对乙酰氨基酚缓释制剂的安全性研究进展

近年来,欧盟因为对乙酰氨基酚缓释制剂的安全性问题已经暂停其在欧盟国家的销售,目前国内对于对乙酰氨基酚缓释制剂的安全性罕见报道。结合对乙酰氨基酚缓释制剂的发展历史,对正常剂量和过量使用对乙酰氨基酚缓释制剂、曲马多-对乙酰氨基酚复方缓释制剂的安全性和药动学参数等方面进行详细论述,为含对乙酰氨基酚的缓释制剂的安全性评价和合理应用提供参考。     

对乙酰氨基酚非pH依赖性缓释片的处方优化

目的:设计及优化非pH依赖性缓释片处方.方法:以对乙酰氨基酚为模型药物,设计不同配比的海藻酸钠和壳聚糖为混合骨架的缓释片处方,测定各处方在 0.1 mol·L-1盐酸和pH 6.8磷酸盐缓冲液中的释放度,采用多指标同步优化筛选处方.结果:优化的乙酰氨基酚缓释片处方含壳聚糖 85 mg、海藻酸钠 135 mg 时,呈现良好的体外非pH依赖性释放特征.结论:采用海藻酸钠和壳聚糖混合骨架易制得非pH依赖性缓释片,且方法简单、成本低,具有较高的实用价值.     

Reported ingested dose of paracetamol as a predictor of risk following paracetamol overdose

Purpose

To evaluate reported ingested dose of paracetamol as a risk assessment tool in acute paracetamol overdose.

Methods

Data was retrospectively obtained from a clinical toxicology database linked to one Australian and two United Kingdom hospitals. Plasma paracetamol concentrations (PPCs) of adult patients presenting with acute single ingestion, non-staggered paracetamol deliberate self-poisoning between 2006 and 2012 were recorded and plotted on a treatment nomogram to determine accuracy of reported dose ingested as an indicator for antidotal treatment. PPC plotted on a treatment nomogram with a line intersecting a 4-h concentration of 100 mg/L [667 μmol/L] was considered an indication for antidotal treatment in the UK; the corresponding Australasian population utilised a line intersecting 150 mg/L [1000 μmol/L].

Results

Of 1246 patients, 65.7 % were female and 88 % were from the UK. Fifty-two percent of patients reporting ingestion of ≥8 g paracetamol had a PPC above the 100 mg/L treatment line; PPV 52 % [95 % confidence interval (CI) 49 %, 55 %], sensitivity 81 % [95 %CI 78 %, 85 %]. Forty-four of patients reporting percent ingestion of ≥10 g had a PPC above the 150 mg/L treatment line; PPV 44 % [95 % CI 41 %, 49 %], sensitivity 85 % [95 % CI 78 %, 89 %], 72 % of patients reporting ingestion of ≥16 g had a PPC above the 100 mg/L treatment line; PPV 72 % [95% CI 67 %, 77 %], sensitivity 50 % [95 % CI 45 %, 54 %]. Overall, there was moderate correlation (R?=?0.58) between reported paracetamol dose ingested and extrapolated 4-h PPC.

Conclusions

There is a positive correlation between reported ingested dose of paracetamol and subsequent chance of a PPC being above a defined treatment line; however, ingested dose of paracetamol alone is a poor risk assessment tool in accurately determining need for treatment with an antidote.     

The use of hair analysis to document a cocaine overdose following a sustained survival period before death

Hair analysis for cocaine was used in the investigation of a case of accidental cocaine poisoning. A 25-year-old man consumed an entire bottle of Pony Malta, an imported Colombian soft drink. Unbeknownst to him, the 6.2-oz bottle contained a large quantity of cocaine. It was subsequently discovered that this bottle was one of 45 recovered that contained cocaine as part of a smuggling scheme. The subject was hospitalized for acute cocaine intoxication but died 24 days later. The admission blood contained 2.3 mg/L of cocaine and 4.5 mg/L of benzoylecgonine. Subsequent segmental analysis by MS/MS of hair samples taken at the autopsy revealed a peak cocaine concentration in the segment corresponding to the time he ingested the tainted beverage. The use of hair analysis as an adjunct to traditional analytical techniques may help document drug use history and is especially useful in situations have blood and urine specimens have not been collected in a timely fashion.     

