{"doi":"10.12688/wellcomeopenres.17202.2","title":"Validation and clinical application of a method to quantify efavirenz in cervicovaginal secretions from flocked swabs using liquid chromatography tandem mass spectrometry","abstract":"<ns4:p> <ns4:bold>Background</ns4:bold> <ns4:bold>:</ns4:bold> 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. </ns4:p> <ns4:p> <ns4:bold>Methods:</ns4:bold> 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. </ns4:p> <ns4:p> <ns4:bold>Results:</ns4:bold> 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 <ns4:sub>0-24h</ns4:sub> was 16370 ng*h/mL (5803-22088), C <ns4:sub>max</ns4:sub> was 1618 ng/mL (610-2438) at a T <ns4:sub>max</ns4:sub> of 8.0 h (8.0-12), and C <ns4:sub>min</ns4:sub> was 399 ng/mL (110-981). Efavirenz CVS:plasma AUC <ns4:sub>0-24h</ns4:sub> ratio was 0.41 (0.20-0.59). </ns4:p> <ns4:p> <ns4:bold>Conclusions:</ns4:bold> 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>","journal":"Wellcome Open Research","year":2022,"id":308327,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9619,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2022-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":800719,"name":"Jacinta N. Nwogu","orcid":"0000-0002-0640-7165","position":1,"is_corresponding":false},{"id":21587,"name":"Oluwasegun Eniayewu","orcid":"0000-0002-8902-4150","position":2,"is_corresponding":false},{"id":21584,"name":"Shakir Atoyebi","orcid":"0000-0002-1393-3753","position":3,"is_corresponding":false},{"id":800720,"name":"Alieu Amara","orcid":"0000-0002-1137-2948","position":4,"is_corresponding":false},{"id":801203,"name":"John Kpamor","orcid":null,"position":5,"is_corresponding":false},{"id":800721,"name":"Oluseye O. Bolaji","orcid":"0000-0002-8295-7150","position":6,"is_corresponding":false},{"id":638411,"name":"Ebunoluwa A. Adejuyigbe","orcid":"0000-0002-8671-4965","position":7,"is_corresponding":false},{"id":254201,"name":"Andrew Owen","orcid":"0000-0002-9819-7651","position":8,"is_corresponding":false},{"id":254199,"name":"Saye Khoo","orcid":"0000-0002-2769-0967","position":9,"is_corresponding":false},{"id":21590,"name":"Adeniyi Olagunju","orcid":"0000-0002-6588-5749","position":0,"is_corresponding":true}],"reference_count":27,"raw_metadata":null,"created_at":"2026-07-19T00:33:03.486542Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}