Impurity profile study of lopinavir and validation of HPLC method for the determination of related substances in lopinavir drug substance

Several related substances (RS4–RS10) were detected in lopinavir drug substance at levels ranging from 0.03% to 0.1% by employing gradient RP-HPLC. The related substances were identified by LC–MS analysis. These related substances were isolated and characterized by Mass, ¹H NMR and FT-IR spectral data. The separation was achieved on a YMC Pack ODS-AQ (250 mm × 4.6 mm, 5 μm) column thermostated at 45 °C using 0.02 M KH₂PO₄ (pH 2.5): acetonitrile as a mobile phase in gradient elution mode. A PDA detector set at 210 nm was used for detection. The investigated validation elements showed the method has acceptable specificity, accuracy, linearity, precision, robustness and high sensitivity with detection limits and quantitation limits ranging from 0.028 μg/ml to 0.063 μg/ml and 0.084 μg/ml to 0.192 μg/ml respectively. The method can be used for routine quality control analysis and stability testing of lopinavir drug substance.     

A retrospective TDM database analysis of interpatient variability in the pharmacokinetics of lopinavir in HIV-infected adults

Lopinavir is one of the most-widely used protease inhibitors in the treatment of HIV-1 infected patients. Concentration-effect relationships have been described for both antiviral activity and toxicity. Less is known about patient characteristics that may determine interpatient variability in lopinavir plasma concentrations. A database was created containing all Therapeutic Drug Monitoring (TDM) results collected at our Department. Patients were included if they were using lopinavir twice daily for at least two weeks; subjects who were known to be nonadherent (based on either a lopinavir concentration <0.2 mg/L or suspected by the physician) were excluded. Demographic data were collected from TDM application forms and patient charts. Patients attending one of the 22 HIV treatment centers in The Netherlands. The Department of Clinical Pharmacy is a national referral center for TDM of antiretroviral agents. Lopinavir concentration ratios (CRs) were calculated for each patient by dividing the individual plasma concentration by the time-adjusted population value. Relationships with lopinavir CRs were tested using regression analysis and analysis of variance. A total of 802 patients were included (607 males; 150 females; 45 unknown). The age and body weight of the patients ranged from 18 to 74 years (mean 42) and 42 to 121 kg (mean 72), respectively. Race was known for 756 persons: Caucasian 76%, African 18% and Asian 6%. The median (+ interquartile range, IQR) lopinavir CR was 0.98 (IQR: 0.67-1.31). Body weight showed an inverse relationship with lopinavir CR (F = 23.1; P < 0.001). Age was not related with lopinavir CR (P = 0.99). Female patients had a significantly higher lopinavir CR than males: 1.18 vs. 1.03 (P = 0.005); race was not associated with differences in lopinavir CR. In a multivariate regression analysis body weight, but not gender, remained significantly related to lopinavir CR. Body weight is the only demographic factor that could be related to lopinavir exposure; clinicians should be alert for an increased risk of suboptimal antiviral efficacy in patients with high body weight, and for an increased risk of toxicity in patients with a low body weight.     

An integrated pharmacokinetic model for the influence of CYP3A4 expression on the in vivo disposition of lopinavir and its modulation by ritonavir

Lopinavir, a human immunodeficiency virus protease inhibitor, has a very low oral bioavailability, which can be enhanced with a low dose of the CYPA4 inhibitor ritonavir. Our aim was to separately quantify the role of intestinal and hepatic cytochrome P450 3A (CYP3A4) expression on lopinavir disposition in a novel mouse model. Lopinavir and ritonavir were administered to mice selectively expressing human CYP3A4 in the intestine and/or liver. Using nonlinear mixed-effects modeling, we could separately quantify the effects of intestinal CYP3A4 expression, hepatic CYP3A4 expression, and the presence of ritonavir on both the absorption and elimination of lopinavir, which was previously not possible using noncompartmental methods. Intestinal, but not hepatic, CYP3A4-related first-pass metabolism was the major barrier for systemic entry of lopinavir. Relative oral bioavailability of lopinavir in mice expressing both hepatic and intestinal CYP3A4 was only 1.3% when compared with mice that were CYP3A deficient. In presence of ritonavir, relative bioavailability increased to 9.5% due to inhibiton of intestinal, but not due to inhibition of hepatic first-pass metabolism. Hepatic CYP3A4 related systemic clearance was inversely related to ritonavir exposure and not only hepatic but also intestinal CYP3A4 expression contributed to systemic clearance of lopinavir.     

