High-performance liquid chromatography assay for the determination of the HIV-protease inhibitor tipranavir in human plasma in combination with nine other antiretroviral medications

Analytical Techniques for the Analysis of Lopinavir and Ritonavir in Pharmaceutical Dosage Form and Biological Matrices: A Review

Background:

Lopinavir and Ritonavir are the protease inhibitor type of anti-retroviral drugs. Both are used for the treatment of HIV/AIDS. This paper reviews many analytical methods for the analysis of LPV and RTV in pharmaceutical formulations (tablet, capsule, syrup, and bulk) and biological fluids (human plasma, serum, cerebrospinal fluid, rat plasma, and human hair).

Objective:

The study aims to summarize various ana¬lytical techniques, such as Chromatography, Spectrophotometry; and also hyphenated techniques, such as LC-MS/MS, UPLC-MS for analysis of Lopinavir and Ritonavir.

Method:

The review deals with com¬prehensive details about the type of various analytical techniques, such as spectroscopy (UV), chromatography (RP-HPLC, HPTLC, UPLC), and hyphenated techniques, i.e., LC-MS/MS, UPLC-MS for the analysis of lopinavir and ritonavir. These techniques are either explored for the quantification, de¬tection of metabolite or for stability studies of the LPV & RTV.

Conclusion:

The present studies revealed that the HPLC technique along with the spectro-scopic, have been most widely used for the analysis. Out of the developed methods, hyphenated UPLC-MS and LC-MS are very sensitive and helps in the easy estimation of drugs compared to that of the other techniques. This review may provide comprehensive details to the researchers working in the area of analytical research of LPV & RTV.

Chromatographic methods in HIV medicine: Application to therapeutic drug monitoring

HIV antiretroviral therapy spans several different drug classes, meant to combat various aspects of viral infection and replication. Many authors have argued the benefits of therapeutic drug monitoring (TDM) for the HIV patient including compliance assurance and assessment of appropriate drug concentrations; however, the array of drug chemistries and combinations makes TDM an arduous task. HPLC-UV and LC-MS/MS are both frequent instruments for the quantification of HIV drugs in biological matrices with investigators striving to balance sensitivity and affordability. Plasma, the dominant matrix for these analyses, is prepared using protein precipitation, liquid-liquid extraction or solid-phase extraction depending on the specific complement of analytes. Despite the range of polarities found in drug classes relevant to HIV therapeutics, most chromatographic separations utilize a hydrophobic column (C₁₈ ). Additionally, as the clinically relevant samples for these assays are infected with HIV, along with possible co-infections, another important aspect of sample preparation concerns viral inactivation. Although not routine in clinical practice, many published analytical methods from the previous two decades have demonstrated the ability to conduct TDM in HIV patients receiving various medicinal combinations. This review summarizes the analytical methods relevant to TDM of HIV drugs, while highlighting respective challenges.

Amplified fluorescent sensing of DNA using luminescent carbon dots and AuNPs/GO as a sensing platform: A novel coupling of FRET and DNA hybridization for homogeneous HIV-1 gene detection at femtomolar level

The demand for simple, sensitive, affordable, and selective DNA biosensors is willing, due to the important role of DNA detection in the areas of disease diagnostics, environment monitoring and food safety. The presented work is devoted to the fabrication of an ultrasensitive homogeneous biosensor for the detection of DNA sequences related to HIV based on fluorescence resonance energy transfer(FRET) between carbon dots(CDs) and AuNPs as nanoquenchers. CDs as fluorophore with average size 3-4nm were prepared by hydrothermal treatment of histidine. In this respect, the hybridization was occurring between the assemblies of fluorescence CDs functionalized 5-amino-labeled oligonucleotides as capture probe and label free oligonucleotides as detection probe. Due to strong fluorescence and good biocompatibility of CDs, the capture probe was covalently conjugated to CDs. In the presence of the target probe, the association between capture probe-CDs and detection probe is stronger than that between capture probe-CDs and AuNPs, leading to the release of the capture probe-CDs from AuNPs, resulting in the recovery of the fluorescence of CDs. This oligonucleotides detection probe was observed to detect target oligonucleotides specifically and sensitively in a linear range from 50.0fM to 1.0nM with a detection limit of 15fM. Furthermore, the sensitivity of this FRET strategy amplified using AuNPs/graphene oxide nanocomposite as quencher. The Sensor response indicates only the complementary sequence showing an obvious change signal in comparison to non-complementary and two bases mismatched sequences. Moreover, satisfactory results from determination of HIV DNA target in human serum were obtained showing great potential of the proposed method for real sample analysis. The proposed biosensor with highly biocompatibility and nontoxicity, can be developed for detection of other DNA biomarkers.

