How Sildenafil Oral Solution Works

13. Nonclinical Toxicology
7. Drug Interactions
Manufacturer Name:
Proper Use
Author information
What special precautions should I follow?
Frequently asked questions

All product and company names are trademarks™ or registered® trademarks of their respective holders. Use of them does not imply any affiliation with or endorsement by them. Sildenafil (Revatio) is a medicine used to treat pulmonary arterial hypertension (PAH), a narrowing of the small blood vessels in the lungs that results in increased pressure. The condition can affect both adults and children. Sildenafil is available as an intravenous infusion, a tablet, and as an oral liquid suspension (10 mg/mL) which is easier to use for children. The oral suspension comes with a 2 mL oral syringe that only has markings for 5 mg (0.5 mL) and 20 mg (2 mL) (Figure 1). This means that if a 10 mg dose is needed, a volume of 1 mL will be needed to give the correct dose. Since there is not a 1 mL marking on the syringe, the medicine should be drawn up to the 0.5 mL mark twice to give the correct dose. Infants with PAH may need an even smaller dose (less than 0.5 mL) based on their weight. So, parents would not be able to measure the correct dose using the enclosed syringe. In a recent case, an infant was to receive a dose of sildenafil oral suspension 2.5 mg (0.25 mL) every 8 hours. When the pharmacy dispensed the medicine, the label included instructions to administer 0.25 mL. However, the pharmacy did not remove the enclosed syringe which could not measure 0.25 mL. At home, the parents used the mg dose number (2.5) to measure the medicine.

13. Nonclinical Toxicology

Each chromatographic run required about 12 minutes. Sildenafil citrate eluted at about 7.1 minutes (Figure 1). Linearity of the standard curve was determined by linear regression analysis of sildenafil citrate concentrations versus peak areas of sildenafil citrate standards. The correlation coefficient was greater than 0.999, with intraday and interday coefficients of variation of less than 1.9% and 3.2%, respectively. Stability was defined as retention of greater than 90% of the drug's initial concentration.

12.2 Pharmacodynamics

Typical chromatogram of (A) sildenafil citrate at time 0 and (B) stored at 80 ºC for 18 hours. aViagra, Pfizer Inc., New York, NY, lot 2074603.b Children's Hospital, Columbus, OH, lot CH109608MG.c Humco Laboratory, Texarkana, TX, lot 88284E.d Paddock Laboratories, Minneapolis, MN, lot 4E6462.e Paddock, lot 7L6459.f Polyethylenephthalate bottles, Owens-Illinois, Toledo, OH.g White-Westinghouse, White Consolidated Inc., Columbus, OH.h Lauda RM20, Brinkman Instruments, Inc., Westbury, NY.i HP 1050 pump, Analytical Products Group, Palo Alto, CA.j HP 1050 autosampler, Analytical Products Group.k HP 1050 variable-wavelength ultraviolet-light detector, Analytical Products Group.l Atlas, Thermo Electron Corporation, Altrincham, Cheshire, United Kingdom.m Zorbax C18 column, 3.0 x 150 mm, MAC-MOD Analytical, Inc., Chadds Ford, PA.n Model 701A, Orion Research Inc., Boston, MA.o Burrell Corp., Pittsburgh, PA.p Fisher Scientific, Pittsburgh, PA.q Fisher Scientific, lot 91090-24.r Fisher Scientific, lot 910043-23.s Fisher Scientific, lot 906524-24.t Sigma Chemical Co., St. Louis, MO, lot 79F5609.u Mallinckrodt, Paris, KY, lot 8817KETG.v Burdick & Jackson, Division of Baxter, Muskegon, MI, lot BS908.w Gelman Sciences, Ann Arbor, MI, lot 0082205.x Sigma Chemical, lot 49H4070.y Malinckrodt Specialty Chemical Co., Chesterfield, MO, lot AB12KBSV.z Sodium hydroxide, Aldrich Chemical Co., Milwaukee, WI, lot 0011ODY.aa Hydrogen peroxide, Aldrich Chemical, lot 05427TX. © 2006 American Society of Health-System Pharmacists Cite this: Extemporaneous Sildenafil Citrate Oral Suspensions for the Treatment of Pulmonary Hypertension in Children - Medscape - Feb 01, 2006. Orodispersible film (ODF) is one of the novel formulations that disintegrate rapidly in the mouth without the requisite for water compared to other conventional oral solid dosage formulations. It is possible that the syringe contributed to the confusion since there are no markings for 0.25 mL. The parents probably used the syringe twice to administer 2.5 mL (one 0.5 mL dose plus one 2 mL dose). The error was not discovered until the parents requested a refill which was too early based on the volume originally dispensed. Fortunately, the infant did not have any adverse effects from the higher dose of medicine. Here's what you can do: When picking up sildenafil oral suspension from your pharmacy, ask to speak to the pharmacist. Open the package in front of the pharmacist and ask how to measure a dose. If the enclosed syringe does not have markings to measure the dose needed, ask the pharmacist for an appropriate size syringe.

