000			03160nas|a2200397 i 4500
005			20260817172702.0
008			200717s2001 th u m rtt 00| a1eng d
035			_a.b11861381
099		9	_aAIT Thesis no. BP-01-01
100	1		_aCruz, Pedro Miguel Filipe
245	1	0	_aChitosan microspheres and beads for the sustained release of theophylline
260			_aBangkok : _bAsian Institute of Technology, _c2001
300			_a66 leaves
490	1		_aThesis ; _vno. BP-01-01
500			_aA thesis submitted in pa1iial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development
502			_aThesis (M.Sc.) - Asian Institute of Technology, 2001
520			_aThe main purpose of this study was to develop a sustained delivery system based on the0phylline containing chitosan microspheres obtained by an optimized spray drying technique. Theophylline is an extensively used bronchodilator with a half-life of 5 hours. Due to its narrow therapeutic levels, it should be applied preferentially in a well-controlled delivery system. The spray drier LabPlant SD-05 was used to microencapsulate the theophylline into a chitosan microspheres. Several operational parameters and theophylline: chitosan ratios were investigated in order to establish a correlation with the dissolution characteristics and loading efficiency. Spherical chitosan microspheres loaded with theophylline were about 5 æm in diameter. It was found that a lower chitosan concentration (0.5% w/v) and theophylline: chitosan ratio (20% w/w) resulted in the best loading efficiency and sustained release. This suggests a more effective heat and mass transfer and therefore better drying conditions for proper entrapment of the drug. Additionally chitosan beads loaded with theophylline were prepared by ionotropic gelation technique: dropping chitosan/theophylline solution into a coagulation bath of penta-sodium tripolyphosphate (TPP). A very low total release, dependent on the theophylline content, was attained, likely due to the agglomeration of the beads under the conditions used.
650		0	_aChitosan
650		0	_aTheophylline
700	1		_aSuwalee Chandrkrachang, _eChairperson
700	0		_aPreeda Pakpian, _eExamination Committee
700	1		_aSuwabun Chirachanchai, _eExamination committee
710	2		_aPost graduated Studies Program (PTS) European Commission, _eScholarship donor
810	2		_aAsian Institute of Technology. _tThesis ; _vno. BP-01-01
856			_3Full-Text _uhttp://203.159.5.9/ait-thesis/detail.php?q=B07818
907			_a.b11861381 _bmnait _cu
902			_a240402
998			_b0 _c020717 _dm _ea _fu _g0
945			_lmnait
945			_lmnarc
942			_c22
942			_c40
909			_aBarcode : 30050120683130 _bCREATED : 2013-06-09 _cRECORD # : i12740032 _dLPATRON : 1024926 _eLCHKIN : 2014-01-23 _f# RENEWALS : 0 _g# OVERDUE : 0 _hIUSE3 : 0 _iTOT CHKOUT : 1 _jTOT RENEW : 1
909			_aBarcode : 30050120350854 _bCREATED : 2016-10-06 _cRECORD # : i13029666 _dLPATRON : 0 _eLCHKIN : - _f# RENEWALS : 0 _g# OVERDUE : 0 _hIUSE3 : 0 _iTOT CHKOUT : 0 _jTOT RENEW : 0
999			_c17093 _d17093