Methocel e5lv

Felodipine (Nivedita Chemicals PVT Ltd, India); lactose monohydrate (LM) (Pharmatose 80M and Pharmatose 200M, DMV International, Holland) and microcrystalline cellulose (MC) (Vivapur 101 and Vivapur 102, JRS Pharma, Germany) were used as diluents; polyvinylpirrolidone – PVP (Kollidon K30, BASF, Germany) was used as binder; aqueous dispersion of ethyl acrylate and methyl methacrylate (Eudragit NE 40D, Evonix, Germany), acrylate, methyl methacrylate and a low content of methacrylic acid ester with quaternary ammonium groups (Eudragit RS 30D, Evonix, Germany), aqueous ethyl-cellulose dispersion (Surelease E719040, Colorcon, UK) were used as film forming polymers and low viscosity hydroxipropylmethylcellulose; HPMC (Methocel E5LV, Colorcon, U.S.A.) was used as a pore forming agent in the polymeric coating; triethyl citrate; TEC (Merck, Germany) was used as plasticizer in the polymeric coating. All the other substances used in this research were analytic grade from Merck, Germany.

Different sorts of the two APIs and intragranular filler were used in the formulation. The ingredient sorts were obtained from different suppliers or the same supplier, but presenting different characteristics. All samples were of commercial grade and complied with the European Pharmacopoeia specifications. For confidential reasons, samples were codded as: Ibu A, B, C for ibuprofen sorts; Par A, B, C for paracetamol sorts and MCC A, B for the two tested microcrystalline cellulose sorts.
The sodium starch glycolate used as disintegrant was Explosol from Blanver (Brazil) and the chosen binder was hydroxypropyl methylcellulose-Methocel E5LV kindly donated by Colorcon (UK).
During preformulation studies, in order to gain as much information as possible about the different sorts of APIs and excipients, X-ray powder diffraction and differential scanning calorimetry studies were performed (results not shown). Those studies did not reveal any polymorphism or behaviour differences between the different sorts. Besides this, all substances were stored in the same conditions, with the intention to minimize any differences in the materials’ moisture content.