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Then ask the pharmacist to show you how to measure a dose using the syringe. For example, in the case described above, since the dose was less than 1 mL, the pharmacy should have given the parents a 1 mL oral syringe. The pharmacist should have shown them what marking to use to measure the correct dose (0.25 mL).

7. Drug Interactions

Sildenafil citrate, a selective phosphodiesterase-5 inhibitor, is recommended as a first-line treatment for ED owing to its proven efficacy and established safety profile. Recently, a novel sildenafil orodispersible film (ODF) dosage form, which offers rapid disintegration in seconds when placed on the tongue, was developed. We conducted this narrative review to understand the advancements, advantages, and disadvantages of these innovative formulations. ODFs are innovative and sophisticated drug delivery systems that offer several advantages over conventional formulations. The unique benefits of sildenafil ODF includes administration of the film before engaging in sexual activity without the need for water and rapid disintegration of ODF within seconds unlike traditional pills.

Statistical Analysis

The sildenafil ODF also demonstrated reliable performance at elevated temperature (stress test), ensuring the stability of the pharmaceutical product during transport, storage, and handling. Finally, you should also repeat back, and show the pharmacist how you will measure a dose using the device. Sildenafil citrate 25-mg tabletsa were used to prepare the suspensions. The tablets were ground to fine powder using a mortar and pestle and combined with a 1:1 mixture of methyl-cellulose 1%b (Appendix A) and Simple Syrup, NF,c or a 1:1 mixture of Ora-Plusd and Ora-Sweete (Appendix B). The nominal concentration of sildenafil citrate in each suspension was 2.5 mg/mL.

Manufacturer Name:

If the enclosed syringe does not have markings to measure the dose needed, ask the pharmacist for an appropriate size syringe. Then ask the pharmacist to show you how to measure a dose using the syringe. For example, in the case described above, since the dose was less than 1 mL, the pharmacy should have given the parents a 1 mL oral syringe. The pharmacist should have shown them what marking to use to measure the correct dose (0.25 mL). Finally, you should also repeat back, and show the pharmacist how you will measure a dose using the device.

