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At least 19 recordsLinked to original sources

Effects of cromakalim (BRL 34915) on mechanical responses of rat vas deferens to noradrenaline and naphazoline.

The contractile responses produced by noradrenaline were compared to those produced by naphazoline in the rat isolated vas deferens, a preparation which is usually quiescent. The responses to noradrenaline were biphasic: prominent spontaneous contractile activity was superimposed on contractions produced by naphazoline. After removal of naphazoline the rat vas deferens displayed periodic spontaneous activity. The effects of cromakalim and verapamil were compared on contractions induced by noradrenaline and naphazoline and on spontaneous activity induced by exposure to naphazoline. Cromakalim (1-10 x 10(-7) M) shifted to the right the cumulative concentration-response curve of naphazoline but not that of noradrenaline; at the same range of concentrations, cromakalim inhibited naphazoline-induced periodic spontaneous activity. Verapamil (3-30 x 10(-8) M) flattened in a dose-dependent manner the concentration-response curves of noradrenaline and naphazoline; higher concentrations of verapamil (3-30 x 10(-6) M) were required to modify periodic spontaneous activity. It was concluded that naphazoline but not noradrenaline can block K+ channel(s) and that this property can represent an important difference between imidazolines and phenethylamines.

Animals

Naphazoline nasal drops intoxication in children.

Naphazoline, a sympathomimetic and an imidazoline derivative, is used as 0.05-0.1% solution for local decongestion of the nasal and ocular mucosa. In excessive dosage, or if ingested by accident, may cause depression of the central nervous system (disturbances of consciousness progressing to coma), hypothermia, bradycardia and sweating. These naphazoline effects are particularly strongly pronounced in children. Anglo-Saxon pharmacotherapy excludes the application of naphazoline nasal drops in children younger than six years, whereas the Croatian pharmacotherapeutic literature (and practice) allows its use even in infancy. At the Kantrida Paediatric Clinic, Clinical Hospital Centre in Rijeka, 11 children with signs of intoxication with naphazoline nasal drops were hospitalized from 1990 to 1992. The symptoms pertaining to the central nervous system i.e. disturbances of consciousness in the form of somnolence were clearly marked in all children. Some children developed skin pallor, bradycardia, bradypnoea and hypothermia. Resolution occurred within 24 hours and the findings returned to normal values. Clinical picture followed by rapid resolution and normal findings, with a personal history of drug taking, is a safe indication for diagnosis. There are several reasons to account for intoxication (drops difficult to use with children, containers inadequate for proper dosage), but the major factor is the age of the patient--all hospitalized children were younger than six years. It is pointed out that administration of naphazoline drops at an early age is not advisable.

Administration, Intranasal

Intravenous naphazoline intoxication.

Nine pale perspiring drug addicts with drowsiness, nausea, headache, normal blood pressure and marked sinus bradycardia with premature ventricular beats were seen at the Casualty Department soon after alleged i.v. cocaine administration. Eight were treated with atropine, as the bradycardia suggested intoxication with a parasympathomimetic compound. Seven were discharged in good condition after a few hours' observation. One patient developed a blood pressure of 150/120 mmHg after atropine. Subsequently, a hemiparesis was found and an intracerebral haematoma was evaluated at surgery. Another patient was admitted forthwith to the CCU. He did not receive any medication and recovered within two days. Urinalysis of these two patients disclosed contents of naphazoline, a powerful alpha-adrenergic agent. Samples of the alleged cocaine contained 97% naphazoline HCl. A conscious rabbit was injected with naphazoline and thereafter with atropine. I.v. naphazoline doubled mean arterial pressure (MAP) and reduced heart rate (HR) from 167 to 30 beats/min. Atropine doubled HR, but caused a marked rise in MAP, too, stressing the adverse effects of atropine in these cases. When confronted with patients after alleged cocaine abuse, the role of substitute drugs, especially alpha-adrenergic compounds, should be considered as this should influence the therapeutic approach.

Adult

Topical naphazoline in treatment of myopathic ptosis.

We instilled naphazoline Hcl (0.1%), an imidazole derivative with preferential alpha-2 activity, in 17 eyes of 12 patients with myopathic ptosis due to involvement of the levator palpebrae superioris, in the attempt to selectively stimulate Müller's smooth muscle. Naphazoline significantly widened the palpebral fissure with little change in pupillary diameter and no significant change in ocular pressure, visual acuity and near point determination. However, a reduction of the effect, probably due to tachyphylaxis, was noticed when using naphazoline regularly several times a day for few weeks. In conclusion naphazoline has powerful cosmetical and functional effects in mild to moderate myopathic ptosis above all if taken occasionally.

