The propionic acids: a personal perspective

Ibuprofen-induced multiorgan malformation during embryogenesis in Xenopus laevis (FETAX)

Ibuprofen, one of the most commonly prescribed nonsteroidal anti-inflammatory drugs, has not been fully assessed for embryonic toxicity in vertebrates. Here, we systematically assessed the embryotoxicity of ibuprofen in Xenopus laevis at various concentrations during embryogenesis. Embryos were treated with different concentrations of ibuprofen, ranging from 8 to 64 mg/L, at 23 °C for 96 h, and examined daily and evaluated at 72 hpf. Lethal or teratogenic effects were documented. For histological analysis, paraffin embedded embryos were transversely sectioned at a thickness of 10-μm and stained with hematoxylin and eosin. Total RNA was isolated from embryos at stages 6, 12, 22 and 36, and real-time quantitative PCR was performed. Ibuprofen-treated embryos showed delayed or failed dorsal lip formation and its closure at the beginning of gastrulation. This resulted in herniation of the endodermal mass after gastrulation under high concentrations of ibuprofen-treated embryos. Underdeveloped intestines with stage and/or intestinal malrotation, distorted microcephaly, and hypoplastic heart, lungs, and pronephric tubules were observed in ibuprofen-treated embryos. Cephalic, cardiac, and truncal edema were also observed in them. The severity of the deformities was observed in a concentration-dependent manner. The teratogenic index was 2.28. These gross and histological disruptions correlated well with the altered expression of each organ marker gene. In conclusion, ibuprofen induced delayed and disrupted gastrulation in the early developmental stage and multiorgan malformation later in the organogenesis stage of Xenopus laevis embryos.

Effect of time-dependent ibuprofen administration on the post operatory after impacted third molar extraction: a cross-over randomized controlled trial

PURPOSE

To evaluate time-dependent administration of ibuprofen in a lower third molar extraction model.

METHODS

Eleven patients requiring bilateral surgical removal of lower third molars were recruited and randomized into a blinded crossover randomized controlled trial. For 3 days after surgery, the control group was prescribed ibuprofen 400 mg every 8 h. On the other hand, the experimental group received also ibuprofen 400 mg at breakfast and lunch, replacing the dinner intake with a placebo. Pain measurements (Visual Analog Scale from 0 to 10) were recorded at baseline, 24, 48, and 72 h postoperatively. Facial swelling and trismus were also measured at baseline, 24, and 72 h postoperatively.

RESULTS

Postoperative swelling and pain perception did not show significative difference between the control and experimental groups at 24, 48, and 72 h. Trismus was significantly lower in the control group than in the experimental group at 72 h postoperatively (p = 0.008). Rescue medication consumption seemed to be comparable between groups.

CONCLUSION

Eliminating night time ibuprofen might be insignificant for pain control after third molar extraction.

Comparing the Efficacy of Paracetamol, Ibuprofen, and a Combination of the Two Drugs in Relieving Pain and Fever in the Pediatric Age Group: A Prospective Observational Study

Introduction Fever and pain are common afflictions in the pediatric population, prompting the use of paracetamol and ibuprofen as primary treatment options. However, a comprehensive understanding of their comparative efficacy, safety profiles, and potential combined use remains crucial for informed clinical decision-making. In this prospective observational study, we aimed to delve into these aspects, shedding light on the optimal management strategies for fever and pain in pediatric patients. Methodology A total of 108 children were enrolled and categorized into three groups, namely, paracetamol monotherapy, ibuprofen monotherapy, and a combination of both drugs. Axillary temperature monitoring and assessment of pain on the Face, Legs, Activity, Cry, and Controllability (FLACC) scale/Visual Analog Scale (VAS) were employed as critical indicators. Concurrently, associated symptoms encompassing discomfort, activity levels, and appetite were meticulously recorded. To ensure safety, laboratory parameters including serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), serum creatinine, platelet count, and stool for occult blood were closely monitored before and after drug administration. The study duration spanned 48 hours post-initiation of the initial drug dose. Results A total of 108 pediatric cases were included in the study, spanning ages from six months to 18 years. Among them, the majority fell within the age group of six months to five years (n = 77). Participants were categorized based on the duration of fever, with 81 cases having a fever lasting more than 24 hours and 27 cases having a fever lasting less than 24 hours. The majority of cases presented with temperatures ranging from 38°C to 39°C. Comparison of drug efficacy in defervescence within the first four hours revealed that paracetamol alone took significantly longer than ibuprofen monotherapy or the paracetamol and ibuprofen combination (p = 0.026). In terms of the onset of effect, the paracetamol and ibuprofen combination showed comparable efficacy to ibuprofen alone. Regarding the total time without fever in 48 hours, significant differences were observed among the three drug regimens (p = 0.001 by the one-way analysis of variance (ANOVA) test). Paracetamol and ibuprofen were superior to paracetamol alone (p < 0.001) and ibuprofen alone (p = 0.014), while paracetamol alone and ibuprofen alone exhibited similar efficacy (p = 0.197). Based on the laboratory results as well as the clinical profile observed over 48 hours, we confirm safety based on this study. The combination of paracetamol and ibuprofen showed enhanced effectiveness in fever and pain relief. Conclusion This study demonstrates the favourable efficacy of paracetamol, ibuprofen, and their combination in the pediatric population. The combination of paracetamol and ibuprofen showed enhanced effectiveness in fever and pain relief, with minimal adverse effects and no significant derangements in biochemical parameters. This study thus contributes valuable insights to optimize the therapeutic approach to fever and pain in pediatric patients.

NSAID chronotherapy after impacted third molar extraction: a randomized controlled trial

OBJECTIVES

Postoperative pain management impacts patients' quality of life and morbidity. Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are widely used for this following a 3-doses-per-day regime. However, pain and inflammation follow a circadian rhythm, and animal models assessing the scheduling of NSAID administration (e.g., chronotherapy) have shown that while their use during the active phase of the day enhances postoperative recovery, their administration during the resting phase could have detrimental effects. This observation has led us to hypothesize that night administration of NSAID might be unnecessary in post-surgical scenarios. Therefore, a randomized clinical trial was conducted to test this hypothesis in surgical third molar extractions.

