Ribonuclease A-Mineral Carrier Complex as a Potential Antitumor Preparation

<strong>Objective: </strong>The oral administration of therapeutic proteins is complicated by their instability, which leads to loss of their activity in the gastrointestinal tract. Methods of protecting proteins from proteolysis are usually based on their encapsulation, which delays protein release in the stomach and intestines. Nevertheless, the protein is released immediately after capsule damage. The use of sorbents is particu larly promising because they provide prolonged protein release. The aim of this work was to create an organo-mineral preparation of antitumor ribonuclease (RNase) immobilised on hydrated aluminosilicate clinoptilolite, which is the safest agent with detoxifying, antioxidant, and anti-inflammatory properties among the numerous zeolites. <strong>Materials and Methods:</strong> We developed a new method for processing natural clinoptilolite samples from Tatarsko-Shatrashanskoe deposit for use as sorbents for antitumor RNase A. Zeolites’ sorption capacity was analysed, their elemental composition was determined using scanning electron microscopy, images were created using transmission electron microscopy, and porosity was examined using X-ray computed tomography. <strong>Results: </strong>We obtained a detailed characteristic of the mineral carrier and selected the optimal zeolite particle size and conditions for RNase A loading/unloading. The dynamics of RNase A release from clinoptilolite showed that the enzyme was gradually released over 20 h while maintaining its stability and catalytic activity in gastrointestinal fluids. <strong>Conclusion:</strong> The combination of clinoptilolite detoxifying activity and antitumor activity of RNase A allows us to consider the obtained preparation not only as a factor of body nonspecific defence, but also as a promising antitumor drug supplementing well-known chemotherapeutic agents used in the treatment of neoplasms in the gastrointestinal tract.