Alopecia induced by lopinavir plus ritonavir therapy in an HIV patient

The most commonly reported side effects related to lopinavir/ritonavir are diarrhea, vomiting, headache, nausea, and increased serum triglycerides and cholesterol levels. About 4% of the patients prescribed lopinavir/ritonavir stop taking it because of side effects. Alopecia, generally involving the scalp, has been reported in patients with HIV infection treated with indinavir but not with lopinavir/ritonavir. We present a 62-year-old man with HIV infection, stage B2, who experienced alopecia totalis of his scalp, eyebrows, and eyelashes beginning 18 months after initiating antiretroviral treatment including lopinavir/ritonavir. No hair loss on the arms, legs, and pubic area was observed. Our patient's drug regimen consisted of lopinavir/ritonavir, efavirenz, and stavudine; in addition, the patient was receiving treatment for diabetes with glivenclamide and metformin for the last 3 years. These drugs have not been shown to cause alopecia. Alopecia reversed completely 2 months after substituting nelfinavir for lopinavir/ritonavir without any other change of treatment and his eyelashes and eyebrows grew back as well. To our knowledge, this is the second case of lopinavir/ritonavir-associated alopecia totalis reported in the international literature.     

洛匹那韦/利托那韦的不良反应及其机制研究进展

洛匹那韦/利托那韦主要用于人类免疫缺陷（艾滋病）病毒感染的治疗,临床上超说明书用于新型冠状病毒感染的治疗。临床发现使用该药后易引发多种不良反应,主要包括胃肠道反应、肝损伤、代谢紊乱、心血管和神经毒性不良反应。洛匹那韦/利托那韦不良反应机制可能与内质网应激、氧化应激、线粒体应激、细胞凋亡等有关,具有剂量相关性,剂量越高则不良反应越大,主要由肝脏CYP3A代谢,当其与某些具有较强CYP3A4抑制作用的药物共同使用时,往往会加重其不良反应。综述了洛匹那韦/利托那韦片的不良反应及其发生机制,为临床安全、合理用药提供参考。     

Population pharmacokinetics of lopinavir in combination with rifampicin-based antitubercular treatment in HIV-infected South African children

Purpose  

The population pharmacokinetics (PK) of lopinavir in tuberculosis (TB)/human immunodeficiency virus (HIV) co-infected South African children taking super-boosted lopinavir (lopinavir/ritonavir ratio 1:1) as part of antiretroviral treatment in the presence of rifampicin were compared with the population PK of lopinavir in HIV-infected South African children taking standard doses of lopinavir/ritonavir (ratio 4:1).     

Model-based evaluation of the pharmacokinetic differences between adults and children for lopinavir and ritonavir in combination with rifampicin

Aims

Rifampicin profoundly reduces lopinavir concentrations. Doubled doses of lopinavir/ritonavir compensate for the effect of rifampicin in adults, but fail to provide adequate lopinavir concentrations in young children on rifampicin-based antituberculosis therapy. The objective of this study was to develop a population pharmacokinetic model describing the pharmacokinetic differences of lopinavir and ritonavir, with and without rifampicin, between children and adults.

Methods

An integrated population pharmacokinetic model developed in nonmem 7 was used to describe the pharmacokinetics of lopinavir and ritonavir in 21 HIV infected adults, 39 HIV infected children and 35 HIV infected children with tuberculosis, who were established on lopinavir/ritonavir-based antiretroviral therapy with and without rifampicin-containing antituberculosis therapy.