Administration, Topical

Frequency-dependence of the positive inotropic effect of methoxamine and naphazoline mediated by alpha-Adrenoceptors in the isolated rabbit papillary muscle.

Under the conditions of different stimulation frequencies the inotropic effects of the alpha-adrenoceptor stimulationg agents, methoxamine, naphazoling and oxymetazoline were studied on the isolated rabbit papillary muscle. 1. On the papillary muscle stimulated at 0.5 Hz methoxamine in concentrations from 10(-5)M caused a significant and dose-dependent positive inotropic effect. At 10(-3)M methoxamine decreased the developed tension. With increasing frequency of stimulation (0.5--1--1.5Hz), the positive inotropic effect became smaller, while the negative inotropic one was more pronounced. The time course of the disappearance of the negative inotropic effect of methoxamine by washout differed from that of the positive inotropic effect: the negative component disappeared within 30 min, whereas the positive one lasted for about 100 min. The positive inotropic effect of noradrenaline (10(-6)M), in contrast ot that of methoxamine, was not influenced by the frequency under the same conditions of stimulation. Also naphazoline (10(-5)M) caused a significant positive inotropic effect on the papillary muscle stimulated at 0.5 Hz, while oxymetazoline induced exclusively a negative inotropic effect. 2. The positive inotropic effect of metoxamine (10(-4)M) as well as of naphazoline (10(-5)M) evoked at a frequency of 0.5 Hz was abolished by phentolamine (10(-6)M). Methoxamine (10(-4)M) induced a significant negative inotropic effect in the presence of phentolamine. Phentolamine antagonized the positive inotropic effect of methoxamine in a non-competitive manner: the pD2-value was 7.76. 3. In the presence of methoxamine (10(-4)M) the developed tension in the lower range (0.05--1 Hz) of the frequency-force relationship was enhanced, while that in the higher range (greater that 1.5 Hz) was decreased. The enhancement was abolished by phentolamine (10(-6)M). 4. Papaverine (2x10(-5)M) did not affect the positive inotropic effect of methoxamine. 5. The present results show that methoxamine and naphazoline induced a positive inotropic effect via alpha-adrenoceptor in the ventricular myocardium of the rabbit. These effects were caused only at low, but not at high frequencies of stimulation.

Animals

alpha-Adrenoceptors in the ventricular myocardium: clonidine, naphazoline and methoxamine as partial alpha-agonists exerting a competitive dualism in action to phenylephrine.

Tha alpha-sympathomimetic agonists, clonidine, naphazoline, methoxamine, oxymetazoline and phenylephrine were used to further characterize the alpha-adrenoceptors mediating the positive inotropic effect in the isolated papillary muscle of the rabbit heart. The maximal inotropic effects of these amines were compared with the effect of isoprenaline and it was examined whether or not these amines compete for alpha-adrenoceptors. On the papillary muscle stimulated at 0.5 Hz, phenylephrine showed a high affinity (pD2 value=6.13) and produced the most pronounced intrinsic activity of the alpha-sympathomimetic amines. Therefore, the intrinsic activity of phenylephrine, in the presence of prindolol (3 X 10(-8) M), was used for comparison with those of the other alpha-agonists. Clonidine caused a positive inotropic effect: the intrinsic activity amounted to 0.32 of that of phenylephrine; the affinity was the highest among the amines tested (pD2 value=6.46); its effect was inhibited by 10(-6) M phentolamine. The affinity and the intrinsic activity of naphazoline were slightly lower than those of clonidine. Methoxamine showed a relatively high intrinsic activity (0.56) but the lowest affinity (4.68). Oxymetazoline did not cause any positive inotropic effect. Clonidine, naphazoline and oxymetazoline antagonized the positive inotropic effect of phenylephrine, mediated via the alpha-adrenocaptors in the presence of 3 X 10(-8) M prindolol, in a competitive manner. This observation suggests that these alpha-sympathomimetic amines compete with phenylephrine for the same receptor site. Thus the present results provide additional evidence for alpha-adrenoceptors mediating the positive inotropic actions of sympathomimetic amines in the rabbit papillary muscle.

Adrenergic alpha-Antagonists

Comparison of Naphcon-A and its components (naphazoline and pheniramine) in a provocative model of allergic conjunctivitis.

