In vitro and in vivo comparison of the anti-staphylococcal efficacy of generic products and the innovator of oxacillin

Chitosan-carrageenan microbeads containing nano-encapsulated curcumin: Nano-in-micro hydrogels as alternative-therapeutics for resistant pathogens associated with chronic wounds

Antimicrobial resistance is an issue of global relevance for the treatment of chronic wound infections. In this study, nano-in-micro hydrogels (microbeads) of chitosan and κ-carrageenan (CCMBs) containing curcumin-loaded rhamnosomes (Cur-R) were developed. The potential of Cur-R-CCMBs for improving the antibacterial activity and sustained release of curcumin was evaluated. Curcumin-loaded rhamnosomes (rhamnolipids functionalized liposomes) had a mean particle size of 116 ± 7 nm and a surface-charge of -24.5 ± 9.4 mV. The encapsulation efficiency of curcumin increased from 42.83 % ± 0.69 % in Cur-R to 95.24 % ± 3.61 % respectively after their embedding in CCMBs. SEM revealed smooth surface morphology of Cur-R-CCMBs. FTIR spectroscopy confirmed the presence of weak electrostatic and hydrophobic interactions among curcumin, rhamnosomes, and microbeads. Cur-R-CCMBs had demonstrated significant antibacterial activity against multi-drug resistant chronic wound pathogens including Staphylococcus aureus and Pseudomonas aeruginosa. Cur-R-CCMBs also exhibited significantly higher anti-oxidant (76.85 % ± 2.12 %) and anti-inflammatory activity (91.94 % ± 0.41 %) as well as hemocompatibility (4.024 % ± 0.59 %) as compared to pristine microbeads. In vivo infection model of mice revealed significant reduction in the viable bacterial count of S. aureus (∼2.5 log CFU/mL) and P. aeruginosa (∼2 log CFU/mL) for Cur-R-CCMBs after 5 days. Therefore, nano-in-micro hydrogels can improve the overall efficacy of hydrophobic antimicrobials to develop effective alternative-therapeutics against resistant-pathogens associated with chronic wound infections.

Myths and Misconceptions around Antibiotic Resistance: Time to Get Rid of Them

The antibiotic resistance arena is fraught with myths and misconceptions, leading to wrong strategies to combat it. It is crucial to identify them, discuss them in light of current evidence, and dispel those that are unequivocally wrong. This article proposes some concepts that may qualify as misconceptions around antibiotic resistance: the susceptible-resistant dichotomy; that incomplete antibiotic courses cause resistance; that resistance "emerges" in patients and hospitals; that antibiotics are mostly abused clinically; that resistance is higher in countries that use more antibiotics; that reducing antibiotic usage would reduce resistance; that financial incentives would "jumpstart" research and development of antibiotics; that generic and "original" antibiotics are the same; and that new anti-infective therapies are just around the corner. While some of these issues are still controversial, it is important to recognize their controversial status, instead of repeating them in specialized literature and lectures and, especially, in the planning of strategies to cope with resistance.

Nontherapeutic equivalence of a generic product of imipenem-cilastatin is caused more by chemical instability of the active pharmaceutical ingredient (imipenem) than by its substandard amount of cilastatin

Background

We demonstrated therapeutic nonequivalence of “bioequivalent” generics for meropenem, but there is no data with generics of other carbapenems.

Methods

One generic product of imipenem-cilastatin was compared with the innovator in terms of in vitro susceptibility testing, pharmaceutical equivalence, pharmacokinetic (PK) and pharmacodynamic (PD) equivalence in the neutropenic mouse thigh, lung and brain infection models. Both pharmaceutical forms were then subjected to analytical chemistry assays (LC/MS).

Results and conclusion

The generic product had 30% lower concentration of cilastatin compared with the innovator of imipenem-cilastatin. Regarding the active pharmaceutical ingredient (imipenem), we found no differences in MIC, MBC, concentration or potency or AUC, confirming equivalence in terms of in vitro activity. However, the generic failed therapeutic equivalence in all three animal models. Its E_max against S. aureus in the thigh model was consistently lower, killing from 0.1 to 7.3 million less microorganisms per gram in 24 hours than the innovator (P = 0.003). Against K. pneumoniae in the lung model, the generic exhibited a conspicuous Eagle effect fitting a Gaussian equation instead of the expected sigmoid curve of the Hill model. In the brain infection model with P. aeruginosa, the generic failed when bacterial growth was >4 log₁₀ CFU/g in 24 hours, but not if it was less than 2.5 log₁₀ CFU/g. These large differences in the PD profile cannot be explained by the lower concentration of cilastatin, and rather suggested a failure attributable to the imipenem constituent of the generic product. Analytical chemistry assays confirmed that, besides having 30% less cilastatin, the generic imipenem was more acidic, less stable, and exhibited four different degradation masses that were absent in the innovator.

