Pediatrics
`
`Stability of Lisinopril in Two Liquid Dosage Forms
`
`Milap C Nahata and Richard S Morosco
`
`BACKGROUND: Lisinopril is used in pediatric patients with hypertension. It is not commercially available as a liquid. Little is known
`about the stability of lisinopril in extemporaneously prepared liquid dosage forms.
`OBJECTIVE: To determine the stability of lisinopril in 2 oral suspensions stored at 4 and 25 °C in plastic prescription bottles.
`METHODS: Five bottles contained methylcellulose 1%:simple syrup NF (1:13) and the other 5 bottles had Ora Plus–Ora Sweet (1:1)
`at a lisinopril concentration of 1 mg/mL. Three samples were collected from each bottle at 0, 7, 14, 28, 42, 56, 70, and 91 days and
`analyzed by stability-indicating HPLC analytical method (n = 15).
`RESULTS: At 4 °C, the mean ± SD concentration of lisinopril remained >95.1 ± 1.8% of the initial concentration in the methylcellulose
`formulation and 95.1 ± 3.2% of the initial concentration in the Ora Plus–Ora Sweet formulation throughout the 91-day study period.
`At 25 °C, the mean concentration of lisinopril remained >92.4 ± 2.2% of the initial concentration in the methylcellulose formulation
`for 8 weeks and 95.8 ± 2.3% of the initial concentration in the Ora Plus–Ora Sweet formulation throughout the 91-day study period.
`No changes in physical appearance in any samples were seen during this period.
`CONCLUSIONS: Lisinopril can be prepared in either of 2 liquid dosage forms and stored for at least 13 weeks under refrigeration and
`8 weeks at room temperature.
`KEY WORDS: lisinopril, pediatrics, stability.
`Ann Pharmacother 2004;38:396-9.
`Published Online, 12 Jan 2004, www.theannals.com, DOI 10.1345/aph.1D415
`
`Lisinopril may be used for the treatment of hypertension
`
`or congestive heart failure in pediatric patients. It is
`available in tablet formulations of 2.5, 5, 10, 20, 30, and 40
`mg from at least 1 of 2 manufacturers (Prinivil by Merck1
`or Zestril by AstraZeneca2). No liquid dosage form of
`lisinopril is commercially available at this time.3
`Infants and young children are unable to swallow tablets
`and also require dosage based on their body weight. For
`this purpose, an extemporaneously prepared liquid dosage
`form is needed with documented stability of the drug in
`easily accessible vehicles.
`The stability of lisinopril in a liquid dosage form has
`been studied in syrup stored at 5 and 23 ˚C for 30 days4
`and at 25 ˚C over a 6-week period in a vehicle containing
`syrup (Ora Sweet SF) and an oral solution containing sodi-
`um citrate and citric acid (Bicitra).5 It should be noted,
`however, that (1) many pharmacies preparing extempora-
`
`neous liquid dosage forms may not carry Bicitra, (2) the
`most common ready-to-use vehicle is a 50:50 mixture of a
`suspending agent and syrup (Ora Plus with Ora Sweet), (3)
`the liquid formulations are often stored under refrigeration
`(4 ˚C) for an extended period, and (4) long-term stability
`data would be useful for chronic therapy.
`We designed a study to determine the stability of lisino-
`pril in 2 liquid dosage forms (1 with ready-to-use vehicles,
`another prepared from common ingredients) stored at 2
`temperatures (4 and 25 ˚C) in plastic prescription bottles
`over a 3-month period.
`
`Methods
`
`Lisinopril 10-mg tabletsa were used to prepare the suspensions (Ta-
`bles 1-3). The tablets were ground to a fine powder using a mortar and
`pestle, and 2 suspensions were then prepared: 1:13 methylcellulose 1%6,b
`
`Author information provided at the end of the text.
`
`aLot K9509, Merck & Co., West Point, PA.
`bLot CH109608MG, Children’s Hospital, Columbus, OH.
`
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`with simple syrup NFc added while mixing and 1:1 Ora Sweetd and Ora
`Pluse added while mixing. The concentration of lisinopril in each suspen-
`sion was 1 mg/mL. Both lisinopril suspensions were stored in 10 amber
`plasticf prescription bottles (60 mL each). Five plastic bottles of each
`suspension were stored at 4 ˚C in a refrigerator,g and 5 other bottles were
`stored at 25 ˚C in a temperature-controlled water bath.h
`The samples were taken after the bottles were shaken on a wrist-ac-
`tion shaker for 10 minutes and then allowed to stand for 2 minutes. The
`bottles were then gently inverted 3 times and the cap was removed; the
`samples were withdrawn from the center of the bottles at the midlevel of
`liquid. Three 500-µL samples were collected from each bottle on days 0,
`7, 14, 28, 42, 56, 70, and 91 and analyzed in duplicate by an HPLC
`method modified in our laboratory (n = 15).7 The HPLC method was
`proven to be stability indicating to ensure that the degradation products
`did not interfere with the measurement of lisinopril in suspensions. The
`pH was measured using a digital pH meter on each study day.
