甘精胰岛素注射液的临床前安全性评价

目的 通过Beagle犬长期毒性试验及其伴随的免疫原性试验,观察甘精胰岛素注射液的毒性反应,确定未观察到临床不良反应的剂量水平（NOAEL）,为临床不良反应监测及防治提供参考。方法 健康Beagle犬40条,随机分为甘精胰岛素注射液低、中和高（0.5、1.0、2.0 IU/kg）剂量组、溶媒对照组及原研对照组（来得时,2.0 IU/kg）,每组8只动物,雌雄各半。连续sc给药30天,停药恢复16天。试验期间进行一般体征观察、进食量、体质量、肛温、全血血糖及心电图检查;测定血液学常规与凝血指标、血清生化、尿液常规等指标;进行骨髓细胞形态学检查、大体剖检检查以及组织病理学检查。采用间接ELISA法检测不同时期动物血清抗药的结合抗体;采用体外生物活性HPLC法检测产生抗药抗体的阳性血清的中和活性。结果 在给药期的第8和10天,原研对照组和高剂量组各有1只雌性动物在给药后5～6 h出现抽搐和流涎等由低血糖所致的异常症状,其中高剂量组的该异常动物于次日死亡;给药期第11天的心电图检查发现高剂量组的T波倒置比例略高于溶媒对照组（5/7 vs 1/8）,停药后恢复正常;其余存活动物的体质量、肛温、进食量、尿常规、血液学、血清生化和组织病理学等均未见毒理学意义的异常改变。免疫原性结果显示,仅有高剂量组1只雄性动物于给药期第12天产生抗药抗体,抗体滴度为1:16,阳性率为14.3%,产生结合抗体的血清样品经检测为非中和活性抗体。结论 在本试验条件下,Beagle犬sc重复给予甘精胰岛素注射液的NOAEL为1.0 IU/kg,该剂量相当于临床拟用剂量的2倍。该药在高剂量下可能对个别Beagle犬具有较弱的免疫原性。     

重组人胰岛素注射液临床前生物相似性评价研究

目的 通过Beagle犬长期给药毒性试验及免疫原性试验,评价重组人胰岛素注射液(Insulin R)与原研药(Humulin R)的生物相似性。方法 进行Beagle犬scInsulin R 30 d停药14 d长期给药毒性试验,Insulin R剂量为0.5、1.0、1.5 IU/kg,Humulin R剂量为1.5 IU/kg,检测指标包括一般状况、进食量、体温、心电图、血液学、凝血、血清生化、电解质及尿液等,于给药期结束及停药期结束分两次剖杀动物,测定主要脏器的脏器系数并进行常规病理组织学检查;ELISA法检测Beagle犬血清的免疫原性。结果 Beagle犬重复sc Insulin R 30 d毒性试验中,中、高剂量组部分动物出现食欲降低、食量减少,高剂量1只雄性动物出现流涎、站立不稳、心率加速、抽搐等低血糖症状,中、高剂量组动物心率增加;原研药组与InsulinR高剂量组毒性反应相当;Beagle犬给予Insulin R 30 d未检测到抗药抗体。结论 Beagle犬sc Insulin R 30 d时的最大无毒反应剂量为0.5 IU/kg,相当于临床等效剂量的0.5倍,且未产生抗药抗体,与Humulin R具有较好的临床前生物相似性。     

精蛋白重组人胰岛素注射液(预混50/50)与50/50混合重组人胰岛素注射液在Beagle犬体内的生物等效性研究

目的研究精蛋白重组人胰岛素注射液(预混50/50)与已上市的50/50混合重组人胰岛素注射液在Beagle犬体内的药动学和生物等效性。方法采用单剂量试验制剂和参比制剂自身双交叉给药方案,12只健康Beagle犬分别皮下注射同剂量精蛋白重组人胰岛素注射液(预混50/50)和50/50混合重组人胰岛素注射液,给药后不同时间经静脉采集血浆标本,同时采用罗氏血糖仪同步测定动物血糖水平;放射免疫分析(RIA)法检测血药浓度;血药浓度数据用DAS 2.0药动学软件拟合计算参数,并进行生物等效性分析。结果 Beagle犬交叉sc 5 U/只试验制剂与参比制剂后,主要药动学参数分别为:平均t1/2为(2.62±2.14)、(1.99±1.37)h;平均Cmax为(108.30±26.90)、(104.60±18.45)μU/m L;平均tmax为(0.94±0.43)、(0.90±0.39)h;平均AUC(0-t)为(362.3±73.6)、(351.7±53.9)μU/(m L·h)。血浆最低葡萄糖浓度(Cmin)分别为(1.74±0.25)、(1.80±0.33)mmol/L,达到最低浓度所需时间(tmin)分别为(1.58±0.97)、(2.02±0.96)h。结论精蛋白重组人胰岛素注射液(预混50/50)与50/50混合重组人胰岛素注射液在Beagle犬体内具有生物等效性。     

