BENALI, HosnaSEDIRI, Khaldia2025-07-022025-07-022025http://dspace.univ-temouchent.edu.dz/handle/123456789/6359In this work we are interested by extracting Cellulose from a plant source as Alfa plant “Stipa Tenacissima” and from waste of paper. After Extraction, the cellulose extracted was modified to obtain “Cellulose Triacetate CTA” using esterfication process. The cellulose and CTA were characterized by FTIR and DRX. For using our polymer CTA prepared as a polymeric matrice in pharmaceutical formulations, we introduced it to prepare two different discs charged with an antibiotic agent “Cefalexin” and study its release in physiological medium. P1 and P2 were tested microbial with 4 pathogens. The results showed The IR spectrums of both cellulose extracted from Alfa plant P1 and from wastepaper P2 indicates the presence of major characteristic absorption bands of cellulose compared with the spectrum of pure cellulose. The IR results show that the tablet has good correlation between Cefalexin and CTA and the CF was dispersed on the polymer matrix CTA. The main absorption bands of CF which appear clearly in the disk spectrum. The diffractogram XRD of P1 clearly shows that the polymer is semi crystalline polymer. The XRD pattern of CTA modified from P1 shows the amorphous structure. The results of release of CF from two tablets containing cellulose triacetate (CTA) was significantly different depending on the drug load. From microbial test, We observe that the polymer has a good inhibition zones with all strains tasted with different diameters, for Cellulose extracted from Alfa plant (P1) , the highest inhibition zone was observed with staph strain with diameter 11 mm. we obtained also for the cellulose extracted from wastepaper (P2), the highest inhibition zones was observed with Pseudomonas and candida albican with 7mm.enCellulose, Stipa Tenacissima Plant, Cellulose Triacetate, Cefalexin, Kinetics of release, microbial activityThesis