Absorption and bioavailability of diclofenac after rectal administration of diclofenac-na gel preparation in rat and man

Pharmacokinetics of diclofenac in sheep following intravenous and intramuscular administration

OBJECTIVES

The aim of this work was to examine the pharmacokinetics of diclofenac (DCLF) in sheep after intravenous (IV) and intramuscular (IM) dosing.

ANIMALS

Healthy male Najdi sheep.

MATERIALS AND METHODS

Diclofenac (1 mg kg(-1)) was administered to ten clinically healthy-male Najdi sheep IV or IM (n = 5 each). Blood samples (5 mL) were collected and serum was separated for drug analysis by high-performance liquid chromatography with UV detection. Diclofenac pharmacokinetic parameters were determined by noncompartmental analysis.

RESULTS

Diclofenac is quickly eliminated from sheep with a terminal T(1/2lambda) of 2-3 hours for both routes of administration. Total DCLF clearance after IV and IM administration was 87.86 +/- 24.10 and 85.69 +/- 40.76 mL kg(-1) hour(-1) respectively. The absolute bioavailability of IM DCLF appears to be approximately 100%.

CONCLUSIONS AND CLINICAL RELEVANCE

The drug should be administered two to three times daily in sheep by IM or IV injection to maintain therapeutic concentrations. Additional studies are needed to evaluate the route of elimination of DCLF in sheep including metabolites formation and the significance of enterohepatic circulation.

Pharmacokinetics of rectal drug administration, Part II. Clinical applications of peripherally acting drugs, and conclusions

Part I of this article, which appeared in the previous issue of the Journal, covered general considerations, the physiology of the rectum, spreading of drugs into the colon, rectal absorption, partial avoidance of first-pass elimination, rate-controlled rectal delivery of drugs, irritation of the rectal mucosa and clinical applications of rectal administration, and discussed centrally acting drugs. In Part II, this discussion is extended to drugs which act peripherally and to methods of enhancing rectal drug absorption. The overall summary appeared in Part I.

Diclofenac sodium. A reappraisal of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy

Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) advocated for use in painful and inflammatory rheumatic and certain non-rheumatic conditions. It is available in a number of administration forms which can be given orally, rectally or intramuscularly. Conveniently, dosage adjustments are not required in the elderly or in those patients with renal or hepatic impairment. The drug has a relatively short elimination half-life, which limits the potential for drug accumulation. In numerous clinical trials the efficacy of diclofenac is equivalent to that of the many newer and established NSAIDs with which it has been compared. As an analgesic it has a fast onset and long duration of action. When administered intramuscularly it is at least comparable to, and frequently superior to, many narcotic and spasmolytic combinations in renal and biliary colic. Extensive clinical experience has been gained with diclofenac, clearly establishing its safety profile. It is well tolerated compared with other NSAIDs and rarely produces gastrointestinal ulceration or other serious side effects. Thus, diclofenac can be considered as one of the few NSAIDs of 'first choice' in the treatment of acute and chronic painful and inflammatory conditions.