Oxidation of recombinant methionyl human granulocyte colony stimulating factor

The oxidation of methionine residues in recombinant methionyl human granulocyte colony stimulating factor with hydrogen peroxide has been investigated. Kinetic data of the oxidation were obtained by using reversed phase-high performance liquid chromatography. The stability-indicating capability of this system was confirmed with micellar electrokinetic capillary chromatography. In the pH range 1.9–7.5, the k_obs value for the oxidation process is constant. Above pH 7.5, k_obs tends to increase with increasing pH. In the pH range 1.9–11.8, four oxidation products were detected in RP-HPLC. Mass spectrometric analysis revealed that one mono-, one di- and two trioxidation products were formed. Using the cyanogen bromide cleavage method the nature of the oxidation products was determined. The mono-oxidation product is the protein with Met¹²¹ oxidized, while the dioxidation product has oxidized Met¹²¹ and Met¹²⁶ residues. The trioxidation products are the proteins with Met¹²¹, Met¹²⁶ and Met¹³⁷ or Met⁰, Met¹²¹ and Met¹²⁶ oxidized.     

重组人粒细胞集落刺激因子的高效液相色谱分析

目的：测定重组人粒细胞集落刺激因子（ｒｈＧ－ＣＳＦ）的蛋白浓度、分子量及纯度。方法：反相高效液相色谱（ＲＰ－ＨＰＬＣ）法及高效体积排阻色谱法（ＳＥＣ）。结果：蛋白浓度测定方法可靠,平均回收率为１００．１７％,ＲＳＤ＝０．８％,重现性好,日内ＲＳＤ＝０．７％,日间ＲＳＤ＝１．１％,且与福林－酚法（Ｌｏｗｒｙ法）测得结果无显著差异。样品无需处理,可直接上样,同时可得到样品的纯度数据。ＳＥＣ法测得分子量     

重组人粒细胞集落刺激因子致急性肾衰竭

1名54岁男性失代偿期肝硬化患者,皮下注射重组人粒细胞集落刺激因子(rhG-CSF)200μg,1次/d。用药后第2天患者出现尿色变深,第4天出现眼睑水肿,肉眼血尿、少尿等症状。BUN由4.8mmol/L升至7.9mmol/L(最高13.9mmol/L),Cr由113μmol/L升至154μmol/L(最高308μmol/L)。停用rhG-CSF,给予还原型谷胱甘肽、硫普罗宁、呋塞米等对症支持治疗。2周后肾功能恢复正常。     

Pharmacokinetics of recombinant human granulocyte macrophage colony-stimulating factor in Macaca mulata

目的：研究重组人粒细胞巨噬细胞集落刺激因子（ｒｈＧＭＣＳＦ）在恒河猴体内的药物动力学．方法：用酶连接免疫吸附测定法检测血浆中ｒｈＧＭＣＳＦ的含量．结果：ｉｖｒｈＧＭＣＳＦ后血药浓度时间曲线符合三房室模型．第１，２和３相的Ｔ１２分别为００５－００７ｈ，０１４－０５８ｈ和１４－４１ｈ．ＡＵＣ随剂量成比例增加．ｉｖ高剂量和低剂量的Ｃｌ和Ｋ１０都相似．ｓｃｒｈＧＭＣＳＦ后血药浓度的峰值为０９３±０１６μｇ·Ｌ－１，达峰时间为２６５±０１４ｈ，生物利用度为０６１．结论：恒河猴ｒｈＧＭＣＳＦ药物动力学数据为临床试验提供有用参考．     

Pharmacokinetic and pharmacodynamic analysis of subcutaneous recombinant human granulocyte colony stimulating factor (lenograstim) administration.

A total of 72 adult healthy volunteers were administered 1 microgram/kg of rhG-CSF. There was no correlation between Cmax and an increase in peripheral neutrophil count, and there was a negative correlation between AUC and this increase. The mechanism of this is probably based on the correlation between the elimination rate constant (ke) and neutrophil increase. The ke probably has a close relationship with uptake by neutrophil and its progenitor via the G-CSF receptor. An individual with higher ke should therefore show a greater increase in neutrophil count. Therefore, AUC is proportional to the rhG-CSF remainder, that is, the proportion that is not consumed in the course of increasing the neutrophil count. In such a situation, the bioavailability calculated from the AUC is unlikely to indicate the absorbed amount. The authors also analyzed the pharmacokinetics using a two-compartment model with zero-order absorption and first-order elimination. This model was sufficient to obtain a good curve fit, and this demonstrates that the absorption process is not a first-order but a zero-order process. Therefore, there might be an upper limit to the rhG-CSF transfer rate from subcutaneous tissue to blood.     