Development of an HPLC-UV assay method for the simultaneous quantification of nine antiretroviral agents in the plasma of HIV-infected patients

A new method using high-performance liquid chromatography coupled with ultra violet detection (HPLC–UV) was developed and validated for the simultaneous quantification of atazanavir, dolutegravir, darunavir, efavirenz, etravirine lopinavir, raltegravir, rilpivirine and tipranavir in human plasma. For the first time we reported here the development and validation of an HPLC–UV assay to quantify the frequently administered 9 antiretroviral compounds including dolutegravir and rilpivirine. A simple solid phase extraction procedure was applied to 500 µL aliquots of plasma. The chromatographic separation of the drugs and internal standard (quinoxaline) was achieved with a gradient of acetonitrile and sodium acetate buffer on a C₁₈ reverse-phase analytical column with a 25 min analytical run time. Calibration curves were optimised according to the therapeutic range of drug concentrations in patients, and the coefficient of determination (r²) was higher than 0.99 for all analytes. Mean intraday and interday precisions (RSD) for all compounds were less than 15.0%, and the mean accuracy (% deviation from nominal concentration) was also found to be less than 15.0%. Extraction recovery range was between 80% and 120% for all drugs analysed. The solid phase extraction and HPLC–UV method enable a specific, sensitive, and reliable simultaneous determination of nine antiretroviral agents in plasma. Good extraction efficiency and low limit of HPLC–UV quantification make this method suitable for use in clinical trials and therapeutic drug monitoring.

Model-Based Analysis of Unbound Lopinavir Pharmacokinetics in HIV-Infected Pregnant Women Supports Standard Dosing in the Third Trimester

Physiological changes during pregnancy can affect drug pharmacokinetics. Here we present a population pharmacokinetic model to describe the longitudinal change of unbound lopinavir/ritonavir (LPV/RTV) PK parameters with gestational age, and to predict unbound LPV concentrations under different dosing regimens. The changes in apparent intrinsic clearances of LPV and RTV during pregnancy are described using an exponential function of gestational age. The unbound fractions of LPV/RTV are not significantly different between pregnancy and postpartum. Simulation reveals that despite increases in LPV intrinsic clearance, effective LPV inhibitory quotient (IQ) values are predicted with the standard dosing (400/100 mg b.i.d.) in >90% of simulations, with ≤4‐fold increase in viral IC₅₀. As viral susceptibility decreases, higher doses increase the likelihood of efficacy. With ≥40‐fold increases in IC₅₀, IQs suggest alternate regimens be considered. This approach refines previous LPV PK reports, and supports that standard dosing is effective with susceptible virus.

A simple, rapid, economical, and practical method for the determination of efavirenz in plasma of Chinese AIDS patients by reverse phase high-performance liquid chromatography with ultraviolet detector