In vitro Comparison of Generic and Branded Preparations of Amoxicillin with Potassium Clavulanate

INTRODUCTION

The Medical Council of India (MCI) has guidelines for physicians to prescribe drugs with generic names. But physicians and patients might have prejudices against generic drug substitution or concerns regarding quality and generics effectiveness. If the drugs are ineffective, they can result in adverse clinical outcomes such as treatment failure. According to WHO, β-lactams are the most common substandard drugs to be produced amongst antibiotics.

AIM

To evaluate and compare invitro efficacy of generic and branded preparations of Amoxicillin with Potassium Clavulanate.

MATERIALS AND METHODS

One generic (C) and 5 branded formulations (A,B,D,E,F) of amoxicillin with potassium clavulanate were taken for microbiological assay. Coding was done. Sterile disks were instilled with 10μl of preparations and disk diffusion was screened by Kirby Bauer Method using Mueller Hinton Agar. Bacterial Strains used were Staphylococcus aureus (S.aureus) and Escherichia Coli. Zone of inhibition was measured. Statistical Analysis was done using repeated measures one-way ANOVA followed by Tukey's test.

RESULTS

Disk Diffusion test showed that branded Drug F has statistically significant less zone of inhibition (p < 0.001) for S. Aureus and (p < 0.05) for E.coli in comparison with generic drug C. Zone of inhibition of branded Drug A, B & E was comparable with the generic drug C.

CONCLUSION

The results of this study indicate that the generic drug tested was equally effective compared to the tested branded drugs except branded Drug D and F. This suggests that efficacy of generic drug is equivalent to branded drugs and maybe used interchangeably with branded drugs.

Impact on Bacterial Resistance of Therapeutically Nonequivalent Generics: The Case of Piperacillin-Tazobactam

Previous studies have demonstrated that pharmaceutical equivalence and pharmacokinetic equivalence of generic antibiotics are necessary but not sufficient conditions to guarantee therapeutic equivalence (better called pharmacodynamic equivalence). In addition, there is scientific evidence suggesting a direct link between pharmacodynamic nonequivalence of generic vancomycin and promotion of resistance in Staphylococcus aureus. To find out if even subtle deviations from the expected pharmacodynamic behavior with respect to the innovator could favor resistance, we studied a generic product of piperacillin-tazobactam characterized by pharmaceutical and pharmacokinetic equivalence but a faulty fit of Hill's Emax sigmoid model that could be interpreted as pharmacodynamic nonequivalence. We determined the impact in vivo of this generic product on the resistance of a mixed Escherichia coli population composed of ∼99% susceptible cells (ATCC 35218 strain) and a ∼1% isogenic resistant subpopulation that overproduces TEM-1 β-lactamase. After only 24 hours of treatment in the neutropenic murine thigh infection model, the generic amplified the resistant subpopulation up to 20-times compared with the innovator, following an inverted-U dose-response relationship. These findings highlight the critical role of therapeutic nonequivalence of generic antibiotics as a key factor contributing to the global problem of bacterial resistance.

Bioequivalence and in vitro antimicrobial activity between generic and brand-name levofloxacin

Generic agents play a crucial role in reducing the cost of medical care in many countries. However, the therapeutic equivalence remains a great concern. Our study aims to assess the in vitro antimicrobial activity and bioequivalence between generic and brand-name levofloxacin. Enantiomeric purity test, dissolution test, and in vitro antimicrobial susceptibility against seven clinically important pathogens by the agar dilution method were employed to assess the similarity between four generic products and brand-name levofloxacin (Daiichi Sankyo). All the generic and brand-name levofloxacin passed enantiomeric purity test. The results of dissolution tests were not similar among the generic products and the brand-name levofloxacin. Compared with the generic products, the brand-name levofloxacin had the smallest mean variations (-25% to 13%) with reference standard (United States Pharmacopeia levofloxacin Reference Standards). Variations were observed particularly in dissolution profiles and in vitro activity between generic products and brand-name levofloxacin.

Pharmacodynamics of nine generic products of amikacin compared with the innovator in the neutropenic mouse thigh infection model

Background

Previously, we validated the mouse thigh infection model to test the therapeutic equivalence of generic antibiotic products. Here, our aim was to compare the in vivo efficacy of amikacin products in clinical use in Colombia using this animal model.

Results

All except one generic product had the same in vitro potency, judging by the lack of differences on MIC and MBC compared with the innovator. However, eight of nine generic products failed in the neutropenic mouse thigh infection model to achieve the innovator’s maximum effect (E_max ≤ 5.65 for the generics vs. 6.58 log₁₀ CFU/g for the innovator) against Escherichia coli SIG-1, after subcutaneous treatment every 6 h with doses ranging from 1.5 to 3072 mg/kg per day.