A double-masked, randomized, parallel group, placebo-controlled study demonstrated the efficacy of Naphcon-A (naphazoline HCl 0.025% and pheniramine maleate 0.3%). Seventy-two patients with a documented positive skin test or radioallergosorbent test were recruited. Three groups of 24 patients each received 1 drop of Naphcon-A instilled in one eye, and 1 drop of either naphazoline, pheniramine, or placebo in the other eye. After the instillation of test medication, a titrated dose of ragweed antigen was administered bilaterally, and ocular signs and symptoms were evaluated 10, 30, and 120 minutes later. All patients (excluding 4 who had persistent symptoms attributable to ragweed) were rechallenged with ragweed antigen at 120 minutes to assess the duration of action of the test medications. Naphcon-A was significantly more effective than placebo, naphazoline, and pheniramine in reducing redness. Naphcon-A and pheniramine were equally effective in relieving itching.

Adult

Pre-synaptic and post-synaptic effects of xylazine and naphazoline on the bisected rat vas deferens.

The effect of the selective alpha 2-adrenoceptor agonists, naphazoline and xylazine, was studied on the field stimulated bisected rat vas deferens. Xylazine inhibited the twitch response to field stimulation in both the prostatic (ID50 = 0.10 microM) and epididymal (ID50 = 0.08 microM) halves of the rat vas deferens. This effect was antagonized by yohimbine (0.01-0.10 microM). Naphazoline also inhibited the response to field stimulation in the prostatic (ID50 = 0.12 microM) but had no such action on the epididymal half of the rat vas deferens. Indeed, low concentrations of naphazoline (threshold, 0.05 microM) contracted the epididymal vas deferens preparation. These contractions were competitively antagonized by prazosin suggesting an action on post-synaptic alpha 1-adrenoceptors. Neither pre-synaptic nor post-synaptic actions of either drug were affected by cocaine (10 microM) or beta-oestradiol (10 microM) added to the Krebs' solution. The results provide further evidence for the existence of two types of post-synaptic alpha 1-adrenoceptors and suggest a different anatomical localization of these receptors between the two ends of the rat vas deferens.

Animals

Utility of chloranil in assay of naphazoline, clemizole, penicillin G sodium, and piperazine.

A simple and sensitive spectrophotometric method is described for the assay of naphazoline, clemizole, penicillin G sodium, and piperazine. The method was based on the formation of a charge transfer complex between these drugs as n-donors and chloranil, the pi-acceptor. Conformity to Beer's law enabled the assay of dosage forms of these drugs. Compared with official methods, the results obtained were of equal accuracy. A more detailed investigation of th naphazoline-chloranil complex was made with respect to its composition, association constant, and free energy change.

Benzimidazoles

High-performance liquid chromatographic stability-indicating assay for naphazoline and tetrahydrozoline in ophthalmic preparations.

A high-performance liquid chromatographic (HPLC) analysis for tetrahydrozoline and naphazoline in ophthalmic solutions is presented. The analysis allows a more reproducible, direct stability-indicating assay than the colorimetric methods generally employed. The HPLC system is so designed that a variety of ophthalmic solutions containing either naphazoline or tetrahydrozoline can be analyzed concomitantly.

Chromatography, High Pressure Liquid

Synthesis and identification of the primary degradation product in a commercial ophthalmic formulation using NMR, MS, and a stability-indicating HPLC method for antazoline and naphazoline.

HPLC analysis of an anti-infective ophthalmic solution (Albalon-A), containing the active drugs naphazoline and antazoline, revealed a degradation peak of unknown identity. To elucidate the identity of the degradant, the active drugs were each hydrolyzed by refluxing at high pH, and their respective hydrolysis products were isolated and spectrally characterized by NMR, FT-IR, and MS for conclusive structure elucidation. The degradant's identity was confirmed by HPLC-MS analysis of Albalon-A ophthalmic solution to be the antazoline hydrolysis product N-[(N-benzylanilino)acetyl]ethylenediamine (IV). A stability-indicating HPLC method was then developed which was able to resolve IV from the active drugs. This HPLC method was then validated for quantitating the active drugs and IV. Validation studies demonstrated linear UV response at 280 nm, recovery > 98%, good reproducibility, and a detection limit of 2 micrograms/mL IV. Overall, the data demonstrated that the HPLC method was quantitative and specific for antazoline, naphazoline, and IV. Analysis of an expired stabilitry lot of the ophthalmic solution indicated the concentration of IV was 0.002% (w/v).

Antazoline

Inhibition by glibenclamide of the effects of cromakalim on responses of rat vas deferens to naphazoline.

Cromakalim has been shown to inhibit naphazoline-induced contractions and spontaneous activity induced by exposure to naphazoline in the rat isolated vas deferens. Glibenclamide 10(-6) M blocked both these effects of cromakalim. Our data add to the list of data derived mainly from experiments on vascular smooth muscle; they suggest that the same glibenclamide-sensitive K+ channel is present in vascular and non-vascular smooth muscle and that it may be involved in the relaxant actions of cromakalim.