Results

The bioavailability of lopinavir was reduced by 25% in adults whereas children on antituberculosis treatment experienced a 59% reduction, an effect that was moderated by the dose of ritonavir. Conversely, rifampicin increased oral clearance of both lopinavir and ritonavir to a lesser extent in children than in adults. Rifampicin therapy in administered doses increased CL of lopinavir by 58% in adults and 48% in children, and CL of ritonavir by 34% and 22% for adults and children, respectively. In children, the absorption half-life of lopinavir and the mean transit time of ritonavir were lengthened, compared with those in adults.

Conclusions

The model characterized important differences between adults and children in the effect of rifampicin on the pharmacokinetics of lopinavir and ritonavir. As adult studies cannot reliably predict their magnitude in children, drug–drug interactions should be evaluated in paediatric patient populations.     

Lopinavir/Ritonavir pharmacokinetic profile: impact of sex and other covariates following a change from twice-daily to once-daily therapy

The aim of this study was to determine the impact of sex on the pharmacokinetics of lopinavir/ritonavir. Interaction between lopinavir/ritonavir and tenofovir was also evaluated. Steady-state plasma samples were obtained from virologically suppressed HIV-infected patients on lopinavir/ritonavir 800/200-mg soft gel capsule taken once daily. Drug assays were performed by high-performance liquid chromatography. Pharmacokinetic parameters estimated by noncompartmental method were reported as 90% confidence intervals (CIs) about the geometric mean ratio (GMR). There were 9 males and 11 females. No sex differences were observed in lopinavir/ritonavir pharmacokinetics profile. The GMR(sex) (women compared with men) for lopinavir area under the concentration-time curve (AUC(24)), maximum concentration (C(max)), and minimum concentration (C(min)) was 0.95 (90% CI, 0.70-1.29), 0.88 (90% CI, 0.67-1.15), and 1.27 (90% CI, 0.60-2.66), respectively. Similarly, the GMR(sex) for ritonavir AUC(24), C(max), and C(min) was 0.84 (90% CI, 0.57-1.24), 0.79 (90% CI, 0.50-1.22), and 1.02 (90% CI, 0.58-1.80), respectively. Tenofovir coadministration led to a reduction in lopinavir/ritonavir plasma exposure, giving a lopinavir GMR(tenofovir) for C(max) of 0.72 (90% CI, 0.57-0.93) and AUC(24) of 0.74 (90% CI, 0.56-0.98), respectively. No difference in lopinavir/ritonavir plasma concentrations between sexes was demonstrated in this study. However, tenofovir coadministration lowered lopinavir/ritonavir plasma exposure.     

Pharmacokinetics of lopinavir/ritonavir in HIV/hepatitis C virus-coinfected subjects with hepatic impairment

The effect of hepatic impairment on lopinavir/ritonavir pharmacokinetics was investigated. Twenty-four HIV-1-infected subjects received lopinavir 400 mg/ritonavir 100 mg twice daily prior to and during the study: 6 each with mild or moderate hepatic impairment (and hepatitis C virus coinfected) and 12 with normal hepatic function. Mild and moderate hepatic impairment showed similar effects on lopinavir pharmacokinetics. When the 2 hepatic impairment groups were combined, lopinavir Cmax and AUC12 were increased 20% to 30% compared to the controls. Hepatic impairment increased unbound lopinavir AUC12 by 68% and Cmax by 56%. The effect of hepatic impairment on low-dose ritonavir pharmacokinetics was more pronounced in the moderate impairment group (181% and 221% increase in AUC12 and Cmax, respectively) than in the mild impairment group (39% and 61% increase in AUC12 and Cmax, respectively). While lopinavir/ritonavir dose reduction is not recommended in subjects with mild or moderate hepatic impairment, caution should be exercised in this population.     

Model-based approach to dose optimization of lopinavir/ritonavir when co-administered with rifampicin

AIMS

Rifampicin, a key component of antitubercular treatment, profoundly reduces lopinavir concentrations. The aim of this study was to develop an integrated population pharmacokinetic model accounting for the drug–drug interactions between lopinavir, ritonavir and rifampicin, and to evaluate optimal doses of lopinavir/ritonavir when co-administered with rifampicin.