聚乙二醇化重组人粒细胞集落刺激因子大鼠和Beagle犬的免疫原性

目的：在进行聚乙二醇化重组人粒细胞集落刺激因子（PEG30-rhG-CSF）大鼠和Beagle犬重复给药毒性试验时,观察给药后动物血清中抗PEG30-rhG-CSF抗体的产生和抗体的中和活性,为非临床安全性评价的确切性以及临床给药周期提供依据。方法：大鼠分为赋形剂对照组、PEG30-rhG-CSF0.75、3.0、12mg/kg组,sc给药,隔日1次,连续2周;Beagle犬分为赋形剂对照组、PEG30-rhG-CSF0.25、1.0和4.0mg/kg,sc,每周1次,连续4周。采用ELISA法检测动物血清中抗PEG30-rhG-CSF的抗体,采用NFS-60细胞/MTT比色法检测抗体的中和活性。结果：大鼠在给药期和恢复期各剂量组动物血清中均未检测到抗PEG30-rhG-CSF的结合抗体。Beagle犬在给药的第1周和第2周,未检测到结合抗体,但在第4周时,低、中和高3个剂量组各有5只（5/6）的动物血清中检测到结合抗体,而抗体滴度与剂量无明显相关性。恢复4周后,仅高剂量组1只（1/2）动物出现抗体,且抗体滴度呈下降趋势。另外,在给药期和恢复期,血清中所产生的抗体均无中和PEG30-rhG-CSF的活性。结论：大鼠重复给予PEG30-rhG-CSF的毒性试验中,所有动物血清中均未检测到结合抗体和中和抗体;Beagle犬用药组的绝大部分动物血清中出现抗PEG30-rhG-CSF的抗体,但所产生抗体无中和活性。     

Outline of clinical studies on recombinant human granulocyte colony stimulating factor (KRN 8601) in Japan.

In phase I studies of KRN 8601, single administration and six-day consecutive administration studies were conducted in healthy male adults using intravenous drip infusion and subcutaneous administration. Safety and tolerance to KRN 8601 were confirmed and a dose-related increase of neutrophil counts by KRN 8601 was observed. In an early phase II study, the safety and tolerance to KRN 8601 in cases of neutropenia following cancer chemotherapy were shown at doses of 25-800 micrograms/m2 and an improvement of neutropenia was seen at doses of more than 50 micrograms/m2. In a phase II study, the optimal dose was investigated for subcutaneous administration and intravenous drip infusion in cases of neutropenia induced by chemotherapy for malignant lymphomas. The optimal dose was 75 micrograms/body (about 50 micrograms/m2) for subcutaneous administration and 100-200 micrograms/m2 for intravenous drip infusion. In a phase III study, a double-blind prospective randomized trial comparing KRN 8601 with an inactive placebo against malignant lymphomas was performed and the inhibitory, improvement and recovery-promoting effects of KRN 8601 (75 micrograms/body, sc) on neutropenia were demonstrated.     

重组人粒细胞集落刺激因子宿主蛋白质含量的测定

目的根据重组人粒细胞集落刺激因子 (rhG CSF)的生产工艺 ,建立宿主蛋白质 (HCP)含量的测定方法。方法用不含rhG CSF基因的空质粒转染E .coli宿主 (BL2 1) ,按rhG CSF的生产工艺进行发酵、纯化、制备HCP。常规法免疫家兔 ,制备抗HCP多抗血清 ,经纯化后 ,过碘酸钠法标记辣根过氧化物酶 (HRP) ,建立双抗夹心酶标记免疫吸附测定 (ELISA)法测定HCP在rhG CSF原液中的含量。结果所建HCP测定方法能够测定 7.8～ 2 5 0ng/ml范围内的HCP。结论重组蛋白质药物宿主蛋白质含量测定应依据不同的工艺 ,制定不同的方法。     

