# Tablet Scoring: Current Practice, Fundamentals, and Knowledge Gaps
## 6 Tablet Scoring: Challenges and Opportunities  
Tablet splitting can lead to medication errors. One of the main reasons is that the tablets may not have been partitioned into the appropriate dosage. This can lead to overdose or underdose. Other factors to take into consideration include:  
1. Lack of drug substance uniformity with a single tablet. Although a tablet may fall within specified specification of dosage strength, the active ingredient may not be equally distributed within that tablet. Research has revealed that halves of partitioned tablets may contain different concentration of actives [190]. This was typically observed when a drug substance of wide particle size distribution was used. Researchers have studied the effect of drug content uniformity only as variation in half tablet weights [190]. However, there are not enough data to support the in-vitro effect of the drug content of half tablets [191; 192]. 2. Non-conventional shaped tablets. Certain tablet shapes may be difficult to partition, since the geometry of the tablet plays a crucial role in positioning the embossing scored line in the tablet [168]. 3. Fragments or crumble tablets. This issue is related to the lack of robust tablet physical property. The right selection of excipients can circumvent the fragmentation issue [193]. The current available literature focuses on the challenges of splitting scored tablets [194; 195; 196; 197]. However, an important concept that does not garner much attention in the literature is the influence of granule and tablet properties on the practice of splitting tablet. The physical properties of the tablets, such as weight, thickness, hardness, friability, design and shape, are not well understood as they can influence the splitting effectiveness of tablets [197]. Selected excipients such as binders can influence mass loss, mass variation, and tablet fragmentation, and can increase brittle factor and therefore mitigate friability [198]. Because of the intricacy of designing a tablet formulation and process, it is important to consider not only excipient selections and their functions, but also the unit operations [150], particularly for processing steps that involve altering the characteristics of the excipient and drug substance. Tablet compression plays an important role, as that final step may in some cases dictate the effectiveness of splitting a tablet [99]. We discuss below the factors that can potentially influence tablet scoring. These factors are identified here on the basis of knowledge of tablet formulation, as there have been no published studies available that explicitly address these issues. The factors that are important to consider when designing a formulation suitable for tablet scoring are highlighted in Figure 6.  
(1) Particle Size  
Particle size can affect granule flow properties [199], which can influence tablet weight variation [200]. Particle size can cause powder segregation, which can affect blend uniformity [124]. Segregation typically occurs during blend or granulation discharge [201]. Several studies have shown data in which segregated blends were evaluated using a segregation tester. The data revealed significant variability in the blend average particle size granules, confirming the evidence that particle size influence segregation [202; 203; 204]. To overcome the issue of segregation in the final blend, and to reduce the risk of poor content uniformity, it is preferable to used excipients having similar particle sizes [205; 206]. When there is a greater disparity in the particle size of the granulation components, segregation effects can happen making homogenous mixing difficult [159; 206]. Segregation occurs as a result of differences in particle size, density, and structural identities of the materials used. In the pharmaceutical industry, a conical mill (or conical screen mill) is often used to reduce the size of material in a uniform manner [207]. Sieves of different screen mesh opening are used to target the desired granule particle size [208].