Abstract: The choice of proper excipients is one of the key factors for successful formulation of pharmaceutical dosage forms. Increasing number of new therapeutic compounds suffers from poor solubility and/or bioavailability, creating a challenge from the drug formulation point of view. Problems have also been encountered in attempts to formulate biological drugs such as peptides and proteins, considering their sensitivity towards certain production processes and routes of administration. In both cases the choice of the right excipient(s) is essential to provide particular processability and development of systems with desirable drug delivery kinetics. The aim of this work was to evaluate pharmaceutical applications of nanofibrillar cellulose (NFC), a renewable, biodegradable and widely available plant based material, as a potential excipient in the production of pharmaceutical dosage forms. Initially, tablets with immediate drug release were manufactured by methods of direct compression using spray dried NFC as a filler material. Addition of NFC improved the flow properties of commercially available and widely used microcrystalline cellulose. The main focus of the thesis was to evaluate NFC material for immediate drug release purposes. This goal was successfully achieved by setting up a spray drying method for the production of drug loaded NFC solid dispersion. System was able to fast the drug release over short periods of time. The purpose of this study was to further clarify and fully understand the mechanisms behind the successful performance of NFC as immediate drug release material. Binding of drugs to NFC due to the electrostatic interactions was observed. This kind of knowledge is beneficial when choosing the proper drug/excipient combination for the formulation process. In conclusion, NFC was shown to be a versatile excipient for the production of pharmaceutical dosage forms, while the comprehensive evaluation of the full potential of NFC in pharmaceutical applications warrants further experiments in the future.