This study aimed to develop a reverse phase high-performance liquid chromatographic (RP-HPLC) method for the determination of efavirenz in human plasma and to use it for determining the concentrations of efavirenz in Chinese AIDS patient. A simple mobile phase consisting of 0.01 mol/L NaH2PO4 solution and acetonitrile (38:62, V/V) was pumped at a flow rate of 1.0 mL/min through a reverse phase Diamonsil C18 column maintained at 30°C. Diazepam was used as an internal standard and monitored with efavirenz at 247 nm. The protein of 100 μL plasma sample was precipitated before 20 μL of the supernatant was directly injected into the column. The linear response over the concentration ranges 0.10-20.0 μg/mL was obtained and the linear regression equations was Y = 2.2873X ‒ 0.1449 (r = 0.9999). The intra-day and inter-day precisions (1.9-2.6%, 2.2-7.2%, respectively), the relative and absolute recovery (99.3-106.3%, 75.6-80.3%, respectively) met the international standards. Stability of plasma samples were evaluated for short-term (ambient temperature for 16 h) and long-term (-20°C for 30 days) storage conditions and were found to be stable. The mean plasma concentration of efavirenz of the 406 patients was 2.21 ± 1.95 μg/mL, 77.3% of which were within the therapeutic window (1-4 μg/mL), 15.1% were below the window, and 7.6% were over it. In conclusion, the method had advantages of convenience, rapidity, necessary accuracy and precision, high practicality and met the needs for therapeutic drug monitoring and the pharmacokinetic study of efavirenz, especially in underdeveloped countries. For Chinese AIDS patients, it was beneficial to use efavirenz under the guidance of therapeutic drug monitoring.

A sensitive and selective liquid chromatography/tandem mass spectrometry method for quantitative analysis of efavirenz in human plasma

A selective and a highly sensitive method for the determination of the non-nucleoside reverse transcriptase inhibitor (NNRTI), efavirenz, in human plasma has been developed and fully validated based on high performance liquid chromatography tandem mass spectrometry (LC-MS/MS). Sample preparation involved protein precipitation followed by one to one dilution with water. The analyte, efavirenz was separated by high performance liquid chromatography and detected with tandem mass spectrometry in negative ionization mode with multiple reaction monitoring. Efavirenz and ¹³C₆-efavirenz (Internal Standard), respectively, were detected via the following MRM transitions: m/z 314.20243.90 and m/z 320.20249.90. A gradient program was used to elute the analytes using 0.1% formic acid in water and 0.1% formic acid in acetonitrile as mobile phase solvents, at a flow-rate of 0.3 mL/min. The total run time was 5 min and the retention times for the internal standard (¹³C₆-efavirenz) and efavirenz was approximately 2.6 min. The calibration curves showed linearity (coefficient of regression, r>0.99) over the concentration range of 1.0-2,500 ng/mL. The intraday precision based on the standard deviation of replicates of lower limit of quantification (LLOQ) was 9.24% and for quality control (QC) samples ranged from 2.41% to 6.42% and with accuracy from 112% and 100-111% for LLOQ and QC samples. The inter day precision was 12.3% and 3.03-9.18% for LLOQ and quality controls samples, and the accuracy was 108% and 95.2-108% for LLOQ and QC samples. Stability studies showed that efavirenz was stable during the expected conditions for sample preparation and storage. The lower limit of quantification for efavirenz was 1 ng/mL. The analytical method showed excellent sensitivity, precision, and accuracy. This method is robust and is being successfully applied for therapeutic drug monitoring and pharmacokinetic studies in HIV-infected patients.

Protein binding of lopinavir and ritonavir during 4 phases of pregnancy: implications for treatment guidelines

OBJECTIVE

To investigate the intraindividual pharmacokinetics (PKs) of total (protein bound plus unbound) and unbound lopinavir/ritonavir (LPV/RTV) and to assess whether the pediatric formulation (100 mg/25 mg) can overcome any pregnancy-associated changes.

DESIGN

Prospective longitudinal PK study.

METHODS

HIV-infected pregnant antiretroviral therapy-naive and experienced women receiving LPV/RTV 400 mg/100 mg tablets twice daily. Intensive PK evaluations were performed at 20-24 weeks (PK1), 30 weeks (PK2) followed by empiric dose increase using the pediatric formulation (100 mg/25 mg twice daily), 32 weeks (PK3), and 8 weeks postpartum (PK4).

