Steroid isolation , depending on context, is the isolation of chemical matter required for chemical structure elucidation, derivitzation or degradation chemistry, biological testing, and other research needs (generally milligrams to grams, but often more  or the isolation of "analytical quantities" of the substance of interest (where the focus is on identifying and quantifying the substance (for example, in biological tissue or fluid). The amount isolated depends on the analytical method, but is generally less than one microgram.  [ page needed ] The methods of isolation to achieve the two scales of product are distinct, but include extraction , precipitation, adsorption , chromatography , and crystallization . In both cases, the isolated substance is purified to chemical homogeneity; combined separation and analytical methods, such as LC-MS , are chosen to be "orthogonal"—achieving their separations based on distinct modes of interaction between substance and isolating matrix—to detect a single species in the pure sample. Structure determination refers to the methods to determine the chemical structure of an isolated pure steroid, using an evolving array of chemical and physical methods which have included NMR and small-molecule crystallography .  :10–19 Methods of analysis overlap both of the above areas, emphasizing analytical methods to determining if a steroid is present in a mixture and determining its quantity. 
The most common side effect of topical corticosteroid use is skin atrophy. All topical steroids can induce atrophy, but higher potency steroids, occlusion, thinner skin, and older patient age increase the risk. The face, the backs of the hands, and intertriginous areas are particularly susceptible. Resolution often occurs after discontinuing use of these agents, but it may take months. Concurrent use of topical tretinoin (Retin-A) % may reduce the incidence of atrophy from chronic steroid applications. 30 Other side effects from topical steroids include permanent dermal atrophy, telangiectasia, and striae.
Dosing should be individualized on the basis of disease and patient response
-Initial dose: to 8 mg/kg/day oral or IV in 3 or 4 divided doses (20 to 240 mg/m2/day)
Maintenance dose: After a favorable initial response, dose should be decreased in small amounts to the lowest dose that maintains an adequate clinical response; if a positive response is not achieved after a reasonable period of time, alternative therapy should be sought.
-Lower doses, including doses lower than recommended doses, may suffice in less severe disease; doses in excess of recommended doses may be required in severe disease; in life-threatening situations, doses exceeding multiples of the oral dose may be justified.
-Patients should be closely monitored for signs requiring dose adjustments; if therapy is to be stopped after more than a few days, it should be gradually withdrawn.
Uses: For use as a potent anti-inflammatory agent in managing disorders, diseases, and conditions affecting many organ systems including endocrine, dermatologic, ophthalmic, nervous, gastrointestinal, respiratory, musculoskeletal, and hematologic.