If sharpness between film coated layer and tablet core is unclear, it is difficult for film coated materials to be extended smoothly on swelling tablets. This is a reason why small absolute values of IDD in any batch where we find cracks in the film-coated layer. We then examined techniques for predicting crack initiation in the film-coated layer using the analysis

parameters discussed earlier in the manuscript. We confirmed above that FSD and IDD analyzed by terahertz waves tended to be low in batches of film-coated tablets in which a crack occurred in the film-coated layer under high-temperature conditions. This finding therefore suggested that low density of the film-coated layer and indistinctness of the boundary surface between the film-coated layer and tablet core were related Selleck GDC-973 to crack initiation in the film-coated layer under high-temperature conditions. Therefore, the index obtained by multiplying the FSD and IDD could potentially be useful in predicting crack initiation in the film-coated layer. The film-coating strength index (FCSI) was therefore defined to verify its relationship with crack initiation as follows: equation(8) FCSI=|FSD×IDD|FCSI=|FSD×IDD| A smaller FCSI value indicates an elevated risk of crack initiation. Table 4 shows the calculated values of FCSI for the measured film-coated tablets and the results of the two-sided, two-sample t-distribution tests

using the mean value of the parent population. These measurements were conducted before degradation tests. One of the two samples was always from the X6-1 batch, and its significance selleck chemical was verified against the other batches. The dispersion ratio of the samples was evaluated by using an F-test and an appropriate t-test method was selected. The significance level was assumed to

be 5%. Table 4 shows that FCSI was particularly low in the X6-2 batch, which had the largest RCI value of all batches examined; in addition, FCSI was also low in batches Ureohydrolase Z6-1 and W9-1, in which cracks were noted. The p-value (two-sided probability) of the t distribution test in all the batches with cracks in the film-coated layer is sufficiently smaller than the significance level, suggesting a large statistical difference. However, there should be no statistical difference in the batches without cracks where the p-value is higher than the significance level. Taken together, these results indicate a statistically significant difference in FCSI between batches with and without cracks in the film-coated layer. RCIs of batches X6-2, Z6-1, and W9-1, which all showed cracks in the film-coated layer, were 80%, 40%, and 40%, respectively, indicating that some tablets in these batches experienced no cracks even under high-temperature conditions. A histogram of FCSIs from Table 4 was compiled to clarify the relationship between FCSI distribution and the RCI of each batch ( Fig. 5).