MATERIALS AND METHODS

Seventy (18-35 years) healthy participants requiring surgical removal of impacted lower third molars were recruited and randomized into a double-blind placebo-controlled study. For three days postoperatively, the treatment group (n = 33) received ibuprofen (400 mg) at 8 AM, 1 PM, and a placebo at 8 PM, while the control group (n = 37) received ibuprofen (400 mg) at 8 AM, 1 PM, and 8 PM. Pain severity was assessed by visual analog scale (VAS) and healing indicators including facial swelling, mouth opening, and C-reactive protein blood levels were also measured.

RESULTS

Pain VAS measures showed a circadian variation peaking at night. Also, no significant differences were observed between the two groups of the study in terms of postoperative pain scores (estimate: 0.50, 95% CI = [- 0.38, 1.39]) or any other healing indicator.

CONCLUSIONS

Postoperative pain follows a circadian rhythm. Moreover, night administration of ibuprofen might not provide any significant benefits in terms of pain management and control of inflammation, and two doses during the day only could be sufficient for pain management after surgical interventions.

KNOWLEDGE TRANSFER STATEMENT

Even though this study cannot rule out the possibility that a reduced regime is different than a standard regime, nocturnal doses of ibuprofen seem to have no clinical significance in the short term, and the results of this study provide evidence in favor of reducing ibuprofen administration from three doses to two doses only after third molar surgery.

Computer Aided Design of Solvent Blends for Hybrid Cooling and Antisolvent Crystallization of Active Pharmaceutical Ingredients

Choosing a solvent and an antisolvent for a new crystallization process is challenging due to the sheer number of possible solvent mixtures and the impact of solvent composition and crystallization temperature on process performance. To facilitate this choice, we present a general computer aided mixture/blend design (CAMbD) formulation for the design of optimal solvent mixtures for the crystallization of pharmaceutical products. The proposed methodology enables the simultaneous identification of the optimal process temperature, solvent, antisolvent, and composition of solvent mixture. The SAFT-γ Mie group-contribution approach is used in the design of crystallization solvents; based on an equilibrium model, both the crystal yield and solvent consumption are considered. The design formulation is implemented in gPROMS and applied to the crystallization of lovastatin and ibuprofen, where a hybrid approach combining cooling and antisolvent crystallization is compared to each method alone. For lovastatin, the use of a hybrid approach leads to an increase in crystal yield compared to antisolvent crystallization or cooling crystallization. Furthermore, it is seen that using less volatile but powerful crystallization solvents at lower temperatures can lead to better performance. When considering ibuprofen, the hybrid and antisolvent crystallization techniques provide a similar performance, but the use of solvent mixtures throughout the crystallization is critical in maximizing crystal yields and minimizing solvent consumption. We show that our more general approach to rational design of solvent blends brings significant benefits for the design of crystallization processes in pharmaceutical and chemical manufacturing.

Ibuprofen versus paracetamol for treating fever in preschool children in Nigeria: a randomized clinical trial of effectiveness and safety

INTRODUCTION

fever is the primary symptom of most childhood illnesses and a cause of concern to their caregivers. The antipyretics commonly used to treat fever are ibuprofen and paracetamol. Most studies on the effectiveness of ibuprofen and paracetamol in treating fever in under-fives were conducted in Europe and North America with very few in African children. This study was aimed at assessing the effectiveness and safety of a single dose therapy of ibuprofen versus paracetamol for treating childhood fever in Nigeria.

METHODS

a randomized, controlled clinical trial was conducted in the University of Calabar Teaching Hospital, in Nigeria. A total of 140 eligible children aged 6-59 months with tympanic temperature of 38°C-40°C were enrolled, and 70 of them were assigned to one arm that received a single dose of ibuprofen (10mg/kg) and 70 had paracetamol (15mg/kg). After drug administration, the children were admitted and observed in the hospital for six hours during which period a half-hourly temperature measurement and monitoring for adverse events were done.

RESULTS

the overall result showed that ibuprofen had a better fever reducing effect compared to paracetamol. The proportion of afebrile children in the ibuprofen versus paracetamol group at 1.5-2.5 hours of administration of the drugs was statistically significant (p = 0.04). The adverse events of both drugs were mild and quite comparable with vomiting being the commonest.

CONCLUSION

ibuprofen is more effective in the treating fever in under-fives compared to paracetamol. The adverse events of both drugs were mild and comparable.

Comparison of Fever-reducing Effects in Self-reported Data from the Mobile App: Antipyretic Drugs in Pediatric Patients

We compared the fever-reducing efficacy of acetaminophen (AA), ibuprofen (IBU), and dexibuprofen (DEX) using data collected from the mobile healthcare application FeverCoach, which provides parents with guidelines for determining their child’s health condition, according to body temperature. Its dataset includes 4.4 million body temperature measurement records and 1.6 million antipyretics treatment records. Changes in body temperature over time were compared after taking one of three different antipyretics (AA, IBU, and DEX), using a one-way ANOVA followed by a post-hoc analysis. A multivariate linear model was used to further analyze the average body temperature differences, calibrating for the influences of age, weight, and sex. Children administered IBU had average body temperatures that were 0.18 °C (0.17–0.19 °C), 0.25 °C (0.24–0.26 °C), and 0.18 °C (0.17–0.20 °C) lower than those of children administered AA, at time intervals of 1–2 hours, 2–3 hours, and 3–4 hours, respectively. Similarly, children administered DEX had average body temperatures that were 0.24 °C (0.24–0.25 °C), 0.28 °C (0.27–0.29 °C), and 0.12 °C (0.10–0.13 °C) lower than those of children administered AA, at time intervals of 1–2, 2–3, and 3–4 hours, respectively. Although the data were collected from the application by non-professional parents, the analysis showed that IBU and DEX were more effective in reducing body temperature than AA was.