2.3 Reconstitution of the Powder for Oral Suspension

Sildenafil citrate 25-mg tabletsa were used to prepare the suspensions. The tablets were ground to fine powder using a mortar and pestle and combined with a 1:1 mixture of methyl-cellulose 1%b (Appendix A) and Simple Syrup, NF,c or a 1:1 mixture of Ora-Plusd and Ora-Sweete (Appendix B). The nominal concentration of sildenafil citrate in each suspension was 2.5 mg/mL. Approximately 30 mL of each suspension was transferred to 10 2-oz amber plastic prescription bottles.f Five plastic bottles of each suspension were stored at 4 ºC in a refrigerator,g and five were stored at 25 ºC in a temperature-controlled water bath.h The samples were taken after the bottles were shaken on a wrist-action shaker for 10 minutes and then allowed to stand for 2 minutes. The bottles were then gently inverted three times and the caps removed; the samples were withdrawn from the center of the bottles at midlevel of liquid. Approximately 30 mL of each suspension was transferred to 10 2-oz amber plastic prescription bottles.f Five plastic bottles of each suspension were stored at 4 ºC in a refrigerator,g and five were stored at 25 ºC in a temperature-controlled water bath.h The samples were taken after the bottles were shaken on a wrist-action shaker for 10 minutes and then allowed to stand for 2 minutes. The bottles were then gently inverted three times and the caps removed; the samples were withdrawn from the center of the bottles at midlevel of liquid. Three 500-µL samples were collected from each bottle on days 0, 7, 14, 28, 42, 56, 70, and 91 after preparation and analyzed in duplicate by a high-performance liquid chromatographic (HPLC) method modified and validated in our laboratory. The pH of each solution was measured on each study day. All solutions were observed for any changes in color and turbidity using black and white backgrounds. The HPLC instrumentation consisted of a pump,i an autosampler,j a variable-wavelength ultraviolet-light detector,k a chromatography data system,l a C18 column,m a digital pH meter,n a wrist-action shaker,o and a Vortex mixer.p The chemicals and reagents, including acetonitrile,q methanol,r and buffer solutions pH 7.00,s 4.00,t and 10.00,u were American Chemical Society or analytical grade.

The solution is usually flavored for better taste.
Dosing involves measuring with a provided syringe or dropper.
It offers rapid absorption into the bloodstream.

Before use, the mobile phase was passed through a 0.45-µm nylon 66 filterw and then degassed sildenafil oral jelly 100mg lovegra with helium. The detector was set at 245 nm, and the injection volume was 10 µL. The column was maintained at 25 ºC. A stock solution of sildenafil citrate reference standardx was prepared in methanol and then diluted with mobile phase to yield concentrations of 3.0, 2.5, 2.0, 1.0, and 0.5 mg/mL. One hundred microliters of each of these solutions was mixed with 1.0 mL of mobile phase and centrifuged; the supernatant was analyzed in the same manner as the samples. The samples were analyzed as described earlier every 30 minutes until the sildenafil citrate peak decreased by approximately 25%. Each chromatographic run required about 12 minutes. Sildenafil citrate eluted at about 7.1 minutes (Figure 1).

Proper Use

6.2 Postmarketing Experience

The oral suspension comes with a 2 mL oral syringe that only has markings for 5 mg (0.5 mL) and 20 mg (2 mL) (Figure 1). This means that if a 10 mg dose is needed, a volume of 1 mL will be needed to give the correct dose. Since there is not a 1 mL marking on the syringe, the medicine should be drawn up to the 0.5 mL mark twice to give the correct dose. Infants with PAH may need an even smaller dose (less than 0.5 mL) based on their weight. So, parents would not be able to measure the correct dose using the enclosed syringe. Linearity of the standard curve was determined by linear regression analysis of sildenafil citrate concentrations versus peak areas of sildenafil citrate standards. The correlation coefficient was greater than 0.999, with intraday and interday coefficients of variation of less than 1.9% and 3.2%, respectively. Stability was defined as retention of greater than 90% of the drug's initial concentration. Typical chromatogram of (A) sildenafil citrate at time 0 and (B) stored at 80 ºC for 18 hours. aViagra, Pfizer Inc., New York, NY, lot 2074603.b Children's Hospital, Columbus, OH, lot CH109608MG.c Humco Laboratory, Texarkana, TX, lot 88284E.d Paddock Laboratories, Minneapolis, MN, lot 4E6462.e Paddock, lot 7L6459.f Polyethylenephthalate bottles, Owens-Illinois, Toledo, OH.g White-Westinghouse, White Consolidated Inc., Columbus, OH.h Lauda RM20, Brinkman Instruments, Inc., Westbury, NY.i HP 1050 pump, Analytical Products Group, Palo Alto, CA.j HP 1050 autosampler, Analytical Products Group.k HP 1050 variable-wavelength ultraviolet-light detector, Analytical Products Group.l Atlas, Thermo Electron Corporation, Altrincham, Cheshire, United Kingdom.m Zorbax C18 column, 3.0 x 150 mm, MAC-MOD Analytical, Inc., Chadds Ford, PA.n Model 701A, Orion Research Inc., Boston, MA.o Burrell Corp., Pittsburgh, PA.p Fisher Scientific, Pittsburgh, PA.q Fisher Scientific, lot 91090-24.r Fisher Scientific, lot 910043-23.s Fisher Scientific, lot 906524-24.t Sigma Chemical Co., St. Louis, MO, lot 79F5609.u Mallinckrodt, Paris, KY, lot 8817KETG.v Burdick & Jackson, Division of Baxter, Muskegon, MI, lot BS908.w Gelman Sciences, Ann Arbor, MI, lot 0082205.x Sigma Chemical, lot 49H4070.y Malinckrodt Specialty Chemical Co., Chesterfield, MO, lot AB12KBSV.z Sodium hydroxide, Aldrich Chemical Co., Milwaukee, WI, lot 0011ODY.aa Hydrogen peroxide, Aldrich Chemical, lot 05427TX. © 2006 American Society of Health-System Pharmacists Cite this: Extemporaneous Sildenafil Citrate Oral Suspensions for the Treatment of Pulmonary Hypertension in Children - Medscape - Feb 01, 2006.

