61-76-7

white to almost white crystalline powder

DECONGESTANTS

α-Adrenergic agonist. Mydriatic; decongestant.

ChEBI: A hydrochloride that is the monohydrochloride salt of phenylephrine.

Odorless white microcrystalline powder. Bitter taste. pH (1% aqueous solution) about 5.

PHENYLEPHRINE HYDROCHLORIDE(61-76-7) is incompatible with acids, acid chlorides, acid anhydrides and oxidizing agents. PHENYLEPHRINE HYDROCHLORIDE(61-76-7) is also incompatible with butacaine, alkalis and ferric salts.

May be sensitive to prolonged exposure to air and light. Water soluble.

α 1 -adrenoceptor agonist; pK i values are 5.86, 4.87 and 4.70 for α 1D , α 1B and α 1A receptors respectively.

Flash point data for this chemical are not available; however, PHENYLEPHRINE HYDROCHLORIDE is probably combustible.

R-(-)-Phenylephrine is an adrenergic α_1A receptor agonist (K_i = 1.4 μM) that demonstrates selectivity against the α_1B and α_1C receptor subtypes (K_is = 23.9 and 47.8 μM, respectively). By stimulating adrenergic α₁ receptors, L-phenylephrine can induce aortic smooth muscle contractions, although reported relative affinity and potency values in rabbit are 5-fold weaker compared to that of L-norepinephrine (Item No. 16673). This compound is frequently used to precontract smooth muscle in preparations designed to study the properties of various vasodilator agents.

Neosynephrine, Badrial, France ,1953

4.5 g of the hydrochloride of m-hydroxymethylaminoacetophenone aredissolved in a small amount of water; to the solution a solution of colloidal palladium obtained from palladiumchloride is added, and the mixture is treated with hydrogen.
After diluting the reaction liquid with acetone it is filtered, and the residue obtained after the evaporation of the filtrate in vacuo, and complete drying over pentoxide of phosphorus is then dissolved in absolute alcohol, and to this is added about the same volume of dry ether, until turbidity just commences to occur. After a short time the hydrochloride of the m-hydroxyphenylethanolmethylamine will separate out as a colorless mass of crystals at a melting point of 142°C to 143°C.

Afrin 4 Hour Nasal Spray (Schering-Plough Health Care); Biomydrin (Parke-Davis); Mydfrin (Alcon); Neo-Synephrine (Sterling Health U.S.A.); Nostril (Boehringer Ingelheim).

Adrenergic

Phenylephrine is a vasoconstrictor used to differentiate conjunctival vascular injection (blanches with phenylephrine application) versus deep episcleral injection (blanches incompletely) associated with uveitis, glaucoma, or scleritis. It is also used prior to conjunctival surgery to reduce hemorrhage and in combination with atropine prior to cataract or other intraocular surgeries that require maximal pupillary dilation. Phenylephrine can be used to confirm the diagnosis of Horner’s syndrome. Dilution of 2.5% phenylephrine solution with saline (1:10) produces a 0.25% solution. Normal eyes will not demonstrate mydriasis in response to this low concentration of phenylephrine. Third order Horner’s syndrome of greater than two weeks duration is associated with receptor up regulation and therefore a response to 0.25% phenylephrine is noted. In this way, the diagnosis of Horner’s is confirmed and a suggestion as to whether or not the condition is 2nd or 3rd order in nature.
In dogs, maximum mydriasis persists for about 2 hours and effects may last for up to 18 hours. Phenylephrine has significant alpha adrenergic effects (vasoconstriction and pupillary dilation) and minimal effects on beta receptors. When used alone, phenylephrine is reportedly not efficacious in the cat unless used with other mydriatics.

Desiccate at RT