Monitoring Commercial Ibuprofen Potency Changes Over 1 Year When Stored in a Household Setting

Background: Most over-the-counter medications are labeled for storage in a dry, room temperature environment. Despite this, many households store medications in the bathroom, where temperature and humidity extremes may be experienced. Objective: In this project, we sought to investigate the effect that long-term storage in a household bathroom had on potency of over-the-counter ibuprofen (IBU) products as well as on the emergence of a known toxic degradation product, 4-isobutylacetophenone (4-IBP). Methods: A liquid chromatography-tandem mass spectrometry method was developed for the quantitative determination of IBU and 4-IBP in aqueous samples. Three brands each of IBU tablets (200 mg) and suspensions (100 mg/5 mL) were assayed for IBU concentration at the initiation of the study and once monthly thereafter. The samples were stored in a household bathroom, with continuous temperature and humidity monitoring. Each sample was assayed in triplicate and percent recovery was calculated against freshly prepared standards of IBU using bulk powder. Results: Tablets maintained >90% average strength through 3 months, with statistically significant deviation from initial concentration (2-way analysis of variance, P = .05) detected after 6 to 7 months. Suspensions maintained >90% average strength through 5 months, with statistically significant changes from initial concentration emerging after 7 months. After 12 months, the average strength was 73% and 83% for tablets and suspensions, respectively. 4-IBP was not detected in any of the samples during the duration of the study. Conclusions: These data indicate that, while 4-IBP was not detected following 12-month bathroom storage of commercial IBU products, significant changes in potency should negatively affect efficacy.

In Silico Evaluation of Ibuprofen and Two Benzoylpropionic Acid Derivatives with Potential Anti-Inflammatory Activity

Inflammation is a complex reaction involving cellular and molecular components and an unspecific response to a specific aggression. The use of scientific and technological innovations as a research tool combining multidisciplinary knowledge in informatics, biotechnology, chemistry and biology are essential for optimizing time and reducing costs in the drug design. Thus, the integration of these in silico techniques makes it possible to search for new anti-inflammatory drugs with better pharmacokinetic and toxicological profiles compared to commercially used drugs. This in silico study evaluated the anti-inflammatory potential of two benzoylpropionic acid derivatives (MBPA and DHBPA) using molecular docking and their thermodynamic profiles by molecular dynamics, in addition to predicting oral bioavailability, bioactivity and toxicity. In accordance to our predictions the derivatives proposed here had the potential capacity for COX-2 inhibition in the human and mice enzyme, due to containing similar interactions with the control compound (ibuprofen). Ibuprofen showed toxic predictions of hepatotoxicity (in human, mouse and rat; toxicophoric group 2-arylacetic or 3-arylpropionic acid) and irritation of the gastrointestinal tract (in human, mouse and rat; toxicophoric group alpha-substituted propionic acid or ester) confirming the literature data, as well as the efficiency of the DEREK 10.0.2 program. Moreover, the proposed compounds are predicted to have a good oral bioavailability profile and low toxicity (LD50 < 700 mg/kg) and safety when compared to the commercial compound. Therefore, future studies are necessary to confirm the anti-inflammatory potential of these compounds.

Compound property enhancement by virtual compound synthesis

During drug discovery, drug candidates are narrowed down over several steps to develop pharmaceutical products. The theoretical chemical space in such steps is estimated to be [Formula: see text]. To cover that space, extensive virtual compound libraries have been developed; however, the compilation of extensive libraries comes at large computational cost. Thus, to reduce the computational cost, researchers have constructed custom-made virtual compound libraries that focus on target diseases. In this study, we develop a system that generates virtual compound libraries from input compounds. When a user inputs a compound, the system recursively applies virtual synthetic reaction rules to the compound to improve its properties. The synthetic pathway can also be traced by the user because the reaction rules in this system are based on real organic synthesis reactions. This system has useful functions for effective drug design, such as structural preservation, allowing the substructures necessary for potency to be maintained. In this paper, to confirm the effect of directional reaction sets, we applied the reaction sets to 100 compounds. Moreover, to confirm that the system can reproduce real synthetic pathways, the synthetic pathways of Ibuprofen and Ofloxacin were explored by inputting isobutyl benzene and 7,8-difluoro-2,3-dihydro-3-methyl-4H-benzoxazine. This application is available at the following URL: http://enh.sekijima-lab.org .

Comparison of trapping profiles between d-peptides and glutathione in the identification of reactive metabolites

Qualitative trapping profile of reactive metabolites arising from six structurally different compounds was tested with three different d-peptide isomers (Peptide 1, gly–tyr–pro–cys–pro–his-pro; Peptide 2, gly–tyr–pro–ala–pro–his–pro; Peptide 3, gly–tyr–arg–pro–cys–pro–his–lys–pro) and glutathione (GSH) using mouse and human liver microsomes as the biocatalyst. The test compounds were classified either as clinically “safe” (amlodipine, caffeine, ibuprofen), or clinically as “risky” (clozapine, nimesulide, ticlopidine; i.e., associated with severe clinical toxicity outcomes). Our working hypothesis was as follows: could the use of short different amino acid sequence containing d-peptides in adduct detection confer any add-on value to that obtained with GSH? All “risky” agents’ resulted in the formation of several GSH adducts in the incubation mixture and with at least one peptide adduct with both microsomal preparations. Amlodipine did not form any adducts with any of the trapping agents. No GSH and peptide 2 and 3 adducts were found with caffeine, but with peptide 1 one adduct with human liver microsomes was detected. Ibuprofen produced one Peptide 1-adduct with human and mouse liver microsomes but not with GSH. In conclusion, GSH still remains the gold trapping standard for reactive metabolites. However, targeted d-peptides could provide additional information about protein binding potential of electrophilic agents, but their clinical significance needs to be clarified using a wider spectrum of chemicals together with other safety estimates.