`The appearance and color of the samples were assessed by observing
`them against black and white backgrounds, and any changes in odor
`were noted at each sampling time. The HPLC instrumentation included
`an HP 1050 pump,i HP 1050 auto sampler,j HP 1050 variable wave-
`length detector,k and an HP 3396A integrator.l Other equipment included
`a Zorbax C18 3.0 × 150 mm,m a digital pH meter,n Burrell Wrist Action
`Shaker,o and a Voretex Genie 2.p The chemicals and reagents were
`American Chemical Society or analytical grade and included acetoni-
`
`Table 1. Preparation of Methylcellulose 1%6
`
`Ingredient
`
`Strength
`
`Quantity
`
`Methylcellulose powder
`Methylparaben
`Propylparaben
`Purified water, USP
`
`4000 centipoises
`200 mg
`100 mg
`
`10 g
`
`qs 1000 mL
`
`Instructions: Heat 200 mL of purified water to boiling. Add the parabens
`and mix well. Wet the methylcellulose powder and add it to the hot
`parabens solution. Allow to stand for 15 minutes, remove from heat,
`and qs with cold purified water while mixing well with a magnetic stir-
`rer. Keep mixing until a clear, homogeneous solution results.
`
`Table 2. Preparation of Lisinopril Suspension in
`Methylcellulose 1% Syrup
`
`Ingredient
`
`Lisinopril tablets
`Methylcellulose
`Simple syrup, NF
`
`Strength
`
`10 mg
`1% with parabens
`
`Quantity
`
`10
`7.7 mL
`qs 100 mL
`
`Instructions: Crush the tablets and triturate to a fine powder in a mor-
`tar. Levigate the powder with methylcellulose gel into a uniform paste.
`Add simple syrup in geometric proportions with constant mixing and
`transfer to a graduate. Rinse the mortar with syrup, transfer to the grad-
`uate, and qs to 100 mL.
`
`cLot 88284E, Humco Laboratory, Texarkana, TX.
`dLot 7L6459, Paddock Laboratories, Minneapolis, MN.
`eLot 4E6462, Paddock Laboratories.
`fPolyethylenephthalate bottles, OI Owens-Illinois, Toledo, OH.
`gWhite-Westinghouse, White Consolidated, Columbus, OH.
`hLauda RM20, Brinkman Instruments, Westbury, NY.
`iHewlett-Packard, Analytical Products Group, Palo Alto, CA.
`jHewlett-Packard, Analytical Products Group.
`kHewlett-Packard, Analytical Products Group.
`lHewlett-Packard, Analytical Products Group.
`mMAC-MOD Analytical, Chadds Ford, PA.
`nOrion, model 701A, Orion Research, Boston, MA.
`oBurrell, Pittsburgh, PA.
`pFisher Scientific, Pittsburgh, PA.
`
`trile,q methanol,r buffer solution pH 7,s buffer solution pH 4,t and buffer
`solution pH 10.u The mobile phase consisted of 43% water with 0.8% di-
`ethylaminev and 57% acetonitrile filtered through 0.45-µm nylon 66 fil-
`ter,w then degassed with helium.
`Stock solution of lisinoprilx was prepared in methanol and diluted to
`yield concentrations of 1.5, 1.0, 0.5, 0.25, and 0.1 mg/mL. One hundred
`microliters of these solutions were then mixed with 1 mL of mobile
`phase and centrifuged; the supernatant was analyzed the same way as the
`samples. The flow rate was 0.4 mL/min. The detector was set at 220 nm
`and the injection column was 10 µL. The column was maintained at a
`temperature of 25 ˚C.
