Phenazopyridine

213.24

213.24

202-363-2

K2J09EMJ52

145895

DTXSID1023445

C29357

BROWNISH-YELLOW CRYSTALS

G - Genito urinary system and sex hormones

2933399090

89.6

3.82380

dark red to violet crystalline powder

1.32g/cm3

139 °C

442.3ºC at 760mmHg

1.6880 (estimate)

904.20g/L(25 ºC)

LD50 ipr-rat: 560 mg/kg JPETAB 51,200,34

AQ SOLN ARE SLIGHTLY ACID

5.05None

5.05

Slightly bitter taste /Phenazopyridine hydrochloride/|Forms supersaturated soln easily /Phenazopyridine hydrochloride/

WILL PRECIPITATE OUT OF 2% SOLN AT 25 DEG C AFTER ABOUT 2 DAYS, & OUT OF 1% SOLN ONLY AFTER MONTHS /PHENAZOPYRIDINE HYDROCHLORIDE/

P264, P270, P280, P301+P312, P305+P351+P338, P330, P337+P313, P501

H302

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

DHEW/NCI; Bioassay of Phenazopyridine Hydrochloride for Possible Carcinogenicity (1978) Technical Rpt Series No. 99 DHEW Pub No. (NIH) 78-1349|National Toxicology Program. Eleventh Report on Carcinogens (2005). The Report on Carcinogens is an informational scientific and public health document that identifies and discusses substances (including agents, mixtures, or exposure circumstances) that may pose a carcinogenic hazard to human health. Phenazopyridine hydrochloride (136-40-3) is listed as reasonably anticipated to be a human carcinogen. /Phenazopyridine hydrochloride/[Available from, as of July 31, 2009: http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s144phen.pdf]

|Warning|H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]|P264, P270, P280, P301+P312, P305+P351+P338, P330, P337+P313, and P501|Aggregated GHS information provided by 38 companies from 1 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Depending on the extent of possible contact, workers should be provided with personal protective equipment. A charcoal gas mask canister respirator has been found to be effective against a 2% pyridine concentration at 30 l/min for 1 hr. Rubber and plastic gloves should not be relied upon to prevent skin contact because pyridine and many of its derivatives penetrate these materials ... . /Pyridine, homologs, and derivatives/

The oral LD50 of phenazopyridine in rats is 472 mg/kg. Overdose information Administering excess phenazopyridine above the daily recommended dose in those with healthy or impaired kidney function may increase the drug concentration and predispose the patient to toxicity. When a large overdose occurs, methemoglobinemia results. To treat this condition, Methylene blue at 1 to 2 mg/kg/dose should be administered intravenously as a 1% solution as deemed necessary. Its administration is likely to cause a rapid reduction of the methemoglobinemia state and relieve the associated cyanosis. Hemolytic anemia is also a risk when an overdose occurs, and “bite cells” may be observed in a blood smear after an overdose with phenazopyridine. Red blood cell G6PD deficiency may increase the risk of hemolysis, and even normal doses can lead to methemoglobinemia in patients with this condition. Nephrotoxicity, renal failure, and hepatic impairment may also occur in a case of overdose with this drug. Administer symptomatic and supportive treatment as necessary.

LD50 Rat oral 403 mg/kg /Penazopyridine hydrochloride/|LD50 Rat ip 560 mg/kg

A bioassay of phenazopyridine hydrochloride for possible carcinogenicity was conducted by administering the test chemical in feed to Fischer 344 rats and B6C3F1 mice. Groups of 35 rats and 35 mice of each sex were administered /the cmpd/ at one of the following doses, either 3,700 or 7,500 ppm for rats and either 600 or 1,200 ppm for mice. The rats were administered the chemical for 78 wk, then observed for 26 or 27 additional wk; the mice were administered the chemical for 8 wk, then observed for 25-27 additional weeks. Matched controls consisted of 15 untreated rats and 15 untreated mice of each sex. All surviving rats were killed at 104-105 wk, all surviving mice at 105-107 wk. ... Under the conditions of this bioassay, phenazopyridine hydrochloride was carcinogenic in Fischer 344 rats, inducing adenocarcinomas of the colon both in males and females. ... /The cmpd/ was not carcinogenic in male mice. ... The chemical was carcinogenic in females, inducing hepatocellular adenomas and carcinomas. Levels of Evidence of Carcinogenicity: Male Rats: Positive; Female Rats: Positive; Male Mice: Negative; Female Mice: Negative. /Phenazopyridine hydrochloride/

There are no known natural sources of phenazopyridine(1).