Significantly Different Covalent Binding of Oxidative Metabolites, Acyl Glucuronides, and S-Acyl CoA Conjugates Formed from Xenobiotic Carboxylic Acids in Human Liver Microsomes

Xenobiotic carboxylic acids may be metabolized to oxidative metabolites, acyl glucuronides, and/or S-acyl-CoA thioesters (CoA conjugates) in vitro, e.g., in hepatocytes, and in vivo. These metabolites can potentially be reactive species and bind covalently to tissue proteins and are generally considered to mediate adverse drug reactions in humans. Acyl glucuronide metabolites have been the focus of reactive metabolite research for decades, whereas drug-CoA conjugates, which have been shown to be up to 40-70 times more reactive, have been given much less attention. In an attempt to dissect the contribution of different pathways to covalent binding, we utilized human liver microsomes supplemented with NADPH, uridine 5'-diphosphoglucuronic acid (UDPGA), or CoA to evaluate the reactivity of each metabolite separately. Seven carboxylic acid drugs were included in this study. While ibuprofen and tolmetin are still on the market, ibufenac, fenclozic acid, tienilic acid, suprofen, and zomepirac were stopped before their launch or withdrawn. The reactivities of the CoA conjugates of ibuprofen, ibufenac, fenclozic acid, and tolmetin were higher compared to those of their corresponding oxidative metabolites and acyl glucuronides, as measured by the level of covalent binding to human liver microsomal proteins. The highest covalent binding was observed for ibuprofenyl-CoA and ibufenacyl-CoA, to levels of 1000 and 8600 pmol drug eq/mg protein, respectively. In contrast and in agreement with the proposed P450-mediated toxicity for these drug molecules, the reactivities of oxidative metabolites of suprofen and tienilic acid were higher compared to the reactivities of their conjugated metabolites, with NADPH-dependent covalent binding of 250 pmol drug eq/mg protein for both drugs. The seven drugs all formed UDPGA-dependent acyl glucuronides, but none of these resulted in covalent binding. This study shows that, unlike studies with hepatocytes or in vivo, human liver microsomes provide an opportunity to investigate the reactivity of individual metabolites.

Suppression of Inflammatory cytokine production by ar-Turmerone isolated from Curcuma phaeocaulis

Rhizomes of Curcuma phaeocaulis Valeton (Zingiberaceae) have traditionally been used for controlling inflammatory conditions. Numerous studies have aimed to isolate and characterize the bioactive constituents of C. phaeocaulis. It has been reported that its anti-inflammatory properties are a result of cyclooxygenase-2 inhibition; however, its effect on the T-cell function remains to be elucidated. In this study, four known sesquiterpenoids, viz., ar-turmerone (TM), germacrone (GM), (+)-(4S,5S)-germacrone-4,5-epoxide (GE), and curzerenone (CZ), were isolated from C. phaeocaulis rhizomes and evaluated for their effects on the CD4(+) T-cell function. While GM, GE, and CZ had no effect on the activation of splenic T cells or CD4(+) T cells, TM suppressed the interferon (IFN)-γ production, without affecting the interleukin (IL)-4 expression. TM also decreased the expression of IL-2 in CD4(+) T cells, but did not change their cell-division rates upon stimulation. These results suggest that TM, a major constituent of C. phaeocaulis rhizomes selectively exerts potent anti-inflammatory effects via suppression of the inflammatory cytokines IFN-γ and IL-2.

Intravenous non-opioid analgesia for peri- and postoperative pain management: a scientific review of intravenous acetaminophen and ibuprofen

Pain is a predictable consequence following operations, but the management of postoperative pain is another challenge for anesthesiologists and inappropriately controlled pain may lead to unwanted outcomes in the postoperative period. Opioids are indeed still at the mainstream of postoperative pain control, but solely using only opioids for postoperative pain management may be connected with risks of complications and adverse effects. As a consequence, the concept of multimodal analgesia has been proposed and is recommended whenever possible. Acetaminophen is one of the most commonly used analgesic and antipyretic drug for its good tolerance and high safety profiles. The introduction of intravenous form of acetaminophen has led to a wider flexibility of its use during peri- and postoperative periods, allowing the early initiation of multimodal analgesia. Many studies have revealed the efficacy, safety and opioid sparing effects of intravenous acetaminophen. Intravenous ibuprofen has also shown to be well tolerated and demonstrated to have significant opioid sparing effects during the postoperative period. However, the number of randomized controlled trials confirming the efficacy and safety is small and should be used in caution in certain group of patients. Intravenous acetaminophen and ibuprofen are important options for multimodal postoperative analgesia, improving pain and patient satisfaction.

Osteoarthritis of the knee and hip. Part II: therapy with ibuprofen and a review of clinical trials

OBJECTIVES

We review the pharmacological properties and clinical evidence pertaining to the efficacy of ibuprofen as a first-line treatment in hip and knee osteoarthritis (OA). In the context of our previous paper's exploration of the aetiology and pathogenesis of OA as a basis for pharmacotherapy, we discuss the pharmacokinetics (PK) and clinical pharmacodynamics (PD) of ibuprofen relevant to OA.

KEY FINDINGS

Although widely used, the benefits and risks of ibuprofen, especially compared with other non-steroidal anti-inflammatory drugs (NSAIDs) and placebo, have only recently been evaluated in OA of the hip and knee in randomized-controlled clinical trials (RCT). The efficacy and occurrence of adverse reactions from ibuprofen was compared with placebo in a structural review of the literature and systematic review of RCTs in large-scale clinical trials. Ibuprofen has been found to result in approximately 50-60% improvement over placebo in WOMAC scores, including those reflecting inflammatory joint pain in knee and hip OA or other indices of pain, disability and impaired function. Mega-trials performed in comparison with the newer NSAIDs, the coxibs, have shown that ibuprofen has comparable therapeutic benefits and although serious gastrointestinal conditions are sometimes more frequent after short-term treatment, longer-term (several months) therapy in OA reduces the advantages of the coxibs over other NSAIDs including ibuprofen. Cardiovascular risk, though present with coxibs and some NSAIDs in OA, is lower or slightly so with ibuprofen compared with coxibs.

