RESUMEN
Felodipine has a very low bioavailability due to first-pass metabolism. The aim of this study was to enhance its bioavailability by transdermal application. Felodipine-loaded transferosomes were prepared by thin-film hydration using different formulation variables. An optimized formula was designed using statistical experimental design. The independent variables were the used edge activator, its molar ratio to phosphatidylcholine, and presence or absence of cholesterol. The responses were entrapment efficiency of transferosomes, their size, polydispersity index, zeta potential, and percent drug released after 8 h. The optimized formula was subjected to differential scanning calorimetry studies and its stability on storage at 4°C for 6 months was estimated. This formula was improved by incorporation of different permeation enhancers where ex vivo drug flux through mice skin was estimated and the best improved formula was formulated in a gel and lyophilized. The prepared gel was subjected to in vivo study using Plendil® tablets as a reference. According to the calculated desirability, the optimized transferosome formula was that containing sodium deoxycholate as edge activator at 5:1 M ratio to phosphatidylcholine and no cholesterol. The thermograms of this formula indicated the incorporation of felodipine inside the prepared vesicles. None of the tested parameters differed significantly on storage. The lyophilized gel of labrasol-containing formula was chosen for in vivo study. The relative bioavailability of felodipine from the designed gel was 1.7. In conclusion, topically applied lyophilized gel containing felodipine-loaded transferosomes is a promising transdermal delivery system to enhance its bioavailability.
Asunto(s)
Sistemas de Liberación de Medicamentos/métodos , Felodipino/administración & dosificación , Geles/administración & dosificación , Absorción Cutánea/efectos de los fármacos , Administración Cutánea , Animales , Animales Recién Nacidos , Disponibilidad Biológica , Rastreo Diferencial de Calorimetría , Felodipino/química , Felodipino/metabolismo , Liofilización , Geles/química , Geles/metabolismo , Lecitinas/administración & dosificación , Lecitinas/química , Lecitinas/metabolismo , Liposomas , Ratones , Absorción Cutánea/fisiología , Comprimidos , Parche TransdérmicoRESUMEN
The oral bioavailability of griseofulvin (GF) formulated as a fast disintegrating lyophilized dry emulsion (LDE) tablet was studied and compared to the commercially available immediate release (IR) tablet, as a reference, in both the fasted and fed states in nine healthy volunteers after a single oral dose (125 mg) in a crossover design. Furthermore the LDE tablets were ingested with and without water under both the fasted and fed states. In the fasted state, the rate of absorption was found to be significantly faster from LDE tablets, in the presence and absence of water, as shown by a higher C(max) (more than two times higher, p=0.0001) and a shorter t(max) (by more than 3h, p=0.0001) compared to IR tablets. The extent of absorption, expressed as AUC, from LDE tablets in the presence and absence of water was 65% and 77% larger and statistically significantly different relative to the mean AUC from IR tablets (p=0.006). In the fed state, C(max) from LDE tablets ingested with and without water was found to be about 30% and 50% higher, respectively, than the immediate release tablets. A shorter t(max) was also shown whether LDE tablets were ingested with or without water in the fed state as compared to immediate release tablets. The mean AUC from LDE tablets under fed conditions in the presence of water was about 21% larger and was not statistically significantly different from AUC from immediate release tablets (p=0.517). When ingested without water, AUC from LDE tablets was about 43% larger and statistically significantly different relative to AUC from IR tablets (p=0.033). The mean AUC from the LDE tablet ingested with water under fed conditions relative to AUC from LDE tablet ingested without water was not statistically significantly different (p=0.454). Results show that the food effect of the high fat meal is very pronounced in case of the immediate release tablets, Fulvin, than in case of LDE tablets whether given with or without water.
Asunto(s)
Antifúngicos/farmacocinética , Griseofulvina/farmacocinética , Administración Oral , Adulto , Antifúngicos/administración & dosificación , Antifúngicos/química , Disponibilidad Biológica , Química Farmacéutica , Estudios Cruzados , Emulsiones , Ayuno/metabolismo , Interacciones Alimento-Droga , Liofilización , Griseofulvina/administración & dosificación , Griseofulvina/química , Humanos , Absorción Intestinal , Masculino , Periodo Posprandial , Polvos , ComprimidosRESUMEN
Development of a fast-disintegrating lyophilized dry emulsion (LDE) tablet that enhanced the in vitro dissolution and in vivo absorption of griseofulvin (GF) is presented. The LDE tablets were prepared by freeze-drying o/w emulsions of GF, a drug for which bioavailability is known to be enhanced by fat co-administration. Oil-in-water emulsions were prepared using a gelatin solution (2%, w/v) as the water phase and medium chain triglycerides (Miglyol) or sesame oil as the oil phase. In addition, different emulsifiers were evaluated. The influence of formulation parameters on the disintegration and in vitro dissolution of GF from LDE tablets along with other tablet characteristics were investigated. A significant influence of the emulsifier type on the tablet disintegration time was seen (p<0.01). Results obtained from dissolution studies showed that LDE tablets of GF improved the dissolution rate of the drug compared to the plain drug. The extent of absorption of GF from a selected LDE tablet formulation as compared to an immediate release conventional tablet as reference after single oral dose (125mg) administration was determined in four healthy subjects using a randomized crossover design. In this study, the rate of absorption of GF from LDE tablet was faster than that from the reference tablet and had significantly higher (p=0.02) peak plasma concentration (more than three times higher) and shortened time to C(max) by 4h (p=0.014). The extent of absorption expressed by AUC was 85% larger as compared to the commercial tablet. Stability results, after 6 months storage of LDE tablets at 25 degrees C and 60% relative humidity, showed a slight increase in disintegration time and residual moisture content, while results from dissolution studies showed slightly slower initial drug release.