Inhibition of hypoxanthine-guanine phosphoribosyl transferase.

The affinities of eighteen purines or purine analogs for human erythrocytic hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8; HGPRTase) were compared to assess the feasibility of obtaining active inhibitors of the enzyme. Three compounds appeared to inhibit the utilization of hypoxanthine by L5178Y cells in vitro due to inhibition of the enzyme rather than depletion of the intracellular 5-phosphoribosyl-1-pyrophosphate pool. The three competitive inhibitors and their affinity constants (K_i) using 6-mercaptopurine as substrate were: 6-mercapto-9-(tetrahydro-2-furyl)-purine, 37 μM; 2,6-bis-(hydroxyamino)-9-β-d-ribofuranosyl-purine, 12 μM; and 6-iodo-9-(tetrahydro-2-furyl)-purine, 108 μM. The KInm for 6-mercaptopurine was 9 μM. Thus, the enzyme tolerates bulky substitution at N⁹. 6-Mercapto-9-(tetrahydro-2-furyl)-purine also potentiated the chemotherapeutic effect of azaserine, an inhibitor of de novo purine biosynthesis, in L5178Y ascites tumor-bearing mice. Four 2-substituted, oxazolo-[5, 4-d]-pyrimidine-7-ones and 2-methylthiazolo-[5, 4-d]-pyrimidine-7-one had K_i values in the range of 84–173 μM. Consequently, isosteric substitution at N⁹ may also be a fruitful and logical course to pursue in the design and synthesis of more potent inhibitors of this important enzyme.     

7-ribosyl-3-deazaguanine—Mechanism of antibacterial action

The mechanism by which 7-ribosyl-3-deazaguanine $\text{[7}\text{R}\text{3}\text{DG}\text{, 6-}\text{amino}\text{-3-β-}\text{d}\text{-}\text{ribofuranosylimidazo}\text{[4,5-c]}\text{pyridin}\text{-4(5H)-}\text{one}\text{]}$ exerts its antibacterial effect was examined. Escherichia coli was found to contain an enzyme that exhibited the properties of a nucleoside phosphorylase and that converted 7R3DG to 3-deazaguanine (3DG, 6-aminoimidazo[4,5-c]pyridin-4(5H)-one], but no mammalian system that was examined (Erilch ascites, rat liver and human liver) was able to convert 7R3DG to 3DG. The 3DG arising from the phosphorolysis of 7R3DG was converted to 3-deaza-GMP [3DGMP, 6-amino-l-β-D-riboluranosylimidazo [4,5-c]pyridin-4(5H)-one-5′-phosphate] by the guanine phosphoribosyltransferase present in E. coli. A strain of E. coli, resistant to 7R3DG, was found to lack this enzyme and, therefore, was unable to convert 3DG to 3DGMP.     

Pharmacokinetics of inhibition of adenosine deaminase by erythro-9-(2-hydroxy-3-nonyl)adenine in CBA mice

The pharrnacokinetics oferythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) inhibition of adenosine deaminase (ADA) was measured in vivo in CBA mice. The in vivo assay utilized injection of 10–100 nmoles [2-³H]adenosine and measurement of blood ³H₂O 20 min later. A single oral dose of EHNA (50 mg/kg) totally inhibited ADA for 4 hr and caused a large increase in conversion of [2-³H]adenosine to [2-³H]ATP. EHNA (3 mg/kg) decreased deamination by 50% for 2–6 hr, depending on the dose of adenosine used. Mice dosed with EHNA (100 mg/kg) once daily for 7 days showed the same ADA recovery rate as mice dosed only once. High single oral doses of EHNA had no effect on blood ATP and GTP pools.     

Effect of L-glutamine antagonists on 5-phosphoribosyl 1-pyrophosphate levels in P388 leukemia and in murine colon adenocarcinomas in vivo