基因重组人粒细胞集落刺激因子在骨肉瘤大剂量综合化疗中的临床应用研究

目的　研究基因重组人粒细胞集落刺激因子 (rhG CSF)对骨肉瘤大剂量综合化疗所致白细胞和抗中性粒细胞计数 (ANC)减少的防治作用及毒副反应。方法　将 5 8例患者按经济情况分为研究组及对照组 ,均采用相同的化疗方案 ,研究组于化疗后 72h给予皮下注射rhG CSF 15 0 μg ,连用 5～ 7d。对照组化疗后给予常规升白细胞药物。结果　rhG CSF可明显减轻化疗所致白细胞和ANC的下降程度 ,缩短白细胞和ANC降至正常值以下的持续时间 ,促进白细胞和ANC的早日恢复 ,降低化疗延迟率及延迟时间 ,提高化疗完成率。rhG CSF副作用较轻 ,且可以耐受。结论　rhG CSF可有效防治白细胞和ANC的减少 ,提高化疗完成率 ,是防止化疗所致骨髓抑制的有效方法     

Albugranin,a recombinant human granulocyte colony stimulating factor (G-CSF) genetically fused to recombinant human albumin induces prolonged myelopoietic effects in mice and monkeys

Purpose. Albugranin^TM fusion protein is recombinant granulocyte colony stimulating factor (rG-CSF) genetically fused at its N-terminus to the C-terminus of recombinant serum human albumin and is expected to have a relatively long half-life compared with rG-CSF alone. In this study, the pharmacodynamics and pharmacokinetics of Albugranin were evaluated in BDF1 mice and cynomolgus monkeys. Methods. Single doses of Albugranin (0.25-5 mg/kg) or Filgrastim (methionyl rG-CSF, 0.25, or 1.25 mg/kg) were administered subcutaneously (SC) to mice and multiple doses of Albugranin (25-100 g/kg every 4 or 7 days) or Filgrastim (5 g/kg daily) were administered SC for 14 days to monkeys for hematologic evaluation. For pharmacokinetics studies, mice were injected intravenously (IV) or SC with single doses of Albugranin (0.25-1.25 mg/kg) or Filgrastim (0.25 mg/kg) and monkeys were injected SC with multiple doses of Albugranin (100-1000 g/kg once weekly for 5 weeks). Plasma levels of Albugranin and Filgrastim were measured by enzyme-linked immunosorbent assay. Results. In mice, administration of Albugranin effectively increased the number of peripheral granulocytes and mobilized hematopoietic progenitor cells for up to 5 days. The magnitude and duration of this effect were dose-dependent. In contrast, administration of Filgrastim resulted in a small increase in both cell types on day 1 only. Albugranin administered to cynomolgus monkeys caused an increase in peripheral neutrophils, with a less prominent increase in peripheral monocytes. Albugranin-induced neutrophilia peaked 24 h following each dose administration. Administration of Filgrastim daily in monkeys resulted in moderate increases in neutrophils that were maximal on days 8-12 during the course of treatment. Compared with Filgrastim, Albugranin had a longer terminal half-life (t_1/2,term), and mean residence time (MRT), and slower clearance (CL/F) in mice. The t_1/2,term, MRT, and CL/F of Albugranin following SC administration to BDF1 mice were 5.6-5.7 h, 16.7-20.7 h, and 6.37-12.2 mL/h/kg, respectively, compared with 2.54 h, 4.9 h, and 164 mL/h/kg, respectively for Filgrastim. In cynomolgus monkeys, the corresponding values of t_1/2,term, MRT, and CL/F for Albugranin were 7.73-13.3 h, 19.4-27.3 h, and 7.90-27.5 mL/h/kg, respectively, for doses of 100-1000 g/kg. An exposure-response relationship that could be empirically described with a simple E_max model with baseline was found between day 15 absolute neutrophil count and area under the curve following the first dose in cynomolgus monkeys. Conclusion. The sustained activity of Albugranin in mice and monkeys demonstrated in these studies suggests that this agent could be given less frequently than Filgrastim to achieve similar therapeutic effects in patients.     

