API characterization

A well-defined, precise, and validated method will help to determine the drug content accurately, whereas an assay method capable of detecting at low levels can help calculate drug losses during the manufacturing process. Different vendors can supply common APIs. The API characterization accompanied by information from the manufacturer on the synthetic route determines the impurities profile and the method used for the active assay. 

Three frequently specified properties are density—specific gravity—API gravity, characterization factor, and sulfur content (2,6,7). The API (American Petroleum Institute) gravity is a measure of density or specific gravity (sp gr) ... 

The simple API gravity test provides valuable information about the quality of a feed. But the shift in API usually signals changes in other feed properties, such as carbon residue and aniline point. Addi tional tests are needed to fully characterize the feed. 

Tatemoto K, Hosoya M, Habata Y et al (1998) Isolation and characterization of a novel endogenous peptide ligand for the human API receptor. Biochem Biophys Res Commun 251 471-476... 

MW, Grunwald T, Spillner E Identification, recom- 28 binant expression and characterization of the 100 kDa high molecular weight hymenoptera venom allergens Api m5 and Ves v3. Allergy 2008 63(Suppl 88) 13-14. 29... 

The most important of these manifolds for the purposes of TST are, as before, the surface given by AQi = APi that serves as a recrossing-free dividing surface and the stable and unstable manifolds that act as separatrices between reactive and nonreactive trajectories. The latter are given by AQi = 0 (stable manifolds) or APj = 0 (unstable manifolds), respectively. Together, they can be characterized as the zeros of the reactive-mode action... 

Prud homme, R.K. "Rheological Characterization of Fracturing Fluids," Final Report API PRAC Project 84-45, American Petroleum Institute, Dallas, TX (1985). 

Several methodologies can be used to identify not only crude or refined product type, but also the brand, grade, and, in some instances, the source crude. The petroleum industry has yielded conventional methods for the characterization of refined products. The simplest is the routine determination of API gravity and development of distillation curves where NAPL is present. More sophisticated methods include gas chromatography and statistical comparisons of the distribution of paraffinic or n-alkane compounds between certain C-ranges. With increased degradation and decomposition, the straight-chain hydrocarbons ( -alkanes) become less... 

Characterization of LNAPL in pools underlying the site consisted of collecting and analyzing over 120 LNAPL samples. LNAPL product samples were distilled and analyzed to determine API gravity, lead, and sulfur content. Boiling point and percent recovery data were used to generate distillation curves. 

The following list identifies the most important analytical techniques that are regularly used in the support of industrial crystallization process development and API solid phase characterization. 

Petroleum is typically described in terms of its physical properties (such as density and pour point) and chemical composition (such as percent composition of various petroleum hydrocarbons, asphaltenes, and sulfur). Although very complex in makeup, crude can be broken down into four basic classes of petroleum hydrocarbons. Each class is distinguished on the basis of molecular composition. In addition, properties important for characterizing the behavior of petroleum and petroleum products when spilled into waterways or onto land and/or released into the air include flash point, density (read specific gravity and/or API gravity), viscosity, emulsion formation in waterways, and adhesion to soil. 

Direct isolation of sufficient quantities of each metabolite for structural characterization, assay validation and pharmacological or toxicological testing from in vivo studies using biological specimens is, therefore, often impossible, particularly from dmgs with a low therapeutic index. Furthermore, many metabolites have structural modifications which are difficult to replicate by traditional chemical methods. A number of synthetic steps may be required to prepare such metabolites from the API, or, in the worst case, a completely new synthetic route may need to be developed. 

Several useful publications describing early direct injection API-electrospray methods appHcable to neurochemical studies include studies on acetylchoHnesterase phosphonylation products (Barak et al., 1997) glycerophosphocholine lipids (Flarrison and Murphy, 1996) receptor antibody characterization (Lewis et al., 1994) neuropeptide Yanalogs (Beck-Sickinger et al., 1994) and large biomolecules (Loo et al.,... 

UV spectra, solubility, pKa, stability of API and related compounds. Early methods for characterizing DP and DS. 

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