Stability of Oral Suspensions of Ursodiol Made From Tablets

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Stability of Oral Suspensions of Ursodiol Made From Tablets

Cary E. and Darcie D. Streetman

Am J Health-Syst Pharm 59(4):361-363, 2002. © 2002 American Society of

Health-System Pharmacists

Introduction

Ursodiol (ursodeoxycholic acid) is a nontoxic, naturally occurring bile acid

that constitutes 1-2% of human bile. It suppresses hepatic synthesis of

cholesterol and aids in the desaturation of biliary cholesterol and

dissolution of cholesterol gallstones. Ursodiol is indicated for the

treatment of primary biliary cirrhosis[1] and cholesterol gallstones in

patients who cannot or will not undergo cholecystectomy.[2] It is also used

to treat many other hepatobiliary disorders.

FDA-approved package labeling does not include an indication for ursodiol

use in children, but such use has been described in the treatment of

cholestasis associated with cystic fibrosis, total parenteral nutrition,

Alagille syndrome, Byler disease, and biliary atresia.[3-6] Defective bile

acid elimination may be responsible for the cholestasis associated with

these disorders, causing accumulation of toxic bile acids in the liver,

systemic circulation, and peripheral tissues.[7] Ursodiol dissolves in the

small intestine and is delivered to hepatocytes in portal blood where it

displaces the toxic bile acids, protecting the liver and promoting bile

flow.[5] The recommended dosage in pediatric patients with primary biliary

cirrhosis ranges from 15 to 30 mg/kg given once daily.[3-7]

There are two commercial formulations of ursodiol available: a 300- mg

capsule and a 250-mg tablet. However, no commercially available liquid

preparations of ursodiol exist for patients who are unable to take tablets

and capsules. Two reports about the stability of extemporaneously compounded

liquid preparations of ursodiol have been published. High-performance liquid

chromatography (HPLC) analysis of a 60-mg/mL formulation performed by

and Nesbitt[7] showed that the preparation was stable for 35 days

while refrigerated, and a 25-mg/ mL formulation studied by Mallett et al.[8]

was stable for 60 days at room temperature or while refrigerated. Both

preparations were formulated with the 300-mg ursodiol capsule. Although

there are currently no published reports describing the stability of a

sugar-free oral liquid formulation of ursodiol, this product would be

beneficial for children receiving a ketogenic, diabetic, or oral liquid diet

or having other dietary restrictions. The purpose of this study was to

prepare an oral liquid formulation of ursodiol from commercially available

tablets in both syrup and a sugar-free vehicle and to determine the

shortterm stability of these formulations over a 90-day period.

Methods

Sample Preparation

A liquid suspension of ursodiol 50 mg/ mL (equivalent to 1 tablet per

teaspoon) was prepared by crushing 12 250-mg tablets of ursodiol[a] in a

glass mortar. Thirty milliliters of Ora- Plus and 30 mL of either

strawberry syrup or Ora-Sweet SF[c] were mixed and added to the crushed

ursodiol to make a final volume of 60 mL. The strawberry syrup was prepared

by mixing 3200 mL of simple syrup, NF,[d] and 600 mL of strawberry fountain

syrup.[e]

Six identical samples of each preparation (Ora-Plus and strawberry syrup,

and Ora-Plus and Ora-Sweet SF) were prepared and placed into 2- oz amber

plastic prescription bottles with child-resistant caps.[f] Three samples of

each preparation were stored either at room temperature (23-25 °C) or in the

refrigerator (3-5 °C). A 1-mL sample was withdrawn from each of the 12

bottles with a micropipette immediately after preparation and at 7, 15, 30,

60, and 90 days. After further dilution to an expected concentration of 1250

µg/mL with methanol, the samples were assayed in duplicate by HPLC.

HPLC Method

The HPLC method developed by Baillet-Guffroy et al.[9] was used for the

ursodiol assay. The instrumentation included a constant flow

solvent-delivery system[g] and a 250 x 4.6 mm inside diameter, 5-µm particle

column[h] maintained at 40 °C with a column heater. A variablevolume

injector,[j] an ultraviolet light detectork set at 201 nm, and a recording

integrator[l] were also used. The mobile phase consisted of methanol and

aqueous 0.01 M dihydrogen potassium phosphate buffer (75:25, by volume)

delivered at a rate of 1.2 mL/ min. The pH of the mobile phase was adjusted

to 5.25 with dilute phosphoric acid after the addition of methanol.