基于倾向性评分匹配的聚乙二醇化重组人粒细胞刺激因子预防宫颈癌同步放化疗中性粒细胞减少症效果分析

目的 探讨聚乙二醇化重组人粒细胞刺激因子（PEG-rhG-CSF）在宫颈癌同步放化疗中预防中性粒细胞减少的疗效及安全性。方法 按单中心单臂历史对照研究,选取2019年6月—2021年1月32例符合入排条件,拟行同步放化疗的宫颈癌患者组成试验组,同时搜集2017年1月—2019年6月行同步放化疗且符合对照组治疗方案的宫颈癌患者病历资料,按1∶1倾向性评分匹配法组成对照组。试验组为前瞻性入组,患者第1次化疗给药结束24 h后sc聚乙二醇化重组人粒细胞刺激因子注射液,每次6 mg,每化疗周期1次,共给药2次。若使用PEG-rhG-CSF预防后,中性粒细胞计数（ANC）仍＜1.0×109·L^-1,可给予短效重组人粒细胞刺激因子注射液5 μg·kg^-1,sc给药,直至ANC≥2.0×109·L^-1。对照组患者采用倾向性评分匹配既往同步放化疗的宫颈癌患者,初始不给予PEG-rhG-CSF,当患者出现ANC＜1.0×109·L^-1后sc给予重组人粒细胞刺激因子注射液,5 μg·kg^-1,持续使用,每日1次,直至ANC≥2.0×109·L^-1。记录两组患者3、4度中性粒细胞减少症发生率及持续时间;粒细胞减少性发热（FN）发生率;中性粒细胞减少导致化疗延迟和放疗中断发生率;评价两组不良反应情况,包括乏力、骨关节痛、发热、皮肤黏膜反应、恶心及呕吐等。结果 试验组与对照组各32例,两组基线均衡。试验组中性粒细胞减少症发生率59.4%,对照组为84.3%,试验组显著低于对照组（P＜0.05）;3、4度中性粒细胞减少症发生率试验组为31.3%（10/32）,对照组为56.3%（18/32）,试验组显著低于对照组（P＜0.05）。3度中性粒细胞减少持续时间,试验组中位时间为0 d（0～29 d）,显著低于对照组2 d（0～38 d）;4度中性粒细胞减少持续时间,试验组中位时间为0 d（0～22 d）,显著低于对照组1 d（0～38 d）。两组FN发生率比较无明显差异,但试验组有降低趋势。试验组放疗中断1例,对照组2例,两组比较无显著统计学差异（P＞0.05）;试验组延迟化疗出现4例（12.5%）,对照组出现12例（37.5%）,两组比较差异显著（P＜0.05）。两组不良反应主要包括乏力、骨关节痛、发热、皮肤黏膜反应、恶心及呕吐等,组间比较,差异不显著（P＞0.05）。结论 宫颈癌同步放化疗过程中预防性应用PEG-rhG-CSF具有安全性、有效性,可以降低中性粒细胞减少症发生率,减少FN和不良反应,避免治疗延迟。     

Effects of pH, temperature, and sucrose on benzyl alcohol-induced aggregation of recombinant human granulocyte colony stimulating factor

Antimicrobial preservatives (e.g., benzyl alcohol), which are required in multidose formulations, can induce protein aggregation. In this study, the mechanism of benzyl alcohol-induced aggregation of recombinant human granulocyte colony-stimulating factor (rhGCSF) was investigated by determining the effects of temperature, pH, and sucrose on this process. rhGCSF was incubated at 25 and 37 degrees C and at pH 7.0 (phosphate-buffered saline, PBS) and pH 3.5 (HCl). Benzyl alcohol (0.9% w/v) accelerated aggregation of rhGCSF at pH 7.0, an effect that was much greater at 37 degrees C than at 25 degrees C and partially counteracted by 1.0 M sucrose. At pH 3.5, benzyl alcohol did not induce aggregation of rhGCSF. Spectroscopic studies showed that 0.9% benzyl alcohol altered the tertiary structure of rhGCSF at both pH, without detectably altering secondary structure. Structural perturbation was greater at 37 degrees C than at 25 degrees C. At both pH 7.0 and 3.5, the hydrogen-deuterium (H-D) exchange rate for rhGCSF was increased by 0.9% benzyl alcohol. Sucrose (1.0 M) partially counteracted the benzyl alcohol-induced perturbation of tertiary structure and the increase in H-D exchange rate. Thus, benzyl alcohol accelerates aggregation of rhGCSF at pH 7.0, because it favors partially unfolded aggregation-prone conformations of the protein. Sucrose partially counteracts benzyl alcohol-induced rhGCSF aggregation by shifting the molecular population away from these species and towards more compact conformations. We postulate that the absence of aggregation at pH 3.5, even with benzyl alcohol-induced structural perturbation, is due to the unfavorable energetics of intermolecular interactions (i.e., colloidal stability) between rhGCSF molecules at this pH.     

