Tromethamine

In patients with acute respiratory distress syndrome (ARDS), permissive hypercapnia reduces ventilator-induced lung injury but may impair myocardial contractility. This randomized study in 12 ARDS patients compared uncorrected respiratory acidosis versus pH correction with tromethamine (THAM), a buffer that does not generate CO₂. Myocardial contractility was assessed by transesophageal echocardiography-derived maximal elastance (Emax). Permissive hypercapnia significantly decreased systemic vascular resistance and increased cardiac output in both groups. However, myocardial contractility decreased less in the THAM group than in the uncorrected group. Mean arterial pressure decreased and mean pulmonary artery pressure increased significantly only in the uncorrected group. THAM attenuated hypercapnia-induced myocardial depression and hemodynamic instability, suggesting that buffering respiratory acidosis may allow the lung-protective benefits of permissive hypercapnia while minimizing adverse cardiac effects.

Sodium alginate and acrylic acid hydrogel beads were developed for pH-responsive delivery of ketorolac tromethamine. The beads, fabricated by ionic gelation in calcium chloride, were spherical with smooth surfaces. Monte Carlo simulations showed negative adsorption energy, indicating spontaneous, exothermic, and thermodynamically favorable drug-polymer binding. Swelling and drug release were significantly higher at pH 7.4 than at pH 1.2, confirming pH-responsive behavior. The HET-CAM test showed no irritation or toxicity. In vivo pharmacokinetic studies in rabbits demonstrated higher plasma drug concentrations from hydrogel beads compared to drug solution, indicating improved bioavailability. The beads possess favorable physicochemical, biocompatibility, and pharmacokinetic properties, making them promising candidates for controlled drug delivery systems.

Fig. 1 pH-sensitive hydrogel beads for controlled delivery of Ketorolac Tromethamine. (Ullah H.; et al. 2025)