Eudragit® RL in 2-pyrrolidone as antisolvent-based in-situ forming matrix

Abstract

Eudragit® RL (ERL) is pH independent copolymer. ERL is high permeability polymer with sustained released function; therefore, ERL is interesting polymer for the periodontal pocket drug delivery. The doxycycline hyclate (DH)-incorporated ERL-based in-situ forming matrix (ISF) was fabricated for intra-periodontal route employing 2-pyrrolidone (PYR) as a solvent. The various ERS concentrations in range of 10 to 25% w/w comprising 5% w/w DH in PYR were prepared as solution dosage forms. The viscosity of prepared formulations was polymeric concentration dependent (121 to 2134 cPs) with Newtonian-flow behavior. For 10, 15 and 20% w/w ERL solutions, there was no complete matrix formation after contact phosphate buffer solution pH 6.8 whereas the opaque solid matrix was apparently formed for 25% w/w ERL solution. Therefore, in situ phase separation of 25% w/w ERL solutions was achieved. The time to reach more than 80% drug release were 10, 24, 24 and 48 h for ISFs comprising 10, 15, 20 and 25% w/w ERL, respectively. Thus, ISFs containing ERL dissolved in PYR showed a potential system to deliver DH by intra-periodontal route of administration. By comparison, the 25% w/w ERL solution were most suitable for antisolvent-based ISF development.