The role of sodium lauryl sulfate on formulation of directly compressed tablets containing simvastatin and aspirin: Effect on drugs dissolution and gastric mucosa

According to the American College of Cardiology/American Heart Association (ACC/AHA), both aspirin and statin are used in the primary prevention of cardiovascular diseases. Aspirin (ASA) is contraindicated if there is gastrointestinal bleeding because it will exaggerate the condition. In this study, the effect of surfactant; sodium lauryl sulfate (SLS), in enhancing the in vitro dissolution of simvastatin (SIM) and ASA, as well as gastric irritation and upset, was studied. Oral tablets containing both ASA and SIM with and without the SLS were manufactured using the direct compression technique. The prepared tablets were characterized with respect to hardness, friability, uniformity of dosage units, in vitro disintegration, and dissolution. The effect of the addition of SLS in reducing the in vivo irritation and protection of gastric mucosa were also investigated. The results showed that the compressed tablets possessed sufficient hardness, acceptable friability, and are uniform with respect to disintegration, drugs contents, and tablet weight. The results showed that SIM alone exhibited a gastroprotective effect on the induced irritation. In addition, the incorporation of the SLS in the tablets containing SIM and ASA significantly enhanced the dissolution rates of both drugs and significantly decreased the gastric irritation and the ulcer index. The ulcer index of aspirin was decreased from 2.3 for tablets manufactured without SLS to 0.8 for tablets containing SLS. In a conclusion, the addition of pH modifier surfactant; SLS could enhance the dissolution rate of poorly soluble acidic drugs, reduce gastric upset and irritation without any effect on the main characters of the tablets. Moreover, the addition of SLS is very useful in improving the therapeutic activities and reducing the side effects of ASA and SIM for patients who require long-term administration of these drugs.