`To establish the stability-indicating nature of the method, lisinopril 1.0
`mg/mL, the vehicles alone, and their mixtures were subjected to forced
`degradation. This was done by acid (2.0M HCl)y and base (2.0M NaOH)z
`hydrolysis, oxidation (H2O2 0.3%),aa and heat at 80 ˚C. The samples were
`analyzed as described earlier every 30 minutes until approximately one-half
`of the lisinopril peak disappeared to show that the quantification of lisinopril
`was not influenced by degradation products. Each chromatographic run re-
`quired about 10 minutes, and lisinopril eluted at about 3.8 minutes. The lin-
`earity was determined by linear regression analysis of lisinopril concentra-
`tion versus peak areas of lisinopril standards. The correlation coefficient
`was >0.999, with a coefficient of variation <2.7% intraday and 3.3% inter-
`day. Lisinopril was considered stable at >90% of initial concentration.
`
`Results
`
`The stability data for lisinopril in the 2 extemporaneous-
`ly prepared suspensions stored in plastic bottles at 2 tem-
`peratures are presented in Table 4. In the suspension with
`simple syrup and methylcellulose 1%, the mean concentra-
`tions of lisinopril were >95.1% of the initial concentration
`at 4 ˚C over the 3-month study period and >92.4% of the
`original concentration at 25 ˚C for 8 weeks. In the suspen-
`sion with Ora Plus–Ora Sweet, the mean concentration of
`lisinopril was >95.1% of the initial concentration at 4 ˚C
`and 95.8% of the original concentration at 25 ˚C during the
`3-month period. No change in pH, appearance, color, or
`odor was noted with any of the samples during the course
`of this study.
`
`Table 3. Preparation of Lisinopril Suspensions in
`Ora Plus–Ora Sweet
`
`Ingredient
`
`Lisinopril tablets
`Ora-Plus
`Ora-Sweet
`
`Strength
`
`10 mg
`
`Quantity
`
`10
`
`aa qs 100 mL
`
`Instructions: Crush the tablets and triturate to a fine powder in a mor-
`tar. Levigate the powder with a small amount of the vehicle into a uni-
`form paste. Add the vehicle in geometric proportions with constant mix-
`ing and transfer to a graduate. Rinse the mortar with vehicle, transfer
`to the graduate, and qs to 100 mL.
`
`qFisher lot 91090-24, Fisher Scientific.
`rFisher lot 910043-23, Fisher Scientific.
`sFisher lot 906524-24, Fisher Scientific.
`tLot 79F5609, Sigma Chemical, St. Louis, MO.
`uLot 8817KETG, Mallinckrodt, Paris, KY.
`vLot BS908, Burdick & Jackson, Division of Baxter, Muskegon, MI.
`wLot 0082205, Gelman Sciences, Ann Arbor, MI.
`xLot 49H4070, Sigma Chemical.
`yLot AB12KBSV, Mallinckrodt Specialty Chemical, Chesterfield, MO.
`zSodium hydroxide lot 0011ODY, Aldrich Chemical, Milwaukee, WI.
`aaHydrogen peroxide lot 05427TX, Aldrich Chemical.
`
`www.theannals.com
`
`The Annals of Pharmacotherapy ■ 2004 March, Volume 38 ■ 397
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`MC Nahata and RS Morosco
`
`Discussion
`
`Our data indicated that lisinopril was chemically and
`physically stable in 2 extemporaneously prepared suspen-
`sions for an extended period. The liquid preparation may
`improve the ease and accuracy of drug administration in
`infants and young children.
`Documentation of stability in 2 formulations provides a
`choice for clinicians preparing an extemporaneous formu-
`lation. Those preferring a ready-to-use vehicle may choose
`Ora Plus and Ora Sweet, while those desiring to prepare a
`less expensive methylcellulose suspension may use its
`powder for compounding the suspension. Further, most
`countries may not have ready-to-use suspension vehicles
`(eg, Ora Plus, Ora Sweet) on their markets.
`Our study extends the available lisinopril stability data on
`the 30 days of stability at 5 and 23 ˚C4 and 6-week stability
`at 25 ˚C.5 It offers a choice of 2 vehicles, as well as storage
`under refrigeration or at room temperature. The drug was
`stable for 8 weeks in one vehicle and 3 months in another.
`Lisinopril is among many drugs not labeled for use in in-
`fants and children and yet is used routinely for their treat-
`ment. In such cases, the availability of extemporaneously
`prepared liquid dosage forms with documented stability be-
`comes an important consideration in making decisions about
`whether to use these drugs. Our results make it possible for
`treatment using lisinopril in infants and young children.
`
`Summary
`
`An extemporaneous liquid formulation of lisinopril can
`be prepared in Ora Plus and Ora Sweet (1:1) and stored in
`plastic prescription bottles for 13 weeks under refrigeration
`or at room temperature without substantial loss of potency.
