Aim: Developing extended release matrix tablets containing 350 mg ascorbic acid and hydroxypropyl methylcellulose (HPMC) or polyethylene oxide (PEO) as hydrophilic polymer/s which control the rate and degree of drug release through 12 hour period. Materials and methods: Six batches of matrix tablets (P1, P2, P3, P4, P5, P6) were produced by direct compression. Ascorbic acid 97% was used as active compound. HPMC K4M, HPMC K15M, PEO 1105 and PEO 301 were used as hydrophilic polymers. Cellulose microcrystaline was used as diluent, copovidone was employed as binder, colloidal silica as flow-aid while magnesium stearate was used as lubricant. Before tableting powder mixtures were sieved and evaluated for bulk density, tapped density, angle of repose, compressibility index and Hausner ratio. Compressed tablets were evaluated for average mass, hardness, friability, average drug content and dissolution profile through 12 hours in phosphate buffer pH=7.2 . All test were conducted according pharmacopoeial standards (PhEur 7 and USP 35) Results: All six batches of powder mixtures demonstrated good flow properties and didn’t tend to make any problems during tableting process. Also all six batches of tablets complied the pharmacopeial requirements concerning average mass, hardness, friability and drug content. Dissolution studies demonstrated that all six batches of tablets provided extended release of ascorbic acid through 12 hours period, but only tablets containing PEO 1105, PEO 301 and their 1:1 mixture liberated more than 80% active compound, which is generally due to the lower viscosity and higher erodability of these PEO-s compared with the used HPMC-s. It was also demonstrated that low viscosity PEO 1105 or HPMC K4M released higher percent of active compound compared with higher viscosity PEO 301 or HPMC K15M, while both PEO 1105/PEO 301 1:1 mixture and HPMC K4M/HPMC K15M 1:1 mixture gave intermediate drug release, which is connected to the intermediate viscosity obtained by mixing these polymers. Conclusion: From the results received from all test it was concluded that tablets containing PEO 1105 as hydrophilic polymer (P1) are the most suitable choice for developing 12 hour extended release matrix tablets containing 350mg ascorbic acid as active compound.

Urični arthritis (giht, ulozi) je sistemska bolest, a najčešće se ispoljava na zglobovima. Nastaje kao posljedica povećane koncentracije urične kiseline u krvi koja kristalizira u formi mononatrijevog urata, akumulirajući se u zglobovima, tetivama, te u okolnim tkivima. Nastali kristali pokreću lokalne imunološki posredovane upalne procese u tkivima. Urična kiselina nastaje složenom endogenom enzimski posredovanom razgradnjom purina ali i drugih jednostavnih metabolita. Purini su komponente nukleoproteina, a nalaze se u različitim količinama u većini vrsta hrane. Ograničenje egzogenog unosa purina sa hranom smanjuje mogućnosti stvaranja urične kiseline, reducira metabolički stres i nastanak upalnih procesa. Prema nivou sadržaja purina hrana se može podijeliti na hranu sa visokim sadržajem (100 do 1000 mg purina/100 g), hranu sa srednjim (10 do 100 mg purina /100 g) i hranu sa niskim sadržajem purina. Način ishrane samo dijelom može uticati na tretman bolesti. Tradicionalno, dijeta sa vrlo niskim egzogenim unosom purina preporučuje se u akutnim stanjima uz medicinski tretman. Nutritivni tretman bolesti treba biti bazirana na smanjenju tjelesne mase, primjerenom unosu ugljičnih hidrata, smanjenom unosu zasićenih masnoća i holesterola, primjerenom u unosu proteina, povećanim unosom tekućine i eliminacijom konzumiranja alkohola. Nutritivni tretman može dati značajanu podršku medicinskom tretmanu bolesti.