Formulation, bioavailability and pharmacokinetic properties of combined paracetamol/orphenadrine in tablets

Document Type : Original Article


Department of Pharmaceutical Technology, Faculty of Pharmacy, Tanta University, Tanta, Egypt


In this investigation, the in-​vitro characters, the bioavailability, as well as the pharmacokinetic parameters of two different paracetamol​/orphenadrine citrate tablet formulations were compared.  The first formulation (product A) was Norgesic tablets (Manufd. by E.I.P.I.Co., A.R.E) while the other (product B) was formulated tablets of the same compn.  The in-​vitro dissoln. revealed faster dissoln. rate in case of product A.  Bioavailability study was conducted on healthy male subjects after receiving a single oral dose of either product A or B according to a 2-​way crossover study.  Blood samples were collected over an eight hour period and analyzed for their drug contents using HPLC.  Pharmacokinetic parameters were detd. for both formulations including, mean max. plasma concn. (Cmax)​, time of max. concn. (Tmax)​, half-​life (t1​/2)​, terminal rate of elimination (Ke) and area under serum concn.-​time curve (AUC)​.  It was found that Cmax obtained with product A was higher than that with product B.  Regarding Tmax, t1​/2, and Ke, both products were found to be not statistically different.  Furthermore, the two products were not found significantly different in the extent of absorption as indicated by area under serum concn.-​time curve.  These findings may indicate that the two products are bioequivalent in terms of bioavailability and pharmacokinetic properties detd. in normal healthy male volunteers