Quality assessment of hydroquinone, mercury, and arsenic in skin-lightening cosmetics marketed in Ilorin, Nigeria

Hydroquinone, Mercury (Hg), and Arsenic (As) are hazardous to health upon long-term exposure. Hydroquinone, Hg, and As were analysed in skin-lightening cosmetics randomly purchased from different cosmetic outlets within the Ilorin metropolis, Nigeria. The amount of hydroquinone in the samples was determined using a UV-spectrophotometry method at 290 nm. Hg and As were quantified using atomic absorption spectrophotometry (AAS). UV-spectrophotometry method validation showed excellent linearity (r2 = 0.9993), with limits of detection (0.75 g/mL), limits of quantification (2.28 g/mL), relative standard deviation (0.01–0.35%), and recovery (95.85–103.56%) in the concentration range of 5–50 g/mL. Similarly, r2, LOD, and LOQ for Hg and As were 0.9983 and 0.9991, (0.5 and 1.0 g/L) and 1.65 and 3.3 g/L) respectively. All the samples contained hydroquinone, Hg and As in varying amounts. The amounts of hydroquinone, Hg and As present were in the ranges of 1.9–3.3%, 0.08–2.52 g/g and 0.07–5.30 g/g respectively. Only three of the analysed samples contained hydroquinone within the permissible limit of 2.0% w/w in cosmetic products. All the samples analysed contained mercury and arsenic in varying amounts. The need to periodically monitor the levels of hydroquinone, mercury, and arsenic in skin-lightening cosmetics marketed in Nigeria is recommended

Validation and Clinical Application of a Liquid Chromatography-Ultraviolet Detection Method to Quantify Dolutegravir in Dried Blood Spots

BACKGROUND: Dolutegravir is currently the preferred component of first-line antiretroviral therapy. To facilitate clinical pharmacology studies in key populations, quantitative analytical methods compatible with microsampling and adaptable to resource-limited settings are desirable. The authors developed and validated a liquid chromatography-ultraviolet detection method to quantify dolutegravir in dried blood spots (DBS). METHODS: Calibration standards and quality control samples were prepared by spotting 50 μL of dolutegravir-spiked whole blood on each circle of DBS cards. Three spots (two 6-mm punches/spot) were extracted with methanol. Chromatographic separation was achieved with gradient elution of acetonitrile/potassium phosphate monobasic buffer (pH 5) on a reverse-phase C18 column (flow rate, 1 mL/min) using pioglitazone as the internal standard. UV detection was performed at 260 nm. In the clinical pharmacokinetic study, DBS from finger prick was collected from participants (n = 10) at 8 time points over 12 h post-dosing, with paired plasma at 1 and 12 h. The method was used to quantify dolutegravir, estimating pharmacokinetic parameters. Agreement between DBS and plasma concentrations was evaluated using linearity and Bland-Altman plots. RESULTS: The method was validated over the concentration range of 0.4-10 μg/mL, accuracy was 102.4-114.8%, and precision was 3.4-14.7%. The mean recovery was 42.3% (%CV: 8.3). The mean (±standard deviation) dolutegravir concentration in DBS was 37.5% (±3.8%) lower than that in the plasma. DBS-derived and measured plasma concentrations showed strong correlation with linearity (R(2) = 0.9804) and Bland-Altman plots. Means (%CV) of AUC, C(max), and C(24) from the DBS-derived plasma concentration were 37.8 (23.2) μg.h/mL, 2.7 (24.7) μg/mL and 1.34 (31.6) μg/mL, respectively. CONCLUSIONS: The application of this simple, accurate, and precise method will expand opportunities for clinical assessment of dolutegravir in resource-limited settings

Pharmacogenetics of efavirenz exposure in cervicovaginal fluid during pregnancy and postpartum