精蛋白锌重组人胰岛素混合注射液治疗2型糖尿病患者31例

目的研究精蛋白锌重组人胰岛素混合注射液对2型糖尿病患者的疗效影响及并发症发生率。方法采用随机数字表法将62例患者随机分为观察组和对照组,各31例。对照组采用降糖药物治疗,观察组采用胰岛素联合降糖药物治疗,比较两组患者血糖控制效果、治疗依从性、药物不良反应发生率和糖尿病并发症发生率。结果观察组患者空腹血糖为（7．07±0．25）mmol／L,餐后2h血糖（8．43±0．37）mmol／L,糖化血红蛋白（6．92±0．44）％,对照组分别为（7．34±0．30）mmol／L,（9．12±0．48）mmol／L,（7．29±0．54）％,组间比较差异具有统计学意义（P〈0．05）。观察组患者糖尿病急性并发症发生率为16．13％,慢性并发症发生率为9．68％;对照组患者分别为38．71％和29．03％,组间比较差异具有统计学意义（P〈0．05）。结论精蛋白锌重组人胰岛素混合注射液有助于患者血糖控制,可有效降低药物不良反应和糖尿病并发症发生率。     

精蛋白重组人胰岛素混合注射液(30/70)与门冬胰岛素30注射液治疗糖尿病临床疗效的比较研究

目的比较精蛋白重组人胰岛素混合注射液(30/70)与门冬胰岛素30注射液治疗糖尿病的临床疗效。方法选取芜湖市第一人民医院2017年2月-2018年8月收治的糖尿病患者120例,随机分为对照组和治疗组,各60例。对照组给予进口门冬胰岛素30注射液,治疗组给予国产精蛋白重组人胰岛素混合注射液(30/70),连续治疗3个月。比较两组每日平均胰岛素使用剂量,治疗前后体质量、空腹血糖、餐后2 h血糖及糖化血红蛋白水平,临床疗效、低血糖发生率。结果两组每日平均胰岛素使用剂量比较,差异无统计学意义(P>0.05)。治疗前两组体质量比较,差异无统计学意义(P>0.05);治疗后治疗组体质量高于对照组(P<0.05)。治疗前两组空腹血糖、餐后2 h血糖、糖化血红蛋白比较,差异无统计学意义(P>0.05);治疗后治疗组空腹血糖、餐后2 h血糖、糖化血红蛋白低于对照组(P<0.05)。治疗组总有效率高于对照组,低血糖发生率低于对照组(P<0.05)。结论国产精蛋白重组人胰岛素混合注射液(30/70)治疗糖尿病的临床疗效优于进口门冬胰岛素30注射液,可更有效控制血糖,安全性更高。     

国内外精蛋白重组人胰岛素注射液的有关物质比较

目的 精蛋白重组人胰岛素适用于2型糖尿病患者的治疗,现行标准中仅对本品有关物质A₂₁脱氨人胰岛素进行控制,未进行B₃和B₃iso脱氨人胰岛素限度的控制。采用两种方法对精蛋白重组人胰岛素注射液中的有关物质进行测定并比较国内外共17批样品的质量。方法 采用高效液相色谱法梯度洗脱,色谱柱：Waters Xbridge C₁₈ 4.6 mm×250 mm(5μm),检测波长：214 nm,柱温：40℃,流速：1.0ml/min,进样体积：20μl;《中国药典》2020年版方法：流动相A为0.2 mol/L硫酸钠溶液(pH值2.3)-乙腈(82∶18),流动相B为乙腈-水(50∶50);某企业自拟方法：流动相A为0.2 mol/L硫酸钠溶液(pH值3.6)-乙腈(90∶10),流动相B为乙腈-水(50∶50)。结果 国内外样品的A₂₁脱氨人胰岛素含量差异不大、国内一家企业B₃和B₃iso脱氨人胰岛素含量低于其他企业,国内另一家企业有关物质总和高...     

