Sorbitol SR Granules are specialized pharmaceutical excipient granules based on d-sorbitol and developed in a finished sustained-release granule format. Sorbitol, also known as d-glucitol, has the molecular formula C₆H₁₄O₆, molecular weight 182.17, and CAS Number 50-70-4. The current USP-NF monograph specifies 91.0% to 100.5% d-sorbitol, calculated on the anhydrous basis.
The designation SR, or Sustained Release, refers to the performance of the finished granule or formulation system. Sorbitol itself is a highly water-soluble polyhydric alcohol and is not inherently a sustained-release material. Sustained-release behavior therefore requires an appropriate release-control mechanism, such as a polymeric matrix, functional coating, barrier layer, or another validated formulation approach.
FCC describes sorbitol as very soluble in water and available in forms including granules. Sorbitol is also hygroscopic, making moisture management important during manufacturing and storage.
Sorbitol SR Granules are granulated sorbitol-based pharmaceutical excipient materials developed for sustained-release formulation applications. The granulated core may be incorporated into a formulation together with appropriate release-controlling components to obtain a desired release profile.
The SR designation should be applied only when the finished product has been specifically developed and evaluated for sustained-release performance. Sorbitol's water solubility alone does not establish sustained-release behavior.
The final release characteristics depend on the composition and structure of the complete granule system, including the sorbitol core, release-control material, coating where applicable, particle size, porosity, density, processing conditions, and dissolution environment.
Sorbitol is a polyhydric alcohol used as a pharmaceutical excipient. Current USP-NF identifies Sorbitol as d-glucitol with the formula C₆H₁₄O₆, molecular weight 182.17, and CAS Number 50-70-4.
The current USP-NF monograph defines a d-sorbitol content of 91.0–100.5%, calculated on anhydrous basis. This chemical requirement applies to Sorbitol and should be distinguished from additional physical and functional requirements established for finished Sorbitol SR Granules.
Sorbitol is very soluble in water. This characteristic is important in SR formulation development because a highly water-soluble core generally requires a suitable release-control mechanism when gradual release is intended.
A sustained-release granule system is designed to control the rate at which the formulation interacts with the surrounding dissolution medium.
Possible mechanisms can include:
The selected mechanism depends on the intended formulation and product design.
For Sorbitol SR Granules, the release-controlling component should be identified in the approved product specification when applicable. Sorbitol should not be described as the release-controlling polymer unless the actual product formulation supports that claim.
The sustained-release performance of a finished granule can be affected by several variables, including:
Because these variables are formulation-specific, generic claims such as “12-hour release” or “24-hour release” should not be included unless supported by validated product-specific dissolution data.
Particle size is an important physical attribute for Sorbitol SR Granules. It can affect surface area, packing, coating uniformity, flowability, hydration, and release characteristics.
Product-specific physical parameters may include:
A controlled particle-size distribution can support consistent manufacturing and reproducible granule performance.
The actual D10, D50, D90 and granule-size ranges should be based on the approved product specification.
Bulk density and tapped density provide information about the packing behavior of granulated material.
These properties can influence:
Where actual measurements are available, Carr Index and Hausner Ratio may also be calculated to evaluate flow behavior.
Flowability is important for manufacturing Sorbitol SR Granules and for incorporating them into downstream formulations.
Flow can be influenced by:
Consistent flow can help improve material transfer, blending, filling, and processing.
Flowability should be established using an appropriate test method and actual product data.
Sorbitol is hygroscopic, making moisture control an important consideration for Sorbitol SR Granules.
Moisture can affect:
The moisture specification should therefore be established using actual product development, manufacturing, and stability data.
Packaging and storage conditions should be selected according to the validated stability requirements of the finished material.
Where the sustained-release mechanism uses a coating, additional coating-related attributes become important.
These may include:
The coating system should be designed and evaluated according to the intended release profile.
A specific coating weight gain should not be published as a universal value because the required amount depends on the coating polymer, formulation, granule size, process conditions, and target release characteristics.
An alternative approach is to incorporate sorbitol into a matrix system containing an appropriate release-controlling material.
In a matrix-based system, water penetration, swelling, polymer relaxation, diffusion, erosion, and other mechanisms may contribute to release control.
The performance of such a system depends on the complete formulation rather than sorbitol alone. Therefore, the type and concentration of matrix-forming material should be documented where relevant to the finished product.
Sorbitol SR Granules can be evaluated during development of sustained-release oral formulations where a water-soluble polyol core or excipient component is required.
Development studies may evaluate:
The formulation should be optimized according to the desired release characteristics and manufacturing process.
Dissolution testing is particularly important for sustained-release granules because the release profile must be demonstrated experimentally.
Testing can evaluate the amount of material released at defined time points under specified dissolution conditions.
The final acceptance criteria should be established according to the applicable produc
| Parameter | Specification |
|---|---|
| Appearance | White to off-white granules |