Formulation, development, and in-vitro/ex-vivo evaluation of vaginal bioadhesive salbutamol sulfate tablets for preterm labor

Abstract

Preterm labor is the main cause of death and serious illness of both infants and pregnant women in Africa and worldwide. Parenteral and oral salbutamol sulfate as a B2 antagonist has been used for the treatment of preterm labor. The study aims are to formulate salbutamol sulfate non-invasive vaginal bioadhesive tablets to avoid the side effects of conventional formulations. Full factorial design 41 ×31 ×21 was used for the preparation of 24 vaginal bioadhesive tablet formulations. The independent factors were polymer type (Carbopol 934, HPMC 4000, HEC, and PEG 6000), polymer to drug ratio (1:1, 2:1, and 3:1), and diluent (lactose and mannitol). Vaginal bioadhesive tablets were evaluated for residence time and time required for release 50% of salbutamol sulfate T50% as dependent variables. The formulations were evaluated in terms of drug content, mass variation, hardness, friability, swelling index, residence time, and in-vitro drug release. Results revealed that polymer and diluent types are the most significant factors in both residence time and T50%. A strong positive correlation (0.91) between in-vitro and ex-vivo permeation was observed, which predict the best in-vivo performance of salbutamol vaginal bioadhesive tablet. Thus, salbutamol sulfate vaginal bioadhesive tablets could be a successful remedy for preterm labor.