SUMMARY

Ibuprofen is effective and relatively safe (especially at low over-the-counter doses and in the short term) for mild-to-moderate OA of the knee and hip. The PK properties of ibuprofen in OA (short plasma t½) confer advantages of this drug for OA, while evidence for clinically relevant PD benefits in joints of patients with OA, though limited, is suggestive of local anti-inflammatory activity.

Production of ibuprofen acyl glucosides by human UGT2B7

UDP-glycosyltransferases (UGTs) are an important group of enzymes that participate in phase II metabolism of xenobiotics and use the cofactor UDP-glucuronic acid for the production of glucuronides. When acting on molecules bearing a carboxylic acid they can form acyl glucuronides, a group of metabolites that has gained significant interest in recent years because of concerns about their potential role in drug toxicity. In contrast, reports about the production of drug acyl glucosides (which might also display high reactivity) have been scarce. In this study, we discovered the formation of acyl glycoside metabolites of R- and S-ibuprofen (Ibu) by human liver microsomes supplied with the cofactor UDP-glucose. Subsequently, human UGT2B7*1 and UGT2B7*2 recombinantly expressed in fission yeast Schizosaccharomyces pombe could be shown to catalyze these reactions. Moreover, we could enhance the glucoside production rate in fission yeast by overexpressing the fission yeast gene SPCC1322.04, a potential UDP-glucose pyrophosphorylase (UGPase), but not by overexpression of SPCC794.10, and therefore suggest to name this gene fyu1 for fission yeast UGPase1. It was interesting to note that pronounced differences between the two polymorphic UGT2B7 variants were observed with respect to acyl glucoside production. Finally, using the metabolic precursor [(13)C(6)]glucose, we demonstrated the production of stable isotope-labeled reference standards of Ibu acyl glucoside and Ibu acyl glucuronide by whole-cell biotransformation in fission yeast.

Acyl glucuronides: the good, the bad and the ugly

Acyl glucuronidation is the major metabolic conjugation reaction of most carboxylic acid drugs in mammals. The physiological consequences of this biotransformation have been investigated incompletely but include effects on drug metabolism, protein binding, distribution and clearance that impact upon pharmacological and toxicological outcomes. In marked contrast, the exceptional but widely disparate chemical reactivity of acyl glucuronides has attracted far greater attention. Specifically, the complex transacylation and glycation reactions with proteins have provoked much inconclusive debate over the safety of drugs metabolised to acyl glucuronides. It has been hypothesised that these covalent modifications could initiate idiosyncratic adverse drug reactions. However, despite a large body of in vitro data on the reactions of acyl glucuronides with protein, evidence for adduct formation from acyl glucuronides in vivo is limited and potentially ambiguous. The causal connection of protein adduction to adverse drug reactions remains uncertain. This review has assessed the intrinsic reactivity, metabolic stability and pharmacokinetic properties of acyl glucuronides in the context of physiological, pharmacological and toxicological perspectives. Although numerous experiments have characterised the reactions of acyl glucuronides with proteins, these might be attenuated substantially in vivo by rapid clearance of the conjugates. Consequently, to delineate a relationship between acyl glucuronide formation and toxicological phenomena, detailed pharmacokinetic analysis of systemic exposure to the acyl glucuronide should be undertaken adjacent to determining protein adduct concentrations in vivo. Further investigation is required to ascertain whether acyl glucuronide clearance is sufficient to prevent covalent modification of endogenous proteins and consequentially a potential immunological response.

Morphological alteration in mitochondria following diclofenac and ibuprofen administration

This study was conducted to identify and to compare the mitochondrial morphological alterations in livers of rats treated with various doses of diclofenac and ibuprofen. Hundred and forty-four male Sprague Dawley rats were dosed with 3, 5 and 10 mg kg(-1) diclofenac and ibuprofen in saline via intraperitoneal injection for 15 days. The control group was administered with saline in a similar manner. Four rats were euthanised every 3 days until day 15. While 200 mg kg(-1) diclofenac and ibuprofen-treated rats (n = 4) were euthanized 10 h posttreatment. The livers were removed, cleaned and a section across the right lobe was taken and fixed in 4% (v/v) glutaraldehyde for electron microscopy analysis and the remaining samples were kept at -80 degrees C for Western blot analysis. Five milligram per kilogram and 10 mg kg(-1) diclofenac-administered rats for 15 days revealed the presence of enlarged mitochondria, irregular and ruptured mitochondrial membranes. While rats administered with 10 mg kg(-1) ibuprofen also showed the presence of mitochondria with irregular membrane structure and ruptured membranes. Western blotting analysis of mitochondrial fractions revealed the expression of cytochrome c in all samples and complete absence of cytochrome c expression in the cytosolic fraction of all samples after day 15. Analysis in 200 mg kg(-1) diclofenac and ibuprofen-treated groups, revealed expression of cytochrome c in both mitochondrial and cytosolic fractions. This observation indicates that both diclofenac and ibuprofen may alter the morphology of mitochondria, leading to cytochrome c release into the cytosol. Further studies needs to be conducted to investigate on the activity of the mitochondria following both treatments.

