Stereoselective disposition of ibuprofen enantiomers in man. 1985

Single dose oral dexibuprofen [S(+)-ibuprofen] for acute postoperative pain in adults

BACKGROUND

This review is an update of a previously published review in The Cochrane Database of Systematic Reviews Issue 3, 2009 on single dose oral dexibuprofen (S(+)-ibuprofen) for acute postoperative pain in adults.Dexibuprofen is a non-steroidal anti-inflammatory drug (NSAID) licensed for use in rheumatic disease and other musculoskeletal disorders in the UK, and widely available in other countries worldwide. It is an active isomer of ibuprofen. This review sought to evaluate the efficacy and safety of oral dexibuprofen in acute postoperative pain, using clinical studies in patients with established pain, and with outcomes measured primarily over four to six hours, using standard methods. This type of study has been used for many decades to establish that drugs have analgesic properties.

OBJECTIVES

To assess the efficacy and adverse effects of single dose oral dexibuprofen for acute postoperative pain using methods that permit comparison with other analgesics evaluated in standardised studies using almost identical methods and outcomes.

SEARCH METHODS

Searches were run for the original review in 2009 and subsequent searches have been run in August 2013. We did not find any new published studies as a result of the updated search.We searched for randomised studies of dexibuprofen in acute postoperative pain in MEDLINE, EMBASE, and CENTRAL (The Cochrane LIbrary), and for clinical trial reports and synopses of published and unpublished studies from Internet sources.

SELECTION CRITERIA

Randomised, double blind, placebo-controlled clinical studies of oral dexibuprofen for relief of acute postoperative pain in adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted data. We extracted pain relief or pain intensity data and converted it into the dichotomous outcome of number of participants with at least 50% pain relief over four to six hours, from which relative risk and number needed to treat to benefit (NNT) were calculated. Numbers of participants using rescue medication over specified time periods, and time to use of rescue medication, were sought as additional measures of efficacy. We collected information on adverse events and withdrawals.

MAIN RESULTS

New data were identified for this update in one unpublished trial synopsis (BR1160 1995) in addition to the single study (Dionne 1998) that was included in the original review. In both studies dexibuprofen gave high levels of response, with 51/96 (53%) participants experiencing at least 50% pain relief with dexibuprofen 200 mg and 35/50 (70%) with dexibuprofen 400 mg, compared with 75/147 (51%) with racemic ibuprofen 400 mg, and 12/62 (13%) with placebo. The numbers of participants was too small to calculate NNTs with any meaning. The median time to additional analgesic use was greater than four hours for all active therapies, but about two hours for placebo.Adverse events were generally of mild or moderate intensity and consistent with events normally associated with anaesthesia and surgery. There were no serious adverse events or deaths.Additional data did not alter the conclusions from the earlier review.

AUTHORS' CONCLUSIONS

The information from these two studies in acute postoperative pain suggested that dexibuprofen may be a useful analgesic, but at doses not very different from racemic ibuprofen, for which considerably more evidence exists.

Bioequivalence assessment of two formulations of ibuprofen

BACKGROUND

This study assessed the relative bioavailability of two formulations of ibuprofen. The first formulation was Doloraz(®), produced by Al-Razi Pharmaceutical Company, Amman, Jordan. The second forumulation was Brufen(®), manufactured by Boots Company, Nottingham, UK.

METHODS AND RESULTS

A prestudy validation of ibuprofen demonstrated long-term stability, freeze-thaw stability, precision, and accuracy. Twenty-four healthy volunteers were enrolled in this study. After overnight fasting, the two formulations (test and reference) of ibuprofen (100 mg ibuprofen/5 mL suspension) were administered as a single dose on two treatment days separated by a one-week washout period. After dosing, serial blood samples were drawn for a period of 14 hours. Serum harvested from the blood samples was analyzed for the presence of ibuprofen by high-pressure liquid chromatography with ultraviolet detection. Pharmacokinetic parameters were determined from serum concentrations for both formulations. The 90% confidence intervals of the ln-transformed test/reference treatment ratios for peak plasma concentration and area under the concentration-time curve (AUC) parameters were found to be within the predetermined acceptable interval of 80%-125% set by the US Food and Drug Administration.

