Weight and content uniformity of lorazepam half-tablets: A study of correlation of a low drug content product.

The aim of this study was to investigate the degree of correlation between the weight and the content of spilt-halves of lorazepam 2.5 mg tablets. Weight variation and drug content of lorazepam half-tablets were evaluated according to the European Pharmacopoeia tests. Only one individual mass of the 30 half tablets was outside the limits of 85-115% of the average mass, but since it was within 75-125% of the average mass, the product passed the test. Each individual content was between 85% and 115% of the average content (99.8% expressed as a percent to label claim) and within the limits of 75-125%, so the product passed the uniformity of content test. The correlation coefficient (r) between the weight and the content of split halves was found to be 0.994. The weights of split tablet halves appear to be directly correlated with their drug content even for a medication with a low drug content, thus it is recommended that pharmacists who split tablets into two halves, assure the weight uniformity of the resultant halves. Manufacturers should develop formulation and manufacturing procedures that ensure high degree of correlation between weight and content not only among the whole tablet but also among the obtained tablet halves.