Propionyl-L-carnitine Reduces Proliferation and Potentiates Bax-related Apoptosis of Aortic Intimal Smooth Muscle Cells by Modulating Nuclear Factor-κB Activity

Propionyl-l-carnitine (PLC) has been introduced among the therapeutic approaches of peripheral arterial disease, and more recently, an increase of intimal cell apoptosis has been demonstrated to contribute to its effectiveness in rabbit carotid postinjury myointimal hyperplasia prevention. How PLC mediates these effects on vascular smooth muscle cells (SMCs) remains poorly understood. We investigated the role of NF-kappaB in PLC-induced arterial remodeling. In vivo, daily PLC treatment 15 days after injury resulted in a reduction of relative rat aortic intimal volume, an increase of apoptosis, Bax up-regulation without changing the Bcl-2 level, and a reduction of NF-kappaB, vascular cell adhesion molecule-1, monocyte chemotactic protein-1, and survivin in myointimal thickening compared with controls. In the presence of 10% serum, a reduced G(1) --> S phase progression preceded PLC-induced intimal cell apoptosis; in 0.1% serum cultures, in a dose-dependent manner, PLC rapidly induced intimal cell apoptosis and reduced p65, p50, IAP-1, and IAP-2 expression. Inhibiting NF-kappaB activation through SN50 increased apoptotic rate and Bax expression in intimal but not in medial SMCs, and successive PLC treatment failed to induce a further increase in apoptotic rate. Bax antisense oligodeoxynucleotide reduced PLC-induced intimal cell apoptosis and cytochrome c release. The PLC-induced attenuation of NF-kappaB activity in intimal cells was also due to the increase of IkappaB-alpha bioavailability, as the result of a parallel induction of IkappaB-alpha synthesis and reduction of phosphorylation and degradation. Collectively, these findings document that NF-kappaB activity inhibition contributes to PLC-induced proliferative arrest and Bax-related apoptosis of intimal SMCs.

Detection of Drug−Membrane Interactions in Individual Phospholipid Vesicles by Confocal Raman Microscopy

Optical-trapping confocal Raman microscopy is developed as a method to study the interactions of drugs or other compounds with the membranes of individual phospholipid vesicles. This technique allows membrane disorder, permeability, and drug localization to be assessed without the need for labeling of the membrane or the compounds of interest. We have applied this technique to study the interactions of two nonsteroidal antiinflammatory drugs, salicylate and ibuprofen, with vesicles prepared from 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). The results show that both salicylate and ibuprofen increase membrane disorder, as determined from increases in the Raman scattering from gauche conformers in the phospholipid acyl chains. By monitoring the Raman scattering of the drug molecules in optically trapped DMPC vesicles, the membrane permeability and partitioning of the drugs could be determined; the spatial distributions of the drugs were also measured by scanning the laser focus through surface-adhered 1,2-dipalmitoyl-sn-glycero-3-phosphocholine vesicles, producing a profile of the vesicle and its contents. Though the membrane is permeable to both drugs, ibuprofen preferentially accumulates in the membrane, whereas salicylate does not. The measured ibuprofen accumulation agrees quantitatively with the water/octanol partition coefficient of the drug and the estimated volume of the lipid membrane. The results suggest that ibuprofen localizes in the hydrophobic acyl chain region of the membrane, whereas salicylate weakly associates with the phospholipid headgroups.

NMR spectroscopic studies of the transacylation reactivity of ibuprofen 1-β-O-acyl glucuronide

The products arising from the intra-molecular acyl migration reactions of drug ester glucuronides can be reactive towards cellular proteins and have been proposed to cause toxic side effects. The relative reactivity of a range of drug and model glucuronides have previously been determined by measuring the rate of disappearance of a peak characteristic of the 1-beta-O-acyl glucuronide using 1H NMR spectroscopy. Here the degradation rate of ibuprofen 1-beta-O-acyl glucuronide has been investigated using NMR spectroscopy for the first time using material isolated from human urine with solid-phase extraction chromatography (SPEC). The degradation rate was measured by following the disappearance of the 1H NMR signal from the 1-beta-anomeric proton of the glucuronic acid moiety as the reaction progressed in pH 7.4 buffer inside an NMR tube. The measured degradation rate represents a pseudo-first order rate constant, a combination of the transacylation rate (1-beta-isomer to 2-beta-isomer) and the hydrolysis rate, and is presented as a half-life of 3.5 h. This value is compared to those from drug glucuronides where adverse effects have been observed in patients after administration of the drug.

Propionyl-L-carnitine reduces intimal hyperplasia after injury in normocholesterolemic rabbit carotid artery by modulating proliferation and caspase 3-dependent apoptosis of vascular smooth muscle cells

Previously we documented that propionyl-L-carnitine (PLC) reduces the growth of atherosclerotic lesions in cholesterol-fed aged rabbits in association with a decrease of plaque smooth muscle cell (SMC) proliferation and plasma triglycerides. To clarify whether PLC might influence SMC growth through mechanisms other than triglyceride lowering, we investigated the effect of a daily treatment per os with PLC on carotid intimal hyperplasia after ballooning in normocholesterolemic rabbits. PLC did not induce variations of plasma triglyceride and cholesterol. One week later, the number of proliferating SMCs was reduced in PLC as compared with controls. After 3 weeks, morphometric analysis demonstrated a reduced neointimal relative volume and percentage of stenosis but not vessel area in PLC as compared with controls. This associated with an intimal reduced SMC number and an increased apoptotic rate as detected by nick-end labelling (TUNEL) and ligation-mediated polymerase chain reaction (PCR). Western blotting also demonstrated an increase of caspase-3 cleavage in PLC carotids. Antiproliferative and pro-apoptotic effects of PLC were confirmed in vitro on actively proliferating and serum deprived SMCs, respectively. Molecules with an additional cell-specific, pro-apoptotic action may represent a new therapeutic tool in reducing intimal SMC hyperplasia following angioplasty or stenting procedures.

Over-the-counter analgesics and antipyretics: a critical assessment

BACKGROUND

It is just 100 years since the introduction of aspirin to medicine. Since then, aspirin and its derivatives have been joined by acetaminophen, and the nonsteroidal anti-inflammatory drugs--ibuprofen, naproxen sodium, and ketoprofen--as the only over-the-counter (OTC) agents approved by the US Food and Drug Administration for the short-term treatment of pain, headache, dysmenorrhea, and fever. Recently the prescription use of aspirin has expanded to include a number of antiplatelet indications.

OBJECTIVE

The purpose of this paper is to review critically the history, mechanisms of action, efficacy, and tolerability of OTC analgesic and antipyretic products. Relatively new and potential future indications for these drugs are also discussed.