Objectives: Adequate antiretroviral drug distribution into the female genital tract (FGT) could play an important role in reducing the risk of heterosexual and mother-to-child transmission of HIV. In this study, we investigated the combined influence of pregnancy and genetic polymorphisms on efavirenz pharmacokinetics in cervicovaginal fluid (CVF) of women receiving antiretroviral therapy. Methods: A total of 159 women (147 pregnant and 12 postpartum) living with HIV and receiving efavirenz-containing antiretroviral therapy were recruited across two sites in Nigeria (Federal Medical Centre, and Bishop Murray Medical Centre, Makurdi) between 2017-2020. In stage 1, sparse CVF and dried blood spot (DBS) samples were obtained from each participant during pregnancy to assess possible association between drug concentration and CYP2B6 polymorphisms (516G>T and 983 T>C). In the second stage, participants were stratified into three genotype groups (extensive, intermediate and low metabolisers) and re-enrolled for intensive pharmacokinetic sampling. Results: In stage 1 (88 CVF, 81 plasma and 73 paired samples), CYP2B6 516G>T was independently associated with both CVF (β = 997 ng/mL (90% CI: 598, 1357), p = 5.7 x 10-5) and plasma (β = 1400 ng/mL (90% CI: 1051, 1748), p = 5.7 x 10-9) efavirenz concentration during pregnancy. In the second stage (12 pregnant, 12 postpartum), median (IQR) efavirenz Cmin in CVF during pregnancy versus postpartum was 243 ng/ml (168-402) vs 447 ng/ml (159-974), Cmax was 1031 ng/ml (595-1771) vs 1618 ng/ml (675-2695), and AUC0-24 was 16465 ng.h/ml (9356-30417) vs 30715 ng.h/ml (10980-43714). Overall, median CVF-to-plasma AUC ratio was 0.34 during pregnancy and 0.46 postpartum. When patients were stratified using CYP2B6 516G>T, efavirenz median clearance increased by 57.9% during pregnancy compared with postpartum control (p = 0.232) in patients with the CYP2B6 516GT genotype. The AUC0-24h , Cmax and Cmin reduced by 33.8% ((p=0.182) , 8.6% (0.175) and 59.5% (0.171) during pregnancy, with values of 20671 ng.h/ml (15993-28712), 1550 ng/ml (1090-2090) and 330 ng/ml (250-440), respectively, compared with 31229 ng.h/ml (27660-41873), 1695 ng/ml (1540-3003) and 814 ng/ml (486-981) during postpartum in this genotype. Median efavirenz Cmin in CVF was 1.93 and 3.55 times higher than the PBIC90 of 126 ng/ml in the pregnant and postpartum cohorts, respectively. Conclusions: Efavirenz is well distributed into the CVF, and both pregnancy and polymorphisms in its disposition genes affect CVF exposure

Pharmacogenetics of Efavirenz Exposure in Cervicovaginal Fluid during Pregnancy and Postpartum.

In this study, we investigated the combined influence of pregnancy and genetic polymorphisms on efavirenz pharmacokinetics in cervicovaginal fluid (CVF) of women receiving antiretroviral therapy. Women receiving efavirenz-containing antiretroviral therapy were recruited from two hospitals in Nigeria during 2017-2020. Sparse CVF and plasma samples were obtained during pregnancy to assess the possible association between drug concentration and CYP2B6 polymorphisms (stage I). Participants were stratified into three CYP2B6 516G>T (rs3745274) genotype groups and re-enrolled for intensive pharmacokinetic sampling (stage II). Overall, 159 women (142 pregnant and 12 postpartum) contributed samples in stage I (88 CVF, 81 plasma and 73 paired). CYP2B6 516G>T (rs3745274) remained independently associated with log10 efavirenz CVF concentration during pregnancy after adjusting for plasma concentration, with β (Log10 efavirenz concentration, 95%CI) of 0.204 (0.027, 0.382), P = 0.025). Median (IQR) efavirenz Cmin in CVF during pregnancy (n = 12) vs. postpartum (n = 12) was 243 ng/mL (168-402) vs. 447 ng/mL (159-974), Cmax was 1,031 ng/mL (595-1,771) vs. 1,618 ng/mL (675-2,695), and AUC0-24h was 16,465 ng.h/mL (9,356-30,417) vs. 30,715 ng.h/mL (10,980-43,714). CVF-to-plasma AUC ratio was 0.36 during pregnancy and 0.46 postpartum. Upon stratification, efavirenz clearance during pregnancy was 57.9% higher than postpartum in patients with the CYP2B6 516GT genotype; the AUC0-24h and Cmax were 33.8% and 8.6% lower, respectively. Efavirenz Cmin in CVF exceeded the protein binding-adjusted IC90 (PBIC90) of 126 ng/mL during pregnancy and postpartum. Efavirenz is well distributed into the CVF; both pregnancy and CYP2B6 polymorphisms affect the extent of exposure

Atazanavir/ritonavir increased tizoxanide exposure from oral nitazoxanide through pharmacokinetic interaction in healthy volunteers

