Research paper
Biopharmaceutics of rectal administration of drugs in man 7. Absorption rate and bioavailability of phenobarbital and its sodium salt from rectal dosage forms

https://doi.org/10.1016/0378-5173(79)90057-7Get rights and content

Abstract

In this report it will be shown that rectal administration of phenobarbital and its sodium salt can be looked upon as an alternative route of administration.

Plasma phenobarbital concentrations were measured in 6 volunteers after a single oral dose (219 mg) of sodium phenobarbital and after single rectal doses of phenobarbital (200 mg) or sodium phenobarbital (219 mg). In the case of the rectally administered aqueous dosage forms of phenobarbital no distinct difference in absorption rate occurred whether the sodium salt or the free acid was used. Rectal administration of both types of micro-enemas results in absorption which is less rapid than after oral administration of the sodium salt. However, the final and total absorption of phenobarbital and its sodium salt after 6.5 h is practically complete, compared with oral administration. The in vitro release of phenobarbital from fatty suppositories using a coarse powder (125–250 μm) of sodium phenobarbital and with a fine powder (<20 μm) of phenobarbital showed marked differences. The rectal absorption profile of the aqueous and fatty dosage forms of sodium phenobarbital in vivo was quite similar. A much slower absorption rate was observed if the free acid was used in the fatty suppository dosage form.

References (16)

  • H.G.M. Westenberg et al.

    Rapid and sensitive liquid Chromatographie determination of carbamazepine suitable for use in monitoring multiple-drug anticonvulsant therapy

    J. Chromatogr.

    (1976)
  • E.M. Boyd et al.

    Acute toxicity following rectal thiopental, phenobarbital and leptazol

    Anesth. Analg.

    (1967)
  • D.D. Breimer

    Pharmacokinetics of Hypnotic Drugs

    Ph.D. Thesis

    (1974)
  • F. Buchthal et al.
  • G. Heimann et al.

    Die rektale absorption von phenobarbital bei Kindern unter dem Einfluss verschiedener Vehikel

    Arzneim-Forsch./Drug Res.

    (1978)
  • B. Jailing

    Plasma and cerebrospinal fluid concentrations of phenobarbital in infants given single doses

    Develop. Med. Child. Neurol.

    (1974)
  • Kleijn E. van der, Guelen P.J.M., Wijk C. van, Baars I., In Clinical Pharmacology of Anti-Epileptic Drugs....
  • S.E. Leucuta et al.

    Bioavailability of phenobarbital from different pharmaceutical dosage forms

    Pharm. Acta Helv.

    (1977)
There are more references available in the full text version of this article.

Cited by (11)

  • Pharmacokinetics of Phenobarbital in Microenema Via Macy Catheter Versus Suppository

    2016, Journal of Pain and Symptom Management
    Citation Excerpt :

    Our study demonstrates that phenobarbital oral tablets crushed and suspended in water and administered via the MC is superior to suppository in delivering the medication reliably, rapidly, and comfortably. Our data are consistent with that of Moolenaar et al. who demonstrated that phenobarbital in both sodium and acid forms mixed in a 20 mL aqueous microenema solution consisting of 0.5% methylcellulose and distilled water is well absorbed rectally, with practically complete absorption at 6.5 hours after drug administration.7 They further demonstrated that drug absorption from microenema solution was faster than from suppositories.

  • Intramuscular and rectal therapies of acute seizures

    2015, Epilepsy and Behavior
    Citation Excerpt :

    The rectal solution was compared to IV, IM, and oral solutions. As expected, the IV solution was the most rapid, but rectal solution was faster than oral solution, which was faster than IM solution; a suppository was the slowest [58]. However, DZP in a gel preparation may be more reliable.

  • In vivo evaluation of anticonvulsant and antioxidant effects of phenobarbital microemulsion for transdermal administration in pilocarpine seizure rat model

    2015, Pharmacology Biochemistry and Behavior
    Citation Excerpt :

    In the literature, there are several papers describing the study of alternative formulations available in the market for the drug phenobarbital. Among these formulations, there can be cited: suppositories (Moolenaar et al., 1979); oral suspension (Yska et al., 2000; Morantes et al., 2010); oral solution (Jelveghari and Nokhodchi, 2008); hydrogel and emulsion for transdermal use (Odria et al., 2005). There are also studies about new drug delivery system, such as skin penetration of phenobarbital using iontophoresis (Djabri et al., 2012).

  • Rectal and Vaginal

    2023, Practical Pharmaceutics: An International Guideline for the Preparation, Care and Use of Medicinal Products, Second Edition
View all citing articles on Scopus
View full text