RESULTS

Twelve women completed prespecified PK evaluations. Median (range) age was 28 (18-35) years and baseline BMI was 32 (19-41) kg/m. During pregnancy, total area under the time concentration (AUC0-12h) for LPV was significantly lower than postpartum (PK1, PK2, or PK3 vs. PK4, P = 0.005). Protein-unbound LPV AUC0-12h remained unchanged during pregnancy [PK1: 1.6 (1.3-1.9) vs. PK2: 1.6 (1.3-1.9) μg·h/mL, P = 0.4] despite a 25% dose increase [PK2 vs. PK3: 1.8 (1.3-2.1) μg·h/mL, P = 0.5]. Protein-unbound LPV predose concentrations (C12h) did not significantly change despite dose increase [PK2: 0.10 (0.08-0.15) vs. PK3: 0.12 (0.10-0.15) μg/mL, P = 0.09]. Albumin and LPV AUC0-12h fraction unbound were correlated (rs = 0.3, P = 0.03).

CONCLUSIONS

Total LPV exposure was significantly decreased throughout pregnancy despite the increased dose. However, the exposure of unbound LPV did not change significantly regardless of trimester or dose. Predose concentrations of unbound LPV were not affected by the additional dose and were 70-fold greater than the minimum efficacy concentration. These findings suggest dose adjustments may not be necessary in all HIV-infected pregnant women.

[Evidence-based therapeutic drug monitoring for indinavir]

The HIV protease inhibitor indinavir presents a wide inter-individual variability related to an intense hepatic metabolism. Published studies were analyzed to establish whether there is evidence that therapeutic drug monitoring of indinavir could improve patient care. It was reported that indinavir virological efficacy in HIV-infected patients with wild-type virus was significantly associated with trough concentrations > 100-150 ng/mL. Concerning the exposure-toxicity relationship, the risk of occurrence of nephrotoxicity was more frequently associated with trough concentrations > 500-1 000 ng/mL. Studies with concentration-controlled indinavir therapy suggest that therapeutic drug monitoring allows to achieve safe and effective concentrations, therefore, the level of evidence of the interest of indinavir therapeutic drug monitoring is highly recommended when indinavir is not associated with ritonavir and recommended when ritonavir is combined with ritonavir.

Measurement of antiretroviral drugs in the lungs of HIV-infected patients

AIMS: Prior studies have shown that HAART is associated with decreased HIV viral load in the lungs. The correlation between antiretroviral exposure in bronchoalveolar lavage (BAL) fluid and virologic response was evaluated in patients starting HAART and enrolled in The AIDS Clinical Trial Group Protocol 723. MATERIALS #ENTITYSTARTX00026; METHODS: A total of 24 subjects underwent blood and BAL sampling prior to starting HAART, and after 4 and 24 weeks of HAART. Drug concentrations and HIV RNA were measured in paired plasma and BAL samples. RESULTS: Antiretroviral drugs, including efavirenz, were detectable in BAL fluid of HIV-infected subjects beginning HAART. Efavirenz was also associated with a higher likelihood of clearing HIV RNA from the lungs. CONCLUSION: These results suggest the excellent pulmonary virologic response to antiretroviral therapy may, in part, be due to penetration of antiretroviral drugs into the alveolar compartment.

Transmitted antiretroviral drug resistance among acute and recent HIV infections in North Carolina from 1998 to 2007

Background

Transmitted drug resistance (TDR) limits antiretroviral options and thus complicates the management of HIV-positive patients. HIV disproportionately affects the southern US, but available national estimates of TDR prevalence principally reflect large metropolitan centres outside this region.

Methods

The Duke/UNC Acute HIV Program has collected data on acute or recent HIV infections (ARHI) in North Carolina since 1998. Acute infections represent antibody-negative, RNA-positive patients. Recent infection was determined by history of HIV testing or concordance between detuned ELISA and antibody avidity assays. Genotypic sequence data from the earliest collected pretreatment plasma samples were analysed with the Stanford HIV Database and screened for surveillance drug resistance mutations (SDRMs).