Phenazopyridine's production and use in the manufacture of 2,6-diamino-3-phenylazopyridine hydrochloride(1) may result in its release to the environment through various waste streams(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 870(SRC), determined from a structure estimation method(2), indicates that phenazopyridine is expected to have low mobility in soil(SRC). Volatilization of phenazopyridine from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 3.30X10-15 atm-cu m/mole(SRC), using a fragment constant estimation method(3). Phenazopyridine is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 8.65X10-7 mm Hg(SRC), determined from a fragment constant method(4).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 870(SRC), determined from an estimation method(2), indicates that phenazopyridine is expected to adsorb to suspended solids and sediment in water(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 3.30X10-15 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). According to a classification scheme(5), an estimated BCF of 10(SRC), from an estimated log Kow of 2.77(6) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low.|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), phenazopyridine, which has an estimated vapor pressure of 8.65X10-7 mm Hg at 25 °C(SRC), using a fragment constant estimation method(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase phenazopyridine is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 2 hrs(SRC), calculated from its rate constant of 2X10-10 cu cm/molecule-sec at 25 °C(SRC) determined using a structure estimation method(3). Particulate-phase phenazopyridine may be removed from the air by wet and dry deposition(SRC).

The rate constant for the vapor-phase reaction of phenazopyridine with photochemically-produced hydroxyl radicals has been estimated as 2X10-10 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 2 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1).

An estimated BCF of 10 was calculated for phenazopyridine(SRC), using an estimated log Kow of 2.77(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low.

208.93 L/kg|Using a structure estimation method based on molecular connectivity indices(1), the Koc for phenazopyridine can be estimated to be 870(SRC). According to a classification scheme(2), this estimated Koc value suggests that phenazopyridine is expected to have low mobility in soil.

The Henry's Law constant for phenazopyridine is estimated as 3.30X10-15 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that phenazopyridine is expected to be essentially nonvolatile from water surfaces(2). Phenazopyridine's Henry's Law constant(1) indicates that volatilization from moist soil surfaces will not occur(SRC). Phenazopyridine is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 8.65X10-7 mm Hg(SRC), determined from a fragment constant estimation method(2).

Occupational exposure to phenazopyridine may occur through inhalation of dust and dermal contact with this compound at workplaces where phenazopyridine is produced or used(SRC). The general population may be exposed to phenazopyridine via ingestion as the hydrogen chloride form is used as a medicine(1).

Phenazopyridine hydrochloride is indicated to relieve uncomfortable symptoms that occur as a consequence of mucosal irritation of the lower urinary tract in adults. The irritation may be a result of trauma, surgery, endoscopic procedures, infection, or the insertion of instruments or urinary catheters. Phenazopyridine may be used in combination with antimicrobial therapy but is not used as an antimicrobial agent. It contributes to the relief of discomfort and pain before antimicrobial therapy begins to take effect. It is important to note that the duration of treatment with this drug should last a maximum of 2 days. Phenazopyridine is available in many countries as an over the counter drug.

Anesthetics, Local|PHENAZOPYRIDINE HYDROCHLORIDE, USP (PYRIDIUM) IS NOT A URINARY ANTISEPTIC. HOWEVER, IT DOES HAVE ANALGESIC ACTION ON URINARY TRACT & ALLEVIATES SYMPTOMS OF DYSURIA, FREQUENCY, BURNING & URGENCY. /SRP: RELIEF IS MOSTLY ATTRIBUTABLE TO ITS LOCAL ANESTHETIC ACTION RATHER THAN TO ANTIBACTERIAL ACTION/. /PHENAZOPYRIDINE HYDROCHLORIDE/|... 2,6-DIAMINO-3-(PHENYLAZO)PYRIDINE HYDROCHLORIDE MAY FREQUENTLY BE USED IN COMBINATION WITH SULFONAMIDES TO TREAT CYSTITIS, PROSTATITIS, URETHRITIS & PYELONEPHRITIS, AS LOCAL ANESTHETIC PRIOR TO URETHRAL MEDICATION & TO TREAT INFECTIONS OF MOUTH & CONJUNCTIVA. /PHENAZOPYRIDINE HYDROCHLORIDE/|MEDICATION (VET): TOPICAL APPLICATIONS ... /PRODUCE/ LONG-LASTING CORNEAL ANESTHESIA IN RABBITS.|MEDICATION (VET): Urinary analgesic.