氯酚伪麻缓释片治疗普通感冒和流行性感冒的疗效和安全性

目的评价氯酚伪麻缓释片(抗感冒药)治疗普通感冒和流行性感冒的安全性和有效性。方法用多中心、随机、双盲、平行对照临床试验,试验组(n=118)给予氯酚伪麻缓释片,对照组(n=119)给予双扑伪麻片。结果试验组的临床症状改善率不低于对照组(P<0.05),试验前后2组临床症状总积分均无明显差别(P>0.05);试验组和对照组的总有效率分别为96.33%和96.36%(P>0.05)。试验组和对照组的药物不良反应发生率分别为7.02%和11.82%(P>0.05)。结论氯酚伪麻缓释片治疗普通感冒和流行性感冒具有明显疗效和安全性。     

对乙酰氨基酚缓释干混悬剂中对氨基酚限量的控制

目的建立高效液相色谱法测定对乙酰氨基酚缓释干混悬剂中对氨基酚含量的方法。方法采用Hypersil C18（4．6mm×250mm,5um）色谱柱;流动相：0．01mol·L^-1戊烷磺酸钠甲醇溶液．甲酸-水（15：0．4：85）;流速：1．0mL·min^-1;检测波长为272nm;进样量20uL。结果对氨基酚浓度在2．0～20．0ug·mL^-1范周内与峰面积呈良好的线性关系,r=0．9995。对氨基酚与对乙酰氨基酚能完全分离。结论本方法简便、准确、专属性强。可用于对乙酰氨基酚缓释干混悬剂的质量控制。     

Management of paracetamol overdose: current controversies.

Paracetamol (acetaminophen) is one of the most frequently used analgesics, and is the most commonly used substance in self-poisoning in the US and UK. Paracetamol toxicity is manifested primarily in the liver. Treatment with N-acetyl-cysteine (NAC), if started within 10 hours from ingestion, can prevent hepatic damage in most cases. Pharmacokinetic data relating plasma paracetamol concentration to time after ingestion have been used to generate a 'probable hepatoxicity line' to predict which cases of paracetamol overdose will result in hepatotoxicity and should be treated with NAC. However, later studies use a 25% lower line as their 'possible hepatotoxicity line'. Although adopting the original line may save considerable resources, further studies are needed to determine whether such an approach is safe. On the basis of the metabolism of paracetamol, several risk factors for paracetamol toxicity have been proposed. These risk factors include long term alcohol (ethanol) ingestion, fasting and treatment with drugs that induce the cytochrome P450 2E1 enzyme system. Although some studies have suggested that these risk factors may be associated with worse prognosis, the data are inconclusive. However, until further evidence is available, we suggest that the lower line should be used when risk factors are present. In Canada and the UK, the intravenous regimen for NAC is used almost exclusively; in the US, an oral regimen is used. Both regimens have been shown to be effective. There is no large scale study with direct comparison between these 2 therapeutic protocols and controversy still exists as to which regimen is superior. During the last few years there has been an increase in the number of reports of liver failure associated with prolonged paracetamol administration for therapeutic reasons. The true incidence of this phenomenon is not known. We suggest testing liver enzyme levels if a child has received more than 75 mg/kg/day of paracetamol for more than 24 hours during febrile illness, and to treat with NAC when transaminase levels are elevated. Paracetamol overdose during pregnancy should be treated with either oral or intravenous NAC according to the regular protocols in order to prevent maternal, and potentially fetal, toxicity. Unless severe maternal toxicity develops, paracetamol overdose does not appear to increase the risk for adverse pregnancy outcome.     

Analgesic efficacy of immediate and sustained release paracetamol and plasma concentration of paracetamol. Double blind,placebo-controlled evaluation using painful laser stimulation

Summary The analgesic efficacy of single doses of immediate release paracetamol 500 mg and 1000 mg, sustained release paracetamol 2000 mg, and placebo was evaluated over a 12 h period in 10 healthy volunteers. The efficacy was related to the concurrent plasma concentrations of paracetamol. Experimental pain was induced by brief cutaneous application of argon laser pulses, and the analgesic effect was assessed as change in pricking pain threshold.Both 0.5 g and 1.0 g immediate release paracetamol had an analgesic effect superior to that of placebo from 1 to 5 h after administration. Peak analgesia was reached after 2 h. No difference was found in the analgesic effect of the two dosages. Sustained release paracetamol was not significantly superior to placebo at any time. The plasma concentration of paracetamol had peaked in the 1 h sample after of the immediate release tablet. The peak plasma concentration was reached 3–4 h after 2.0 g sustained release paracetamol.It is not known why the sustained release formulation did not produce any detectable analgesia. It is proposed, that the rate of increase in the plasma concentration of paracetamol might be important in the alleviation of acute (laser-induced) pain.     