Results

A total of 253 individuals with ARHI between May 1998 and May 2007 had complete genotypic sequence data for analysis; 39.5% were acute infections, 78.7% were male, 64.8% were non-White and 53.8% were men who have sex with men. The overall prevalence of TDR was 17.8%, with SDRMs for non-nucleoside/ nucleotide reverse transcriptase inhibitors (NNRTIs) in 9.5% of the cohort. Mutations for nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) were detected in 7.5% and for protease inhibitors (PIs) in 3.2%. K103N was the most common mutation (7.5%). Thymidine analogue mutations were found in 4.7% of samples; the most common PI SDRM was L90M (2.4%). Dual- or triple-class antiretroviral resistance was rare, encountered in only six (2.4%) samples.

Conclusions

The prevalence of TDR in North Carolina is similar to estimates from the US metropolitan areas. These findings have implications for initial regimen selection and secondary prevention efforts outside of large, metropolitan HIV epicentres.

Quantification of 8 HIV-Protease Inhibitors and 2 Nonnucleoside Reverse Transcriptase Inhibitors by Ultra-Performance Liquid Chromatography with Diode Array Detection

Background: Most HPLC-UV methods for therapeutic drug monitoring of anti-HIV drugs have long run times, which reduce their applicability for high-throughput analysis. We developed an ultra-performance liquid chromatography (UPLC)–diode array detection method for the simultaneous quantification of the HIV-protease inhibitors (PIs) amprenavir, atazanavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, and tipranavir (TPV), and the nonnucleoside reverse transcriptase inhibitors (NNRTIs) efavirenz and nevirapine.

Methods: Solid-phase extraction of 1 mL plasma was performed with Waters HLB cartridges. After 3 wash steps, we eluted the drugs with methanol, evaporated the alcohol, and reconstituted the residue with 50 μL methanol. We injected a 4-μL volume into the UPLC system (Waters ACQUITY UPLC BEH C8 column maintained at 60 °C) and used a linear gradient of 50 mmol/L ammonium acetate and 50 mmol/L formic acid in water versus acetonitrile to achieve chromatographic separation of the drugs and internal standard (A-86093). Three wavelengths (215, 240, and 260 nm) were monitored.

Results: All drugs were eluted within 15 min. Calibration curves with concentrations of 0.025–10 mg/L (1.875–75 mg/L for TPV) showed coefficients of determination (r2) between 0.993 and 0.999. The lower limits of quantification were well below the trough concentrations reported in the literature. Inter- and intraassay CVs and the deviations between the nominal and measured concentrations were <15%. The method was validated by successful participation in an international interlaboratory QC program.

Conclusions: This method allows fast and simultaneous quantification of all commercially available PIs and NNRTIs for therapeutic drug monitoring.

Development and validation of a reversed-phase liquid chromatographic method with fluorescence detection for the study of Saquinavir pharmacokinetics in rat plasma

This research work aims to exploit the high selectivity and sensitivity of fluorescence detector to develop and validate a high performance liquid chromatography (HPLC) method having very small sampling volume, much better mass-sensitive detection limit and lower operating cost for the determination of Saquinavir (SQV), known to have low oral bioavailability, in rat plasma. Unlike the traditional methods that require at least 0.25 mL of plasma for each measurement, the present method requires only a 0.1 mL sample volume. This is very useful in reducing the blood collection from study rats, offering the possibility to make sufficient number of samples for pharmacokinetic study and minimizing the amount of blood-derived biological waste. After liquid-liquid extraction, the compounds were separated on a Vydac C18 monomeric column (250 mm x 4.6 mm i.d. x 5 microm particle size) using a mobile phase composed of acetonitrile and potassium dihydrogen phosphate buffer (45:55, v/v). Fluorescence detection was performed at 237 nm (excitation) and 380 nm (emission). Validity of the method was studied and the method was found to be precise and accurate with a linearity range from 0.005 to 1.000 microg mL(-1) (r>0.9980). The limit of detection (LOD) was found to be 0.001 microg mL(-1). The intra-day and inter-day precision studies showed good reproducibility with coefficients of variation (C.V.) less than 11.4%. The developed method was applied successfully to monitor the pharmacokinetic profile following oral administration of SQV to rats.