The intratumoral content of 5-phosphoribosyl 1-pyrophosphate (PRPP) and the activity of the enzymes anabolizing and catabolizing the sugar phosphate were determined following i.p. administration of an LD10 dose of an L-glutamine antagonist or saline to tumor-bearing animals. Elevation of PRPP pool size following administration of L-[alpha S,5S]-alpha-amino-3-chloro-4,5-dihydro-5-isopazoleacetic acid (NSC-163501) (AT-125) was maximal at 8 hr and returned to pretreatment levels by 24 hr. In P388 leukemia, dose for dose, at 4 hr, 6-diazo-5-oxo-L-norleucine (NSC-7365) (DON) was the most potent of the L-glutamine antagonists in elevating basal PRPP pool size (50% above control) followed by AT-125 and azaserine, 300 and 100% above control respectively. Moreover, such augmentation in PRPP pool size preferentially affected P388 tumor rather than the small intestine. Following i.p. administration of LD10 doses of AT-125, DON and azaserine, the specific activities of PRPP anabolizing and catabolizing enzymes were determined. A significant inhibition of PRPP amidotransferase was demonstrated with DON and AT-125 (P less than 0.05), and no inhibition with azaserine. A similar modulation of PRPP pool size demonstrated in vivo following administration of 250 mg/kg of ART-125 in mice bearing colonic adenocarcinoma lines. It was suggested that a significant increase of PRPP pool size might cause the possible synergism of a selected L-glutamine antagonist and 5-fluorouracil as reported after the appropriately scheduled administration of methotrexate and 5-fluorouracil.     

Mode of action of 2-amino-6-chloro-1-deazapurine

2-Amino-6-chloro-1-deazapurine is of interest as a purine analog with demonstrated in vivo activity against mouse leukemia L1210. That the active form of this agent is a nucleotide and that the nucleotide is formed by the action of hypoxanthine (guanine) phosphoribosyltransferase were shown by the facts that (a) L1210 cells deficient in hypoxanthine phosphoribosyltransferase were insensitive to the analog; (b) hypoxanthine, but not adenine, prevented the formation of the analog nucleotide by enzyme preparations containing activities of both hypoxanthine and adenine phosphoribosyltransferases; and (c) the cytotoxicity of the analog was prevented by hypoxanthine. The ribonucleoside of this analog was not toxic to cell cultures and hence is not phosphorylated or cleaved to the base. In intact HEp-2 cells and L1210 cells, the analog was metabolized to the nucleoside 5'-phosphate which accumulated to concentrations as high as 1000 nmoles/10(9) cells; no di- or triphosphates were detected. In HEp-2 cells, the analog reduced the pools of purine nucleotides with some accumulation of IMP. The toxicity of minimal inhibitory concentrations of the analog to HEp-2 cells could be prevented or reversed by 4(5)-amino-5(4)-imidazolecarboxamide (AIC); the toxicity of higher concentrations could be prevented or reversed by a combination of adenine and guanosine but not by AIC. The analog inhibited the incorporation of formate into purine nucleotides and into macromolecules at concentrations that had no effect on utilization of hypoxanthine; at higher concentrations the incorporation of hypoxanthine was inhibited. Low concentrations also inhibited the utilization of uridine and thymidine. The incorporation of hypoxanthine and AIC into guanine nucleotides, but not adenine nucleotides, was inhibited. These results indicate two sites of inhibition of the biosynthesis of purine nucleotides, the more sensitive one being on an early step of the pathway and the less sensitive one on the IMP-GMP conversion. That the blockade of de novo synthesis probably was at the site of feedback inhibition was indicated by the fact that the analog inhibited the accumulation of formylglycinamide ribonucleotide in azaserine-treated cells but did not inhibit the synthesis of 5'-phosphoribosyl 1-pyrophosphate. Comparative studies were performed with the related analog, 2-amino-6-chloropurine, which has been reported to produce a similar dual blockade of the purine pathway. This purine was less toxic than its 1-deaza analog; it produced a modest decrease in adenine nucleotides but increased pools of guanine nucleotides.(ABSTRACT TRUNCATED AT 400 WORDS)     