An alteration in the liver microsomal membrane of the rat following paracetamol overdose

Fluorescence polarization of dansyl chloride covalently labelled microsomal membranes revealed an alteration in rat liver microsomal membranes following as a consequence of a paracetamol overdose. This suggests that dansyl chloride would be a useful probe in the study of the effects of paracetamol on microsomal membranes.     

Nabumetone: therapeutic use and safety profile in the management of osteoarthritis and rheumatoid arthritis

Nabumetone is a nonsteroidal anti-inflammatory prodrug, which exerts its pharmacological effects via the metabolite 6-methoxy-2-naphthylacetic acid (6-MNA). Nabumetone itself is non-acidic and, following absorption, it undergoes extensive first-pass metabolism to form the main circulating active metabolite (6-MNA) which is a much more potent inhibitor of preferentially cyclo-oxygenase (COX)-2. The three major metabolic pathways of nabumetone are O-demethylation, reduction of the ketone to an alcohol, and an oxidative cleavage of the side-chain occurs to yield acetic acid derivatives. Essentially no unchanged nabumetone and < 1% of the major 6-MNA metabolite are excreted unchanged in the urine from which 80% of the dose can be recovered and another 10% in faeces. Nabumetone is clinically used mainly for the management of patients with osteoarthritis (OA) or rheumatoid arthritis (RA) to reduce pain and inflammation. The clinical efficacy of nabumetone has also been evaluated in patients with ankylosing spondylitis, soft tissue injuries and juvenile RA. The optimum oral dosage of nabumetone for OA patients is 1 g once daily, which is well tolerated. The therapeutic response is superior to placebo and similar to nonselective COX inhibitors. In RA patients, nabumetone 1 g at bedtime is optimal, but an additional 0.5-1 g can be administered in the morning for patients with persistent symptoms. In RA, nabumetone has shown a comparable clinical efficacy to aspirin (acetylsalicylic acid), diclofenac, piroxicam, ibuprofen and naproxen. Clinical trials and a decade of worldwide safety data and long-term postmarketing surveillance studies show that nabumetone is generally well tolerated. The most frequent adverse effects are those commonly seen with COX inhibitors, which include diarrhoea, dyspepsia, headache, abdominal pain and nausea. In common with other COX inhibitors, nabumetone may increase the risk of GI perforations, ulcerations and bleedings (PUBs). However, several studies show a low incidence of PUBs, and on a par with the numbers reported from studies with COX-2 selective inhibitors and considerably lower than for nonselective COX inhibitors. This has been attributed mainly to the non-acidic chemical properties of nabumetone but also to its COX-1/COX-2 inhibitor profile. Through its metabolite 6-MNA, nabumetone has a dose-related effect on platelet aggregation, but no effect on bleeding time in clinical studies. Furthermore, several short-term studies have shown little to no effect on renal function. Compared with COX-2 selective inhibitors, nabumetone exhibits similar anti-inflammatory and analgesic properties in patients with arthritis and there is no evidence of excess GI or other forms of complications to date.     

HPLC法测定对乙酰氨基酚缓释干混悬剂的有关物质

目的建立高效液相色谱法测定对乙酰氨基酚缓释干混悬剂的对氨基酚及有关物质的方法。方法采用Diamonsil C18（4.6mm×150mm,5μm）色谱柱;流动相：甲醇-水（20∶80）;流速：1.0mL·min-1;检测波长为275nm;进样量10μL。结果方法的最低检测限浓度为0.03μg.mL-1,对氨基酚及有关物质与主峰达到基线分离。结论本方法简便、准确、专属性强,可用于对乙酰氨基酚缓释干混悬剂的对氨基酚及有关物质的测定。     

Analgesic efficacy of sustained release paracetamol in patients with osteoarthritis of the knee

