Carboxylesterases are a multi-gene family of enzymes widely distributed throughout the body of mammals that catalyze the hydrolysis of esters, amides, thioesters, and carbamates. In humans, two carboxylesterases, hCE1 and hCE2, are important pathways of drug metabolism. Both are expressed in the liver, but levels of hCE1 greatly exceed those of hCE2. In the intestine only high levels of hCE2 are expressed. The most common drug substrates are ester prodrugs specifically designed to enhance oral bioavailability that must be hydrolyzed to their active carboxylic acid by hydrolysis after absorption from the gastrointestinal tract. However, carboxylesterases also play an important role in the hydrolysis of some drugs to inactive metabolites. It has been widely accepted that drugs undergoing hydrolysis by hCE1 and hCE2 are not subject to clinically significant alterations in their disposition, but there is now a significant and growing body of evidence that genetic polymorphisms, drug-drug interactions, drug-disease interactions and other factors are important determinants of the variability in the therapeutic response to carboxylesterase-substrate drugs. The implications for the safe and effective use of drug therapy is far-reaching, as the patient exposure to substrate drugs includes numerous agents from widely prescribed therapeutic classes such as angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, antiplatelets, HMG-CoA inhibitors, antivirals, and central nervous system agents.

Regardless of practice setting, it is imperative that pharmacists be able to either participate in generating new knowledge or use the ever-expanding body of literature to guide patient care. However, competing priorities in Pharm.D. curricula and residency training programs have resulted in limited emphasis on acquiring research and scholarly skills. Factors likely contributing to this reduced focus include the lack of curricular and postgraduate training standards emphasizing the development of research skills, time to commit to scholarly activity, and accessibility to experienced mentors. Strategies for increasing scholarly activity for pharmacy students and residents should therefore continue to be a focus of professional degree and residency training programs. Several resources are available for academic planners, program directors, and institutions to augment scholarly experience for pharmacy trainees and clinicians. This commentary highlights the importance of providing research opportunities for students and residents, describes the potential barriers to these activities, and provides recommendations on how to increase the instruction and mentoring of trainees to generate and use research.

This report describes an open surgical technique for pancarpal arthrodesis and its efficacy in 45 canine cases. Indications for carpal arthrodesis include hyperextension injuries, severe fracture/luxations, end‐stage arthritis, and selected neurologic deficits. Chronic joint instability was the major indication for surgery (76%). Degenerative joint disease (18%) and neurologic deficits (6%) accounted for the other cases. In a subjective owner survey, 97% of the owners reported that their animals' gait improved following arthrodesis, and 74% stated that their animals walked and ran normally.

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Dabigatran etexilate (DABE) is an oral prodrug that is rapidly converted to the active thrombin inhibitor, dabigatran (DAB), by serine esterases. The aims of the present study were to investigate the in vitro kinetics and pathway of DABE hydrolysis by human carboxylesterase enzymes, and the effect of alcohol on these transformations. The kinetics of DABE hydrolysis in two human recombinant carboxylesterase enzymes (CES1 and CES2) and in human intestinal microsomes and human liver S9 fractions were determined. The effects of alcohol (a known CES1 inhibitor) on the formation of DABE metabolites in carboxylesterase enzymes and human liver S9 fractions were also examined. The inhibitory effect of bis(4-nitrophenyl) phosphate on the carboxylesterase-mediated metabolism of DABE and the effect of alcohol on the hydrolysis of a classic carboxylesterase substrate (cocaine) were studied to validate the in vitro model. The ethyl ester of DABE was hydrolyzed exclusively by CES1 to M1 (K m 24.9 6 2.9 mM, V max 676 6 26 pmol/min per milligram protein) and the carbamate ester of DABE was exclusively hydrolyzed by CES2 to M2 (K m 5.5 6 0.8 mM; V max 71.1 6 2.4 pmol/min per milligram protein). Sequential hydrolysis of DABE in human intestinal microsomes followed by hydrolysis in human liver S9 fractions resulted in complete conversion to DAB. These results suggest that after oral administration of DABE to humans, DABE is hydrolyzed by intestinal CES2 to the intermediate M2 metabolite followed by hydrolysis of M2 to DAB in the liver by CES1. Carboxylesterase-mediated hydrolysis of DABE was not inhibited by alcohol.