CONCLUSION

Although all of the OTC analgesic/antipyretic agents seem to share a common mechanism of prostaglandin inhibition, there are important differences in their pharmacology, efficacy, and side-effect profiles. Considering their often-unsupervised use, the risk-benefit ratio of this class of drugs has been extremely favorable. However, when used inappropriately, even these drugs pose significant risks to certain patient populations.

Choosing the right nonsteroidal anti-inflammatory drug for the right patient: a pharmacokinetic approach

Effective use of the growing number of nonsteroidal anti-inflammatory drugs (NSAIDs), a group that has recently been augmented by the introduction of the selective cyclo-oxygenase-2 inhibitors, requires adequate knowledge of their pharmacokinetics. After oral administration, the absorption of NSAIDs is generally rapid and complete. NSAIDs are highly bound to plasma proteins, specifically to albumin (>90%). The volume of distribution of NSAIDs is low, ranging from 0.1 to 0.3 L/kg, suggesting minimal tissue binding. NSAID binding in plasma can be saturated when the concentration of the NSAID exceeds that of albumin. Most NSAIDs are metabolised by the liver, with subsequent excretion into urine or bile. Enterohepatic recirculation occurs when a significant amount of an NSAID or its conjugated metabolites are excreted into the bile and then reabsorbed in the distal intestine. NSAID elimination is not dependent on hepatic blood flow. Hepatic NSAID elimination is dependent on the free fraction of NSAID within the plasma and the intrinsic enzyme activities of the liver. Renal elimination is not an important elimination pathway for NSAIDs, except for azapropazone. The plasma half-life of NSAIDs ranges from 0.25 to >70 hours, indicating wide differences in clearance rates. Hepatic or renal disease can alter NSAID protein binding and metabolism. Some NSAIDs with elimination predominantly via acylglucuronidation can have significantly altered disposition. Pharmacokinetics are also influenced by chronobiology, and many NSAIDs exhibit stereoselectivity. There appear to be relationships between NSAID concentration and effects. At therapeutically equivalent doses, NSAIDs appear to be equally efficacious. The major differences between NSAIDs are their therapeutic half-lives and safety profiles. NSAIDs undergo drug interactions through protein binding displacement and competition for active renal tubular secretion with other organic acids. When choosing the right NSAID for the right patient, individual patient-specific and NSAID-specific pharmacokinetic principles should be considered.

Effects of Butyrate and Propionate on the Adhesion, Growth, Cell Cycle Kinetics, and Protein Synthesis of Cultured Human Gingival Fibroblasts

BACKGROUND

Various periodontal and root canal pathogens, such as the Bacteroides species, can produce significant amounts of short chain fatty acids (SCFA). The roles of SCFA in the pathogenesis of periodontal disease are still not fully understood.

METHODS

We therefore investigated 2 main SCFA, butyrate and propionate, on the functional behavior of cultured human gingival fibroblasts (GF) such as cell growth, protein synthesis, cell adhesion capacity, and cell cycle progression.

RESULTS

Butyrate and propionate inhibited the growth of healthy (HGF) and inflamed gingival fibroblasts (IGF) in a dose dependent manner. At concentrations of 4, 8, and 16 mM, butyrate suppressed the cell growth by 11 to 58%, 16 to 60%, and 50 to 71%, respectively. The response of cultured gingival fibroblasts to SCFA showed individual differences. Morphologically, GF became larger and more flattened in appearance following exposure to butyrate (>8 mM) and propionate (>24 mM) for 5 days. Inhibitory effects of butyrate (>2 mM) and propionate (>8 mM) on the growth of GF were due possibly to their inhibition of cell-cycle progression. At concentrations of 2 and 8 mM, butyrate led to G0/G1 arrest. Elevation of the exposure concentration to 8 to 24 mM further result in G2/M phase arrest of GF. On the other hand, propionate, at concentrations ranging from 4 to 24 mM, led to G0/G1 arrest. Butyrate (>2 mM) inhibited the proline-rich protein synthesis of GF. At concentrations of 4, 8, 16, and 24 mM, butyrate inhibited the protein synthesis of HGF-1 by 42%, 43%, 51%, and 54%, respectively. In all strains of cultured GF, the suppressive effect of propionate is less than that of butyrate. At concentration range of 4 to 24 mM, propionate suppressed the protein synthesis of HGF-1 by 23 to 43%. However, both butyrate and propionate (4 to 48 mM) exerted little effects on the adhesion of GF to type I collagen within 3 hours of incubation.

CONCLUSIONS

These results suggested that SCFA released by pathogenic microorganisms can contribute to the gingival tissue dysfunction and breakdown through their actions on specific biological functions of GF.

Short-chain carboxylic-acid-stimulated, PMN-mediated gingival inflammation

This communication reviews the effects of short-chain carboxylic acids on human cells of importance to the periodontium. The central hypothesis is that these acids can alter both cell function and gene expression, and thus contribute to the initiation and prolongation of gingival inflammation. Short-chain carboxylic acids [CH3-(CH2)x-COOH, x < 3] are metabolic intermediates with a broad range of apparently paradoxical biological effects. For example, lactic acid (CH3-CHOH-COOH), a 3-carbon alpha-hydroxy-substituted acid, is widely recognized for its cariogenicity. Lactic acid, however, also occurs in tropical fruits, and is the active ingredient in a variety of anti-wrinkle creams developed by dermatologists. In marked contrast, the unsubstituted 3-carbon propionic acid (CH3-CH2-COOH) is used as a food preservative and is the active principle for one class of non-steroidal anti-inflammatory agents. Interestingly, the addition of one carbon to propionic acid dramatically changes the biological effects. The unsubstituted 4-carbon butyric acid (CH3-CH2-CH2-COOH) is used by hematologists as a de-differentiating agent for the treatment of sickle cell anemia, but by oncologists as a differentiating agent for cancer chemotherapy. Finally, acting either individually or in concert, these acids can increase vascular dilation. Clearly, these acids, while metabolically derived, have a number of very divergent activities which are cell-type-specific (Fig. 1). It may be telling that periodontal bacteria produce these acids in millimolar concentrations, and that these bacteria can be characterized by their acid production profiles. It is no less interesting that these acids occur in the gingival crevices of human subjects with severe periodontal disease at millimolar levels which are > 10-fold higher than those found in mildly diseased subjects, and are undetectable in healthy subjects. Further, when applied directly to healthy human gingiva, short-chain carboxylic acids stimulate a gingival inflammatory response and inflammatory cytokine release. At the cellular level, these acids inhibit proliferation of gingival epithelial and endothelial cells, and inhibit leukocyte apoptosis and function, but can stimulate leukocyte cytokine release. At the molecular level, these acids can stimulate neutrophil gene transcription, translation, and protein expression. Thus, the likelihood is high that these acids, in addition to their cariogenic activity, can promote and prolong gingival inflammation. Our challenge will be to identify the cell or cells of the periodontium which respond to short-chain carboxylic acids, to delineate their responses and the molecular mechanism(s) of these effects, and to categorize the aspects of the inflammatory components which damage and those which protect the host. With this information, it may be possible to begin to rationally identify and test pharmaceutical agents which diminish the harmful aspects, while enhancing the beneficial components, of the inflammatory response.

