[Quantifying the chemical composition of crack-cocaine (bazuco) samples seized in Colombia during the first half of 2010]. 
Quantifying crack-cocaine (known locally as bazuco or smokable cocaine base paste-PBC) use and identifying other components in study conditions regarding samples of crack-cocaine seized in Colombia and held by the Colombian Institute of Legal Medicine and Forensic Science Narcotics Laboratory in Bogota during the first half of 2010.  A cross-sectional, exploratory analytical study was carried out for chemically characterizing crack-cocaine samples by the gas chromatography analytical methodology using ion trap mass spectrometry developed and validated in the Universidad National de Colombia's Medicine Faculty's Toxicology Laboratory in Bogota.  A 4 % to 70 % w/w cocaine base concentration was found in the 109 samples tested (37 % w/w mean); 73 % of the samples had 20 % to 50 % w/w concentration.  Other coca alkaloids were identified, such astropacocaine, trans-cinnamoylcocaine, norcocaine and ecgonine methyl ester.  Caffeine was identified as an adulterantin 57 % of the samples and phenacetin in 2.8 % of them.  The toxicological significance of the results concerning crack-cocaine consumers was quantified, given the profile for chronic users.