METHODS

Steady-state pharmacokinetics of lopinavir and ritonavir were sequentially evaluated after the introduction of rifampicin and gradually escalating the dose in a cohort of 21 HIV-infected adults. Intensive pharmacokinetic sampling was performed after each dose adjustment following a morning dose administered after fasting overnight. A population pharmacokinetic analysis was conducted using NONMEM 7.

RESULTS

A simultaneous integrated model was built. Rifampicin reduced the oral bioavailability of lopinavir and ritonavir by 20% and 45% respectively, and it increased their clearance by 71% and 36% respectively. With increasing concentrations of ritonavir, clearance of lopinavir decreased in an E_max relationship. Bioavailability was 42% and 45% higher for evening doses compared with morning doses for lopinavir and ritonavir, respectively, while oral clearance of both drugs was 33% lower overnight. Simulations predicted that 99.5% of our patients receiving doubled doses of lopinavir/ritonavir achieve morning trough concentrations of lopinavir > 1 mg l⁻¹ during rifampicin co-administration, and 95% of those weighing less than 50 kg achieve this target already with 600/150 mg doses of lopinavir/ritonavir.

CONCLUSIONS

The model describes the drug–drug interactions between lopinavir, ritonavir and rifampicin in adults. The higher trough concentrations observed in the morning were explained by both higher bioavailability with the evening meal and lower clearance overnight.     

Pharmacokinetics and safety of the lopinavir/ritonavir tablet 500/125 mg twice daily coadministered with efavirenz in healthy adult participants

A study was conducted in healthy adults (n = 19) to evaluate the pharmacokinetics of lopinavir/ritonavir when coadministered with efavirenz. Participants were administered lopinavir/ritonavir 400/100 mg alone twice daily (bid) from the morning of day 1 through the morning of day 10, and then lopinavir/ritonavir 500/125 mg bid was coadministered with efavirenz 600 mg every evening (qhs) from the evening of day 10 through day 20. Lopinavir and ritonavir exposures when administered alone versus with efavirenz were determined on days 10 and 20 and compared using point estimates and 90% confidence intervals. The point estimates for the ratios of lopinavir maximum observed plasma concentration (C(max)), plasma concentration prior to morning dosing (C(trough)), and area under the plasma concentration-time curve over a dosing interval (AUC(12)) were 1.121, 0.954, and 1.060, respectively. The lopinavir/ritonavir dose of 500/125 mg bid administered with efavirenz most closely approximates the pharmacokinetic exposure of lopinavir/ritonavir 400/100 mg bid administered alone.     

Simultaneous Population Pharmacokinetic Model for Lopinavir and Ritonavir in HIV-Infected Adults

BACKGROUND: Lopinavir is a protease inhibitor indicated for the treatment of HIV infection. It is coformulated with low doses of ritonavir in order to enhance its pharmacokinetic profile. After oral administration, plasma concentrations of lopinavir can vary widely between different HIV-infected patients. OBJECTIVE: To develop and validate a population pharmacokinetic model for lopinavir and ritonavir administered simultaneously in a population of HIV-infected adults. The model sought was to incorporate patient characteristics influencing variability in the drug concentration and the interaction between the two compounds. METHODS: HIV-infected adults on stable therapy with oral lopinavir/ritonavir in routine clinical practice for at least 4 weeks were included. A concentration-time profile was obtained for each patient, and blood samples were collected immediately before and 1, 2, 4, 6, 8, 10 and 12 hours after a morning lopinavir/ritonavir dose. Lopinavir and ritonavir concentrations in plasma were determined by high-performance liquid chromatography. First, a population pharmacokinetic model was developed for lopinavir and for ritonavir separately. The pharmacokinetic parameters, interindividual variability and residual error were estimated, and the influence of different patient characteristics on the pharmacokinetics of lopinavir and ritonavir was explored. Then, a simultaneous model estimating the pharmacokinetics of both drugs together and incorporating the influence of ritonavir exposure on oral clearance (CL/F) of lopinavir was developed. Population analysis was performed using nonlinear mixed-effects modelling (NONMEM version V software). The bias and precision of the final model were assessed through Monte Carlo simulations and data-splitting techniques. RESULTS: A total of 53 and 25 Caucasian patients were included in two datasets for model building and model validation, respectively. Lopinavir and ritonavir pharmacokinetics were described by one-compartment models with first-order absorption and elimination. The presence of advanced liver fibrosis decreased CL/F of ritonavir by nearly half. The volume of distribution after oral administration (V(d)/F) and CL/F of lopinavir were reduced as alpha(1)-acid glycoprotein (AAG) concentrations increased. CL/F of lopinavir was inhibited by ritonavir concentrations following a maximum-effect model (maximum inhibition [I(max)] = 1, concentration producing 50% of the I(max) [IC(50)] = 0.36 mg/L). The final model appropriately predicted plasma concentrations in the model-validation dataset with no systematic bias and adequate precision. CONCLUSION: A population model to simultaneously describe the pharmacokinetics of lopinavir and ritonavir was developed and validated in HIV-infected patients. Bayesian estimates of the individual parameters of ritonavir and lopinavir could be useful to predict lopinavir exposure based on the presence of advanced liver fibrosis and the AAG concentration in an individual manner, with the aim of maximizing the chances of treatment success.     