Short-chain carboxylic acid concentration in human gingival crevicular fluid

Short-chain carboxylic acids (e.g., lactic acid, propionic acid, butyric acid) are metabolic by-products of bacterial metabolism which can accumulate in the gingival crevice. It is of no small consequence, therefore, that 1- to 5-mM concentrations of these acids exhibit significant biological activity, including the ability to alter cell proliferation and gene expression in cells of importance to the periodontium. This communication reports on the in vivo concentrations of propionic and butyric acid in the gingival crevices of periodontal subjects with severe and mild disease. The results indicated that severely diseased subjects exhibited a > 10-fold increase in the mM concentration of these acids when compared with mildly diseased subjects (mean propionic acid-severe = 9.5 +/- 1.8 mM, and mild = 0.8 +/- 0.3 mM; mean butyric acid-severe = 2.6 +/- 0.4 mM, and mild = 0.2 +/- 0.04 mM). These differences (mean +/- SE) were significant (p < 0.0001). The propionic and butyric acid concentrations were below detection limits in healthy sites of mildly diseased subjects. The propionic and butyric acid concentrations also associated significantly with clinical measures of disease severity (e.g., pocket depth, attachment level) and inflammation (e.g., subgingival temperature, % of sites bleeding when probed), and with the total microbial load (all p < 0.05). Taken together, these data suggest that short-chain carboxylic acids play a mediating role in periodontal disease pathogenesis.

The relationship of gingival crevicular fluid short chain carboxylic acid concentration to gingival inflammation

Short-chain carboxylic acids (SCCA; C < or = 5; e.g., lactic acid, propionic acid, butyric acid) are metabolic by-products of bacterial metabolism which accumulate in the gingival crevice, and exhibit significant biological activity, including the ability to alter gene expression. It has been hypothesized that among the activities of SCCAs are their ability to contribute to gingival inflammation. This concept complements the notion that specific periodontal pathogens are the causative agents of gingival inflammation. To begin testing these 2 hypotheses, we examined the relationship between SCCA concentrations, specific putative periodontal pathogens, and gingival inflammation in medically healthy periodontally diseased subjects. We reasoned that if SCCAs and/or specific periodontal pathogens were causative gingival inflammatory agents, gingival inflammation should increase with increasing concentration of the inflammatory mediator. We also recognized that other clinical variables needed to be controlled for, and an objective quantitative assessment of gingival inflammation used. To accomplish these tasks, sites within subjects were stratified by location and pocket depth, and the following quantified: bacterial presence; SCCA concentration; and gingival inflammation. The results indicated that gingival inflammation directly and significantly correlated with SCCA concentrations in the maxillary and mandibular molars, incisors and canines (all r > or = 0.47; all p < or = 0.015; too few bicuspids were available for complete analysis). The relationship between gingival inflammation and SCCA concentration was best described by a natural log relationship. Gingival inflammation did not, however, correlate positively with either the total number of specific putative periodontal pathogens, or the sum of subsets of these pathogens (-0.31 < or = r < or = 0.39; 0.08 < or = p < or = 0.75) for any of the locations. Finally, the SCCA concentration did not correlate with the level of individual or groups of pathogens. These data, together with historical work and other preliminary data, support the hypothesis that SCCA, rather than specific putative periodontal pathogens, may be a causative agent in gingival inflammation. This work may, in part, begin to explain the apparent lack of a direct relationship between current gingival inflammation and the prediction of bacterially mediated periodontal attachment loss.

Disposition and covalent binding of ibuprofen and its acyl glucuronide in the elderly

Ibuprofen is an over-the-counter nonsteroidal anti-inflammatory drug with a low incidence of severe adverse reactions. It is metabolized by oxidation to carboxyibuprofen and hydroxyibuprofen and by conjugation to an acyl glucuronide. In vitro studies have indicated that ibuprofen glucuronide is labile and reactive, forming covalent adducts with proteins. To verify the formation of ibuprofen-protein adducts in vivo, the pharmacokinetics of ibuprofen glucuronide and its covalent binding to plasma proteins were studied in five elderly patients who received long-term administration of oral doses of ibuprofen. Plasma levels of ibuprofen glucuronide were low relative to those of ibuprofen; the ratio of area under the plasma concentration versus time curve for the glucuronide relative to the parent drug was only 4%. Covalent binding of ibuprofen to plasma protein was observed in all patients, correlating well with the area under the plasma concentration versus time curve of ibuprofen glucuronide (r = 0.966). Compared with reports for other nonsteroidal anti-inflammatory drugs that form acyl glucuronides, plasma levels of ibuprofen-protein adduct are low during long-term administration. The observed lower reactivity in vivo is probably attributable to the greater stability of ibuprofen glucuronide relative to other acyl glucuronides.