CMPD IS AZO DYE, & URINE IS COLORED ORANGE OR RED; PATIENT SHOULD BE SO INFORMED. /PHENAZOPYRIDINE HYDROCHLORIDE/|DRUG IS CONTRAINDICATED IN RENAL INSUFFICIENCY, SEVERE HEPATITIS, & PYELONEPHRITIS OF PREGNANCY, & IT SHOULD BE USED CAUTIOUSLY IN PRESENCE OF GI DISTURBANCES. /PHENAZOPYRIDINE HYDROCHLORIDE/|IN ONE EPIDEMIOLOGICAL STUDY, INVOLVING LIMITED PERIOD OF OBSERVATION, NO ASSOC WAS OBSERVED BETWEEN USE OF PHENAZOPYRIDINE HYDROCHLORIDE & ANY CANCER. THERE IS SUFFICIENT EVIDENCE FOR CARCINOGENICITY ... IN EXPTL ANIMALS. AVAIL EPIDEMIOLOGICAL DATA ARE INSUFFICIENT TO EVALUATE CARCINOGENICITY ... TO HUMANS. IN ABSENCE OF ADEQUATE DATA IN HUMANS, PHENAZOPYRIDINE HYDROCHLORIDE SHOULD BE REGARDED, FOR PRACTICAL PURPOSES, AS IF IT PRESENTED A CARCINOGENIC RISK TO HUMANS. /PHENAZOPYRIDINE HYDROCHLORIDE/|IT PRODUCES HEINZ BODY ANEMIA IN PATIENT WHOSE RED CELLS HAVE NORMAL GLUCOSE-6-PHOSPHATE DEHYDROGENASE ACTIVITY, BUT REACTION IS MORE INTENSE IN ERYTHROCYTES DEFICIENT IN ... ENZYME. /PHENAZOPYRIDINE HYDROCHLORIDE/|For more Drug Warnings (Complete) data for PHENAZOPYRIDINE (7 total), please visit the HSDB record page.

Phenazopyridine acts as a local anesthetic offering relief from irritating conditions of the urinary tract. It relieves urinary urgency frequency, burning, pain, and discomfort. **A note on urine and skin discoloration and interference with test results** Yellowing of the skin or sclerae of the eyes may indicate that the accumulation of phenazopyridine has occurred. This may be a consequence of overdose, decreased renal function, taking the drug for over two days. Elderly patients may be at particular risk due to a decline in renal function, potentiating the risk of phenazopyridine accumulation. The drug should be discontinued if yellowing of the skin or sclerae is observed. Hemolytic anemia is a risk of phenazopyridine, especially in cases of overdose. In addition to the above effects, this drug may impart an orange or red color of urine and feces, causing staining of clothing. Other body fluids may also be stained, and in patients wearing contact lenses, phenazopyridine may cause lens staining. Due to its orange-red color, this drug may interfere with laboratory requiring colorimetric, spectrophotometric or fluorometric methods of analysis. In patients with G6PD enzyme deficiency, this drug poses a greater risk of hemolysis, even at normal doses and is not recommended. **A note on carcinogenesis** Based on the results of in vivo studies in rats, this drug has been listed as a carcinogen in the USA since 1981. Rats given this drug were found to demonstrate increased rates of hepatocellular carcinoma and colorectal tumors. Use this agent with caution and limit the administration of this drug when possible.

