The form of administration of a joint supplement is often considered a simple practical choice: powder to mix in food, syrup, tablet, capsule, or palatable chew.

However, the pharmaceutical form can influence several important parameters: absorption rate, blood concentrations achieved, stability of certain active ingredients, or ease of administration.

Its influence, however, depends on many factors: the nature of the molecule, solubility, stability, formulation, food intake, or the dog's behavior.

In joint supplements, this question is particularly important because several ingredients already show variable bioavailability.

In the long term, another factor also becomes crucial: compliance.

A theoretically effective product administered irregularly quickly loses its practical value.

Main forms available

The most commonly used forms are:

• powders;
• liquids or syrups;
• tablets and capsules;
• palatable chewable forms.

Each presentation has its advantages and limitations.

Powders often allow for easy dose adjustment and integrate easily into the food when the dog eats properly.

Liquid forms bypass the disintegration step of the tablet and sometimes facilitate administration.

Tablets and capsules generally offer good stability and precise dosing.

Palatable forms primarily aim to improve spontaneous acceptance.

None of these forms can be considered systematically superior to others.

The choice depends mainly on the dog, the ingredient used, and administration habits.

What pharmacokinetics shows

Veterinary pharmacokinetics shows that a molecule already dissolved or integrated into a suitable carrier can sometimes be absorbed more quickly than a solid form requiring prior disintegration.

In dogs, gastric emptying, food intake, digestive content, or even the composition of the formulation influence these phenomena.

The review by Stegemann et al. highlights the importance of these digestive peculiarities in veterinary species.

The example of glucosamine is particularly interesting.

The study by Maxwell et al. compared a liquid formulation, a chewable form, and a tablet form in dogs.

The liquid formulation produced a higher maximum plasma concentration than the other formulations.

These results, however, concern a specific molecule and specific formulations. They do not allow for the assertion that a liquid form is always superior to a solid form.

The same limitations apply to other molecules.

The study by Limsuwan et al. on different CBD formulations showed significant differences in plasma exposure depending on the presentations used.

Some liquid formulations achieved higher blood concentrations than some semi-solid forms.

These works primarily illustrate the importance of the carrier and the formulation.

The influence of food

Food intake sometimes modifies absorption.

For some lipophilic molecules, a meal can improve dispersion and promote absorption.

For others, the presence of food can slow gastric transit or modify absorption kinetics.

There is no single rule applicable to all supplements.

Certain oils rich in omega-3 or certain lipophilic compounds are often administered with food.

For other ingredients, the effect of food seems less important or depends directly on the formulation used.

Compliance: a major factor

Joint supplements are generally administered for several weeks or months.

Compliance therefore becomes an essential element.

The study by Cabezas et al. on prolonged UC-II supplementation showed good compliance at three months, then a significant decrease at six months.

These results remind us that the duration of treatment, owner habits, food refusal, or dog's weariness directly influence the regularity of doses.

A very palatable form can thus improve daily intake.

Conversely, a perfectly dosed powder that is regularly refused loses much of its value.

The limits of marketing arguments

Terms such as "high bioavailability," "ultra-absorbable," or "optimized formulation" are frequently used.

These claims are not always based on pharmacokinetic studies conducted in dogs with the commercialized product.

Available data sometimes concern humans, an isolated ingredient, or another formulation.

A palatable form does not necessarily provide more active ingredients.

A concentrated powder is not necessarily superior if it is poorly accepted.

In practice, the actual dose consumed remains more important than the theoretical dose listed on the label.

Stability and storage

Some molecules are sensitive to oxidation, light, or heat.

The type of packaging, storage conditions, and shelf life after opening can therefore influence the quality of the product.

Oils, certain plant extracts, and certain lipophilic ingredients sometimes require special precautions.

Stability depends on the type of active ingredient and the formulation used.

Which form for which dog?

For a dog that readily eats its food, a powder can be a simple and flexible solution.

For a picky or selective dog, a palatable form can improve compliance.

Liquid formulations may be beneficial for certain ingredients or in specific situations.

Dogs with food allergies, obesity, or dietary restrictions also require special attention to excipients and secondary ingredients.

In some cases, these elements become as important as the active ingredient itself.

Interactions and precautions

There is no general contraindication related to a powder, liquid, tablet, or palatable chew form.

However, the pharmaceutical form can influence:

• digestive tolerance;
• ingredient stability;
• product acceptance;
• regularity of doses.

Certain specific forms should not be crushed, opened, or split when doing so alters their release mechanism.

This situation remains relatively rare in veterinary joint supplements, but the principle is worth remembering.

Source

1. Martinez M.N., Papich M.G. et al. / Stegemann S. et al. (2022). Impact of gastrointestinal differences in veterinary species on the oral drug solubility, in vivo dissolution, and formulation of veterinary therapeutics.

2. Maxwell L.K. et al. (2016). Comparison of Glucosamine Absorption After Administration of Oral Liquid, Chewable, and Tablet Formulations to Dogs.

3. Limsuwan S. et al. (2024). Pharmacokinetics behavior of four cannabidiol preparations following single oral administration in dogs.

4. Cabezas M.Á. et al. (2022). Long-term supplementation with an undenatured type-II collagen (UC-II) formulation in dogs with degenerative joint disease: compliance data at 3 and 6 months.