聚乙二醇化重组人胰岛素注射液Beagle犬毒动学研究

目的 研究毒性剂量暴露下聚乙二醇化重组人胰岛素注射液（PEG-Det）的毒动学（TK）,以评价系统暴露与剂量、时间及毒性结果之间的关系,通过重复给药分析药物在体内是否存在蓄积及代谢方式是否改变等特性。方法 32只健康Beagle犬随机分为4组,每组8只,雌雄各半,分别sc低、中、高剂量（37.5、75.0、150.0 μg/kg）PEG-Det及溶媒,每周给药2次,重复给药9个月。分别于首次（d1）、中期（d89）和末期（d260）给药后采用放射免疫分析（RIA）法检测不同时间血药浓度,采用罗氏血糖仪同步测定动物血糖水平。试验数据采用DAS 3.0药动程序拟合分析并计算TK参数。结果 各剂量组动物sc给药后,随血药浓度升高伴随血糖降低,且与给药剂量呈正相关;随给药频率增加,血糖降低幅度减小;单次和多次给药后,PEG-Det的C_max和AUC与剂量均呈正相关;随给药频率增加,各剂量组的C_max和AUC_ss降低,且给药末期（9个月）的蓄积指数（R_Cmax和R_AUC）均小于1;各剂量组在给药不同阶段的消除半衰期t_1/2z为20~30 h;达峰时间T_max和清除率CL_z/F均在一定范围内波动,不与剂量相关。结论 Beagle犬重复sc给予PEG-Det 37.5、75.0、150.0 μg/kg,随给药剂量增加,药物暴露量增大;经多次给药后,血浆中胰岛素浓度趋于平稳,体内无药物蓄积;且血糖降低幅度减少,在维持有效浓度和药效的基础上,降低了由低血糖带来的安全性风险。     

国产与进口重组人胰岛素注射液Beagle犬皮下注射的生物等效性研究

目的：以美国礼来公司重组人胰岛素注射液（优泌林R,Humulin R）为对照品,评价国产重组人胰岛素注射液（Insulin R）的相对生物利用度和生物等效性。方法采用自身随机交叉给药方案,12只健康Beagle犬分别sc同剂量Insulin R和Humulin R,按设计采集6 h内动态血标本。采用罗氏血糖仪与检测血药浓度同步测定动物血糖水平;放射免疫分析（RIA）法检测血药浓度;试验数据采用DAS 3.0药动学程序拟合计算参数,并进行生物等效性分析。结果 Beagle犬自身交叉sc Insulin R和Humulin R 0.5 U/kg后的血浆最低葡萄糖浓度（Cmin）分别为（1.6±0.4）、（1.6±0.2）mmol/L;达到最低浓度所需时间（tmin）分别为（1.0±0.5）、（1.1±0.6）h。Insulin R和Humulin R的主要药动学参数均值分别为：达峰时间（tmax）为（0.43±0.21）、（0.42±0.09）h;峰浓度（Cmax）为（203.2±63.3）、（193.5±63.1）μU/mL;药时曲线下面积（AUC0-6 h）为（281.2±47.5）、（266.6±62.5）μU/(mL·h);受试药Insulin R相对于对照药Humulin R的相对生物利用度为（109.4±25.5）%。结论两种重组人胰岛素注射剂在健康Beagle犬体内具有生物等效性。     

壮药清毒伸筋颗粒安全性评价

目的:通过单次给药和重复给药毒性试验,对壮药清毒伸筋颗粒进行安全性评价。方法:40只小鼠随机分为清毒伸筋颗粒组和空白对照组,每组20只,清毒伸筋颗粒给药剂量为75.3 g·kg^-1,空白对照组给予等体积蒸馏水,详细观察动物体征至给药后14 d,剖检肉眼大体观察各脏器形态。120只大鼠随机分为清毒伸筋颗粒9,18,36 g·kg^-1剂量组和空白对照组,每组30只,连续灌胃给药3个月,分别于给药3个月和停药后1个月时,取部分大鼠进行血液学指标、血液生化指标及病理组织学检查。结果:75.3 g·kg^-1清毒伸筋颗粒单日灌胃组给药后14 d小鼠仍未见明显毒性反应。清毒伸筋颗粒9,18,36 g·kg^-1剂量连续灌胃给药3个月,大鼠体质量、血液学指标、血液生化学指标及组织病理学未见明显毒性反应。结论:清毒伸筋颗粒小鼠单次给药最大给药量为75.3 g·kg^-1(相当于每千克178.4 g生药),大鼠重复给药3个月最大无毒反应剂量大于36 g·kg^-1(相当于每千克85...     