Phenazopyridine is absorbed in the gastrointestinal tract. The mean Cmax is 65.00 ± 29.23 ng/mL, the mean Tmax is 2.48 ± 0.50 h, and the mean AUC(0 – ∞)is 431.77 ± 87.82 ng.h/mL.|Up to 65% of an oral phenazopyridine dose is quickly excreted by the kidneys as unchanged drug measured in the urine. The pharmacokinetics of this drug have not been evaluated in depth in man. In a small group of healthy research volunteers, 90% of a daily 600 mg oral dose of phenazopyridine hydrochloride was found to be excreted within 1 day, with 41% as unchanged drug and 49% as phenazopyridine metabolites. Another study in humans determined that 80.07 ± 4.54 percent of the dose was cleared in the urine within 48 hours of administration. In rats, biliary excretion was high, with 40.7% of a dose excreted in 8 hours.|Small, trace quantities of phenazopyridine are thought to cross the placenta and the blood-brain barrier, reaching cerebrospinal fluid. A pharmacokinetic study in rats determined that phenazopyridine metabolites were present in high levels in the kidney and liver.|This drug is rapidly excreted by the kidneys, up to 65% of a dose administered orally may be excreted as unchanged drug in the urine. The clearance of phenazopyridine may be decreased with impaired renal or hepatic function and is contraindicated in these conditions.|IN HUMANS, ORALLY ADMIN DOSES OF 200 MG PYRIDIUM ... EXCRETED WITHIN 14-48 HR, MAINLY IN URINE BUT PARTLY IN FECES: ABOUT 80% OF ORALLY ADMIN DOSE OF 600 MG IS ELIMINATED IN URINE WITHIN 24 HR. /PHENAZOPYRIDINE HYDROCHLORIDE/|Following oral administration, approximately 90% of the dose is eliminated in the urine within 24 hours, about 40% as unchanged drug & 50% as aniline & its metabolites, mainly p-aminophenol & N-acetyl-p-aminophenol (acetaminophen).|Renal clearance appears to be the major route of elimination of phenazopyridine. In one human study, following ingestion of 200 mg three times daily, 90% of an administered dose of phenazopyridine was cleared by the urine in 24 hours; 41% was unchanged phenazopyridine, 6.9%, was aniline (known to be linked with methemoglobin in humans), 18% was N acetyl-p-aminophenol, and 24% was p-aminophenol.

Phenazopyridine is metabolized in the liver, and acetaminophen has been discovered to be one metabolite of this drug. Hydroxylation is a pathway by which this drug is metabolized. In humans, 5-hydroxyl PAP is the major metabolite (48.3% of the dose) and small amounts of other hydroxy metabolites are produced. The metabolism of phenazopyridine produces aniline, which is likely associated with methemoglobinemia in some patients or in the case of an overdose. This dye accumulates in the skin, and yellow skin pigmentation has been observed when high doses of this drug have been taken. Triaminopyridine is also a metabolite of phenazopyridine. During a pharmacokinetic study, aniline contributed to approximately 6.9% of urinary metabolites. N acetyl-p-aminophenol (acetaminophen) contributes to about 18%, P-aminophenol (PAP) contributes 24%, and finally, DPP (unchanged phenazopyridine) contributes to about 41% of excreted urinary metabolites.|AFTER ORAL DOSE OF 600 MG PHENAZOPYRIDINE HYDROCHLORIDE /IN MAN/, ABOUT 80% IS ELIMINATED IN URINE WITHIN 24 HR: 41-45% APPEARS AS CONJUGATED PHENAZOPYRIDINE, 24-27% AS PARA-AMINOPHENOL, 18-20% AS CONJUGATED N-ACETYL-PARA-AMINOPHENOL, 7-8% AS ANILINE & TRACES OF ORTHO-AMINOPHENOL & 2,3,6-TRIAMINOPYRIDINE. /PHENAZOPYRIDINE HYDROCHLORIDE/|FOLLOWING ORAL ADMIN OF 150 MG/KG BODY WT PHENAZOPYRIDINE HYDROCHLORIDE TO RABBITS ... ANILINE, PARA-AMINOPHENOL (AS 50% OF DOSE), N-ACETYL-PARA-AMINOPHENOL, ORTHO-AMINOPHENOL (AS TRACES), 2,3,6-TRIAMINOPYRIDINE & UNCHANGED DRUG APPEAR IN URINE. ... IN ADDN TO REDUCTIVE METABOLISM, PHENAZOPYRIDINE ALSO UNDERGOES OXIDATIVE METABOLISM: IN URINE OF RATS TREATED WITH 50 MG/KG BODY WT PHENAZOPYRIDINE, 2,6-DIAMINO-3-((4-HYDROXYPHENYL)AZO)PYRIDINE & 2,6-DIAMINO-3-((2-HYDROXYPHENYL)AZO)PYRIDINE HAVE BEEN DETECTED. /PHENAZOPYRIDINE HYDROCHLORIDE/|FOLLOWING ORAL ADMIN OF 50 MG/KG PHENAZOPYRIDINE TO RATS & EXTRACTION OF URINE AQ SAMPLES, 4-ACETAMIDOPHENOL, 2,6-DIAMINOPYRIDINE-3-NNO-AZOXYBENZENE & AN UNIDENTIFIED AZOXY DERIV OF HYDROXYPYRIDINE WERE ISOLATED. FORMATION OF AZOXY DERIV FROM AZO-COMPD IS UNUSUAL IN MAMMALS & HAS GREAT TOXICOLOGICAL IMPORTANCE.|FOLLOWING THE ORAL ADMIN OF PHENAZOPYRIDINE (100 MG/KG) TO RATS, 2,6-DIAMINO-5-HYDROXY-3-(PHENYLAZO)PYRIDINE WAS IDENTIFIED AS A NEW METABOLITE IN URINE BY MASS SPECTRA. BASED ON THE FRAGMENTATION OF THE MASS SPECTRUM, A SELECTIVE METABOLIC OXIDN OF THE HETEROCYCLIC RING, RATHER THAN OF THE BENZENE RING, WAS EVIDENT.