AIMS: Paracetamol is widely recommended as the initial treatment for pain associated with osteoarthritis (OA). A sustained release (SR) paracetamol formulation (Panadol Extend) was compared with standard immediate release (IR) paracetamol (Panadol) in patients with knee pain secondary to OA. The primary parameter for assessment of efficacy was patient-assessed global pain relief as determined on day 8 of the treatment period. METHODS: A double-blind, double-dummy, randomized study was conducted. Patients (n=403) were treated for 7 days with paracetamol 4 g day(-1) (SR paracetamol, two 665 mg tablets taken three times daily; IR paracetamol, two 500 mg tablets taken four times daily). Patients completed daily pain measurements and assessed global pain relief at the end of the study. Therapeutic noninferiority was defined on the basis of achieving statistical noninferiority for global pain relief. RESULTS: Analysis of the primary parameter for the intention to treat population showed that the difference in proportion of patients (SR-IR paracetamol) achieving a successful response on day 8 was -0.7%; 90% CI (-8.82%, 7.45%), P=0.890. For the per protocol population the difference in proportion was -3.0%; 90% CI (-11.61%, 5.66%), P=0.571. As the lower bound of the 90% CI for the treatment difference in each case was greater than the prespecified value (-15%), SR paracetamol was considered to be statistically noninferior to IR paracetamol in terms of pain relief. The treatments were not significantly different for any of the secondary parameters in either populations. CONCLUSIONS: SR paracetamol taken three times daily was statistically and therapeutically noninferior to IR paracetamol taken four times daily in patients with knee pain due to OA. SR paracetamol may be more convenient for patients with chronic pain and has the potential to enhance compliance and therefore pain relief.     

The effect of chronic alcohol intake on prognosis and outcome in paracetamol overdose.

1. In a retrospective study, we stratified 79 patients with paracetamol hepatotoxicity into two groups according to weekly alcohol consumption below (n = 49) or above (n = 30) Royal College of Physicians' guidelines of 21 units week-1 for males and 14 for females. 2. Survival was lower (33%) and serum creatinine on admission higher (median 207 mumol) in patients whose alcohol consumption was above recommended guidelines than in those whose drank less than this (65.9% and 138 mumol, P less than 0.01 and P = 0.027, respectively). An arterial blood pH less than 7.30 on admission was also more common in those patients with a higher alcohol consumption (30% v 12.2%, P = 0.05). 3. In all patients whose alcohol consumption exceeded the guidelines, paracetamol overdose was fatal if associated with a serum creatinine greater than 300 mumol in conjunction with a prothrombin time over 100 s and grade 3 or 4 encephalopathy or a peak prothrombin time over 180 s. 4. Chronic alcohol intake above suggested limits is an adverse prognostic feature in cases of severe paracetamol overdose. This effect is partly related to increased nephrotoxicity.     

泛昔洛韦缓释胶囊的人体药代动力学研究及其特征分析

目的:研究泛昔洛韦缓释胶囊的人体药代动力学行为,证明受试制剂的缓释特征,评价其与参比制剂泛昔洛韦片的相对生物利用度.方法:单次给药试验四阶拉丁方试验设计,受试制剂250、375、750 mg 三剂量组及参比制剂 750 mg 组;多次给药试验两周期随机交叉试验设计.HPLC法测定血药浓度,3P97软件进行数据处理及药代动力学分析.结果:12例受试者单次口服泛昔洛韦缓释胶囊250、375、750 mg 后,Cmax分别为(0.31±0.06)、(0.51±0.09)、(1.0±0.16) μg/mL,tmax分别为(4.4±1.8)、(4.0±1.4)、(4.3±1.8) h,平均滞留时间(MRT)分别为(6.9±1.3)、(7.3±1.0)、(7.6±0.7) h,AUC0-24分别为(3.3±0.8)、(5.2±1.1)、(11.3±1.4)μg·mL-1·h;普通片 750 mg 给药后,Cmax为(3.81±0.38) μg/mL,tmax为(1.2±0.6) h, MRT为(3.3±0.4) h,AUC0-24为(13.7±1.5) μg·mL-1·h.缓释胶囊单次给药后的相对生物利用度为(81.96±2.54)%,两种制剂的生物利用度相当.10例受试者每日口服 750 mg 泛昔洛韦缓释胶囊和普通片 3 d 后缓释胶囊和普通片血药浓度均已达稳态,Cmin分别为(0.32±0.13)、(0.16±0.04) μg/mL.达稳态后的Cmax分别为(0.71±0.14)、(1.67±0.44) μg/mL,Cav分别为(0.44±0.09)、(0.56±0.13) μg/mL,波动度DF分别为(90±26)%、(270±59)%.缓释胶囊谷浓度明显高于普通片,波动度则明显小于普通片.结论:泛昔洛韦缓释胶囊具有明显缓释特征,并与普通片生物利用度相当.     

