Sensory Evaluation of Isomalt as a Filler–Binder in Chewable Tablet Formulations: Comparative Analysis of Palatability, Mouthfeel, and Disintegration

Introduction

Chewable tablets represent an important patient-centric dosage form, particularly for pediatric, geriatric, and dysphagic populations where ease of administration and compliance are critical [1]. Unlike conventional tablets, chewables remain in the oral cavity for an extended period, making organoleptic properties—taste, mouthfeel, and aftertaste—key determinants of patient acceptance [2]. Unpleasant taste and poor palatability are major formulation challenges that can negatively impact patient compliance, particularly in long-term treatments [3].

Filler–binders strongly influence a chewable tablet’s sweetness, texture, and disintegration kinetics. Polyols such as Isomalt are widely used due to their sugar-like taste, low hygroscopicity, and good compactability [4]. Isomalt provides approximately 50–60% of sucrose’s sweetness and exhibits a milder cooling effect than mannitol, which is known for its pronounced cooling sensation. Its low hygroscopicity ensures shelf life stability in humid environments, and its non-cariogenic nature supports dental safety. Furthermore, Isomalt can attenuate bitterness and astringency in formulations containing APIs with poor taste profiles [5].

Beyond Isomalt, this study also evaluates the impact on the sensory attributes of three widely used excipients that are recommended for chewable tablet formulations and that were used in this study in combination with Isomalt: dextrates, tricalcium phosphate (TCP), and microcrystalline cellulose (MCC).

Dextrates, a blend of glucose monohydrate and different polysaccharides derived from starch. offer sweetness, good solubility, and smooth mouthfeel, though it may absorb moisture at high humidity [6]. Tricalcium phosphate is a stable, non-hygroscopic inorganic filler with good compressibility but lacks sweetness and may cause chalky mouthfeel, requiring taste masking [7]. Microcrystalline cellulose offers good compressibility but it has gritty, chalky mouthfeel [8]. Given these distinct attributes, the present study aimed to systematically evaluate the sensory performance of Isomalt as a filler–binder in chewable tablets, in comparison with formulations containing the combination of Isomalt with dextrates, tricalcium phosphate, and MCC. Key parameters of palatability, mouthfeel, and disintegration behavior were analyzed to elucidate how each excipient influences the overall patient experience of chewable tablets. By understanding the strengths and limitations of each filler–binder, formulators can better tailor chewable tablet formulations for optimal taste and texture without compromising pharmaceutical quality.

Materials And Methods

Four chewable tablet formulations were developed to evaluate the sensory performance of Isomalt as a filler-binder and its combinations with commonly used excipients. The formulations included Isomalt (galenIQ™ 721, d₅₀ ≈ 210 μm, BENEO), Dextrates (Emdex®, d₅₀ ≈ 200 μm, Rettenmaier), Tricalcium Phosphate (TriCaFos 500, d₅₀ ≈ 100 μm, Budenheim), and Microcrystalline Cellulose (Vivapur 105, d₅₀ ≈ 20 μm, Rettenmaier). These excipients were selected based on their intended functional roles: dextrates for sweetness enhancement, tricalcium phosphate MCC for altering bite texture, disintegration and dissolving kinetics.

Each formulation was prepared by direct compression. Tablets were standardized to a diameter of 12 mm, a target weight of 600 mg, and a hardness of 80 N.

Sensory evaluation was conducted by a trained panel under standardized conditions. Each panelist assessed the tablets using a structured scoring sheet with a 0–6 intensity scale for sweetness, mouthfeel (smoothness versus sandiness), grittiness, astringency, and dissolution kinetics (perceived melt-away). Scores were averaged across panelists, and results were visualized using spider plots for attribute comparison.

Results And Discussions

The sensory evaluation revealed clear differences among the formulations across sweetness, mouthfeel, and aftertaste attributes (Figure 1). Isomalt achieved a high sweetness score and delivered a smooth mouthfeel with negligible grittiness, chalkiness, or sandiness. Its rapid melt-away and disintegration minimized tooth-picking and left a clean sweet aftertaste, while astringency was virtually absent, confirming its suitability for patient-friendly chewables.

The blend of Isomalt with 30 % dextrates introduced a slightly higher sweetness compared to Isomalt itself but introduced noticeable sandiness during the first bite. Dissolution was the fastest, though the initial texture was less smooth, and the aftertaste was acceptable with minimal tooth-picking and moderate astringency.

In contrast, Isomalt combined with 30 % tricalcium phosphate markedly reduced sweetness and was overshadowed by strong chalky and gritty sensations. Astringency and tooth-picking were prominent, and melt-away was delayed, making this blend the least preferred from a sensory standpoint. These characteristics reflect the non- aq. solubility of tricalcium phosphate, which compromises palatability despite its functional benefits as a mineral source in chewables.

Blends with MCC at 10–30 % showed concentration-dependent effects. At 10 %, MCC improved initial bite texture, while maintaining reasonable sweetness and dissolution. At 20–30 %, however, astringency increased significantly, and chalkiness became perceptible, reducing overall acceptability. Higher MCC levels also slightly delayed melt-away, though still within acceptable limits for chewable dosage forms.

Conclusion

Isomalt chewable tablets showed pleasant sensory properties and functional performance, offering balanced sweetness, smooth mouthfeel, rapid disintegration and dissolution. Its non-cariogenicity adds to its suitability for patient-centric formulations. Combining Isomalt with MCC (Type 105) or dextrates with the intention to customization of mouthfeel and sweetness allows to meet diverse taste and texture preferences — an essential feature to meet patient preferences for chewable products on a global scale.

See the full technical brochure on Sensory Evaluation of Isomalt as a Filler–Binder in Chewable Tablet Formulations here

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Authors:
Oliver Luhn; Ali Yousefinejad; Maj-Britt Cepok, PBP 2026 abstract “Sensory Evaluation of Isomalt as a Filler–Binder in Chewable Tablet Formulations”

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