The effect of myosin light chain kinase inhibitor (ML7) loaded polymeric nanofiber formulations on myometrial contraction

The aim of this thesis is to design and formulate a nano-based controllable drug delivery and release system and to investigate its' in-vitro effectiveness for preventing premature birth. The effect of nanofibers loaded with calcium channel blocker (nifedipine) and myosin light chain kinase inhibitor (ML7) on spontaneous and stimulated myometrial contractions was investigated using uterine tissue obtained from pregnant women (n= 10) who gave birth by cesarean section at term. Nifedipine and ML7 loaded nanofibers were prepared using the electrospinning method with PLGA polymer. The prepared polymers were, Group I: Control; Group II: Drug-free nanofiber; Group III: Nifedipine (10-5M); Group IV: ML7 (3x10-5 M); Group V: ML7 (3x10-5 M) and Nifedipine (10-5 M); Group VI: ML7 (3x10-5 M) and Nifedipine (3x10-5 M); Group VII: ML7 (3x10-5 M) and Nifedipine (10-4 M) loaded nanofibers. Nanofibers were applied to the myometrium strips (3x10 mm) prepared from the term uterine tissue samples and placed in an in-vitro organ bath. Spontaneous, KCl (120 mM), and cumulative oxytocin (10-11-10-5 M) evoked contractions were recorded. Contraction amplitudes were normalized by strip weight and KCl-stimulated contraction, and contraction frequency and area under the curve were measured. The data were evaluated by the SPSS statistical program. Application of drug-loaded polymers resulted in a significant reduction in the frequency and amplitude of the spontaneous and stimulated contractions in all groups (p<0.01). The results of in the control and the drug-free nanofiber groups were similar (p=0.704). In terms of amplitude and frequency of contractions, the most significant effect to the oxytocin dose-contraction response was recorded in Group VII (p<0.05). In Group VI, the intensity and frequency of contraction were significantly reduced compared to the control and drug-free nanofiber groups, as well (p<0.05). These differences became prominent with increasing doses. The use of Nifedipine or ML7-loaded nanofibers also resulted in decrease in the amplitude and frequency of contractions, but this decrease was not significant compared to the control and empty polymer groups. While the maximum contraction response was also significantly reduced in the drug-applied strips, the most significant difference was observed in Groups VI and VII (p<0.01). The results of this study show that Nifedipine and ML7-loaded nanofibers can suppress contractions in human uterine tissue strips. Demonstrating the in vivo effectiveness of these formulations in further studies will enable locally effective and safe, controllable drug release systems with reduced systemic side effects to be recommended as potential treatment options in preterm birth.