Purasorb pdlg 7502

Terconazole was provided by Minapharm Pharmaceuticals (Cairo, Egypt). Syloid^®244 FP was received as a gift sample from W.R. Grace & Co. (St. Neots, UK). Poly(D, L-lactic/glycolic acid); PLGA with a lactide to glycolide ratio of 50:50, end-capped with acid terminal and an inherent viscosity of 0.2 dL/g (Purasorb^® PDLG 5002 A); PLGA with a lactide to glycolide ratio of 50:50, end-capped with ester terminal and an inherent viscosity of 0.2 dL/g (Purasorb^® PDLG 5002); PLGA with a lactide to glycolide ratio of 75:25, end-capped with acid terminal and an inherent viscosity of 0.22 dL/g (Purasorb^® PDLG 7502 A) and PLGA with a lactide to glycolide ratio of 75:25, end-capped with ester terminal and an inherent viscosity of 0.22 dL/g (Purasorb^® PDLG 7502) were kindly provided by Corbion (Amsterdam, Netherlands). Acetonitrile (HPLC grade), sodium chloride, sodium dihydrogen phosphate monohydrate and disodium hydrogen phosphate heptahydrate were purchased from El-Nasr Pharmaceutical Chemicals (Cairo, Egypt). Dialysis tubing cellulose membrane (molecular weight cutoff 12000-14000 g/mole) was procured from Sigma Aldrich (Saint louis, MO, USA). The rest of chemicals and solvents were of analytical grade and were utilized as received. Water was used as deionized, bi-distilled water.

TAF (also known as GS-7340) was provided by Gilead Sciences, Inc. TAF and TFV and their stable isotopically labelled (SIL) internal standards (TFV-d6 and TAF-d5) were obtained from Toronto Research Chemicals (Canada). Poly(vinylpyrrolidone) (PVP K29-32; and PVP K90) was provided by Ashland (Kidderminster, UK). Poly(vinyl alcohol) (PVA 9–10 ​kDa) and solvents methanol ≥99.9%, dimethyl sulfoxide (DMSO), tetrahydrofuran (THF) inhibitor-free ≥ 99.9% and acetonitrile (ACN) ​≥ ​99.9% (all HPLC grade), ammonium acetate ≥98%, and Acetic acid ≥99.7% were purchased from Sigma-Aldrich, St. Louis, USA. Two different types of poly(d,l-lactide-co-glycolide) (PLGA) were used, a low viscosity PLGA, Purasorb® PDLG 7502 with a lactide:glycolide ratio of 75:25 and ester end (Purac®, Corbion, Netherlands) (LV-PLGA) and a high viscosity PLGA with a lactide:glycolide ratio of 75:25 and ester end (Viatel® DLG 7503 ​E) (HV-PLGA). Both PLGAs were a donation from Ashland (Kidderminster, UK). All other reagents used in this work were of analytical grade and purchased from Sigma-Aldrich. Elga purified water was used in all cases (Purelab option® Elga LabWater, High Wycombe, UK).