Relative safety of mirtazapine overdose.

A 43-y-o male with a history of AIDS, atrial fibrillation, and alcohol abuse presented to the emergency department 2 h after ingestion of 25 tablets of 15 mg mirtazapine (total 375 mg) with ethanol in a suicide attempt (no other coingestion). Vital signs were normal except for a mild tachycardia (rate 112). Physical examination was unremarkable except for lethargy. Fifty grams of activated charcoal with sorbitol was given. Electrocardiogram showed sinus tachycardia, left ventricular hypertrophy, and non-specific ST-segment changes. Serum mirtazapine on admission was 530 ng/mL (therapeutic level 20-50 ng/mL). Overnight monitoring revealed no tachyarrythmias, and discharge occurred after psychiatric evaluation. It appears that ingestions of mirtazapine approximately 10-fold of therapeutic exhibit minimal acute toxicity. From this and other cases in the literature exhibiting a 10-fold overdose, we conclude that isolated mirtazapine ingestions of this magnitude require no acute intervention other than short term (about 6 h) observation.     

Release profile comparison and stability of diltiazem-resin microcapsules in sustained release suspensions

A sustained release suspension of diltiazem, a short half-life calcium channel blocker, was developed to reduce frequency of drug administration, ease of dose adjustment and improve patient compliance. In this study, the sustained release of diltiazem was obtained by complexing the drug with Dowex 50W x 4 and Dowex 50W x 8, strong cationic exchange resins with 4% and 8% degree of cross-linking, respectively. The diltiazem-Dowex 50W x 4 complexes provided the highest drug release and were subsequently used to prepare the microcapsules by emulsion-solvent evaporation method, using 0.75-5.00% cellulose acetate butyrate (CAB) in methylene chloride as a coating solution. As the concentration of CAB increased, the size of microcapsule increased and the drug release from the microcapsule was retarded. From release profile comparison using f(1) and f(2) factors, it was found that the microcapsules coated with 1.75% CAB provided a release profile equivalent to the commercial product of diltiazem sustained release capsule, Herbesser 90SR. Furthermore, sustained release suspensions of the diltiazem microcapsules were formulated with the use of 0.8% sodium carboxymethylcellulose or 0.4% xanthan gum as a suspending agent. The suspension of 0.4% xanthan gum showed superior in physical appearance after 120-day storage at 30 and 45 degrees C. In addition, all sustained release suspensions possessed good stability with low drug leaching and their release profiles were unchanged when compared with the dried microcapsules for 120 days at 30 and 45 degrees C.     

A safety profile of controlled release naproxen tablets

This randomised single blind controlled study examines adverse reactions to standard Naprosyn (naproxen) 750 mg daily with controlled release naproxen, Naprosyn CR, 750 mg daily, in a total of 520 patients. Overall there were no major differences between the two preparations. The reporting rate of any adverse clinical event was greater in the group taking the controlled release preparation but withdrawals from medication were similar in the two groups, for whatever reason. The main finding of the study was that patients in each decile age group, mainly between 40 and 80 years, were more likely to continue on this preparation for the full 10 weeks of the trial: 57% of patients on controlled release and 46% on plain Naprosyn completed the study. Patients over 60 years, particularly females, tended to complete the study, indicating that the simpler treatment regimen without any increase in major adverse effects is useful in the elderly who are thought to be at special risk of adverse reactions from NSAIDs. In addition, a review of spontaneous reports of adverse reactions to naproxen reported nationally to the Medicines Adverse Reactions Committee shows that the pattern has not changed over the last two years during which the controlled release formulation has been available. This experience supports the acceptability of controlled release naproxen.     

In vitro release profile of estradiol transdermal therapeutic systems

The in vitro release profiles of two sizes of estradiol patches were determined by the paddle method, where the patch was held in position at the bottom of the dissolution vessel by sandwiching it between a watch glass and an aluminum wire mesh or Teflon screen, and also by the manufacturer's paddle-over-disk method. The estradiol content of test aliquots of the dissolution medium was determined by HPLC. The release profiles by both procedures were comparable and showed that approximately 10% of the labeled drug was released in 4 days.