The stability-indicating capacity of the assay was previously determined in

our laboratory and was reevaluated for this experiment.[7] Decomposition of

ursodiol[a] was forced by allowing two separate 50-mg/mL samples to stand in

direct sunlight for 90 days after adjusting the pH to 12 with 1 N sodium

hydroxide or to a pH of 2 with 1 N sulfuric acid solution. The solutions

were then heated to 60 °C for two hours. The pH was corrected to 7, and the

solutions were diluted with mobile phase to an expected concentration of

1250 µg/mL and assayed. Approximately 50% degradation was achieved with the

basic solution, and 75% was achieved with the acidic solution; no

interfering peaks were found. The peak for ursodiol appeared at 6.6 minutes.

Peaks for two unidentified degradation products were noted at 10.2 and 12

minutes.

Standard Solutions and Standard Curve

A 25-mg/mL stock solution of analytic grade ursodiol[m] was prepared in

methanol on each day of sample analysis. Standard samples of ursodiol were

prepared by diluting the stock solution with methanol to 1100, 1125, 1250,

1375, and 1500 µg/ mL. A 1250-µg/mL concentration of ursodiol was assayed in

duplicate from approximately every tenth sample as an external control. A

standard curve was produced on each day of sample analysis by linear

regression of the peak heights of ursodiol against ursodiol[a]

concentration. The standard curve was linear (r2 > 0.999) over the working

range of concentrations. The between-day and withinday coefficients of

variation for the ursodiol assay were 2.42% and 1.23%, respectively.

Sample Analysis

Each of the ursodiol samples was shaken thoroughly by hand immediately

before assay. All samples were centrifuged at 1000 rpm for two minutes to

separate the insoluble components. Fifteen microliters of each sample was

injected into the HPLC system, and each sample was assayed in duplicate. The

samples were visually examined for any color change, evaluated for odor, pH

tested,[n] and taste tested on each day of analysis. Microbiological testing

was not performed because each vehicle contained effective preservatives.

Data Analysis

The stability of ursodiol was assessed by evaluating the percentage of the

initial concentration remaining at each time interval. Stability was defined

as the retention of at least 90% of the initial concentration. The

percentage remaining at 90 days in sugar-free preparations was compared with

corresponding percentages remaining in regular preparations using the

Mann-Whitney U test. The remaining percentages at 90 days in refrigerated

and room temperature preparations were also compared using the Mann-Whitney

U test (overall and within sugar-free and regular groups). All p values of

<0.05 were considered significant. All data were analyzed by using SPSS for

Windows release 10.0.5 (SPSS Inc., Chicago, IL).

Results and Discussion

At least 98% of the initial concentration of ursodiol remained throughout

the 90-day study period in all suspensions (Table 1). There were no

significant differences in the percentage remaining at day 90 among samples

that contained strawberry syrup compared with those that contained Ora-Sweet

SF (p = 0.82). No difference was found in the percentage of initial

concentration remaining between refrigerated and room temperature samples (p

= 0.31). There was no detectable change in color, odor, or taste and no

visible microbial growth in any sample. There was no appreciable change from

the initial mean ± S.D. pH (4.51 ± 0.02) in any of the samples containing

strawberry syrup or samples prepared with Ora- Sweet SF (4.53 ± 0.01). Both

preparations were found to be sweet with a slightly bitter aftertaste;

however, the sugar-free preparation was slightly sweeter for a longer period

of time than the preparation made with strawberry syrup.

The absorption of ursodiol has been reported to be 90% following an oral

dose.[2] The absorption of the ursodiol formulation used in the current

study has not been evaluated. However, the absorption and therapeutic

effectiveness of a drug in a suspension compounded from crushed tablets are

unlikely to differ appreciably from those of the original dosage form.

