Phenylephrine Preparation

The analysis of a pharmaceutical preparation for pheniramine maleate and phenylephrine hydrochloride is described in this experiment. 

Dissolve 0.25 g of phenylephrine hydrochloride in water to make 8.9 mL of an isotonic solution, and adjust the preparation to 50 mL with isotonic boric acid solution. 

Rhinocort Aqua and Nasonex are preparations containing topical nasal corticosteroids (budesonide and mometasone furoate respectively). Otrivine contains a nasal decongestant (xylometazoline) and Sudafed is a systemic preparation containing a nasal decongestant (phenylephrine). Molcer is a preparation for ear-wax removal and which contains docusate sodium. Emadine contains an antihistamine (emedastine) and is presented as eye drops. 

Q71 Cold preparations containing phenylephrine intended for systemic administration should be avoided in patients with ... 

Vasoconstriction in regional anesthesia IV The manufacturer states that the optimum concentration of phenylephrine HCl is 0.05 mg/ml (1 20,000). Solutions maybe prepared for regional anesthesia by adding 1 mg of phenylephrine HCl to each 20 ml of local anesthesia solution. Some pressor response can be expected when at least 2 mg is injected. 

Curare-like activity, lowered blood pressure (dogs) antagonized phenylephrine-induced contractions of isolated rabbit aorta blocked neuromuscular transmission in rat hemidiaphragm preparation 440... 

SYMPATHOMIMETICS CYTOTOXICS -PROCARBAZINE Co-administration of ephedrine, metaraminol, methylphenidate, phenylephrine or pseudoephedrine (including nasal and ophthalmic solutions) with procarbazine may cause a prolongation and t intensity of the cardiac stimulant effects and effects on BP, which may lead to headache, arrhythmias, hypertensive or hyperpyretic crisis The metabolism of sympathomimetics is impaired due to an inhibition of MAO It is recommended that sympathomimetics not be administered during and within 14 days of stopping procarbazine. Do not use any OTC nasal decongestants (sprays or oral preparations) or asthma relief agents without consulting the pharmacist/doctor... 

Practitioners should be aware of over-the-counter (OTC) medications and folk or home remedies that patients may be using. Many patients may not consider OTC agents, especially antihistamines and decongestants for hay fever and colds, as drugs. These can affect the autonomic nervous system. OTC preparations can potentially interact with ocular drugs, such as homatropine and phenylephrine, that also influence autonomic functions. 

Phenylephrine and tropicamide have been mixed together into a single combination solution for routine pupillary dilation. In one study commercially available preparations of 1% tropicamide and 2.5% phenylephrine were mixed together in equal amounts, thus producing a combination solution containing 0.5% tropicamide and 1.25% phenylephrine. This combination solution... 

The various clinical effects of phenylephrine and the imidazole derivatives have been studied. The ability of several ocular decongestant formulations to counteract histamine-induced erythema was compared. Phenylephrine 0.12%, tetrahydrozoline 0.05%, and naphazoline ranging in concentrations from 0.012% to 0.1% were tested in a double-masked fashion in human eyes with no ocular disease. All preparations tested produced... 

To facilitate the application of mydriatics in neonates and infants, a single-instillation solution may be prepared by combining 3.75 ml cyclopentolate 2% with 7.5 ml tropicamide 1% and 3.75 ml phenylephrine 10%.The final solution contains 0.5% cyclopentolate, 0.5% tropicamide, and 2.5% phenylephrine.This combination produces no major side effects and provides an effective pupillary dilation. Alternatively, equal amounts of 1% tropicamide and 2.5% phenylephrine may be mixed together to yield a single combination solution with final concentrations of 0.5% tropicamide and 1.25% phenylephrine. This too should produce adequate pupillary dilation with no major side effects. Again, these solutions can also be applied as a spray. Cyclopentolate, tropicamide, and phenylephrine administered in microdrops (mean drop volume, 5.6 micro liters, as opposed to commercially available standard drops) have the same efficacy with a decreased risk for systemic side effects. 

Solutions of phenylephrine hydrochloride, for example, develop a brown color as a result of photodegradation (2). Many dyes, including FD C dyes, used for coloring liquid pharmaceutical preparations such as syrups and elixirs, fade on exposure to light (9). Curcumin, a natural food colorant, fades on exposure to UV-VIS radiation (10). 

Most sympathomimetic amines, such as amphetamine, are available only by prescription others such as phenylephrine and pseudoephedrine, which also are reported to interact similarly with MAO inhibitors, are found in most popular non-prescription cold and allergy preparations. It is important that patients being treated with MAO inhibitors avoid using products containing these agents. 

Krishnan G, Talwar SK, Sharma SC, Sharma RG. Estimation of phenylephrine hydrochloride in multi-component pharmaceutical preparations. Eastern Pharmacist 1990 33 143-145. 

Note Hydrocodone is included in many combination drugs. Other medications that can be included in these preparations include phenylpropanolamine, phenylephrine, pyrilamine, pseudoephedrine, acetaminophen, ibuprofen, and others... 

Sulfacetamide has been determined in glacial acetic add and isopropanol by titration with perchloric add (39,40). The end-point in glacial acetic add is improved by adding acetic anhydride to the medium and can be detected by potentiometry or with gention violet, solvent blue 19, or quinidine red indicators. Sulfacetamide can be determined in ophthalmic preparations containing phenylephrine hydrochloride or phenyltoloxamine dihydrogen dtrate by this method. Recoveries range from 100.1 to 101.2% (41). 

Martin etal. (2002) also found that (+)-kavain (10 —10 M) dose-dependently relaxed isolated rat aortic ring preparations that had previously been contracted with phenylephrine (PE), as an effect not dependent on functional epithelium. In addition, kavain pretreatment attenuated muscle contraction evoked by PE. However, PE elicited contraction in Ca free buffer was not affected by kavain, suggesting that intracellular signaling mechanisms probably were not involved. In rings pretreated with the L-type Ca channel blocker nifedipine, kavain mediated relaxation was appreciably attenuated. Further, muscles selectively contracted with Bay K 8644, an L-type Ca channel activator, were dose-dependently relaxed by kavain. The findings suggest that kavain impairs vascular smooth muscle contraction probably through inhibition of Ca ion channels. 

Interactions of MAOIs with other sympathomimetic drugs are well known. The increased neuronal stores of NE represent a booby-trap hazard that can easily be triggered by indirectly acting adrenergic agents such as the amphetamines found in many antiobesity preparations. Drugs such as ephedrine, phenylpropanolamine, and phenylephrine are potentially more dangerous because of their ready availability to the public in over-the-counter medications such as cold medicines and nose drops. 

Phthalide 30 dose-dependently relaxed phenylephrine- and KCl-induced precontractions in aortas isolated from spontaneous hypertensive rats [354]. Neither endothelium removal nor /V°-nitro-L-arginine methyl ester (L-NAME) affected the vasodilatory response of 30 [354], These results were not in line with Xu s observation that 30 stimulated NO release from bovine aortic endothelial cells [342]. Phthalide 30 also non-competitively right-shifted cumulative phenylephrine and high K+-depolarized Ca2+ dose-response curves but did not affect caffeine-induced Ca2+ release from internal stores [354]. The discrepancies among experiments may have been due to the differences in the choice of animals and preparations utilized. 

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