Characterization and origin of the ‘B’ and ‘C’ compounds in the acid/neutral forensic signatures of heroin – products from the acylation of porphyroxine and subsequent hydrolysis

Abstract

Two significant compounds often found in the gas chromatographic analysis of the acid/neutral extracts from illicit heroin have remained uncharacterized for 30 years. The unknown compounds are referred to as the 'B' and 'C' compounds. It has been postulated that these compounds arise from acetylation of porphyroxine, a rhoeadine alkaloid found at trace levels in the opium poppy, Papaver somniferum. Porphyroxine was isolated from opium and acetylated to produce N,O -diacetylporphyroxine. Mild hydrolysis produced N,O -diacetyl-O -desmethyl-epi-porphyroxine (the C compound) and N-acetyl-O -desmethyl-epi-porphyroxine (the B compound). Both N,O -diacetyl-O -desmethyl-epi-porphyroxine and N-acetyl-O -desmethyl-epi-porphyroxine were determined to be C-14 epimers of porphyroxine and N,O -diacetylporphyroxine. The non-epimerized isomers of the B and C compounds were also detected in illicit heroin, but at much lower levels. Chromatographic and spectroscopic data are presented for the aforementioned compounds. The presence/absence and relative concentrations of these compounds is presented for the four types of heroin (Southwest Asian, South American, Southeast Asian, and Mexican). The prevalence of detection for the B and C compounds are Southwest Asian = 92-93%, South American = 64-72%, Southeast Asian = 45-49%, and Mexican ≤ 3%. When detected, the overall trend of relative concentrations of dicaetylporhyroxine, the B-compound, and C-compound is Southwest Asian > South American > Southeast Asian, each by an order of magnitude. These compounds were rarely detected in Mexican heroin. The presence/absence and relative concentrations of these compounds provide pertinent forensic signature characteristics that significantly enhance the final regional classifications. Copyright © 2015 John Wiley & Sons, Ltd.

UHPLC–MS/MS quantitation of porphyroxine in opium and application of porphyroxine‐acetylated products as signature markers for heroin

“…Though the porphyroxine‐related compounds were found to be abundant in crude heroin from SWA by acidic and neutral signature profiles, their presence was relatively low in crude samples from MEX. It was hypothesized by Casale et al that either porphyroxine is relatively low in MEX opium or the unique morphine base to HCl conversion step employed in that area results in the lower concentrations of porphyroxine‐related products in MEX heroin samples . The result of this study indicate that the absence or low concentrations of porphyroxine‐related compounds in the crudely manufactured MEX heroin samples is due to the low concentration of porphyroxine in the opium harvested in MEX.…”

“…As a result, B and C have been instrumental for decades in classifying heroin samples for HSP, especially from SWA. However, their structures have only recently been elucidated and characterized by this laboratory as N ‐acetyl‐ O 14 ‐desmethyl‐ epi ‐porphyroxine ( B ) and N,O 8 ‐diacetyl‐ O 14 ‐desmethyl‐ epi ‐porphyroxine ( C ) …”

“…The study of porphyroxine was carried out in two parts: the first phase characterized porphyroxine‐acetylated products and demonstrated the presence or relative amount of porphyroxine‐related compounds in heroin samples from the four major producing regions; while the second phase involved the development of a sensitive and straightforward “dilute‐and‐shoot” UHPLC–MS/MS method to analyze porphyroxine alkaloid in opium. The resulting UHPLC–MS/MS method was consequently applied to quantify porphyroxine and major alkaloids in opium samples from four regions: MEX (Mexico), SEA (Southeast Asia), SA (South America), and SWA.…”

“…However, their structures have only recently been elucidated and characterized by this laboratory as N-acetyl-O 14 -desmethyl-epi-porphyroxine (B) and N,O 8 -diacetyl-O 14 -desmethyl-epi-porphyroxine (C). 12 For the HSP, the quantitation of major alkaloids or their basic byproducts have been traditionally carried out by high performance liquid chromatography−photo diode array (HPLC−PDA) or capillary electrophoresis-photo diode array (CE−PDA) and currently, with a UHPLC−PDA system. [13][14][15] Semi-quantitative analysis of trace levels of acid/neutral impurities is conducted by extraction and derivatization followed by gas chromatography-mass spectrometry (GC-MS) analysis.…”

Addressing the challenges in forensic drug chemistry

“…The authors also confirmed that the prevalence of detection for the B and C compounds differed based on geographical origin: Southwest Asian samples (92–93%) > South American (64–72%) > Southeast Asian (45–49%) > Mexican samples (≤ 3%). In total, five compounds were identified that reflect the acetylation of porphyroxine contaminated‐morphine during illicit production of heroin …”