Corticosteroids sodium succinate hydrocortisone

A number of other agents may be required for the treatment of anaphylactic reactions. Corticosteroids (hydrocortisone sodium succinate intravenously) are recommended to reduce the risk of late-phase reactions. Aminophylline may be used as adjunctive therapy for bronchospasm. Histamine (Hi) receptor blockers (such as diphenhydramine) may be administered to reduce some of the symptoms associated with anaphylaxis however, these agents are not effective as primary therapy. 

Esters of corticosteroids with a polyvalent acid group, for example succinic acid or phosphoric acid, are soluble in their salt form. This is because most of the non-esterified acid groups are deprotonated when sufficiently high pH is chosen. Examples of corticosteroids which are esterified with polybasic acids are hydrocortisone sodium succinate, prednisolone sodium phosphate and dexamethasone sodium phosphate. In an aqueous medium with a pH of about 7 or higher, hydrocortisone sodium succinate is largely ionised and thus fairly soluble. At this pH, however, the hydrolysis of the ester is quite fast (this ester is most stable at a pH of about 4.5). As a result, dissolved in water, this substance is unstable and therefore its shelf life is limited. 

In aqueous solution, prednisolone sodium phosphate and dexamethasone sodium phosphate are more stable than hydrocortisone sodium succinate. At a pH of about 8, the acid groups are sufficiently ionised to make the substance very soluble, while the phosphate ester is reasonably stable at this pH. Water soluble corticosteroids are mainly used in parenteral preparations, eye drops, oral mixtures and enemas. Examples are prednisolone oral mixtures and dexamethasone injections. 

---