Animals

Oxymetazoline ophthalmic solution versus naphazoline solution in non-infectious conjunctivitis.

A double-blind, randomized study was carried out in 38 adult patients with non-infectious conjunctivitis to compare the efficacy and tolerance of oxymetazoline (0.025%) ophthalmic solution with that of naphazoline (0.04%) solution. Treatment was continued for 7 to 8 days and severity of symptoms was recorded before, during and at the end of therapy. At the end of the study period, 11 (69%) of 16 patients treated with oxymetazoline demonstrated a good to excellent response to therapy compared with 8 (53%) of 15 patients in the naphazoline-treated group. A statistically significant difference favouring oxymetazoline was observed in duration of action and the mean number of applications needed. No adverse reactions were reported in either treatment group.

Adult

Effects of diphenhydramine, naphazoline and m-amino-alpha(1-aminoethyl)benzyl alcohol dihydrochloride on the nasal mucosa determined by impedance method: a simple method for evaluation of nasal decongestant.

A simple, new method was devised for evaluating nasal decongestants. In anesthetized dogs, two needle electrodes were inserted bilaterally into the superficial mucosa of the nasal wings. An impedance plethysmorgraphy provided with a DC output was used to measure impedance between the two electrodes. When 1% histamine solution was sprayed into a nostril focusing on the inside mucosa of a nasal wing, impedance decreased markedly and thereafter recovered to a control level within 1-1.5 h. Comparable responses were obtained when the same solution was sprayed into the opposite nostril. The drugs to be tested were administered intravenously or topically between these two histamine application. Intravenous administrations of diphenhydramine (0.5 mg/kg) and m-amino-alpha)1-aminoethyl) benzyl alcohol dihydrochloride (0.1 mg/kg) inhibited the histamine effect completely. Pretreatment with naphazoline administered topically also inhibited impedance changes cause by histamine application. Local appliations of acetycholine (10%) and bradykinin (0.1%) did not change nasal impedance significantly in any instances.

Acetylcholine

Antazoline phosphate and naphazoline hydrochloride, singly and in combination for the treatment of allergic conjunctivitis-a controlled, double-blind clinical trial.

A controlled, double-blind comparison of naphalzoline hydrochloride 0.05%, antazoline phosphate 0.5%, a combination of both components and a placebo was performed on 51 ragweed sensitive patients presenting allergic conjunctivitis. Evaluation of response at various times after instillation of medication for lacrimation, conjunctival inflammation, pruritus, photophobia and pain showed naphazoline hydrochloride, antazoline phosphate and the combination product superior to placebo. The combination product was statistically significantly superior for conjunctival inflammation and photophobia. The need for post-challenge treatment with epinephrine hydrochloride was significantly less in those eyes treated with the combination product. demonstrating prophylactic efficacy.

Adolescent

[The effect of bioadhesiveness of viscous solutions with naphazoline hydrochloride on the elimination of the drug from the eye of swine].

Solutions of sodium carboxymethylamylopectine, tragant, hydroxyethylcellulose, polyvinylalcohol, polyacrylic ester D 339, polyacrylic ester D 340 and polyacrylic acid, all of the same viscosity and with the same concentration of naphazoline hydrochloride, were applied on the isolated eye of pig. After sink the eye in a solution of sodium chloride the elimination of the drug from the eye was investigated. The results were compared with the bioadhesion of the viscous solutions measured ex vivo on the intestine of pigs. There were correlations between the eliminated mass after 5 min, after 30 min and the bioadhesion. Furthermore the calculated initial elimination constant was indirect proportional to the bioadhesion. The elimination of the drug between 5 and 30 min was independent on the bioadhesion.

Adhesiveness

High-performance liquid chromatographic determination of benzalkonium and naphazoline or tetrahydrozoline in nasal and ophthalmic solutions.

A high-performance liquid chromatographic method is described for the determination of benzalkonium chloride homologues and naphazoline nitrate or tetrahydrozoline hydrochloride in ophthalmic and nasal solutions. The technique involves a one-step dilution (1:5) for sample preparation and direct injection onto a 5 mm RP C-8 column. The mobile phase is acetonitrile-diluted acetic acid (80:20, v/v) with 6 mM tetramethylammonium bromide. Detection is carried out at 260 nm with a diode array. The method is rapid, specific, reproducible and is especially useful for quality control procedures.

Benzalkonium Compounds