血浆普卢利沙星活性代谢物的测定及其人体药动学研究

目的:建立人血浆普卢利沙星活性代谢物(UFX)浓度的高效液相色谱测定法,研究普卢利沙星片在健康人体内的药动学。方法:10例健康志愿受试者分别服用普卢利沙星片(相当于UFX为200 mg)单剂量和连续多次给药达稳态时进行药动学研究。血浆样品经甲醇沉淀蛋白,以Zorbax ODS柱、甲醇-0．015 mol·L~(-1)磷酸二氢钾缓冲溶液(pH 3．0)为流动相(35:65),进行HPLC荧光检测分析,测定血浆普卢利沙星活性代谢物浓度经时过程,并计算药动学参数。结果:HPLC测定血浆UFX的色谱峰面积与浓度在0．025～3．00μg·mL~(-1)范围线性关系良好,最低定量限浓度为0．025μg·mL~(-1)。血浆样品分析的回收率、精密度和准确度均良好。受试者单剂量口服普卢利沙星片后与UFX相应的主要药动学参数为C_(max)(1．48±0．44)μg·mL~(-1),T_(max)(0．9±0．8)h,AUC_(0-36h)(6．74±0．96) h·μg·mL~(-1),AUC_(0-∞)(6．97±1．06)h·μg·mL~(-1),t_(1/2)(7．21±1．60)h,MRT(8．44±1．94)h;口服普卢利沙星片达稳态后,C_(max)(1．34±0．41)μg·mL~(-1),T_(max)(0．9±0．4)h,AUC_(0-36h)(8．46±1．43)h·μg·mL~(-1),AUC_(0-∞)(8．61±1．43)h·μg·mL~(-1),t_(1/2)(6．27±0．86)h,MRT(8．38±0．94)h。结论:建立的HPLC荧光测定法专属准确,灵敏度适宜,测得的药动学参数可为普卢利沙星临床用药提供了参考依据。     

冰片对灯盏花素在大鼠体内药动学的影响

目的:观察冰片对灯盏花素在大鼠体内药动学的影响。方法:建立高效液相色谱(HPLC)方法测定大鼠血浆中灯盏乙素的浓度。大鼠尾静脉注射灯盏花素注射液(灯盏乙素24 mg.kg-1)及灯盏花素冰片注射液(灯盏乙素24 mg.kg-1 冰片0.96 mg.kg-1),用HPLC法测定大鼠给药后不同时间血浆灯盏乙素的浓度,BAPP数据处理软件计算药动学参数。结果:灯盏乙素在0.05~60μg.mL-1范围内线性良好(r=0.999 4)。灯盏花素与冰片配伍给药可使灯盏花素中灯盏乙素的药动学参数t1/2α,t1/2β和t1/2γ较单独给药时明显减小[t1/2α:(1.87±0.14)vs(3.46±0.45),P<0.01;t1/2β:(11.18±2.07)vs(14.74±2.89),P<0.05;t1/2γ:(53.31±8.21)vs(161.16±15.48),P<0.01],而K12较单独给药时明显增大[(0.120±0.042)vs(0.039±0.037),P<0.05]。结论:冰片可加快灯盏花素在大鼠体内的分布与消除。     

Conversion of 2,6-diamino-9-(2-hydroxyethoxymethyl)purine to acyclovir as catalyzed by adenosine deaminase

Adenosine deaminase (ADA) was partially purified from several sources using affinity chromatography. These enzymes have the capacity to catalyze the deamination of 2,6-diamino-9-(2-hydroxyethoxymethyl)purine (A134U) to form the antiviral agent acyclovir [9-(2-hydroxyethoxymethyl)guanine]. Their relative substrate efficiencies (Vmax/Km) with A134U (standardized to adenosine = 100) were: dog ADA, 0.092; human ADA, 0.015-0.029; rat ADA, 0.025; calf ADA, 0.016; and Escherichia coli ADA, 0.0003. In addition to having the lowest efficiency with A134U, the bacterial ADA was also distinguished by its lack of binding of the mammalian ADA inhibitor erythro-9-(2-hydroxy-3-nonyl)adenine and by its weak binding to the 9-(p-aminobenzyl)adenine-agarose affinity column. Four minor metabolites of A134U and acyclovir have been reported to be produced in the rat. These compounds are oxidized on either the C-8 position of the ring or the terminal carbon of the side chain. Neither acyclovir nor any of these metabolites produced significant inhibition of calf intestine ADA. The oxidized metabolites containing an N-6 amino group were extremely slow substrates of this enzyme.     