The mean elimination half-life of phenazopyridine is 7.35 hours in rats with healthy renal function. The half-life in man is not readily vailable in the literature.

The full mechanism of action of phenazopyridine is not fully elucidated, however, it is reported to exert a direct topical analgesic effect on the mucosal lining of the urinary tract via the inhibition of voltage-gated sodium channels and possibly group A nerve fibers, as suggested by the results of a study in rats. The above actions likely lead to the relief of unpleasant urinary symptoms.|The most serious finding in phenazopyridine overdose is progressive oliguric renal failure. This may be due to a direct toxic effect of the drug, on the renal tubules, as renal failure may occur as the only adverse effect without hemolysis. The yellow pigmentation in the absence of marked hyperbilirubinemia is probably due to deposition of azo dye in the skin and sclerae and occurs primarily in patients with impaired renal function. Hemolysis may follow ingestion of either phenazopyridine or aniline alone (one of the phenazopyridine metabolites). Methemoglobinemia probably follows phenazopyridine oxidation of hemoglobin iron (Fe2+ to Fe3+). A predisposition to hemolysis and methemoglobinemia may be present in patients with a glucose- 6-phosphate dehydrogenase deficiency. Muscle damage may express itself as rhabdomyolysis and myoglobinuria.

In acute overdosage of phenazopyridine hydrochloride, the stomach should be emptied immediately by inducing emesis or by gastric lavage. If the patient is comatose, having seizures, or lacks the gag reflex, gastric lavage may be performed if an endotracheal tube with cuff inflated is in place to prevent aspiration of gastric contents. Supportive and sympotmatic treatment should be initiated. IV administration of methylene blue 1-2 mg/kg or oral administration of ascorbic acid 100-200 mg should cause prompt reduction of methemoglobinemia and disappearance of cyanosis. Exchange transfusions have been used successfully in acute phenazopyridine overdosage in infants. Peritoneal dialysis may be useful for managing fluid and electrolyte disturbances in phenazopyridine-induced acute renal failure. /Phenazopyridine hydrochloride/