Conclusion

As we demonstrated previously with other antibiotics such as vancomycin, gentamicin and oxacillin, the generic products of amikacin failed the in vivo efficacy testing. The therapeutic equivalence should be assessed in vivo before clinical approval of generic products.

Re-positioning protein-kinase inhibitors against schistosomiasis

For decades, Praziquantel (PZQ) is the drug of choice against one of the most afflicting helminthic diseases worldwide, schistosomiasis. With respect to the fear of upcoming PZQ resistance, efforts are needed to find new chemotherapeutic options. Protein kinases (PKs) are essential molecules in signaling processes and indispensable to life. Aberrant PK functions take distinctive roles in human diseases and represent targets in chemotherapies. In schistosomes, conserved PKs were found to possess similar pivotal roles contributing not only to reproduction processes, but also to the pathology of schistosomiasis, which is closely associated to egg production. Exploiting the similarity of PKs of humans and schistosomes, PK inhibitors designed to treat human diseases may serve as lead compounds for new drugs against schistosomiasis.

KEY DIFFERENCES AND SIMILARITIES IN WAYS OF MANAGING AND SUPPORTING RADICAL PHARMACEUTICAL FRONT END INNOVATION — A CASE STUDY OF THE PHARMACEUTICAL INDUSTRY

The purpose of this paper is to explore how Front End Innovation (FEI) is supported and managed among companies of different nationality within the context of pharmaceutical R&D. The present study is carried out in order to contribute to the development of a clearer understanding of active facilitation of innovation management and FEI in theory and in practice across international borders. I aim to show how different aspects of Pharma and nationality affect the way innovation management and radical FEI are supported within organisations. This is examined through an in-depth case study of the Danish and US based pharmaceutical company, H. Lundbeck A/S, and a comparative study including five European and American pharmaceutical companies. The findings from the study reveal a number of similarities and differences in innovation management and FEI support of radical projects and among the different nationalities. This presents propositions of important aspects to consider in facilitation of radical FEI in general and in multinational pharmaceutical companies. In addition, proposals are made for a global study of innovation management and FEI support including Chinese and other Asian pharmaceutical companies, which represent a growing market. The value added and the contribution of this paper to the existing FEI literature is therefore in the specificity of the empirical setting in which the issue is investigated.

Relevance of various animal models of human infections to establish therapeutic equivalence of a generic product of piperacillin/tazobactam

After demonstrating with diverse intravenous antibacterials that pharmaceutical equivalence (PE) does not predict therapeutic equivalence, we tested a single generic product of piperacillin/tazobactam (TZP) in terms of PE, pharmacokinetics and in vitro/vivo pharmacodynamics against several pathogens in neutropenic mouse thigh, lung and brain infection models. A generic product was compared head-to-head against the innovator. PE was evaluated by microbiological assay. Single-dose serum pharmacokinetics were determined in infected mice, and the MIC/MBC were determined by broth microdilution. In vivo experiments were done in a blind fashion. Reproducibility was tested on different days using different infecting organisms and animal models. Neutropenic MPF mice were infected in the thighs with Staphylococcus aureus GRP-0057 or Pseudomonas aeruginosa PA01 and in the lungs or brain with Klebsiella pneumoniae ATCC 10031. Treatment started 2h (thigh and brain) or 14 h (lung) after infection and was administered every 3h over 24h (thigh and lung) or 48 h (brain). Both products exhibited the same MIC/MBC against each strain, yielded overlaid curves in the microbiological assay (P>0.21) and were bioequivalent (IC90 83-117% for AUC test/reference ratio). In vivo, the generic product and innovator were again undistinguishable in all models and against the different bacterial pathogens involved. The relevance of these neutropenic murine models of infection was established by demonstrating their accuracy to predict the biological response following simultaneous treatment with a generic product or the innovator of TZP. Therapeutic equivalence of the generic product was proved in every model and against different pathogens.

Serum albumin and α-1 acid glycoprotein impede the killing of Schistosoma mansoni by the tyrosine kinase inhibitor Imatinib

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The Abl tyrosine-kinase inhibitor Imatinib is toxic to S. mansoni in vitro but not in vivo in rodents.

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Blood components like serum albumin and alpha-1 acid glycoprotein (AGP) negated Imatinib’s toxicity in vitro.

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Erythromycin partially restored the toxicity of Imatinib in vitro.

•

High levels of AGP upon infection make rodents poor models for examining some small molecule inhibitors.