淡豆豉药材的高效液相指纹图谱研究

目的建立淡豆豉药材高效液相色谱指纹图谱(HPLC-FPS),为其质量控制提供依据。方法应用高效液相色谱法(HPLC),利用反相色谱柱:Diamonsil C18(250 mm×4.6 mm,5μm),流动相:乙腈-3%冰乙酸梯度洗脱,流速:1 ml/min,柱温:30℃,检测波长:261 nm,进样量:10μl。结果不同产地淡豆豉在化学成分方面具有明显相似性,可建立淡豆豉的指纹图谱。结论建立的HPLC指纹图谱可用于淡豆豉的质量评价。     

人红细胞衰老过程能量代谢和胞龄依赖性变化研究

采用固定角转头１５０００ｒ／ｍｉｎ、８℃高速离心，将红细胞按胞龄分为少龄、中龄和老龄，分别聚集在离心管上、中、下三层。结果表明，随着红细胞在外周血中走向衰老，其胰岛素结合能力和ＡＴＰ、ＮＡＤ浓度都显著降低。这种变化有３种可能解释：１．成熟红细胞不再有蛋白质合成能力。２．与红细胞整个发育过程中，不断走向适应于担负简单而又特殊的生理功能的趋势有关。３．这种变化很大程度上是人体各种细胞衰老过程机制所决定     

Constituents of Corydalis heterocarpa and their anti-proliferative effects on human cancer cells

Two new coumarins, 1 and 2, along with four known coumarins (3–6) have been isolated from Corydalis heterocarpa. On the basis of spectroscopic and chemical methods, compounds 1 and 2 were elucidated as (2′S,7′S)-O-2-methylbutanoyl-columbianetin and (2′S)-columbianetin-3′-sulfate, respectively. The anti-proliferative activity against human cancer cells of compounds 1–6 isolated from C. heterocarpa was evaluated using a MTT assay and by mRNA expression of several factors related to apoptosis. Among them, compound 2 exerted the more potent anti-proliferative activity compared with the other compounds treated. The potent inhibitory effect of compound 2 was produced by induction of apoptosis through activating Bax, p53 and p21 expressions.     

Chronic treatment with citalopram facilitates the effect of a challenge dose on cortical serotonin output: role of presynaptic 5-HT1A receptors

In animals given citalopram (10 mg/kg) twice daily for 14 days a further dose of 1 mg/kg, administered 24 h after the last dose, markedly increased cortical dialysate serotonin (5-hydroxytryptamine, 5-HT), but had no effect in control animals. The effect on dialysate 5-HT in the dorsal raphe was not increased by the chronic treatment. At 25 μg/kg, 8-hydroxy-2-(di-n-propylamino) tetralin, an agonist at 5-HT_1A receptors, reduced cortical 5-HT output in controls but not in animals treated chronically with citalopram whereas 50 μg/kg reduced 5-HT output in both groups. These findings suggest that somatodendritic 5-HT_1A receptors are desentisized after chronic treatment with citalopram and this results in facilitation of its effect on cortical dialysate 5-HT. These results also agree with the concept that the effect of 5-HT re-uptake inhibitors on increasing 5-HT output in the frontal cortex is attenuated by their simultaneous ability to activate somatodendritic 5-HT_1A receptors via an increase of endogenous 5-HT in the raphe region.     

HPLC法测定西格列羧的含量及有关物质

目的:建立抗2型糖尿病新药西格列羧的含量及有关物质的HPLC测定方法。方法:采用C18柱(150 mm×4．6 mm,5μm),流动相为甲醇-水-四氢呋喃-醋酸(35:35:30:0．5),检测波长为236 nm,流速为1．0 mL·min-1。结果:西格列羧在1.0-200μg·mL-1的浓度范围内,峰面积与浓度呈良好线性关系(r=1．0),回收率RSD小于0．2％,最低检测限为0．48 ng。结论:本方法专属、灵敏、可靠,可用于测定西格列羧的含量和有关物质。     

中国健康志愿者的奥美拉唑及其代谢产物的药代动力学

目的　观察中国人CYP2C19基因型与奥美拉唑羟化代谢的关系。方法　采用高效液相 二极管阵列色谱法测定 2 5名po 2 0mg奥美拉唑胶囊后 2 4h内的奥美拉唑及其主要代谢产物的血药浓度 ,计算药代动力学参数。结果　在 2 5名奥美拉唑药物代谢的志愿受试者中 ,7名是CYP2C19强代谢者〔homoEMS(wt/wt,G1组 )〕 ;12名是CYP2C19中强代谢者〔heteroEMS(wt/m1orwt/m2 ,G2组 )〕 ;6名是CYP2C19弱代谢者〔PMS(m1/m1,G3组 )〕。奥美拉唑在G1,G2和G3组平均清除率分别为 2 2 .9,12 .7和 4 .9mL·h- 1,曲线下面积分别为 1.0 9,1.4 7和4 .87mg·L- 1·h ;G1,G2组的奥美拉唑的代谢动力学与G3组存在显著差别 ,表明奥美拉唑的代谢速率与CYP2C19的基因型有关系。结论　奥美拉唑羟化代谢存在着多态性。基因型为m1/m1的受试者的奥美拉唑羟化代谢明显低于基因型为wt/wt,wt/m1和wt/m2两组受试者     

