Dosage of hydrochlorothiazide split tablets to verify the uniformity of unit dose

Abstract

A common practice among the population is tablet splitting, which consists in physically dividing a tablet into two or more fractions, usually using knives, or specific pill splitters. Normally, it is performed to achieve dose flexibility or reduce costs. Ideally, it is expected that the subdivided parts would have equal dosages, each corresponding to half of the dosage of the whole tablet. However, it is often observed that there is an inequality between the parts when the tablet is divided, as well as product loss. This study aims to assess whether tablet splitting realiably results in halves with equal dosages. The Uniformity of Unit Dose procedure was conducted using a spectrophotometric method, as described in the Brazilian Pharmacopeia (6th edition), with dilution adjustments made for half-tablest. Tablets of hydrochlorotiazide 25 mg from four manufacturers — three generics and one reference brand —, were tested to compare the results. The experiments demonstrated that splitting tablets is inefficient, resulting in halves with unequal weights and dosages. As the parts obtained are not uniform, this practice can lead to underdosing or overdosing. However, it is not appropriate to generalize that tablet splitting should always be avoided. It is essential to evaluate the drug in question, as well as the advantages and disadvantages of splitting. To make an informed decision, this issue should be discussed with healthcare professionals to explore alternatives. If tablet splitting is deemed necessary, identifying the safest and most effective method is crucial.