are activated by a flocculating agent to form floccules. The nanoparticles within the floccules are loosely bound to each other by weak van der Waals forces. After that, the flocculated nanoparticles are lyophilized to remove the liquid. This method produces nanocomposites with appealing aerodynamic properties. The size of the nanocomposites can be controlled by manipulating the ratio between the nanoparticles and flocculating agent. Nanocomposites of different drugs have been produced via this approach such as budesonide [249], ciprofloxacin [250], paclitaxel [251], diatrizoic acid [252], and nifedipine [253].