精蛋白锌重组赖脯胰岛素混合注射液治疗初发2型糖尿病的疗效及安全性观察

摘 要 目的：比较精蛋白锌重组赖脯胰岛素混合注射液与精蛋白锌重组人胰岛素混合注射液治疗初发2型糖尿病的疗效及安全性。方法: 初发2型糖尿病患者49例随机分为观察组和对照组。2组患者均给予常规饮食治疗及健康教育。观察组餐前皮下注射精蛋白锌重组赖脯胰岛素混合注射液 ,对照组餐前皮下注射精蛋白锌重组人胰岛素混合注射液。治疗2周后,比较两组患者的空腹血糖（FBG）、餐后血糖(PBG)、糖化血红蛋白（HbA1c）、血糖达标时间、低血糖发生率。结果: 治疗后,两组患者FBG、PBG 、HbA1c均较治疗前显著降低（P<0.05）,但2组间FBG、PBG、HbA1c比较差异无统计学意义（P>0.05）。观察组低血糖发生率低于对照组,血糖达标时间短于对照组（P<0.05）。结论:精蛋白锌重组赖脯胰岛素混合注射液治疗初发2型糖尿病血糖达标快,安全性高,优于精蛋白锌重组人胰岛素混合注射液。     

Preclinical safety evaluation of ET-26 hydrochloride,a novel intravenous anesthetic agent,in beagle dogs

ET-26 hydrochloride (ET-26HCl) is a novel etomidate analogue, approved for clinical trials, which has an effective sedative-hypnotic effect, a stable myocardial performance, and milder adrenocortical suppression than etomidate in rats and beagle dogs. Additionally, ET-26HCl showed similar hemodynamic stability as etomidate in the rat uncontrolled hemorrhagic shock model. Furthermore, ET-26HCl, in the rat lipopolysaccharide-induced sepsis model, was found to have a higher survival rate, a lower inflammatory reaction, and less organ injury. In the present study, we measured the potential adverse effects of ET-26HCl in beagle dogs in accordance with the Guidance on single- and repeated-dose toxicity published by the China Food and Drug Administration. In toxicity studies, single and repeated (14 days) intravenous doses of up to 16 mg/kg were well tolerated, with only pharmacologically related clinical signs seen in both studies. Thus, the no-observed-adverse-effect level (NOAEL) of ET-26HCl was found at 16 mg/kg/day. Toxicokinetic examination demonstrated that ET-26HCl showed a dose-dependent increase to exposure, no gender difference, and no evidence of accumulation. These results provide useful information for guiding a phase I clinical trial of ET-26HCl in healthy volunteers.     

Nonclinical safety evaluation of muraglitazar, a novel PPARalpha/gamma agonist.

The toxicity of muraglitazar, an oxybenzylglycine, nonthiazolidinedione peroxisome proliferator-activated receptor (PPAR) alpha/gamma agonist, was evaluated in a comprehensive nonclinical toxicology program that included single-dose oral toxicity studies in mice, rats, and monkeys; repeat-dose toxicity studies in rats, dogs, and monkeys; a battery of in vitro and in vivo genetic toxicity studies; carcinogenicity studies in mice and rats; reproductive and developmental toxicity studies in rats and rabbits; and studies to investigate species-specific findings. Pharmacologically mediated changes, similar to those observed with other PPARgamma agonists, were observed following chronic administration and included subcutaneous edema, hematologic/hematopoietic and serum chemistry alterations, and morphologic findings in the heart and adipose tissue in rats and monkeys. In dogs, a species highly sensitive to PPARgamma agonists, muraglitazar caused pronounced species-specific clinical toxicity and degenerative changes in the brain, spinal cord, and testes at high doses and exposures. Muraglitazar was nongenotoxic in the standard battery of genotoxicity studies. Gallbladder adenomas in male mice and adipocyte neoplasms in male and female rats were seen at suprapharmacologic exposures, whereas urinary bladder tumors occurred in male rats at lower exposures. Subsequent investigative studies established that the urinary bladder carcinogenic effect was mediated by urolithiasis rather than a direct pharmacologic effect on urothelium. Muraglitazar had no effects on reproductive function in male and female rats at high systemic exposures, was not teratogenic in rats or rabbits, and demonstrated no selective developmental toxicity. Overall, there were no nonclinical findings that precluded the safe administration of muraglitazar to humans.     