5'-Methylthioadenosine phosphorylase-L. Substrate activity of 5'-deoxyadenosine with the enzyme from Sarcoma 180 cells

5′-Deoxy-5′-methylthioadenosine phosphorylase (MTA phosphorylase), an enzyme involved in the salvage of adenine moieties from 5′-deoxy-5′-methylthioadenosine (MTA) produced primarily during polyamine biosynthesis, is present in Sarcoma 180 cells (0.0026 ± 0.0002 μM units/mg cytosol protein). 5′-Deoxyadenosine (5′-dAdo), an adenosine analog previously thought not to be metabolizable, has been shown [D. Hunting and J.F. Henderson, Biochem. Pharmac. 27, 2163 (1978)] to have a number of biochemical effects on Ehrlich ascites cells. We have now found that 5′-dAdo is a substrate for the MTA phosphorylase from Sarcoma 180 cells, yielding free adenine and 5-deoxyribose-1-phosphate. The reaction was reversible and totally dependent upon phosphate. Evidence that MTA phosphorylase is responsible for 5′-dAdo phosphorylase activity includes the following: (1) Sarcoma 180 MTA phosphorylase preparations did not show additive rates of adenine production in the presence of saturating concentrations of both 5′-dAdo and MTA; (2) double-reciprocal plots of the rates of adenine formation from 5′-dAdo by Sarcoma 180 enzyme preparations in the presence of MTA displayed a pattern characteristic of alternative, competing substrates; (3) the rate of depletion of 5′-dAdo by Sarcoma 180 preparations was inhibited by the presence of MTA; (4) the K_i value of a competitive inhibitor of Sarcoma 180 MTA phosphorylase, 5′-deoxy-5′-chloroformycin, was the same when either MTA or 5′-dAdo was employed as substrate; and (5) the apparent K_m values of phosphate for both MTA and 5′-dAdo phosphorylase activities were identical (3.5mM). The K_m of Sarcoma 180 MTA phosphorylase for MTA is 4 μM; the K_m for 5′-dAdo is 23 μM (V_max relative to MTA = 180 per cent). Incubation of Sarcoma 180 cells with either 5′-dAdo or MTA caused profound elevations of adenine nucleotides, as well as an inhibition of 5-phosphoribosyl-l-pyrophosphate (PRPP) accumulation. The reaction of 5′-dAdo with MTA phosphorylase to yield free adenine, which is then salvaged to adenine nucleotides, can account for many of the previously reported biochemical effects of 5′-dAdo, such as inhibitions of PRPP accumulation, purine de novo synthesis, and glycolysis that have previously been attributed to the unmetabolized nucleoside. The other product of this reaction, 5-deoxyribose-l-phosphate, may also contribute to these effects.     

Effects of the chiral isomers of erythro- and threo-9-(2-hydroxy-3-nonyl)adenine on purine metabolism in sarcoma 180 cells

The effects of the chiral isomers of erythro- and threo-9-(2-hydroxy-3-nonyl)adenines (EHNA and THNA) on purine metabolism in Sarcoma 180 cells have been determined. At concentrations of 10–80 μM [10- to 1000-fold greater than their K_i values with adenosine deaminase (ADA)], all isomers inhibited purine salvage and biosynthesis de novo. Although (+)-EHNA, the most potent ADA inhibitor, exerted the greatest effects, there was no direct correlation between the potency of ADA inhibition and the secondary effects on purine metabolism, e.g. (+)-EHNA is about 2-fold more inhibitory than (?)-EHNA in blocking purine base incorporation but about 250-fold more potent as an inhibitor of ADA (K_i of (+)-EHNA = 500nM[Bessodes et al., Biochem. Pharmac.31, 879 (1982)]). All the isomers inhibited the incorporation of radiolabeled purine bases (adenine, guanine and hypoxanthine) and nucleosides (guanosine and inosine) into acid-soluble nucleotides and of glycine into 5′-phosphoribosyl-formylglycineamide. Unlike the results of Henderson et al. [Biochem. Pharmac.26, 1967 (1977)] with Ehrlich ascites cells, the incorporation of adenosine into nucleotides was only slightly inhibited in Sarcoma 180 cells. (+)-EHNA did not inhibit the activities of 5-phosphoribosyl-1-pyrophosphate (PRPP) synthetase, purine phosphoribosyltransferases or nucleotide kinases in cell extracts. Accumulation of PRPP was inhibited only under conditions that fostered rapid synthesis.     