In the search for new drugs and drug targets to treat the flatworm disease schistosomiasis, protein kinases (PKs) have come under particular scrutiny because of their essential roles in developmental and physiological processes in schistosome parasites. In this context the application of the anti-cancer Abl tyrosine kinase (TK) inhibitor Imatinib (Gleevec/Glivec; STI-571) to adult Schistosoma mansoni in vitro has indicated negative effects on diverse physiological processes including survival.

Motivated by these in vitro findings, we performed in vivo experiments in rodent models of S. mansoni infection. Unexpectedly, Imatinib had no effect on worm burden or egg-production. We found that the blood components serum albumin (SA) and alpha-1 acid glycoprotein (AGP or orosomucoid) negated Imatinib’s deleterious effects on adult S. mansoni and schistosomula (post-infective larvae) in vitro. This negative effect was partially reversed by erythromycin. AGP synthesis can increase as a consequence of inflammatory processes or infection; in addition upon infection AGP levels are 6–8 times higher in mice compared to humans. Therefore, mice and probably other rodents are poor infection models for measuring the effects of Imatinib in vivo. Accordingly, we suggest the routine evaluation of the ability of AGP and SA to block in vitro anti-schistosomal effects of small molecules like Imatinib prior to laborious and expensive animal experiments.

The synergetic effect of edaravone and borneol in the rat model of ischemic stroke

Free radical production contributes to the early ischemic response and the neuroinflammatory response to injury initiates the second wave of cell death following ischemic stroke. Edaravone is a free radical scavenger, and borneol has shown anti-inflammatory effect. We investigated the synergistic effect of these two drugs in the rat model of transient cerebral ischemia. Edaravone scavenged OH, NO and ONOO─ concentration-dependently, and borneol inhibited ischemia/reperfusion-induced tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), interleukin-1β (IL-1β) and cyclooxygenase-2 (COX-2) expressions. In the rat model of transient cerebral ischemia and reperfusion, the combination of edaravone and borneol significantly ameliorated ischemic damage with an optimal proportion of 4:1. Emax (% inhibition) of edaravone, borneol and two drugs in combination was 55.7%, 65.8% and 74.3% respectively. ED50 of edaravone and borneol was 7.17 and 0.36 mg/kg respectively. When two drugs in combination, ED50 was 0.484 mg/kg, in which edaravone was 0.387 mg/kg (ineffective dose) and borneol was 0.097 mg/kg (ineffective dose). Combination index (CI)<1 among effects observed in experiments, suggesting a significant synergistic effect. Reduced levels of pro-inflammatory mediators and free radicals were probably associated with the synergistic effect of edaravone and borneol. The combination exhibited a therapeutic time window of 6h in ischemia/reperfusion model, and significantly ameliorated damages in permanent ischemia model. Moreover, two drugs in combination promoted long-term effect, including improved elemental vital signs, sensorimotor functions and spatial cognition. Our results suggest that the combination of edaravone and borneol have a synergistic effect for treating ischemic stroke.

Effect of plasma processing and organosilane modifications of polyethylene on Aeromonas hydrophila biofilm formation

The aim of our research was to study how the modifications of polyethylene—a material commonly used in medicine and water industry—influence bacterial cell attachment and biofilm formation. The native surface was activated and modified using two-step process consisting in the activation of native surface with a H₂O vapor plasma followed by its treatment with various organosilanes, namely, [3(tertbutylamine-2hydroxy) propyloxypropyl] diethoxymethylsilane, 1H,1H,2H,2H-perfluorooctylmethyldimethoxysilane, dimethoxydimethylsilane, and isobutylmethyldimethoxysilane. The effect of polyethylene modification after chemical treatment was analyzed using surface tension measurement. The adhesive properties of Aeromonas hydrophila LOCK0968 were studied in water with a low concentration of organic compounds, using luminometric and microscopic methods, and the viability of the adhered bacterial cells was evaluated using the colony forming units method. After two-week incubation the chemically modified materials exhibited better antiadhesive and antibacterial characteristics in comparison to the native surface. Among the examined modifying agents, dimethoxydimethylsilane showed the best desired properties.