Repeated oral dose toxicity study of nickel oxide nanoparticles in Wistar rats: a histological and biochemical perspective

Despite the increasing use of nickel oxide (NiO) nanoparticles (NPs), limited information is available on their toxicological effects. Health consequences of 28 days repeated oral exposure to NiO NPs have not been explored thoroughly. Hence, toxicity investigations were performed after 28‐day daily exposure in albino Wistar rats with NiO NPs following Organization for Economic Co‐operation and Development test guideline 407. Histopathology, biochemical indices including oxidative stress and biodistribution patterns were evaluated to decipher the toxicological impact of NiO NPs. NiO NP characterization by transmission electron microscopy showed an average size of 12.9 (±3.4) nm. Histological studies depicted a prominent impact on the vital organs of the rats. A dose‐dependent rise in both aminotransferase enzyme values was recorded in the homogenates of liver and kidney tissues. A significant decrease in superoxide dismutase activity and increase in catalase activity was noted. Further, a dose‐dependent decrease in reduced glutathione content was recorded in rats, which suggested generation of reactive oxygen species and oxidative stress. Increase in the malondialdehyde levels was observed with an increase in the dose substantiating the antioxidant enzyme activity profiles. Biodistribution studies indicated maximum accumulation of Ni content in liver followed by kidney. Excretion of Ni was predominantly through feces and a little through renal clearance. Our study indicated that NiO NPs adversely alter the biochemical profile of the rats and cause histological damage. Further investigations are warranted to address the mechanism by which physiological path these NiO NPs exhibit their toxic nature in in vivo.     

Preclinical safety evaluation of levonadifloxacin,a novel anti-methicillin-resistant Staphyloccocus aureus benzoquinolizine fluoroquinolone by intravenous and oral administration

Fluoroquinolone (FQ) antibacterials have drawn heightened attention from various international regulatory agencies due to their class-specific side effects. Levonadifloxacin is a novel broad spectrum benzoquinolizine FQ active against methicillin-resistant Staphyloccocus aureus (MRSA). Owing to FQ-associated safety concerns, extensive preclinical safety pharmacology (central nervous system and cardiac safety) and toxicology studies (subacute repeat-dose toxicity, genotoxicity, phototoxicity and chondrotoxicity) of levonadifloxacin were performed at relatively high doses. Intravenous (IV) and oral studies were conducted using WCK 771 (l -arginine salt of levonadifloxacin) and WCK 2349 (l -alanine ester prodrug of levonadifloxacin), respectively. Safety pharmacology studies following single dose revealed no adverse effects on central nervous system (including seizure) in mice and cardiovascular system (hERG and monkey telemetry). In repeat-dose toxicity studies, except for IV bolus dosing related effects in rat (hyperactivity, mild convulsion, polypnoea and injection site irritation) and dog (emesis and salivation), no other adverse findings limiting the dosing duration were observed. No major biochemical, haematological, gross or histopathological changes suggestive of damage to vital organs were observed in either WCK 771- or WCK 2349-treated groups. WCK 771 and WCK 2349 were found to be nongenotoxic; however, they showed weak phototoxicity that was comparable with levofloxacin. WCK 771 showed chondrotoxicity in the Beagle dog pups on repeat-dose administration; however, the severity level was lower than ofloxacin. Overall, preclinical safety studies helped establish wider safety margin for WCK 771 and WCK 2349 that supports administration of higher therapeutic doses in humans by both IV and oral routes, thereby enabling safe anti-MRSA treatment.     

