Tramadol formulations

Eradiri O, Sista S, Lai JC, et al. Single- and multiple-dose bioequivalence of two once-daily tramadol formulations using stereospedfic analysis of tramadol and its demethylated (Ml and M5) metabolites. Curr Med Res Opin 2007 23 1593-1604. 

The success of prolonged-release morphine prompted the development of prolonged-release formulations for other opioids, for example the matrix made of hydrophobic and hydrophilic matrix formers, for example on hydrocodeine (DHC retard with cetostearyl alcohol and hydroxyethyl-cellulose), oxycodone (oxygesic with stearyl alcohol and polyacrylate) and tramadol (tramundin with cetostearyl alcohol and ethylcellulose). By virtue of the oblong shape of hydrocodeine and tramadol tablets the prolonged-release tablets can be divided, whereby compared with whole tablets release from the divided tablets is slightly accelerated. The difference with these forms is that with increasing dose the release slows down. 

Tramadol is available as drops, capsules, and sustained-release formulations for oral use, suppositories for rectal use, and solution for intramuscular, intravenous, and subcutaneous injection. After oral administration, tramadol is rapidly and almost completely absorbed. Sustained-release tablets release the active ingredient over a period of 12 h, reach peak concentrations after 4.9 h, and have a bioavailability of 87 to 95% compared with capsules. One 100-mg dose given to healthy volunteers resulted in plasma levels of 375 ng/ml at 1.5 h.55 Tramadol is 20% bound to plasma protein and it is rapidly distributed in the body it is mainly metabolized by O- and A-demethylation forming glucuronides and sulfates that are excreted by the kidney. 

Tiwari S, Murthy TK, Pai MR. Mehta PR. Chowdary PB. Controlled release formulation of tramadol hydrochloride using hydrophilic and hydrophobic matrix system. AAPS Pharm Sci Tech 1993 4(3) Article 31. 

Tramadol ER (tramadol hydrochloride) is a centrally acting synthetic analgesic in an extended-release formulation. It offers extended duration of pain relief with potential improvements in tolerability. Tramadol... 

J. Varshosaz, N. Tavakoli, F. Kheirolahi, Use of hydrophihc natural gums in formulation of sustained-release matrix tablets of tramadol hydrochloride, AAPS PharmSciTech. 7 Article 24, 2006. 

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