Even apparently insignificant chemical deviations among bioequivalent generic antibiotics can lead to therapeutic nonequivalence: the case of meropenem

Several studies with animal models have demonstrated that bioequivalence of generic products of antibiotics like vancomycin, as currently defined, do not guarantee therapeutic equivalence. However, the amounts and characteristics of impurities and degradation products in these formulations do not violate the requirements of the U.S. Pharmacopeia (USP). Here, we provide experimental data with three generic products of meropenem that help in understanding how these apparently insignificant chemical differences affect the in vivo efficacy. Meropenem generics were compared with the innovator in vitro by microbiological assay, susceptibility testing, and liquid chromatography/mass spectrometry (LC/MS) analysis and in vivo with the neutropenic guinea pig soleus infection model (Pseudomonas aeruginosa) and the neutropenic mouse thigh (P. aeruginosa), brain (P. aeruginosa), and lung (Klebisella pneumoniae) infection models, adding the dihydropeptidase I (DHP-I) inhibitor cilastatin in different proportions to the carbapenem. We found that the concentration and potency of the active pharmaceutical ingredient, in vitro susceptibility testing, and mouse pharmacokinetics were identical for all products; however, two generics differed significantly from the innovator in the guinea pig and mouse models, while the third generic was therapeutically equivalent under all conditions. Trisodium adducts in a bioequivalent generic made it more susceptible to DHP-I hydrolysis and less stable at room temperature, explaining its therapeutic nonequivalence. We conclude that the therapeutic nonequivalence of generic products of meropenem is due to greater susceptibility to DHP-I hydrolysis. These failing generics are compliant with USP requirements and would remain undetectable under current regulations.

Chemical modification of polyvinyl chloride and silicone elastomer in inhibiting adhesion of Aeromonas hydrophila

Disease-causing bacteria of the genus Aeromonas are able to adhere to pipe materials, colonizing the surfaces and forming biofilms in water distribution systems. The aim of our research was to study how the modification of materials used commonly in the water industry can reduce bacterial cell attachment. Polyvinyl chloride and silicone elastomer surfaces were activated and modified with reactive organo-silanes by coupling or co-crosslinking silanes with the native material. Both the native and modified surfaces were tested using the bacterial strain Aeromonas hydrophila, which was isolated from the Polish water distribution system. The surface tension of both the native and modified surfaces was measured. To determine cell viability and bacterial adhesion two methods were used, namely plate count and luminometry. Results were expressed in colony-forming units (c.f.u.) and in relative light units (RLU) per cm(2). Almost all the chemically modified surfaces exhibited higher anti-adhesive and anti-microbial properties in comparison to the native surfaces. Among the modifying agents examined, poly[dimethylsiloxane-co-(N,N-dimethyl-N-n-octylammoniopropyl chloride) methylsiloxane)] terminated with hydroxydimethylsilyl groups (20 %) in silicone elastomer gave the most desirable results. The surface tension of this modifier, was comparable to the non-polar native surface. However, almost half of this value was due to the result of polar forces. In this case, in an adhesion analysis, only 1 RLU cm(-2) and less than 1 c.f.u. cm(-2) were noted. For the native gumosil, the results were 9,375 RLU cm(-2) and 2.5 × 10(8) c.f.u. cm(-2), respectively. The antibacterial activity of active organo-silanes was associated only with the carrier surface because no antibacterial compounds were detected in liquid culture media, in concentrations that were able to inhibit cell growth.

Cefazolin high-inoculum effect in methicillin-susceptible Staphylococcus aureus from South American hospitals

OBJECTIVES

Clinical failures with cefazolin have been described in high-inoculum infections caused by methicillin-susceptible Staphylococcus aureus (MSSA) producing type A β-lactamase. We investigated the prevalence of the cefazolin inoculum effect (InE) in MSSA from South American hospitals, since cefazolin is used routinely against MSSA due to concerns about the in vivo efficacy of isoxazolyl penicillins.

METHODS

MSSA isolates were recovered from bloodstream (n = 296) and osteomyelitis (n = 68) infections in two different multicentre surveillance studies performed in 2001-02 and 2006-08 in South American hospitals. We determined standard-inoculum (10(5)cfu/mL) and high-inoculum (10(7) cfu/mL) cefazolin MICs. PFGE was performed on all isolates that exhibited a cefazolin InE. Multilocus sequence typing (MLST) and sequencing of part of blaZ were performed on representative isolates.

RESULTS

The overall prevalence of the cefazolin InE was 36% (131 isolates). A high proportion (50%) of MSSA isolates recovered from osteomyelitis infections exhibited the InE, whereas it was observed in 33% of MSSA recovered from bloodstream infections. Interestingly, Ecuador had the highest prevalence of the InE (45%). Strikingly, 63% of MSSA isolates recovered from osteomyelitis infections in Colombia exhibited the InE. MLST revealed that MSSA isolates exhibiting the InE belonged to diverse genetic backgrounds, including ST5, ST8, ST30 and ST45, which correlated with the prevalent methicillin-resistant S. aureus clones circulating in South America. Types A (66%) and C (31%) were the most prevalent β-lactamases.

CONCLUSIONS

Our results show a high prevalence of the cefazolin InE associated with type A β-lactamase in MSSA isolates from Colombia and Ecuador, suggesting that treatment of deep-seated infections with cefazolin in those countries may be compromised.