Efficacy and safety of idebenone in the long-term treatment of Alzheimer's Disease: a double-blind,placebo controlled multicentre study

The efficacy and safety of idebenone were studied in a prospective, randomized, double-blind, placebo controlled multicentre study in 3 parallel groups of patients with dementia of the Alzheimer type (DAT) of mild to moderate degree. Diagnosis was based on DSM-III-R (primary degenerative dementia) and NINCDS-ADRDA criteria (probable Alzheimer's disease). A total of 450 patients were randomized to either placebo (n = 153) or idebenone 90 mg tid (n = 148) or 120 mg tid (n = 149) and treated up to 12 months. The primary endpoint for the evaluation of efficacy was at month 6. Data of the month-12 assessments were considered for the evaluation of long-term treatment effects. The primary outcome measure was the total score of the Alzheimer's Disease Assessment Scale (ADAS-Total) at month 6. Secondary outcome measures were the ADAS cognitive (ADAS-Cog) and noncognitive score (ADAS-Noncog), the clinical global response (CGI-Improvement), the SKT neuropsychological test battery, and the Nurses' Observation Scale for Geriatric Patients (NOSGER-Total and IADL subscale). Safety parameters were adverse events, vital signs, ECG and clinical laboratory parameters. Clinical and psychometric evaluations were made at screening, at baseline, and after 1, 3, 6, 9 and 12 months of treatment. After months 6 and 12, idebenone showed statistically significant dose-dependent improvement in the primary efficacy variable ADAS-Total and in all the secondary efficacy variables. An analysis of therapy responders performed on 3 outcome measures (CGI, ADAS-Cog, NOSGER-IADL), selected to represent different levels of assessment, revealed significant dose-related superiority of idebenone with respect to placebo in each of the 3 variables and in the concordance of responses across the 3 measures. Safety results were inconspicuous on all assessments. The study results confirm the efficacy, clinical relevance and safety of idebenone in the long-term treatment of DAT.     

The consumption ratio of flavouring materials: a mechanism for setting priorities for safety evaluation

The toxicological testing of the millions of known chemicals or even the thousands of food components is not practical at present. Therefore, priorities for testing should be set carefully, to ensure that primary attention is given to materials for which risk management can potentially improve public health. Most flavouring materials used today by the food industry occur widely in natural and traditional foods. A proposed Consumption Ratio (CR) relates the amount of a flavouring material found in natural and traditional foods to the amount added to food by food processors. A CR above 1 means that the consumption of the flavouring material takes place predominantly via traditional food. High CR values should establish that the priority ranking for testing these flavouring substances needs to be no higher than that for testing the complete foods.     

A dose dependent adaptogenic and safety evaluation of Rhodiola imbricata Edgew, a high altitude rhizome

To examine the dose dependent adaptogenic activity aqueous extract of Rhodiola imbricata root was orally administered in rats at different doses, 30 min prior to cold (5 degrees C)-hypoxia (428 mm Hg)-restraint (C-H-R) exposure. The maximal effective adaptogenic dose of the extract was 100 mg/kg body weight. The acute and sub-acute toxicity of the extract was also studied in rats. Sub-acute toxicity studies included administration of single oral dose of 1 g/kg and 2 g/kg of extract once daily for 14 days and maximal effective single oral dose of 100 mg/kg once daily for 30 days. At the end of each treatment period the biochemical parameters related to liver function, kidney function, lipids (triglycerides, cholesterol) and hematological parameters were estimated in serum and blood. Biochemical and hematological analysis showed no significant changes in any of the parameters examined in treated group's animal, in comparison to control animals. No significant change was observed in organ weight/body weight ratios, of any organ studied in comparison to control rats. The oral LD(50) of the extract was observed to be >10 g/kg, indicating an adequate margin of safety. No histopathological changes were observed in the vital organs studied of the treated animals. These results suggest that aqueous extract of R. imbricata root possess potent adaptogenic activity with no acute and sub-acute toxicity.     

N-(3-(2-amino-6,6-difluoro-4,4a,5,6,7,7a-hexahydro-cyclopenta[e][1,3]oxazin-4-yl)-phenyl)-amides as BACE1 inhibitors: a patent evaluation of WO2013041499

A new series of oxazin amides have been synthesized from isoxazoles using a reaction to increase the heterocyclic ring size and were evaluated as BACE1 inhibitors. The innovative compounds were able to diminish amyloid-β peptide concentration in cell and proved to be selective toward peptidases from the same family. Further studies on the toxicity of this series showed that these new molecules were not recognized by P-glycoprotein and that they were unsusceptible to rapid metabolization by cytochrome P450 or glutathione conjugation. These results indicate that such compounds could be useful in developing drugs to fight Alzheimer's disease and that this novel oxazin scaffold should be considered as a starting point to tackle this pathology.