Pediatric drug products require formulation strategies that account for age, dose, administration, palatability, excipient safety, stability, and dosing accuracy. A formulation that performs well for an adult population may not meet the practical or safety requirements of younger patients.
Oral liquids can provide the dosing flexibility and ease of administration needed for pediatric patients, particularly when swallowing tablets or capsules is difficult. Developing these products requires more than converting an adult dosage form into a liquid. The formulation, manufacturing process, analytical strategy, delivery device, and packaging must work together to support the intended pediatric population.
What Makes Pediatric Formulation Different?
Pediatric formulation development must account for the physiological and practical needs of the intended age group. Dose flexibility, safety, palatability, and ease of administration can influence the selection of the dosage form and the formulation itself.
Age is an important consideration because pediatric patients are not a single population. Formulation requirements can differ significantly between infants, toddlers, older children and body weight. A formulation intended for an infant may require a substantially different dose volume, excipient strategy, and administration approach than one intended for an older child.
These considerations make the target patient population an important starting point for formulation development.
Why Oral Liquids Are Important for Pediatric Patients
Oral liquid dosage forms can simplify administration when a child cannot comfortably swallow a tablet or capsule. Non-sterile liquid drug products also provide dosing flexibility and can accommodate diverse patient populations, including pediatric patients.
For younger children, the ability to administer a relatively small and measurable dose can be particularly important. The formulation must deliver the required amount of active pharmaceutical ingredient without creating an impractical dose volume.
The physical properties of the formulation also matter. A product that is too viscous may be difficult to administer through a syringe. A suspension that settles excessively may create challenges for dose uniformity. A formulation with an unpleasant taste may be difficult to administer consistently.
The dosage form therefore needs to be evaluated in the context of how the patient will actually receive the medication.
What Makes an Oral Liquid Age Appropriate?
An age-appropriate pediatric formulation must address more than whether a child can swallow the product.
Dose volume is one consideration. A formulation requiring a large volume for each dose may not be practical for a younger patient. The concentration of the active ingredient, API solubility, and required dose all influence the volume that must be administered.
Palatability is another critical factor. A child may refuse or expel a medication with an unpleasant taste, regardless of how well the formulation performs from a pharmaceutical perspective.
Excipient selection also requires careful consideration. Excipients used in adult formulations cannot automatically be assumed to be appropriate at the same levels for pediatric populations. The intended age group, exposure level, available safety information, and target market all need to be considered during formulation development.
FDA, EMEA and ICH guidance address age-appropriate dosage forms, ease of preparation, palatability, excipient selection, delivery systems, and packaging as important considerations in pediatric drug development.
Start With the API and the Required Dose
A pediatric oral liquid formulation strategy should begin with the characteristics of the molecule and the intended dose.
API solubility is a fundamental consideration when determining whether an active ingredient can be incorporated into a solution or whether a suspension or another formulation approach is more appropriate. The required dose also influences the formulation strategy. A high dose may require a concentration that is difficult to achieve while maintaining acceptable dose volume, stability, and physical properties.
Understanding these factors early can help formulators determine which formulation approaches are technically feasible.
CPL evaluates API solubility, excipient compatibility, formulation performance, and other development considerations before advancing prototypes. Its formulation development capabilities from molecule to market strategy support the development of non-sterile liquid products with attention to critical quality attributes and shelf-life performance.
Pediatric Excipient Selection Requires a Different Approach
Excipient selection is one of the areas where pediatric formulation development can differ substantially from adult drug product development.
An excipient may have established use in adult products without being appropriate for a particular pediatric population at the same concentration or exposure level. Formulators therefore need to evaluate the safety profile of each excipient in the context of the intended patient population and market.
Regulatory expectations also vary by market. Sponsors developing products for the United States and Europe may need to evaluate excipient use against different regulatory resources and requirements. The U.S. FDA Inactive Ingredient Database and European resources such as the STEP database can inform excipient selection and exposure considerations.
The rationale for excipient selection should be established during development rather than addressed after the formulation has already been finalized.
Taste Masking Is a Formulation Strategy
Palatability can directly affect whether a pediatric patient will accept a medication.
When an API has a bitter or otherwise unpleasant taste, formulators can evaluate several approaches. Sweeteners and flavors may help reduce the perception of an unpleasant taste. Other approaches can use polymers or complexation techniques to limit the interaction between the API and taste receptors.
The appropriate strategy depends on the API and the formulation. Solubility, concentration, excipient compatibility, stability, and the intended dosage form all influence which taste-masking approach is feasible.
Taste evaluation can involve specialized sensory testing or instrumental approaches. CPL can develop prototypes for subsequent evaluation through appropriate external testing resources rather than relying on internal personnel to taste pharmaceutical formulations.
Stability Must Support the Intended Shelf Life
A pediatric oral liquid must maintain its critical quality attributes throughout its intended shelf life.
For a solution, API solubility needs to remain controlled throughout stability testing. Precipitation or crystallization can alter the product’s physical characteristics and may affect the consistency of the administered dose.
Suspensions create additional considerations. Particle size, viscosity, sedimentation, redispersibility, and uniformity can all affect product performance and dose consistency.
Microbiological stability is another consideration for non-sterile liquid formulations. The formulation and preservative system must be appropriate for controlling microbial growth throughout the intended shelf life.