`
`Day
`
`OS/OPc
`
`Table 4. Stability of Lisinopril in Two Suspensions at 4 and 25 ˚C
`% Initial Concentration Remaininga
`4 ˚C
`25 ˚C
`1% MC/Syrupb
`1% MC/Syrupb
`
`It can also be prepared in methycellulose 1% and simple
`syrup NF (1:13) and stored in plastic prescription bottles
`for 8 weeks at room temperature and 13 weeks under re-
`frigeration without significant loss of drug concentration.
`
`Milap C Nahata PharmD, Professor of Pharmacy and Division
`Chair, College of Pharmacy; Professor of Pediatrics and Internal
`Medicine, College of Medicine and Public Health, Ohio State Uni-
`versity and Children's Hospital, Columbus, OH
`Richard S Morosco, Research Associate, College of Pharmacy,
`Ohio State University
`Reprints: Milap C Nahata PharmD, College of Pharmacy, Ohio
`State University, 500 W. 12th Ave., Columbus, OH 43210-1291, fax
`614/292-1335
`
`We appreciate the assistance of Elizabeth Wilhite BS (Pharmacy).
`
`References
`
`1. Package information. Prinivil. In: Physicians’ desk reference. Montvale,
`NJ: Thompson PDR, 2003:2070-3.
`2. Package information. Zestril. In: Physicians’ desk reference. Montvale,
`NJ: Thompson PDR, 2003:691-5.
`3. Taketomo CK, Hooding JH, Kraus DM. Pediatric dosage handbook. 9th
`ed. Chicago: Lexi-Comp, 2002:656-8.
`4. Thompson KC, Zhao Z, Mazakas JM, Beasley CA, Reed RA, Moser
`CL. Characterization of an extemporaneous liquid formulation of lisino-
`pril. Am J Health Syst Pharm 2003;60:69-74.
`5. Webster AA, English BA, Rose DJ. The stability of lisinopril as an ex-
`temporaneous syrup. Int J Pharmaceut Comp 1997;1:352-3.
`6. Methylcellulose. In: Nahata MC, Pai VB, Hipple TF. Pediatric drug for-
`mulations. 5th ed. Cincinnati, OH: Harvey Whitney Books, 2003:174.
`7. Lisinopril. In: The United States pharmacopeia, the National Formulary
`(USP24, NF19). Rockville, MD: United States Pharmacopeial Conven-
`tion, 2000:980-1.
`
`OS/OPc
`
`EXTRACTO
`ANTECEDENTES: El lisinopril es usado en pacientes pediátricos con
`hipertensión, aunque no está disponible comercialmente
`en forma líquida. Se conoce muy poco sobre la
`estabilidad del lisinopril en las formas de dosificación
`líquidas preparadas improvisadamente.
`OBJETIVO: El propósito del estudio fue determinar la
`estabilidad del lisinopril en 2 suspensiones orales
`almacenadas a temperaturas de 4 y 25 ˚C en botellas de
`prescripción plásticas por un período de 3 meses.
`MÉTODOS: Tabletas de 10 mg de lisinopril cada una fueron
`utilizadas en la preparación de las suspensiones. Se
`prepararon 5 botellas conteniendo metilcelulosa
`1%:jarabe simple FN (1:13) y otras 5 botellas
`conteniendo Ora Plus:Ora Sweet (1:1), a una
`concentración de lisinopril de 1 mg/mL. Cinco botellas
`de cada suspensión fueron almacenadas en un
`refrigerador a 4 ˚C, y otro grupo de 5 botellas de cada
`suspensión fue almacenado en un baño de agua a una
`temperatura controlada de 25 ˚C. Se coleccionaron 3
`muestras de cada botella los días 0, 7, 14, 28, 42, 56, 70,
`y 91, y se analizaron a través del método analítico de la
`HPLC (por sus siglas en inglés) indicando estabilidad (n
`= 15).
`RESULTADOS: A una temperatura de 4 ˚C, la concentración
`media del lisinopril se mantuvo sobre 95.1 ± 1.8% de la
`concentración inicial en la formulación de metilcelulosa y
`95.1 ± 3.2% de la concentración inicial en la formulación
`de Ora Plus:Ora Sweet a través de los 91 días del estudio.
