Key Findings
Formulating tablets with poorly compressible active pharmaceutical ingredients (APIs) can be challenging. Selecting an excipient with suitable tablet-forming properties is essential for achieving adequate mechanical strength and low friability.
At Westpoint Pharma, our comparative evaluation of a challenging formulation containing 30% vitamin C demonstrated that DESU® Mannitol 200SD maintained high tablet hardness across compression forces of 10–40 kN. It also showed lower tablet friability than the tested European reference grade at all four compression-force settings.
These results highlight the potential of spray-dried mannitol to support tablet integrity in direct compression formulations containing poorly compressible APIs.
Why Is Tabletability Important for Poorly Compressible APIs?
Poorly compressible APIs can make it difficult to achieve sufficient tablet hardness and mechanical integrity during direct compression. Formulators may encounter weak tablets, increased friability, and challenges in maintaining consistent manufacturing quality.
In these formulations, the choice of filler is particularly important. A functional excipient should contribute to tablet formation while helping maintain mechanical strength across the intended compression range.
At Westpoint Pharma, we focus on the functional performance of pharmaceutical excipients under practical formulation conditions. Our DESU® Mannitol 200SD is designed to support direct compression applications where reliable tablet formation is important.
How Does DESU® Mannitol 200SD Perform in Vitamin C Tablets?
To evaluate its performance in a challenging formulation, we compared DESU® Mannitol 200SD with a European reference grade in a model formulation containing 30% vitamin C.
The tablets were evaluated at four main compression forces: 10, 20, 30, and 40 kN. Tablet hardness and friability were used to assess mechanical performance.
Tablet Hardness
DESU® Mannitol 200SD maintained high tablet hardness across all four compression-force settings.
Its hardness-versus-compression-force profile closely matched that of the tested European reference grade, demonstrating comparable mechanical support in a formulation containing a high proportion of a poorly compressible API.
This performance indicates that DESU® Mannitol 200SD can be a valuable filler candidate when tablet strength is a key formulation requirement.
Tablet Friability
Tablet hardness alone does not fully describe tablet integrity. Friability is another important quality attribute because it reflects a tablet's tendency to lose material through abrasion and mechanical stress.
In our comparison, tablets formulated with DESU® Mannitol 200SD showed lower friability than those prepared with the tested European reference grade at all four compression-force settings.
Lower friability can help reduce tablet damage during handling, packaging, and transportation, supporting more robust manufacturing outcomes.
Why Does the Particle Structure Matter?
The performance of DESU® Mannitol 200SD is associated with its spray-dried, porous agglomerated particle structure.
Scanning electron microscopy reveals particles with relatively rough surfaces and numerous microscopic pores. These structural features can influence how particles interact during compression.
The porous agglomerates can undergo fragmentation and generate fresh surfaces under pressure. Particle rearrangement, mechanical interlocking, and the formation of new contact surfaces can contribute to interparticle bonding during tablet formation.
In a formulation containing 30% vitamin C, these properties can help the mannitol contribute to the mechanical integrity of the resulting tablets, compensating in part for the challenges associated with a poorly compressible API.
The actual performance will depend on the complete formulation and manufacturing conditions, so application-specific evaluation remains essential.
What Are the Benefits for Direct Compression?
For direct compression formulations containing poorly compressible APIs, DESU® Mannitol 200SD offers several potential advantages:
- Consistent tablet hardness: Maintained high hardness across the tested compression-force range.
- Low friability: Lower friability than the tested European reference grade under the evaluated conditions.
- Engineered particle structure: A porous, agglomerated morphology that supports particle interaction during compression.
- Formulation flexibility: A potential filler option for challenging direct compression formulations.
- Tablet integrity: Mechanical properties that can help support handling and downstream manufacturing.
These characteristics make DESU® Mannitol 200SD a candidate for evaluation in formulations where tablet strength and resistance to abrasion are important.
How Should Formulators Select a Mannitol Grade?
Selecting a pharmaceutical mannitol grade requires consideration of both material properties and the needs of the final formulation.
Key factors include:
- API compressibility and loading level
- Mannitol grade and particle structure
- Target tablet hardness and friability
- Compression force and manufacturing process
- Compatibility with other excipients
- Disintegration and dissolution requirements
For formulations containing poorly compressible APIs, it is particularly important to evaluate tablet hardness and friability together rather than relying on a single performance indicator.
At Westpoint Pharma, we emphasize functional excipient evaluation to help pharmaceutical manufacturers identify suitable materials for their formulation and process requirements.
Conclusion
Mannitol can play an important role in direct compression formulations containing poorly compressible APIs.
In our comparative evaluation of a model formulation containing 30% vitamin C, DESU® Mannitol 200SD maintained high tablet hardness across compression forces of 10–40 kN and demonstrated lower friability than the tested European reference grade at all four settings.
Its spray-dried, porous agglomerated particle structure provides a plausible explanation for its favorable tablet-forming performance.
For pharmaceutical manufacturers developing challenging direct compression formulations, DESU® Mannitol 200SD is a promising functional filler to evaluate. Final selection should be based on formulation-specific testing and the required tablet quality attributes.
DESU® Mannitol 200SD — Supporting Tablet Integrity in Challenging Direct Compression Formulations.
About Westpoint Pharma
Westpoint Pharma is a pharmaceutical excipients manufacturer focused on functional excipients and formulation performance. Through the Westpoint Excipients platform, we provide pharmaceutical manufacturers with excipient solutions for formulation development and oral solid dosage manufacturing.
Our DESU® portfolio includes pharmaceutical mannitol and microcrystalline cellulose, supporting the development of formulations with demanding performance requirements.
Explore our pharmaceutical excipient portfolio at www.westpointexcipients.com.