Release of lidocaine from polymer film dosage forms.
We investigated the in vitro drug release from mixed polymer films using lidocaine (LC), which is poorly water-soluble. The mixed polymer films consisted of various ratios of hydroxypropylcellulose (HPC) and hydroxypropylmethylcellulose phthalate (HPMCP). The effects of the presence glycyrrhizic acid (GL) or polyethylene glycol (PEG) in the films upon LC release were also studied. LC crystallinity decreased in the polymer film and this decrease was remarkable in the presence of GL, resulting in an amorphous state. During the initial stage, drug release was regarded as a zero-order dissolution. The apparent release rate constant, ka, varied with the ratios of the two polymers and the amount of additives as well as with the pH of the test solution. The results indicated that GL enhanced the dissolution rate of LC from mixed polymer films, which may be due to the formation of an amorphous state. On the other hand, since PEG is a surfactant, the enhanced wettability of the polymer by the buffered solutions may have caused the increased dissolution rate.
Faculty of Pharmacy, Meijo University, Nagoya, Japan.
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Danjo
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Higuchi
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Otsuka
D002152:Calorimetry, Differential Scanning; D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D004304:Dosage Forms; D065347:Hypromellose Derivatives; D008012:Lidocaine / Q000008:administration & dosage* / Q000737:chemistry; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D014961:X-Ray Diffraction
D004304:Dosage Forms; D011108:Polymers; D065347:Hypromellose Derivatives; D002482:Cellulose; D008747:Methylcellulose; D008012:Lidocaine; C008079:hydroxypropylcellulose