The effect of alkylating agents and other drugs on the accumulation of melphalan by murine L1210 leukaemia cells in vitro

The effect of cytotoxic and other drugs on the accumulation of melphalan by L1210 murine leukaemia cells was studied. We have confirmed that uptake is an active process competitively inhibited by l-leucine. In 36 experiments in amino acid-free medium the mean concentration of melphalan taken up was 225 pmoles/10⁶ cells. High pressure liquid Chromatographie analysis showed that the majority of the drug is present as free native melphalan. 1, 3-Bis(2-chloroethyl)-1-nitrosourea (BCNU) was the only drug that stimulated accumulation, but without significant effect on influx or efflux rates. Busulphan, chlorambucil, cyclophosphamide, interferon, methotrexate and prednisolone had no effect on accumulation after 30 min melphalan transport. Adriamycin, CCNU, methyl CCNU, mustine and vincristine all impaired melphalan accumulation as did the non-cytotoxic drugs aminophylline, chlorpromazine and ouabain. Adriamycin, aminophylline, chloropromazine, indomethacin and ouabain all reduced melphalan influx.     

The effects of 8-OH-DPAT on medulllary 5-HT neurons and sympathetic activity in baroreceptor-denervated animals

The effects of the 5HT_1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) on medullary 5-hydroxytryptamine (5-HT) neuronal firing and inferior cardiac sympathetic nerve activity were simultaneously determined in baroreceptor-denervated cats. 5-HT neuronal firing was inhibited by 50% at a 1 μg/kg i.v. dose of 8-OH-DPAT in the baroreceptor-denervated animal. Unit firing was completely inhibited by a 3 μg/kg dose. In contrast, 8-OH-DPAT inhibited inferior cardiac nerve activity between 10 and 100 μg/kg i.v. A similar relationship between the 8-OH-DPAT-induced inhibition of 5-HT unit activity and sympathetic nerve activity was observed in sham-operated control animals. These data suggest that the sympatholytic effects of 8-OH-DPAT cannot be explained on the basis of an autoreceptor effect of the drug.     

Behavioral and biochemical effects of the 5-HT1A receptor agonists flesinoxan and 8-OH-DPAT in the rat.

The 5-HT_1A receptor agonists flesinoxan (0.2–3.2 mg kg⁻¹ s.c.) and 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) (0.025–0.4 mg kg⁻¹ s.c.) produced (1) a dose-dependent facilitation of male rat ejaculatory behavior and (2) characteristic, dose-dependent effects on spontaneous motor activity. Thus, total locomotor activity and rearing activity were decreased. However, forward locomotion and peripheral locomotion were increased relative to the total horizontal activity. Furthermore, (3) 5-HTP accumulation, after inhibition of cerebral decarboxylase, was dose dependency decreased by both compounds in the ventral striatum and in the prefrontal cortex. There was a statistically significant decrease in DOPA accumulation in the ventral striatum after administration of a high dose of flesinoxan (3.2 mg kg⁻¹), and a tendency for 8-OH-DPAT to produce the same effect. The efficacy of the compounds to affect male rat sexual behavior, spontaneous motor activity in the open-field and forebrain 5-HT synthesis was approximately the same, whereas flesinoxan was about an order of magnitude less potent than 8-OH-DPAT.     

Determination of 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG) in biological fluids by reversed-phase high pressure liquid chromatography

In this article a simple method for the determination of 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG) in biological fluids is presented, based on reversed-phase ion-pair HPLC with UV detection at 254 nm. No complicated extraction procedure is needed. The stationary phase consists of a reversed-phase C18 stainless steel column and the mobile phase of 0.005M sodium acetate and 0.0025M pentanesulfonic acid sodium salt (PIC-B5) as an ion-pair reagent in water (pH 6.5). DHPG is a new antiviral drug in research of the treatment of cytomegalovirus infections. As a pilot study serum and urine samples of a few patients were investigated to gain an impression of the therapeutic range of DHPG. The method is suitable for routine assay of DHPG.