Sustained in vivo activity of recombinant bovine granulocyte colony stimulating factor (rbG-CSF) using HEPES buffer

The purpose of this study was to develop a long-acting injectable formulation of bG-CSF for veterinary use. However, in order to achieve sustained in vivo activity it was first necessary to stabilize the protein at the injection site. Preformulation studies, as well as literature, suggest that bG-CSF aggregates at neutral pH ranges (i.e., pH 6-8) and at temperatures of approximately 40 degrees C. Therefore, bG-CSF will not retain its activity for an extended period of time at the injection site. During this study we determined that HEPES buffer has a very significant impact on protein stability as well as on biological performance. Recombinant bovine granulocyte colony stimulating factor (rbG-CSF) was formulated in 1 M HEPES buffer for subcutaneous injection into cows. bG-CSF formulated in 1 M HEPES buffer resulted in sustained in vivo activity of bG-CSF compared to the "control" formulation (control formulation: 5% mannitol, 10 mM acetate buffer, 0.004% tween-80, pH 4). White blood cell (WBC) count was used as a marker to evaluate in vivo activity of the formulation. WBC numbers remained above a threshold value for only 24-30 h for the control formula. However, when bG-CSF was formulated in 1 M HEPES, the WBC remained above threshold for 3 days or 72 h. Formulating bG-CSF in 1 M HEPES at pH 7.5 also resulted in greater solution stability. This was surprising since bG-CSF is intrinsically not stable at neutral pH. The effect of 1 M HEPES on the T(M) (temperature at maximum heat flow on calorimetry scan) of bG-CSF was determined by microcalorimetry. In the absence of 1 M HEPES buffer the T(M) was 48 degrees C (onset approximately 40 degrees C), while bG-CSF formulated in 1 M HEPES buffer has a T(M) of 59 degrees C (onset approximately 50 degrees C). Similar organic buffers, such as MOPS, HEPPS, TES, and tricine, also resulted in improved solution stability as well as in sustained in vivo activity. The dramatic effect of these buffers on stability and biological performance of bG-CSF is not well understood. One hypothesis is that the electrostatic interaction between the zwitterionic form of these buffers and bG-CSF provides stabilization against denaturation.     

重组人粒细胞刺激因子致急性嗜酸性粒细胞肺炎的病例分析

目的 探讨临床药师在识别药物不良反应（ADR）中的作用,提醒临床注意重组人粒细胞刺激因子引起药物性肺损伤的可能,并与感染性疾病相鉴别。方法 对1例粒细胞降低患者因使用重组人粒细胞刺激因子出现急性肺损伤的病例进行分析,评估重组人粒细胞刺激因子与急性嗜酸性粒细胞肺炎的关联并分析可能的机制。同时,临床药师对患者病情进行评估和判断,提出相应的治疗建议。结果 患者使用重组人粒细胞刺激因子后嗜酸性粒细胞增高,双肺炎症加重,抗感染治疗效果不佳,考虑为重组人粒细胞刺激因子相关嗜酸性粒细胞肺炎,及时停用抗感染及抗病毒药物,并予糖皮质激素治疗后,患者肺部症状好转,嗜酸性粒细胞恢复正常。结论 重组人粒细胞刺激因子可引起罕见嗜酸性粒细胞肺炎,临床药师参与临床治疗有助于提高对药源性疾病的识别和管理,从而调整治疗方向,保证临床治疗成功。     

重组人粒细胞巨噬细胞集落刺激因子凝胶剂治疗溃疡药效学研究

目的观察重组人粒细胞巨噬细胞集落刺激因子(gm-csf)凝胶剂治疗溃疡的药效。方法在豚鼠背部造溃疡模型,将凝胶剂外涂于豚鼠背部的溃疡处,不同时间内考察gm-csf凝胶剂对溃疡的药效。结果gm-csf凝胶剂组及gm-csf原液组同盐水组、基质组比较,溃疡面积明显缩小,有显著差异。结论gm-csf凝胶剂对溃疡有明显的治疗作用。     

Quantitative bioanalysis of enantiomeric drugs using capillary electrophoresis and electrospray mass spectrometry

A novel assay method for an enantiomeric pair of drugs has been developed using a combination of capillary electrophoresis and electrospray tandem mass spectrometry connected with a homemade interface. Accurate quantification was demonstrated in plasma from 0.25 to 50 microg/ml. A liquid-liquid sample preparation technique allowed improvement in the quantitation limit to 10 ng/ml. Variables for the enantiomeric separation, including chiral selective reagent, organic solvents, buffer and acid concentration as well as injection technique, were optimized. This assay proved adequate for analysis of neat, spiked plasma, and plasma from a pharmacological study of the drug enantiomers.     

