Controlled stimulation‐burst targeted release by pH‐sensitive HPMCAS/theophylline composite nanofibers fabricated through electrospinning

Abstract

HPMCAS/theophylline composite nanofibers, which displayed a significant pH-responsive behavior, were successfully fabricated through electrospinning. SEM observations demonstrated that the nanofibers were linear with a smooth and unordered structure. Mean diameter of the composite nanofibers increased with the content of drug. FT-IR spectra confirmed that theophylline was successfully loading into HPMCAS nanofibers. XRD, DSC, and TGA verified that theophylline blended with HPMCAS in a physical level and had retained its crystalline state in the composite nanofibers, which further demonstrated that the drug efficacy did not destroy in the electrospinning process. Drug loading testing showed that drug loading percent and encapsulation efficiency increased with the content of drug, except the 4% drug content sample, which was confirmed to be decided by the beaded morphology. Furthermore, the in vitro drug release studies revealed that the composite nanofibers particularly showed rapid theophylline release at weak alkaline pH environment and exhibited a burst release in the first hour followed by a decreased tendency. However, the release ratio was still at a high level after 12 h. The release process can be helpful to the urgent sudden disease, meanwhile to reduce the suffering of patients and the required frequency of drug administration.

Evaluation of poly(N-isopropylacrylamide)/tetraphenylethylene/amphotericin B-based visualized antimicrobial nanofiber wound dressing for whole skin wound healing in rats

“…This is due to the internal filtering effect of TPE and AMB. With the release of AMB, the excitation light of TPE becomes stronger and stronger, making the emission light of TPE stronger and stronger [ 9 , 49 , 50 ].

Figure 5 (a) Plot of cumulative drug release.

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