CONCLUSION

Analysis of variance for peak plasma concentrations and AUC parameters showed no significant difference between the two formulations and, therefore, Doloraz was considered bioequivalent to Brufen.

Enantioselective degradation and unidirectional chiral inversion of 2-phenylbutyric acid, an intermediate from linear alkylbenzene, by Xanthobacter flavus PA1

Microbial degradation of the chiral 2-phenylbutyric acid (2-PBA), a metabolite of surfactant linear alkylbenzene sulfonates (LAS), was investigated using both racemic and enantiomer-pure compounds together with quantitative stereoselective analyses. A pure culture of bacteria, identified as Xanthobacter flavus strain PA1 isolated from the mangrove sediment of Hong Kong Mai Po Nature Reserve, was able to utilize the racemic 2-PBA as well as the single enantiomers as the sole source of carbon and energy. In the presence of the racemic compounds, X. flavus PA1 degraded both (R) and (S) forms of enantiomers to completion in a sequential manner in which the (S) enantiomer disappeared much faster than the (R) enantiomer. When the single pure enantiomer was supplied as the sole substrate, a unidirectional chiral inversion involving (S) enantiomer to (R) enantiomer was evident. No major difference was observed in the degradation intermediates with either of the individual enantiomers when used as the growth substrate. Two major degradation intermediates were detected and identified as 3-hydroxy-2-phenylbutanoic acid and 4-methyl-3-phenyloxetan-2-one, using a combination of liquid chromatography-mass spectrometry (LC-MS), and (1)H and (13)C nuclear magnetic resonance (NMR) spectroscopy. The biochemical degradation pathway follows an initial oxidation of the alkyl side chain before aromatic ring cleavage. This study reveals new evidence for enantiomeric inversion catalyzed by pure culture of environmental bacteria and emphasizes the significant differences between the two enantiomers in their environmental fates.

A fixed dose combination of ibuprofen and famotidine

The NSAID class of medications is frequently used for mild to moderate pain. While overall safe, NSAIDs have several important adverse effects including esophageal, gastric and duodenal ulceration which limit their use. This has led to the development of NSAIDs with either less gastrointestinal side effects or concurrent use of medications to prevent NSAID gastrointestinal side effects. While several classes of medications exist for the prevention of gastrointestinal side effects, few combination treatments are available in a single pill. Towards this end, a combination pill of ibuprofen and famotidine (HZT-501, Horizon Therapeutics, Skokie, IL. USA) has been developed.

[Ibuprofen in childhood: evidence-based review of efficacy and safety]

Ibuprofen is the non-steroidal anti-inflammatory drug most prescribed for the treatment of fever and moderate pain in childhood. Its analgesic and antipyretic efficacy is now well documented: at equal doses ibuprofen appears slightly more effective than acetaminophen in the treatment of fever and is equivalent for analgesia. However, adverse effects should be taken into account in the choice between ibuprofen and acetaminophen. Lot of studies (case reports, cohort studies, case-control studies and one multicenter double-blind randomized control trial) have reported ibuprofen adverse effects at therapeutics doses. These data suggest there is an increased risk of invasive group A streptococcal infection after chickenpox and of acute renal failure in case of hypovolemia after a treatment by ibuprofen. Gastroduodenal and hemorrhagic adverse events could also happen, but the causality with ibuprofen is not demonstrated. Therefore, ibuprofen is not recommended for the treatment of fever or moderate pain during chickenpox or during a disease with a risk of dehydration, until other pharmacoepidemiology studies more accurately quantify the risk of adverse events of ibuprofen in children.