All mammals lose their ability to produce lactase (β-galactosidase), the enzyme that cleaves lactose into galactose and glucose, afterweaning. The prevalence of lactase deficiency (LD) spans from 2 to 15% among northern Europeans, to nearly 100% amongAsians. Following lactose consumption, people with LD often experience gastrointestinal symptoms such as abdominal pain, boweldistension, cramps and flatulence, or even systemic problems such as headache, loss of concentration and muscle pain. These symptomsvary depending on the amount of lactose ingested, type of food and degree of intolerance. Although those affected can avoidthe uptake of dairy products, in doing so, they lose a readily available source of calcium and protein. In this work, gels obtained bycomplexation of Tetronic 90R4 with α-cyclodextrin loaded with β-galactosidase are proposed as a way to administer the enzymeimmediately before or with the lactose-containing meal. Both molecules are biocompatible, can form gels in situ, and showsustained erosion kinetics in aqueous media. The complex was characterized by FTIR that evidenced an inclusion complex betweenthe polyethylene oxide block and α-cyclodextrin. The release profiles of β-galactosidase from two different matrices (gels andtablets) of the in situ hydrogels have been obtained. The influence of the percentage of Tetronic in media of different pH was evaluated.No differences were observed regarding the release rate from the gel matrices at pH 6 (t50 = 105 min). However, in the case ofthe tablets, the kinetics were faster and they released a greater amount of 90R4 (25%, t50 = 40–50 min). Also, the amount ofenzyme released was higher for mixtures with 25% Tetronic. Using suitable mathematical models, the corresponding kinetic parametershave been calculated. In all cases, the release data fit quite well to the Peppas–Sahlin model equation, indicating that therelease of β-galactosidase is governed by a combination of diffusion and erosion processes. It has been observed that the diffusionmechanism prevails over erosion during the first 50 minutes, followed by continued release of the enzyme due to the disintegrationof the matrix.
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