Harry Goldenberg

Metabolism of Chlorpromazine. IV. Identification of 7-Hydroxychlor-promazine and Its Sulfoxide and Desmethyl Derivatives.

Summary A family of 4 phenolic metabolites of chlorpromazine has been isolated from animal (dog) and human urine by solvent extraction and paper chromatography. By subjecting the metabolites to a series of methylation and oxidation or reduction reactions, then comparing the products obtained to authentic material, they have been identified as follows: 7-hydroxychlorpromazine, 7-hydroxychlorpromazine sulfoxide, 7-hydroxy-nor1chlorpromazine, and 7-hydroxy-nor2chlorpromazine. These compounds are excreted both in free form and as glucuronic acid conjugates.

Identification of a new metabolite of imipramine.

Summary Imipramine-N-oxide (IPNO) has been identified as a metabolite of imipramine. The product was isolated from human urine by solvent extraction and chromatography. Its identity with authentic IPKO was established by their similarity in color reactions and electrophoretic behavior, and by paper chromatography and cochromatography in 8 solvent systems. Approximately 2%. of administered imipramine is voided as the N-oxide.

Metabolism of Chlorpromazine. III. Isolation and Identification of Chlorpromazine-N-Oxide.∗

Summary Chlorpromazine-N-oxide (CPNO) has been isolated from human urine and identified as a metabolite of chlorpromazine. Proof is based on the similarity between this product and authentic CPNO with respect to their ultraviolet spectra, color reactions, electrophoretic mobility, and paper chromatographic behavior. Further confirmation has been obtained by oxidation of the metabolite and authentic CPNO to form derivatives (CPNO sulfoxide) which are identical to each other as well as to authentic CPNO sulfoxide. CPNO is not a major human metabolite, but it is voided in somewhat larger amounts than chlorpromazine sulfoxide. Dogs surpass humans in their output of the N-oxide.

Metabolism of Chlorpromazine Organic-Extractable Fraction From Human Urine

Summary Chromatographic studies reveal the presence of 10 Dragendorff (+) compounds in organic (ethylene dichloride) extracts of alkalinized human urine following administration of chlorpromazine. Six of these compounds appear to be sulfoxides. Included in this group are chlorpromazine sulfoxide — which is a relatively minor product — as well as 2 major metabolites whose chromatographic behavior is indistinguishable from Nor1 and Nor2chlorpromazine sulfoxide. A third major metabolite (compound #4) remains unidentified, but it is not a sulfoxide derivative. It is indicated that the residual urine remaining after extraction contains numerous additional (polar) metabolites.

A Detailed Evaluation of Promazine Metabolism.

Summary Thin-layer and paper chroma-tography have been used to study the metabolism of promazine following its oral administration to man and animals. Humans excrete about 33% of the drug in urine, in the form of 26-30 derivatives. These compounds are distributed between nonphenolic (14%) and phenolic (19%) fractions in the ratio of 1 to 1.4. The principal metabolites are nor2promazine sulfoxide (6.3%), nor1-promazine sulfoxide (5.2%), 3-hydroxy-promazine glucuronide (3.7%), 3-hydroxy-noripromazine glucuronide (3.1%), and the glucuronides of L4 and L5 (5.5%). In addition to the desmethyl sulfoxides, the non-phenolic fraction contains promazine-N-ox-ide, promazine sulfoxide, unchanged promazine, nor1promazine and traces of nor2proma-zine. The phenolic fractions consist of glucuronides (15%), ethereal sulfates (3%) and unconjugated phenols (1-2%). The compounds bound to glucuronic acid include 3-hydroxypromazine and its 2 desmethyl derivatives, the 3 corresponding sulfoxides, and L4 and L5. 3-Hydroxypromazine and 3-hydroxy-nor1promazine and their sulfoxides are also excreted as ethereal sulfates. Relatively small amounts of the drug are voided by dogs (13%) and rabbits (10-13%). Furthermore, these animals exhibit markedly different excretion patterns. The metabolites in dog urine are present for the most part in the nonpolar fraction, principally as promazine sulfoxide and nor1promazine sulfoxide, while rabbits tend to excrete the drug as free or conjugated phenols. The major rabbit metabolite, 3-hydroxyproma-zine, is distributed among all 3 phenol fractions. Neither animal produces primary amine metabolites in amounts comparable to man. Addendum. The peach factor (Pe) has recently been identified in our laboratory as phenothiazine sulfoxide. This indicates that both man and dog can degrade the side chain of promazine down to the phenothiazine nucleus. Orc appears to be an oxidation product derived from 3-hydroxyphenothiazine. Chlor-promazine yields the corresponding 2-chloro derivatives as metabolites. Appreciation is expressed to Dr. Herbert S. Posner, St. Elizabeths Hospital, Washington, D.C., for 4 isomeric hydroxypromazine standards, and to Wyeth Laboratories for promazine, nor1promazine, nor2-promazine and promazine sulfoxide.