METHEMOGLOBINEMIA WITH OR WITHOUT HEINZ BODY HEMOLYTIC COMPONENT CONSTITUTED KEY FEATURE IN AT LEAST 7 HUMAN INTOXICATIONS. /PHENAZOPYRIDINE HYDROCHLORIDE/|15 MO OLD GIRL SURVIVED INGESTION OF 8 G, BUT EXHIBITED HEPATIC ENLARGEMENT & TRANSIENTLY ABNORMAL RENAL FUNCTION BEFORE COMPLETE RECOVERY. /PHENAZOPYRIDINE HYDROCHLORIDE/|A 39 YR OLD WOMAN, ADMITTED TO HOSPITAL BECAUSE OF A FISTULA BETWEEN BLADDER AND BOWEL, DEVELOPED A MODERATE DEGREE OF METHEMOGLOBINEMIA (19% OF TOTAL HEMOGLOBIN) AFTER PRESCRIPTION OF 3X200 MG/DAY PHENAZOPYRIDINE FOR 4 WK. SHE SHOWED A GREYISH DISCOLORATION OF THE SKIN; LIPS AND NAILBEDS WERE CYANOSED. ON THE BASIS OF A GLUCOSE-6PH-DEHYDROGENASE DEFICIENCY (71 MU/1X10+9 RBCS INSTEAD OF 131 + OR - 13 MU/1X10+9 RBCS, THE NORMAL VALUE FOR ADULTS), THE MEDICATION WITH PHENAZOPYRIDINE INDUCED METHEMOGLOBINEMIA. THE COINCIDENCE OF ANEMIA (8.7 G/DL) AND METHEMOGLOBINEMIA (19%) CAUSED MILD SIGNS OF HYPOXIA (FATIGUE, HEADACHE, FEEBLENESS AND DYSPNEA ON EXERTION).|An 85-year old woman developed a yellowish-orange pigmentation of the skin and urinary insufficiency after taking phenazopyridine hydrochloride 200 mg by mouth thrice daily. The drug was withdrawn and urinary output was restored the following day. /Phenazopyridine hydrochloride/|For more Human Toxicity Excerpts (Complete) data for PHENAZOPYRIDINE (7 total), please visit the HSDB record page.

Azo Dine

PHENAZOPYRIDINE IS ... MARKETED IN COMBINATION WITH SULFISOXAZOLE (AZO GANTRISIN) & SULFAMETHOXAZOLE (AZO GANTANOL). /PHENAZOPYRIDINE HYDROCHLORIDE/|COMMERCIAL PHENAZOPYRIDINE HYDROCHLORIDE MAY CONTAIN SOME BETA,BETA'-BIS(PHENYLAZO)-ALPHA,ALPHA'-DIAMINOPYRIDINE. IT IS AVAIL IN USA AS NF GRADE CONTAINING 99.0 TO 101.0% ACTIVE INGREDIENT ON DRIED BASIS. ... IT IS AVAIL IN 100 & 200 MG DOSES AS TABLETS CONTAINING 95.0 TO 105.0% OF STATED AMT OF PHENAZOPYRIDINE HYDROCHLORIDE. /PHENAZOPYRIDINE HYDROCHLORIDE/

THERE ARE NO TECHNICAL PRODUCTS OR PHARMACEUTICAL PREPARATIONS CONTAINING THE FREE BASE.|APPLICATIONS (VET): AS SIMPLE TEST TO DETERMINE PRESENCE OF GASTRIC ACIDITY OR ANACIDITY IN DOG ALTHOUGH UNSUITABLE FOR DETERMINING DEGREES OF ACIDITY. ... GIVEN ORALLY ... APPEARS IN URINE ... RED-ORANGE WITHIN 1.5 TO 2 HR. COLORATION ... OCCURS IN ACID MEDIA ... OFTEN GUIDE ... OF URINARY PH ... /&/ PROGRESS CONTROLLING ... URINARY INFECTIONS.|AQ SOLN MAY BE STABILIZED BY ADDITION OF 10% GLUCOSE. /PYRIDIUM HYDROCHLORIDE/

ULTRA-VIOLET SPECTROMETRY IS USED TO ANALYZE PYRIDIUM IN SOLN; HPLC WITH ULTRA-VIOLET SPECTROMETRY IS USED TO ANALYZE FORMULATIONS. /PHENAZOPYRIDINE HYDROCHLORIDE; FROM TABLE/

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