Author information

This delivery system serves as a convenient mode of administration, especially in patients who have dysphagia and fluid restriction, being beneficial to pediatric, geriatric, and bedridden patients. A novel sildenafil ODF containing sildenafil citrate is formulated to be used in patients with erectile dysfunction (ED). This review discusses the advantages of ODF in improving compliance and satisfaction in these patients and describes the manufacturing techniques, evaluation tests, bioequivalence, and stability studies of sildenafil ODF. This formulation offers unique benefit to patients with ED by improving their acceptance and compliance and respecting their privacy and the need for a discreet treatment. Moreover, the comparison of pharmacokinetic parameters between the sildenafil ODF administered with and without water and the conventional film-coated tablet were similar.

What should I know about sildenafil before taking it?

It also demonstrated reliable performance that yielded a consistent product, meeting all specifications at release and after three weeks of storage under stressed conditions (60°C). Sildenafil ODF warrants improved ease of intake, taste, portability, storage, and compliance among ED patients, making it the potential most preferred formulation and drug of choice. Erectile dysfunction (ED) prevails as an unprecedented diagnosis and undertreated condition. It is considered as the perfect gender-dependent (early) biomarker of non-communicable diseases (NCDs) including central and peripheral cardiovascular disease, with a heightened risk of related mortality. The effective management of ED reduces these risk factors and halts the progression of disease. Orodispersible film (ODF) is one of the novel formulations that disintegrate rapidly in the mouth without the requisite for water compared to other conventional oral solid dosage formulations. This delivery system serves as a convenient mode of administration, especially in patients who have dysphagia and fluid restriction, being beneficial to pediatric, geriatric, and bedridden patients. A novel sildenafil ODF containing sildenafil citrate is formulated to be used in patients with erectile dysfunction (ED). This review discusses the advantages of ODF in improving compliance and satisfaction in these patients and describes the manufacturing techniques, evaluation tests, bioequivalence, and stability studies of sildenafil ODF.

What special precautions should I follow?

In a recent case, an infant was to receive a dose of sildenafil oral suspension 2.5 mg (0.25 mL) every 8 hours. When the pharmacy dispensed the medicine, the label included instructions to administer 0.25 mL. However, the pharmacy did not remove the enclosed syringe which could not measure 0.25 mL. At home, the parents used the mg dose number (2.5) to measure the medicine. It is possible that the syringe contributed to the confusion since there are no markings for 0.25 mL.

