Background and Importance Although the choice of oral liquid forms facilitates administration in patients with enteral feeding tubes, it can cause adverse effects such as diarrhoea, vomiting or additional gastrointestinal intolerance associated with an osmolarity >500 mOsm/L, pH <3.5 and high sorbitol content of these preparations.

Aim and Objectives The objective of the study is to obtain updated data on physicochemical and gastrointestinal absorption properties from the main drugs marketed as oral liquid forms in order to establish practical instructions to increase the safety and efficacy of their administration by transpyloric tube.

Material and Methods 45 formulations were analysed for which the pH, osmolality and density were experimentally determined in triplicate. In addition, the sorbitol content was reviewed from the descriptions of the technical data sheet. The pH was measured with a pH meter (Crison-2006, Hach-Lange-Spain, S.L.U., Spain). Osmolarity was determined using the Micro-Osmometer-Fiske Model 210 apparatus (John-Morris-Scientific Pty Ltd., Australia). The osmolality data provided (mOsm/kg), is multiplied by the density of the solution (g/ml) to obtain the osmolarity (mOsm/L). The density data was obtained with two Nahita densimeters with ranges of 1000–1200 mg/ml and 1200–1400 mg/ml.

Results According to the literature, only 23,3% of the drugs presented a similar bioavailability when administered by transpyloric tubes in comparison to oral administration. Of the formulations analysed, only 7% complies with optimal physicochemical properties for transpyloric administration. The causes detected that discouraged a transpyloric administration were that 17,5% had extreme pH values, 92,5% had high osmolarities and 10% contained a high sorbitol content.

Conclusion and Relevance In most of the active ingredients studied, the gastrointestinal absorption of the drug is not sufficiently characterised, which generates uncertainty in its bioavailability when administered by transpyloric tube. Most formulations have a high osmolarity, so prior dilution is necessary. The pH values of some of them can be an added factor for the development of digestive intolerances.

Conflict of Interest No conflict of interest