https://www.selleckchem.com/products/gm6001.html A key advantage of pyfastx over other tools is that it offers an efficient way to randomly extract subsequences directly from gzip compressed FASTA/Q files without needing to uncompress beforehand. Pyfastx can easily be installed from PyPI (https//pypi.org/project/pyfastx) and the source code is freely available at https//github.com/lmdu/pyfastx. Intracellular tenofovir diphosphate (TFV-DP) concentration measured in dried blood spots (DBS) is used to monitor cumulative adherence to pre-exposure prophylaxis (PrEP). We evaluated TFV-DP in DBS following daily oral PrEP (emtricitabine 200mg/tenofovir diphosphate 300mg) among pregnant and postpartum adolescent girls and young women (AGYW). Directly observed PrEP was administered for 12 weeks in a pregnancy group (14-24 weeks gestation, n=20) and a postpartum group (6-12 weeks postpartum, n=20) of AGYW aged 16-24 years in sub-Saharan Africa. Weekly DBS TFV-DP was measured by validated liquid chromatography-tandem mass spectrometry assay. Week 12 TFV-DP distributions were compared between groups with the Wilcoxon test. Population pharmacokinetic models were fit to estimate steady-state concentrations and create benchmarks for adherence categories. Baseline correlates of TFV-DP were evaluated. Participant median age was 20 years (IQR19,22). Of 3360 doses, 3352 (>99%) were directly observed. TFV-DP median half-life was ten days (IQR7, 12) in pregnancy and 17 days (IQR14, 21) postpartum, with steady-state achieved by five and eight weeks, respectively. Observed median steady-state TFV-DP was 965fmol/punch (IQR691, 1166) in pregnancy vs 1406fmol/punch (IQR1053, 1859) postpartum (p=0.006). Modelled median steady-state TFV-DP was 881fmol/punch (IQR 667,1105) in pregnancy vs 1438fmol/punch (IQR 1178,1919) postpartum. In pooled analysis, baseline creatinine clearance was associated with observed TFV-DP concentrations. TFV-DP in African AGYW was approximately one-third lower in pregn