Aims: Nitazoxanide is a broad–spectrum antiviral with potential application in a number of viral infections. Its use is limited by gastrointestinal side effects associated with increasing dose. In this study, we investigated the possibility of enhancing the exposure of its active metabolite, tizoxanide, through pharmacokinetic interaction with atazanavir/ritonavir. Method: This was a crossover drug–drug interaction study, 18 healthy participants received a single dose of 1000 mg of nitazoxanide alone in period 1 and in combination with 300/100 mg atazanavir/ritonavir in period 2 after a washout period of 21 days. On both days, blood samples for intensive pharmacokinetic analyses were collected before and at 0.25, 0.5, 1, 2, 4, 6, and 12 h after dose. To explore the utility of dried blood spots (DBS) as alternative to plasma for tizoxanide quantification, 50 μL of blood from some participants was spotted on DBS cards. Pharmacokinetic parameters were derived by non-compartmental analysis and compared between periods 1 and 2. The correlation between tizoxanide concentration in plasma and DBS was also evaluated. Results: Co-administration of nitazoxanide with atazanavir/ritonavir resulted in a significant increase in tizoxanide plasma exposure. The geometric mean ratios (90% CI) of tizoxanide AUC0-12h, Cmax and C12h were 1.872 (1.870 – 1.875), 2.029 (1.99 – 2.07) and 3.14 (2.268 – 4.352) respectively, were all outside the 0.8 – 1.25 interval, implying clinically significant interaction. DBS concentration (%CV) was 46.3% (5.6%) lower than plasma concentrations, with a strong correlation (R = 0.89, P &lt; 0.001). Similarly, DBS-derived plasma concentration and plasma concentrations displayed a very strong correlation with linearity (R = 0.95, P &lt; 0.001) Conclusion: Co-administration with atazanavir/ritonavir enhanced tizoxanide exposure with no report of adverse events in healthy volunteers.</jats:p

Atazanavir/Ritonavir Increased Tizoxanide Exposure from Oral Nitazoxanide through Pharmacokinetic Interaction in Healthy Volunteers

Nitazoxanide use is limited by gastrointestinal side effects associated with increasing dose. In this drug repurposing study, we investigated the possibility of enhancing the exposure of its active metabolite, tizoxanide, through pharmacokinetic interaction with atazanavir/ritonavir. In this crossover drug–drug interaction study, 18 healthy participants received a single dose of 1000 mg of nitazoxanide alone and in combination with 300/100 mg atazanavir/ritonavir in period 1 and 2 respectively. On both days, blood samples for intensive pharmacokinetic analyses were collected at 0–12 h post-dose. To explore the utility of dried blood spots (DBS) as an alternative to plasma for tizoxanide quantification, 50 µL of blood from some participants was spotted on DBS cards and correlated with plasma concentrations. Pharmacokinetic parameters were derived by non-compartmental analysis and compared between both periods. Co-administration of nitazoxanide with atazanavir/ritonavir resulted in a significant increase in tizoxanide plasma exposure [GMR (90% CI) of AUC0–12h, Cmax and C12h being 1.872 (1.870–1.875), 2.029 (1.99–2.07) and 3.14 (2.268–4.352), respectively]. DBS concentration (%CV) was 46.3% (5.6%) lower than plasma concentrations, and there was strong correlation (R = 0.95, p &lt; 0.001) between DBS-derived plasma concentration and plasma concentrations. Co-administration with atazanavir/ritonavir enhanced tizoxanide exposure with no report of adverse events in healthy volunteers.</jats:p

Validation and clinical application of a method to quantify efavirenz in cervicovaginal secretions from flocked swabs using liquid chromatography tandem mass spectrometry

Background : A liquid chromatography tandem mass spectrometry method to quantify drugs in dried cervicovaginal secretions from flocked swabs was developed and validated using the antiretroviral efavirenz as an example. Methods: Cervicovaginal swabs (CVS) were prepared by submerging flocked swabs in efavirenz-spiked plasma matrix. Time to full saturation, weight uniformity, recovery and room temperature stability were evaluated. Chromatographic separation was on a reverse-phase C18 column by gradient elution using 1mM ammonium acetate in water/acetonitrile at 400 µL/min. Detection and quantification were on a TSQ Quantum Access triple quadrupole mass spectrometer operated in negative ionisation mode. The method was used to quantify efavirenz in CVS samples from human immunodeficiency virus (HIV)-positive women in the VADICT study (NCT03284645). A total of 98 samples (35 paired intensive CVS and DBS pharmacokinetic samples, 14 paired sparse CVS and DBS samples) from 19 participants were available for this analysis. Results: Swabs were fully saturated within 15 seconds, absorbing 128 µL of plasma matrix with coefficient of variation (%CV) below 1.3%. The method was linear with a weighting factor (1/X) in the range of 25-10000 ng/mL with inter- and intra-day precision (% CV) of 7.69-14.9%, and accuracy (% bias) of 99.1-105.3%. Mean recovery of efavirenz from CVS was 83.8% (%CV, 11.2) with no significant matrix effect. Efavirenz remained stable in swabs for at least 35 days after drying and storage at room temperature. Median (range) CVS efavirenz AUC 0-24h was 16370 ng*h/mL (5803-22088), C max was 1618 ng/mL (610-2438) at a T max of 8.0 h (8.0-12), and C min was 399 ng/mL (110-981). Efavirenz CVS:plasma AUC 0-24h ratio was 0.41 (0.20-0.59). Conclusions: Further application of this method will improve our understanding of the pharmacology of other therapeutics in the female genital tract, including in low- and middle-income countries.</ns4:p