`A 25 ˚C, la concentración media del lisinopril se
`mantuvo sobre 92.4 ± 2.2% de la concentración inicial en
`la formulación de metilcelulosa durante 8 semanas y a
`
`0
`
`7
`14
`28
`42
`56
`70
`91
`
`100% ± 0.97d
`pH 6.74 ± 0.02
`100.21 ± 1.04
`99.63 ± 1.02
`99.17 ± 1.33
`98.47 ± 1.23
`97.22 ± 1.45
`96.93 ± 1.67
`95.12 ± 1.83
`
`100% ± 1.98e
`pH 4.83 ± 0.03
`99.9 ± 1.84
`99.53 ± 1.72
`99.17 ± 2.12
`98.47 ± 2.03
`97.68 ± 2.37
`97.21 ± 2.98
`95.12 ± 3.17
`
`100% ± 1.28f
`pH 6.74 ± 0.03
`100.27 ± 1.69
`98.21 ± 1.34
`97.15 ± 1.53
`94.62 ± 2.21
`92.37 ± 2.23
`90.76 ± 2.13h
`88.79 ± 2.83
`
`100% ± 2.03g
`pH 4.82 ± 0.02
`100.09 ± 1.99
`99.05 ± 2.13
`98.31 ± 2.31
`97.91 ± 2.41
`97.22 ± 2.53
`96.45 ± 2.29
`95.79 ± 2.34
`
`aMean ± SD for 15 samples. None of the mean pH values changed during the study
`period.
`bMethylcellulose 1% in syrup.
`c1:1 mixture of Ora Sweet and Ora Plus.
`dThe actual concentration was 1.05 ± 0.01 mg/mL.
`eThe actual concentration was 1.00 ± 0.03 mg/mL.
`fThe actual concentration was 1.02 ± 0.02 mg/mL.
`gThe actual concentration was 1.03 ± 0.04 mg/mL.
`hThe concentration is <90% considering the SD.
`
`398 ■ The Annals of Pharmacotherapy ■ 2004 March, Volume 38
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`aop.sagepub.com
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`95.8 ± 2.3% de la concentración inicial en la formulación de Ora
`Plus:Ora Sweet a través de los 91 días del estudio. No se observaron
`cambios en apariencia física durante este período.
`CONCLUSIONES: El lisinopril puede ser preparado en 1 de 2 formas de
`dosificación líquidas y puede ser almacenado por lo menos por 13
`semanas bajo refrigeración y por 8 semanas a temperatura ambiente.
`
`Brenda R Morand
`
`RÉSUMÉ
`INTRODUCTION: Le lisinopril est utilisé chez les enfants souffrant
`d’hypertension. Aucune formulation liquide n’est cependant disponible
`commercialement. De plus, on en connaît peu sur la stabilité des
`formulations extemporanées.
`OBJECTIF: Cette étude avait pour but de déterminer la stabilité de 2
`suspensions de lisinopril destinées à l’administration par voie orale.
`MÉTHODES: Deux suspensions de lisinopril à 1% ont été préparées en
`utilisant un support différent. Une était à base de methylcellulose à 1%
`et de sirop simple NF (1:13), alors que l’autre utilisait un support d’Ora
`Plus et d’Ora Sweet (1:1). Chacune des 2 suspensions a ensuite été
`transvasée dans 10 bouteilles de plastique ambré. La moitié des
`
`Stability of Lisinopril in Two Liquid Dosage Forms
`
`bouteilles a été conservée au réfrigérateur (4 ˚C), alors que l’autre moitié
`était conservée à la température ambiante (25 ˚C). La teneur en lisinopril
`a été analysée par chromatographie liquide haute performance (HPLC) à
`0, 7, 14, 28, 42, 56, 70, et 91 jours. À chaque fois, 3 échantillons étaient
`prélevés de chaque bouteille (n = 15).
`RÉSULTATS: La teneur moyenne de lisinopril est demeurée au-dessus de
`95.1 ± 1.8% de la concentration initiale avec la formulation à base de
`methylcellulose et au-dessus de 95.1 ± 3.2% de la concentration initiale
`avec la formulation à base d’Ora Plus:Ora Sweet, lorsque celle-ci sont
`conservées à 4 ˚C pendant 91 jours. À 25 ˚C, les concentrations
`moyennes sont demeurées au-dessus de 92.4 ± 2.2% de la concentration
`initiale avec la formulation à base de methylcellulose pendant 8
`semaines et au-dessus de 95.8 ± 2.3% de la concentration initiale avec la
`formulation à base d’Ora Plus:Ora Sweet pendant 91 jours. Aucun
`changement de l’apparence physique des 2 suspensions n’a été observé.
`CONCLUSIONS: Les 2 formulations liquides testées s’avèrent stables
`pendant au moins 13 semaines lorsque conservées au réfrigérateur et
`pendant au moins 8 semaines lorsque conservées à la température
`ambiante.
`
`Suzanne Laplante
`
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`Downloaded from
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