Conclusion

An extemporaneously prepared suspension of ursodiol 50 mg/mL in a 1:1

mixture of Ora- Plus and strawberry syrup or Ora- Sweet SF was stable for at

least 90 days when stored at 3-5 °C or 23-25 °C.

a Urso 250-mg tablets, Axcan Pharma U.S. Inc., Birmingham, AL, lot ET42.

b Ora-Plus, Paddock Laboratories, Minneapolis, MN, lot 5B6216.

c Ora-Sweet SF, Paddock, lot 9D6621.

d Simple Syrup, NF, Humco Laboratory, Texarkana, TX, lot 148610.

e Strawberry fountain syrup, Gordon Food Service, Grand Rapids, MI, lot

K553909117.

f 2-oz amber prescription bottles with childresistant caps, Owens Illinois

Prescription Products. Owens Illinois, OH.

g HPLC pump, Waters Associates, Inc., Milford, MA, model 501.

h Spherisorb ODS-2, 5-µm particle size, 250 x 4.6 mm, P. J. Cobert

Associates, Inc., St. Louis, MO.

i Eppendorf CH-30 column heater, P. J. Cobert Associates.

j Variable-volume injector, Waters, model U6K.

k unable absorbance detector, Waters, model 486.

l Integrator-recorder, Hewlett-Packard Company, Avondale, PA, model 3394.

m Ursodiol analytic grade powder, Axcan Pharma U.S., lot 990496.

n Altex pH 41 meter, Beckman Instruments, Irvine, CA.

Tables

References

Urso package insert. Birmingham, AL: Axcan Pharma U.S.; 2000 Jan.

Balistreri WF. Bile acid therapy in pediatric hepatobiliary disease: the

role of ursodeoxycholic acid. J Pediatr Gastroenterol Nutr. 1997; 24:573-89.

Linblad A, Glaumann H, Strandvik B. A two-year prospective study of the

effect of ursodeoxycholic acid on urinary bile acid excretion and liver

morphology in cystic fibrosis-associated liver disease. Hepatology. 1998;

27:166-74.

Luketic VA, Sanyal AJ. The current status of ursodeoxycholate in the

treatment of chronic cholestatic liver disease. Gastroenterologist. 1994;

2:74-9.

Narkewicz MR, D, C et al. Effect of ursodeoxycholic acid

therapy on hepatic function in children with intrahepatic cholestatic liver

disease. J Pediatr Gastroenterol Nutr. 1998; 26:49-55.

Poupon R, Poupon RE. Ursodeoxycholic acid therapy of chronic cholestatic

conditions in adults and children. Pharmacol Ther. 1995; 66:1-15.

CE, Nesbitt J. Stability of ursodiol in an extemporaneously

compounded oral liquid. Am J Health-Syst Pharm. 1995; 52:1798-800.

Mallett MS, Hagan RL, s DA. Stability of ursodiol 25 mg/mL in an

extemporaneously prepared oral liquid. Am J Health-Syst Pharm. 1997;

54:1401-4.

Baillet-Guffroy A, Baylocq D, Rabaron A et al. Nuclear magnetic resonance

spectometry and liquid chromatography of two bile acid epimers:

ursodeoxycholic acid and chenodeoxycholic acid. J Pharm Sci. 1984; 73:847-9.

Funding Information

Supported in part by a grant from Axcan Pharma U.S. Inc., Birmingham, AL.

Presented at the ASHP Midyear Clinical Meeting, Las Vegas, NV, December 5,

2000.

Reprint Address

Address correspondence to Dr. at the College of Pharmacy, University

of Michigan, 428 Church Street, Ann Arbor, MI 48109-1065.

Cary E. , Pharm.D., is Professor, College of Pharmacy, University of

Michigan (UM), Ann Arbor, and Clinical Pharmacist -- Pediatrics, University

of Michigan Hospitals and Health Centers (UMHHC), Ann Arbor. Darcie D.

Streetman, Pharm.D., is Clinical Pharmacist -- Pediatrics, and Clinical

Assistant Professor, UM; at the time of writing she was Specialty Resident,

Department of Pharmacy, UMHHC, and Clinical Instructor I, College of

Pharmacy, UM.