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. 
QNASL Nasal Aerosol is a pressurized, nonaqueous solution in a metered-dose aerosol device intended ONLY for intranasal use. It contains a solution of beclomethasone dipropionate in propellant HFA-134a (1,1,1,2-tetrafluoroethane) and dehydrated ethanol. QNASL 40 mcg Nasal Aerosol delivers 40 mcg of beclomethasone dipropionate from the nasal actuator and 50 mcg from the valve. QNASL 80 mcg Nasal Aerosol delivers 80 mcg of beclomethasone dipropionate from the nasal actuator and 100 mcg from the valve. Each strength delivers 59 mg of solution from the valve with each actuation. Each canister of QNASL 40 mcg or 80 mcg Nasal Aerosol, contains g of drug and excipients and each provides 120 actuations after priming. Additionally, QNASL 40 mcg Nasal Aerosol contains g of drug and excipients and provides 60 actuations after priming.
40 mcg inhaled twice daily, approximately 12 hours apart, is the recommended starting dose. For patients who do not respond adequately to 40 mcg after 2 weeks of therapy, increasing the dosage to 80 mcg twice daily may provide additional asthma control. The maximum recommended dosage is 80 mcg twice daily. The starting dosage is based on the severity of asthma, including consideration of the patients’ current control of asthma symptoms and risk of future exacerbation. Improvement in asthma symptoms can occur within 24 hours of the beginning of treatment and should be expected within the first or second week, but maximum benefit should not be expected until 3 to 4 weeks of therapy. Improvement in pulmonary function is usually apparent within 1 to 4 weeks after the start of therapy. The National Asthma Education and Prevention Program Expert Panel defines low dose therapy as 80 to 160 mcg/day, medium dose as 161 to 320 mcg/day, and high dose therapy as more than 320 mcg/day for children ages 5 to 11 years. The Global Initiative for Asthma (GINA) guidelines define low dose therapy as 100 mcg/day in this age group. Titrate to the lowest effective dose once asthma stability is achieved.