The consequences of generic marketing on antibiotic consumption and the spread of microbial resistance: the need for new antibiotics

In both human and veterinary medicine, it has been shown that flooding the market with different generics and/or 'me-too' branded drugs has increased overall antibiotic consumption correlating with the emergence and spread of bacterial resistance to antibiotics. Another possible undesirable consequence of the promotion of generics is the promotion of an economic incentive that encourages the use of old drug products with very poor oral bioavailability, marketed with historical dosage regimens and extensively excreted in the environment. What veterinary medicine rather needs is new innovative and 'ecofriendly' antibiotics to actually enforce a more prudent use of antibiotics. For a pharmaceutical company, generics are inexpensive to manufacture and on a short-term basis, the generic market is very appealing. However, on a long-term basis, this marketing orientation provides a disincentive to the development of new and innovative products that will be required to meet the therapeutic needs of the veterinary community while being consistent with public health concerns. Indeed, for veterinary medicine, the key issue surrounding antibiotics is public health. It is the opinion of the authors that veterinary antibiotics and/or veterinary drug formulations should be innovative in terms of selectivity (no or minimal impact on the commensal gut flora), biodegradable (with minimal environmental disruption), and more expensive, with a strictly regulated market rather than unselective, cheap, and freely available drugs.

Use of antibacterial agents in the neonate: 50 years of experience with vancomycin administration

Neonatal sepsis, classified as either early or late onset, has specific pathogen distribution and infection rates in the different neonatal age groups. It is a major cause of mortality and morbidity and administration of antibiotics is urgently required for suspected or proven infection. Vancomycin is the first choice treatment of late onset sepsis due to resistant staphylococci. Although it has been used for more than 50 years, prescription remains a challenge in neonatal intensive care units for many reasons, including: high pharmacokinetic variability, numerous presentations, lack of consensus on dosing regimen and therapeutic drug monitoring. In addition, recent concerns about the increase in minimal inhibition concentration and other more generic problems have prompted reappraisal of the rational use of vancomycin. This article highlights the goal of optimising vancomycin therapy in the neonate and discusses future research directions. Specific attention is given to dosing optimisation of vancomycin to avoid resistance and maximise the likelihood of achieving the therapeutic target. Modelling and simulation approaches have clear advantages in dosing optimisation of antimicrobial agents in the neonate. Neonatologists and paediatric pharmacologists should work closely together to achieve this goal.

Generic antibiotic drugs: is effectiveness guaranteed?

There are recently published arguments suggesting all generic antibiotic drugs do not present the full reliability needed to claim therapeutic equivalence with branded drugs. The problem is especially crucial for generic intravenous drugs, which do not need any bioequivalence study before they can be marketed. The evaluation of generic antibiotic drug effectiveness yields an important dispersion of results according to antibiotic agents and for the same antibiotic agent all generic drugs are not equivalent. There are differences at all levels: drug components, levels of impurity, pharmacokinetics, pharmacokinetic/pharmacodynamic relationship, in vitro effectiveness, therapeutic effectiveness in experimental models, etc. So that finally, the specifications approved in the initial submission file of a brand name drugs are not always respected by a generic drug. There is also a specific problem of taste and treatment acceptability for pediatric oral antibiotic drugs. Available data on clinical effectiveness is excessively rare. The marketing of a great number of generic drugs of the same specialty is followed by a sometimes very important increase of their use, even in countries where consumption is low. The corollary of this increase in consumption is an increase of resistance, and this is especially true for oral fluoroquinolones. Even if most of this information needs to be verified, it seems necessary to review regulations for marketing authorization of generic antibiotic drugs.

Therapeutic equivalence requires pharmaceutical, pharmacokinetic, and pharmacodynamic identities: true bioequivalence of a generic product of intravenous metronidazole

