ABSTRACT
Contact lenses have good biocompatibility and long wearing duration, and can be used as promising ocular drug delivery system. Drug loading contact lenses can retain the drug on the surface of eye and thus improve the bioavailability. In this review, we summarized the advantage of contact lenses as ocular drug delivery system, mechanism of improving drug absorption, drug loading method and release behavior, and influence of drug loading on physical properties of contact lenses.
ABSTRACT
OBJECTIVE: To develop hot melt pressure sensitive adhesive (HMPSA) for transdermal use, and to investigate the in vitro drug release and permeation property of HMPSA based patches. METHODS: HMPSA was prepared using styrene-isoprene-styrene triblock copolymer (SIS), C5 petroleum resin hydrogenate, lanoline, liquid paraffin, dibutyl phthalate, 2, 6-ditertbutyl-cresol as material under orthogonal design. The formulation of HMPSA was screened using stickiness, melt temperature and vapor permeation rate as index. The in vitro drug release behavior and transdermal property of the optimized HMPSA were evaluated using a-asarone as model drug. RESULTS: The optimized formulation of HMPSA (HMPSA-OP) was followed as: SIS: C5 petroleum resin hydrogenate: lanoline: liquid paraffin: dibutylphthalate: 2, 6-ditertbutyl-cresol=100:140:20:40:20:2. HMPSA-OP had shown more rapid drug release than ordinary HMPSA. And the in vitro transdermal flux of HMPSA-OP was (4.75±0.84) μg · cm-2 · h-1, higher than that of ordinary HMPSA and acrylate PSA. CONCLUSION: The HMPSA-OP shows good property and was suitable to prepare transdermal patch.
ABSTRACT
To develop estradiol transdermal film-forming spray (TFS), various polymers were screened using solvent appearance, spray ability, film-forming rate and appearance as indices. The influence of polymer type, plasticizer and penetration enhancer on the transdermal flux were investigated by selecting porcine skin as model, and transdermal flux of TFS was compared with commercial patch and gel. The drug existing state in the formed film was investigated by differential scanning calorimetry (DSC). The solvent appearances, spray abilities, film-forming rates and appearances of eudragit E PO, RL PO, hydroxypropyl cellulose EF, polyvinylpyrrolidone K30, Plasdone S630 and Agrimer VA64 were suitable for the preparation of TFS. TFS prepared by Eudragit RL PO had the biggest transdermal flux of estradiol among all the polymers investigated. Triethyl citrate, the plasticizer, decreased the transdermal flux. Azone increased the transdermal flux, while oleic acid, isopropyl myristate and menthol had opposite effects. TFS had a higher transdermal rate and a higher accumulative penetrated estradiol of 24 h than commercial patch and gel. The DSC result showed that estradiol was spread as molecule in the formed film of TFS. It was indicated that TFS could be expected to be an effective transdermal drug delivery system.