Time-dependent interaction between lopinavir/ritonavir and fexofenadine

This study investigated the effect of single-dose and steady-state lopinavir/ritonavir on the exposure to fexofenadine, as a measure of P-glycoprotein activity. Sixteen volunteers (8 women) received single-dose oral fexofenadine 120 mg alone, in combination with single-dose ritonavir 100 mg or lopinavir/ritonavir 400/100 mg (randomized 1:1, stratified by sex), and in combination with steady-state lopinavir/ritonavir 400/100 mg twice daily. Single-dose ritonavir and lopinavir/ritonavir increased the area under the fexofenadine plasma concentration-time curve from 0 to infinity (AUC(infinity)) by 2.2- and 4.0-fold, respectively (P < .02). Steady-state lopinavir/ritonavir increased the fexofenadine AUC(infinity) by 2.9-fold. No changes were observed in the fexofenadine elimination half-life (P > .12). The fexofenadine AUC(infinity) was increased by lopinavir/ritonavir, likely due to increased bioavailability secondary to P-glycoprotein inhibition. After repeated administration of lopinavir/ritonavir, the interaction was attenuated compared to the single-dose effect, although a net inhibitory effect was maintained. Time-dependent inhibition of P-glycoprotein by lopinavir/ritonavir should be considered when P-glycoprotein substrates are coadministered.     

基于不良反应文献分析探讨洛匹那韦/利托那韦在新型冠状病毒肺炎中的安全使用

目的探究洛匹那韦/利托那韦致不良反应的临床特点,为其在新型冠状病毒肺炎中安全使用提供参考。方法检索中国知网、万方、维普、Pubmed和Embase数据库,收集截至2020年2月15日发表的洛匹那韦/利托那韦致不良反应的文献,对患者的基本信息、药物使用情况、累及系统-器官、临床表现、药物相互作用、治疗及转归等进行回顾性分析。结果共纳入99篇文献,120例患者,其中男性81例,女性39例,平均年龄(39.6±14.8)岁;艾滋病110例,艾滋病毒暴露后预防10例。不良反应中位出现时间为1.0(0.3~5.0)个月,用药10天内出现的有40例。所有时间段内不良反应累及系统-器官主要以内分泌代谢系统、皮肤及其附件、心血管系统、消化系统损害等为主;用药10天内累及系统-器官主要以心血管系统、血液系统、皮肤及其附件、消化系统、泌尿系统损害为主,其中急性肾损伤、白细胞减少、完全性房室传导阻滞、血小板减少、心律失常、皮疹、瘙痒等较为多见。120例不良反应中48例是由于药物相互作用所致,主要涉及氟替卡松、曲安奈德、长春碱、他克莫司、华法林、左甲状腺素、多西他赛、麦角胺等。经过治疗后,111例患者不良反应症状好转,4例患者症状恶化,5例患者死亡。结论应重视用药初期洛匹那韦/利托那韦所致的不良反应,避免药物相互作用,确保用药安全。