Animal models of infection have been used to demonstrate the therapeutic failure of "bioequivalent" generic products, but their applicability for this purpose requires the accurate identification of those products that are truly bioequivalent. Here, we present data comparing one intravenous generic product of metronidazole with the innovator product in a neutropenic mouse thigh anaerobic infection model. Simultaneous experiments allowed comparisons (generic versus innovator) of potency and the concentration of the active pharmaceutical ingredient (API), analytical chemistry (liquid chromatography/mass spectrometry [LC/MS]), in vitro susceptibility testing, single-dose serum pharmacokinetics (PK) in infected mice, and in vivo pharmacodynamics (PD) against Bacteroides fragilis ATCC 25825 in synergy with Escherichia coli SIG-1 in the neutropenic mouse thigh anaerobic infection model. The Hill dose-response model followed by curve-fitting analysis was used to calculate and compare primary and secondary PD parameters. The generic and the innovator products were identical in terms of the concentration and potency of the API, chromatographic and spectrographic profiles, MIC and minimal bactericidal concentrations (MBC) (2.0 mg/liter), and mouse PK. We found no differences between products in bacteriostatic doses (BD) (15 to 22 mg/kg of body weight per day) or the doses needed to kill 1 log (1LKD) (21 to 29 mg/kg per day) or 2 logs (2LKD) (28 to 54 mg/kg per day) of B. fragilis under dosing schedules of every 12 h (q12h), q8h, or q6h. The area under the concentration-time curve over 24 h in the steady state divided by the MIC (AUC/MIC ratio) was the best PD index to predict the antibacterial efficacy of metronidazole (adjusted coefficient of determination [AdjR(2)] = 84.6%), and its magnitude to reach bacteriostasis in vivo (56.6 ± 5.17 h) or to kill the first (90.8 ± 9.78 h) and second (155.5 ± 22.2 h) logs was the same for both products. Animal models of infection allow a thorough demonstration of the therapeutic equivalence of generic antimicrobials.

Product quality of parenteral vancomycin products in the United States

In response to concerns raised about the quality of parenteral vancomycin products, the U.S. Food and Drug Administration (FDA) is investigating the product quality of all FDA-approved parenteral vancomycin products available in the United States. Product quality was evaluated independently at two FDA Office of Testing and Research (FDA-OTR) sites. In the next phase of the investigation, being done in collaboration with the National Institute of Allergy and Infectious Diseases, the in vivo activity of these products will be evaluated in an appropriate animal model. This paper summarizes results of the FDA investigation completed thus far. One site used a validated ultrahigh-pressure liquid chromatography method (OTR-UPLC), and the second site used the high-performance liquid chromatography (HPLC) method for related substances provided in the British Pharmacopeia (BP) monograph for vancomycin intravenous infusion. Similar results were obtained by the two FDA-OTR laboratories using two different analytical methods. The products tested had 90 to 95% vancomycin B (active component of vancomycin) by the BP-HPLC method and 89 to 94% vancomycin by OTR-UPLC methods. Total impurities were 5 to 10% by BP-HPLC and 6 to 11% by OTR-UPLC methods. No single impurity was >2.0%, and the CDP-1 level was ≤ 2.0% across all products. Some variability in impurity profiles of the various products was observed. No adverse product quality issues were identified with the six U.S. vancomycin parenteral products. The quality parameters of all parenteral vancomycin products tested surpassed the United States Pharmacopeia acceptance criteria. Additional testing will characterize in vivo performance characteristics of these products.

Generic vancomycin enriches resistant subpopulations of Staphylococcus aureus after exposure in a neutropenic mouse thigh infection model

Previous studies have shown that "bioequivalent" generic products of vancomycin are less effective in vivo against Staphylococcus aureus than the innovator compound. Considering that suboptimal bactericidal effect has been associated with emergence of resistance, we aimed to assess in vivo the impact of exposure to innovator and generic products of vancomycin on S. aureus susceptibility. A clinical methicillin-resistant S. aureus (MRSA) strain from a liver transplant patient with persistent bacteremia was used for which MIC, minimum bactericidal concentration (MBC), and autolytic properties were determined. Susceptibility was also assessed by determining a population analysis profile (PAP) with vancomycin concentrations from 0 to 5 mg/liter. ICR neutropenic mice were inoculated in each thigh with ∼7.0 log(10) CFU. Treatment with the different vancomycin products (innovator and three generics; 1,200 mg/kg of body weight/day every 3 h) started 2 h later while the control group received sterile saline. After 24 h, mice were euthanized, and the thigh homogenates were plated. Recovered colonies were reinoculated to new groups of animals, and the exposure-recovery process was repeated until 12 cycles were completed. The evolution of resistance was assessed by PAP after cycles 5, 10, 11, and 12. The initial isolate displayed reduced autolysis and higher resistance frequencies than S. aureus ATCC 29213 but without vancomycin-intermediate S. aureus (VISA) subpopulations. After 12 cycles, innovator vancomycin had significantly reduced resistant subpopulations at 1, 2, and 3 mg/liter, while the generic products had enriched them progressively by orders of magnitude. The great capacity of generic vancomycin to select for less susceptible organisms raises concerns about the role of therapeutic inequivalence of any antimicrobial on the epidemiology of resistance worldwide.