A method for routine analysis of recombinant immunoglobulins (rIgGs) by capillary isoelectric focusing (cIEF)

A capillary isoelectric focusing (cIEF) method was developed for routine analysis of recombinant immunoglobulins (rlgGs). The cIEF method used a dimethyl siloxane-coated capillary and a separation matrix of 2% ampholytes in 0.4% methylcellulose (MC). The rIgGs, and internal pI marker protein standards, were mixed with carrier ampholyte in MC, focused using high voltage, and then the protein bands were mobilized past a UV detector by simultaneous application of low pressure and voltage. Qualitatively and quantitatively equivalent rIgG focusing profiles were obtained via cIEF and gel-based IEF, with individual isoform peak area percentages and calculated peak pI values being comparable for the same samples. Linear relationships were obtained for peak area response versus sample concentration, and for the pI gradient developed between the internal pI marker standards. The relative standard deviation (RSD) in rIgG peak areas was less than 2% intra-day and less than 8% inter-day (72 h). The RSD for the mobilization times of rIgG peaks was less than 1% intra-day and less than 3% inter-day (72 h). There was no observed decrease in the performance of the capillary over 150 analyses. cIEF offers several important advantages over gel IEF, e.g. direct, quantitative detection of proteins by intrinsic UV absorbance at 280 nm, rapid analyses ( < or = 30 min), capability of automation, and one-step, electronic data analysis and archival. These data demonstrate the superiority of the cIEF method for routine analysis of rIgGs.     

重组人粒细胞集落刺激因子注射液动员外周血干细胞10例

目的 :探讨重组人粒细胞集落刺激因子(rhG CSF)注射液动员外周血造血干细胞 (PBSC)的效果。方法 :对 6例恶性血液病病人 ,1d内静脉注射长春新碱 1～ 2mg·m- 2 及环磷酰胺 4～ 7g·m- 2 (分 4次 ,间隔 4h) ,外周血白细胞降至 1×10 9·L- 1以下时 ,加rhG CSF 6～ 8μg·kg- 1,皮下注射 ,qd× 5～ 7d ;对 4例健康供者在采集PBSC前 5d予rhG CSF 6～ 8μg·kg- 1,皮下注射 ,qd× 5d。白细胞升至 10× 10 9·L- 1以上时采集PSBC ,并进行CD+ 34 及粒 巨噬细胞集落形成单位 (CFU GM )检测。结果 :一次收集单个核细胞计数 (3.9±s 1.7)×10 8·kg- 1;CD+ 34 (4 .8± 2 .3)× 10 8·kg- 1;粒 巨噬细胞集落形成单位 (5± 3)× 10 4 ·kg- 1。未出现严重不良反应。结论 :rhG CSF无论对病人自体还是对健康供者均能安全、高效地动员PBSC ,满足移植所需要。     

电喷雾离子化多级质谱解析环孢菌素结构

应用电喷雾离子化多级质谱法分析四种环孢菌素同系物，并对它们的裂解规律进行分析归纳。在电喷雾离子化多级质谱条件下，环孢菌素先形成N端加质子的[M＋H]^＋分子离子，然后沿肽链的酰胺键发生断裂，产生相应的碎片离子，开环裂解主要发生在2和3位、1和11位以及5位和6位氨基酸残基之间。这一裂解规律可应用于环孢菌素类化合物的快速结构鉴定。     

Impurity profiling of pholcodine by liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS)

Previously, a dimorpholinoethyl pholcodine manufacturing impurity was reported to be present in some samples of pholcodine. Apart from this impurity and morphine, other unknown impurities were detected in all the samples analysed by HPLC and micellar electrokinetic capillary chromatography. In this study, liquid chromatography mass spectrometry (LC-MS) analysis of samples of pholcodine showed that two of the previously unidentified compounds had mass spectra with molecular ions which differed from pholcodine by 16 amu. From this observation and other experimental data it was concluded that they are hydroxy derivatives of pholcodine. 10-S-hydroxy-pholcodine, which was synthesized by the oxidation of pholcodine with chromic acid, had the same chromatographic properties as one of these compounds. An early eluting compound in the LC-MS chromatograms of pholcodine was identified as pholcodine-N-oxide by matching chromatographic and mass spectral data of a synthesized pholcodine-N-oxide standard. The reaction of pholcodine with m-chloroperoxybenzoic acid not only produced the mono N-oxide, but also pholcodine-di-N,N'-oxide.