Formulation, development, in vivo pharmacokinetics and pharmacological efficacy evaluation of novel vaginal bioadhesive sustained core-in-cup salbutamol sulphate tablets for preterm labor

Preterm labor is a major cause of infant serious illness and deaths in the world. Salbutamol is a betamimetic tocolytic drug used to arrest preterm labor. It is given as I.V. infusion then maintenance of treatment is achieved by oral tablets. This study aims to formulate bioadhesive vaginal sustained core-in-cup salbutamol sulphate tablets to improve patient compliance and overcome the side effects of invasive and non-invasive conventional salbutamol formulations. Vaginal bioadhesive sustained core-in-cup salbutamol sulphate tablets were evaluated for their physicochemical properties, bioadhesion properties and dissolution test. All formulations showed acceptable hardness, friability, weight variation and drug content values. F4 (HEC as core), F5 (PEG as core) and F6 (Carbopol 934 as core) and Carbopol 934 as mucoadhesive cup fulfill the desired criteria of both prolonged release and maximum bioadhesive properties. F4, F5&F6 were selected for stability study. F6 showed better pharmacokinetics parameters (T-max, AUC ((0-24)) & t (1/2)) than that of the marketed product (Ventolin (R)). F6 caused a significant delay of labor than that of the marketed product (Ventolin (R)) using uterine contraction model. So, it could be concluded that a promising vaginal bioadhesive sustained core-in-cup salbutamol sulphate tablet was successfully developed and can provide effective treatment of preterm labor.