Insights into the antibacterial and immunomodulatory functions of tilapia hepcidin (TH)2-3 against Vibrio vulnificus infection in mice

The antimicrobial and immunomodulatory functions of the antimicrobial peptide, tilapia hepcidin (TH)2-3, against a bacterial endotoxin under in vitro conditions was previously reported. In this study, we investigated the antibacterial and immunomodulatory functions of TH2-3 in mice infected with the pathogen, Vibrio vulnificus. A TH2-3 injection in V. vulnificus-infected mice produced an increased survival rate compared to mice injected with V. vulnificus only. In addition, a TH2-3 injection increased the bacteriostatic property against V. vulnificus in mice. Gene expressions examined using a microarray demonstrated that TH2-3 modulated several V. vulnificus-responsive genes in the host. A neutralizing antibody assay of mice serum against inactivated V. vulnificus antigen-coated plates demonstrated the induction of an immune response by TH2-3 against the pathogen. Taken together, TH2-3 enhanced the survival rate of mice against the bacterial pathogen V. vulnificus through both antimicrobial and immunomodulatory functions. These properties make the TH2-3 peptide a good candidate for development as a new antimicrobial drug and suggest that TH2-3 can underpin the design of adjuvants for further development of vaccines.

A NEW MODIFIED TOTAL FRONT END FRAMEWORK FOR INNOVATION: NEW INSIGHTS FROM HEALTH RELATED INDUSTRIES

This paper explores the front end innovation activities in a multinational Global Healthcare Company (GHC). A questionnaire was designed and distributed to front end innovators from 20 operating companies to understand team composition, essential skill sets, and the methodology used to assess customer needs, generate ideas, and define the selection criteria used during the go/no go decision. For each category the current state and best practice (based on the views of the individual respondents) for front end innovation was analyzed and reported in this paper. The results of this study reflect the opinions and suggestions of 37 respondents (23 that were at directorship level or above). These results were amalgamated and used to develop existing models of innovation to produce a framework (termed the Total Front End Framework (TFEF)) that should be useful for both senior managers and innovation teams to optimize their activities and increase the efficiency of the innovation process.

Knowledge, attitudes and practice survey about antimicrobial resistance and prescribing among physicians in a hospital setting in Lima, Peru

Background

Misuse of antimicrobials (AMs) and antimicrobial resistance (AMR) are global concerns. The present study evaluated knowledge, attitudes and practices about AMR and AM prescribing among medical doctors in two large public hospitals in Lima, Peru, a middle-income country.

Methods

Cross-sectional study using a self-administered questionnaire

Results

A total of 256 participants completed the questionnaire (response rate 82%). Theoretical knowledge was good (mean score of 6 ± 1.3 on 7 questions) in contrast to poor awareness (< 33%) of local AMR rates of key-pathogens. Participants strongly agreed that AMR is a problem worldwide (70%) and in Peru (65%), but less in their own practice (22%). AM overuse was perceived both for the community (96%) and the hospital settings (90%). Patients' pressure to prescribing AMs was considered as contributing to AM overuse in the community (72%) more than in the hospital setting (50%). Confidence among AM prescribing was higher among attending physicians (82%) compared to residents (30%, p < 0.001%). Sources of information considered as very useful/useful included pocket-based AM prescribing guidelines (69%) and internet sources (62%). Fifty seven percent of participants regarded AMs in their hospitals to be of poor quality. Participants requested more AM prescribing educational programs (96%) and local AM guidelines (92%).

Conclusions

This survey revealed topics to address during future AM prescribing interventions such as dissemination of information about local AMR rates, promoting confidence in the quality of locally available AMs, redaction and dissemination of local AM guidelines and addressing the general public, and exploring the possibilities of internet-based training.

Local epicardial inotropic drug delivery allows targeted pharmacologic intervention with preservation of myocardial loading conditions

Local myocardial application of inotropes may allow the study of pharmacologically augmented central myocardial contraction in the absence of confounding peripheral vasodilating effects and alterations in heart loading conditions. Novel alginate epicardial (EC) drug releasing platforms were used to deliver dobutamine to the left ventricle of rats. Pressure-volume analyses indicated that although both local and systemic intravenous (i.v.) use of inotropic drugs increase stroke volume and contractility, systemic infusion does so through heart unloading. Conversely, EC application preserves heart load and systemic blood pressure. EC dobutamine increased indices of contractility with minimal rise in heart rate and lower reduction in systemic vascular resistance than i.v. infusion. Drug sampling showed that dobutamine concentration was 650-fold higher in the anterior wall than in the inferior wall. The plasma dobutamine concentration with local delivery was about half as much as with systemic infusion. These data suggest that inotropic EC delivery has a localized effect and augments myocardial contraction by different mechanisms than systemic infusion, with far fewer side effects. These studies demonstrate a pharmacologic paradigm that may improve heart function without interference from effects on the vasculature, alterations in heart loading, and may ultimately improve the health of heart failure patients.