CPL’s formulation and analytical teams work together to evaluate liquid formulations for stability, quality, and performance. Its analytical method development capabilities support testing of non-sterile liquids, including drug distribution in suspensions, pH, viscosity, appearance, in-use behavior, container-closure integrity, and stability-related attributes.
Dose Accuracy Depends on More Than the Formulation
Dose accuracy becomes particularly important when an oral liquid is administered in small volumes or when the API is suspended rather than fully dissolved.
A suspension must remain sufficiently uniform to deliver the intended amount of API with each dose. Particle size distribution, viscosity, sedimentation behavior, and mixing can influence dose uniformity.
CPL has experience addressing these challenges. In one oral suspension development program, CPL optimized viscosity and particle size distribution to maintain suspension stability, pourability, and consistent dosing while scaling the formulation from laboratory batches toward commercial production.
Analytical methods also provide important data for confirming product quality and consistency. Testing can evaluate attributes such as potency, impurities, content uniformity, particle size, and stability.
The Dosing Device Is Part of the Delivery Strategy
The formulation and dosing device should not be evaluated independently.
Oral syringes, measuring cups, and other devices may have different requirements based on the formulation’s viscosity, dose volume, and physical characteristics. A formulation that is technically stable may still require modification if it cannot be administered effectively through the selected device.
Viscosity provides one example. A formulation that is too thick for the intended syringe may require reformulation. A suspension may also require evaluation of how much product can be withdrawn from the container and whether the administered volume consistently reflects the labeled dose.
Packaging compatibility and stability can also influence the final configuration. CPL can perform stability and compatibility studies with selected packaging components and generate data to help evaluate product performance in the intended container.
Packaging Decisions Should Be Considered Early
The packaging configuration should align with the formulation and administration strategy.
Bottle material, container dimensions, closure systems, dose volume, and the selected dosing device can affect how effectively a pediatric oral liquid can be administered. The formulation also needs to remain stable and recoverable from the container throughout its shelf life.
Packaging design may be established by the sponsor, while formulation and manufacturing partners can evaluate compatibility, stability, filling, and dose-delivery considerations.
Considering these requirements early can reduce the risk of developing a formulation that performs well in the laboratory but creates challenges during administration, packaging, or manufacturing.
Common Pediatric Formulation Mistakes
One common mistake is beginning pediatric formulation development without adequately establishing whether the molecule and intended dose are appropriate for the target population.
Another is selecting the dosage form before understanding the API’s properties and the requirements of the intended patient group. A sponsor may have a preferred packaging configuration or dosing device before determining whether the formulation’s viscosity, concentration, or physical characteristics are compatible with it.
Excipient selection can create another challenge when pediatric safety considerations are addressed too late in development.
These decisions are interconnected. The target age group influences the dose and administration strategy. The dose influences concentration and volume. API properties influence whether a solution or suspension is feasible. Those choices influence taste, stability, packaging, and manufacturing.
A pediatric formulation strategy should account for these relationships from the beginning.
Building a Pediatric Oral Liquid With Commercial Manufacturing in Mind
Formulation development should consider manufacturability before a lead formulation is locked in.
Technology transfer can introduce challenges when laboratory development and manufacturing are treated as separate stages. Manufacturing conditions, equipment, material handling, mixing, process timing, and other variables can affect how a formulation performs at larger scale.
Early collaboration between formulation development and manufacturing teams can help identify these considerations while the formulation remains flexible.
CPL integrates formulation, analytical, process development, and manufacturing expertise to support non-sterile liquid products from early development through commercialization. This approach allows formulation decisions to be evaluated against manufacturing requirements as development progresses.
For sponsors, early consideration of scale-up can help prevent a formulation from becoming dependent on laboratory conditions that are difficult to reproduce at larger manufacturing scales.
Choosing a CDMO for Pediatric Oral Liquid Development
The technical requirements of a pediatric oral liquid make CDMO selection an important part of the development strategy.
Sponsors should evaluate a partner’s experience with the relevant dosage form, formulation and analytical capabilities, manufacturing infrastructure, scale-up experience, project management approach, and ability to identify technical risks early.
The evaluation should also consider which technical experts participate before the project is quoted and how development information is carried into manufacturing.
CPL’s approach brings formulation development, analytical expertise, manufacturing, and project management together throughout the product lifecycle. Sponsors evaluating how to select a CDMO should consider how a potential partner addresses technical communication, timeline development, cross-functional collaboration, and continuity throughout development and manufacturing.
Develop the Pediatric Formulation Strategy Early
Pediatric oral liquid development requires decisions that extend beyond selecting a liquid dosage form. The target age group, dose, API properties, excipient safety, palatability, stability, dose accuracy, dosing device, packaging, and manufacturing process all influence the final product.
CPL provides formulation development, analytical development, process development, scale-up, and GMP manufacturing for non-sterile liquid drug products. Its capabilities support programs from early formulation work through clinical and commercial manufacturing.
Sponsors developing a pediatric oral liquid can engage CPL early to evaluate formulation options, identify development risks, and establish a path toward a stable, manufacturable product.
Schedule a meeting with CPL to discuss a pediatric oral liquid program, formulation challenge, or commercialization requirement with the CPL team.