Species Dependence of Chlorpromazine Metabolism.

Summary Man and dog are compared with reference to their metabolism of chlorpromazine following its oral administration (8 mg/kg). Both qualitative and quantitative differences are noted in the urinary metabolite patterns. Humans tend to favor the excretion of polar derivatives, along with one or 2 major nonpolar metabolites (Nor2CPSO, 3.7% and Nor1CPSO, 1.8%). Their output of CP (0.2%) and CPSO (0.4%) is trivial. Dogs excrete less polar material, less Nor2CPSO (1.1%), more Nor1CPSO (5.1%) and substantial amounts of CP (2.8%) and CPSO (5.1%). The human polar fractions contain persulfate-blue as well as persulfate-lavender staining metabolites; the blue series is conspicuously absent from dog urine.

Calcification. V. Influence of Fluoride and Cyanide Ions in the Presence and Absence of Magnesium.

Summary 1. The initial rate of calcification of rachitic cartilage sections in inorganic media is markedly reduced in the presence of 10-4 M fluoride ion. With more prolonged incubation there is a relief of inhibition unless magnesium is included in the calcifying solution. 10−3 M fluoride is similarly effective in preventing mineralization provided the solution contains an adequate amount of magnesium; in its absence, the initial interference by 10−3 M fluoride is rapidly obscured by a secondary effect, interpreted as incorporation of fluoride in the growing mineral deposit, which gives rise to an apparent increase in calcification over the control. 2. Cyanide ion blocks calcification in the presence, but not in the absence of magnesium.

Calcification. IX. Influence of alkaline earths on survival of the calcifying mechanism.

Summary 1. Rachitic bone cartilage slices which are suspended in basal medium at 36.5°C become slowly inactivated as shown by their subsequent inability to calcify. Major loss of calcifiability takes place in the first 7-8 hours with complete inactivation evident after about 12 hours. In the first 11 hours, small amounts of calcium or strontium exert a marked protective action against deterioration of the calcifying mechanism. Unlike calcium and strontium, comparable concentrations of magnesium and barium have no influence on the survival of the calcifying mechanism. 2. Beryllium in basal salt solution inactivates the calcifying mechanism, which can be prevented in part by inorganic phosphate. Manganese, cobalt, and nickel also inactivate the system when added to the basal salt solution. 3. Evidence to date favors the explanation that strontium and calcium ions protect the calcifying mechanism by forming a relatively stable compound with a component of the calcifying matrix essential for the mineralizing process, although an alternate explanation that these ions suppress a system responsible for inactivation cannot be excluded.

Calcification. IV. Influence of Strontium and Magnesium Ions on Calcification in vitro

Summary The intense inhibition of calcification in vitro by strontium ions requires the presence of magnesium ions. The injury to the calcifying mechanism in rickets due to strontium is associated with the presence of magnesium ions. The results suggest the importance of studying the influence of various ions on the calcifying mechanism, both in the presence and absence of magnesium.

Relation of the Mecholyl Test to Catecholamine Excretion.

Summary Following injection of mecholyl, excretion of epinephrine and norepinephrine tends to increase. Excretion ratios for norepinephrine and for epinephrine were compared with the relative change in blood pressure after injection of mecholyl. There is a correlation of low statistical significance between norepinephrine excretion ratios and mecholyl area, which suggests that the more hypertensive responses to mecholyl may be associated with higher norepinephrine reactivity.