Does sildenafil interact with foods or drinks?

The parents probably used the syringe twice to administer 2.5 mL (one 0.5 mL dose plus one 2 mL dose). The error was not discovered until the parents requested a refill which was too early based on the volume originally dispensed. Fortunately, the infant did not have any adverse effects from the higher dose of medicine. Here's what you can do: When picking up sildenafil oral suspension from your pharmacy, ask to speak to the pharmacist. Open the package in front of the pharmacist and ask how to measure a dose. This formulation offers unique benefit to patients with ED by improving their acceptance and compliance and respecting their privacy and the need for a discreet treatment. Moreover, the comparison of pharmacokinetic parameters between the sildenafil ODF administered with and without water and the conventional film-coated tablet were similar. It also demonstrated reliable performance that yielded a consistent product, meeting all specifications at release and after three weeks of storage under stressed conditions (60°C). Sildenafil ODF warrants improved ease of intake, taste, portability, storage, and compliance among ED patients, making it the potential most preferred formulation and drug of choice.

Frequently asked questions

Three 500-µL samples were collected from each bottle on days 0, 7, 14, 28, 42, 56, 70, and 91 after preparation and analyzed in duplicate by a high-performance liquid chromatographic (HPLC) method modified and validated in our laboratory. The pH of each solution was measured on each study day. All solutions were observed for any changes in color and turbidity using black and white backgrounds. The HPLC instrumentation consisted of a pump,i an autosampler,j a variable-wavelength ultraviolet-light detector,k a chromatography data system,l a C18 column,m a digital pH meter,n a wrist-action shaker,o and a Vortex mixer.p The chemicals and reagents, including acetonitrile,q methanol,r and buffer solutions pH 7.00,s 4.00,t and 10.00,u were American Chemical Society or analytical grade. Before use, the mobile phase was passed through a 0.45-µm nylon 66 filterw and then degassed sildenafil oral jelly 100mg lovegra with helium.

6.1 Clinical Trials Experience

The detector was set at 245 nm, and the injection volume was 10 µL. The column was maintained at 25 ºC. A stock solution of sildenafil citrate reference standardx was prepared in methanol and then diluted with mobile phase to yield concentrations of 3.0, 2.5, 2.0, 1.0, and 0.5 mg/mL. One hundred microliters of each of these solutions was mixed with 1.0 mL of mobile phase and centrifuged; the supernatant was analyzed in the same manner as the samples. The samples were analyzed as described earlier every 30 minutes until the sildenafil citrate peak decreased by approximately 25%. Erectile dysfunction (ED) prevails as an unprecedented diagnosis and undertreated condition. It is considered as the perfect gender-dependent (early) biomarker of non-communicable diseases (NCDs) including central and peripheral cardiovascular disease, with a heightened risk of related mortality. The effective management of ED reduces these risk factors and halts the progression of disease.

It is not recommended for use in children or women.
Overdose symptoms include dizziness, vision changes, and prolonged erections.
Seek urgent medical help in case of overdose.

The solution is stored at room temperature, away from light.
Alcohol consumption may increase side effects.
Do not mix with hot beverages, which can affect stability.

ODFs are innovative and sophisticated drug delivery systems that offer several advantages over conventional formulations.

Parameter	Value	Description	Notes
Absorption time	30-60 minutes	Time to reach peak plasma levels	Faster onset compared to tablets
Peak plasma concentration	150-200 ng/mL	Max systemic concentration	Varies per dose and individual
Half-life	4-5 hours	Time to reduce concentration by half	Helps determine dosing intervals
Bioavailability	40-50%	Fraction reaching systemic circulation	Slightly variable across patients

The unique benefits of sildenafil ODF includes administration of the film before engaging in sexual activity without the need for water and rapid disintegration of ODF within seconds unlike traditional pills. The sildenafil ODF also demonstrated reliable performance at elevated temperature (stress test), ensuring the stability of the pharmaceutical product during transport, storage, and handling.