Development, optimization and in vivo characterization of domperidone-controlled release hot-melt-extruded films for buccal delivery.

OBJECTIVE: The aim of the present investigation was the development and in vivo characterization of domperidone (DOM) hot-melt extruded (HME) controlled release films by central composite design (CCD) for buccal delivery. METHODS: Concentration of PEO N750 (X1) and HPMC E5 LV (X2) as independent variables and tensile strength (Y1), percent drug release at 6 h (Q6, Y2) and percent drug permeated at 6 h (Y3, P6) as responses. In total, 13 formulations were prepared and studied. HME films were evaluated for drug excipient compatibility, physico-mechanical properties, drug content, in vitro drug release, bioadhesion, swelling and erosion, ex vivo permeation. Furthermore, statistically optimized formulation was subjected for bioavailability studies in healthy human volunteers. RESULTS: Statistically optimized formulation exhibited a tensile strength (3.86 kg/mm(2)), 93.62 ± 2.84% of drug release and 63.36 ± 2.12% of drug permeated in 6 h. HME films demonstrated no drug excipient interaction and excellent content uniformity. Furthermore, optimized formulation exhibited elongation at break (38.6% mm(2)), peak detachment force (1.75 N), work of adhesion (3.21 mJ), swelling index (240.4%) and erosion (8.5%). Bioavailability from the statistically optimized buccal films was 3.2 times higher than the oral dosage form (p < 0.05). The ex vivo-in vivo correlation was found to have biphasic pattern and followed type A correlation. The stability of the optimized formulation was studied and no significant changes were detected in 6 months. CONCLUSION: The results indicate that hot-melt extrusion is a viable technique for the preparation of DOM buccal-adhesive controlled release films with improved bioavailability by CCD.

Optimization, characterisation and pharmacokinetic studies of mucoadhesive oral multiple unit systems of ornidazole.

The objective of the present study was to investigate the applicability of matrix type mucoadhesive oral multiple unit systems (MUS) for sustaining the release of ornidazole in the gastrointestinal tract (GIT). The MUS were prepared by ionotropic gelation method using chitosan and hydroxypropyl methyl cellulose K4M (HPMC K4M) according to 3(2) factorial designs and were evaluated in vitro and in vivo. The particle size length ranged from 0.78 to 1.30 mm and breadth from 0.76 to 1.30 mm, respectively. The entrapment efficiency was in range of 80 to 96%. The rapid wash-off test was observed faster at intestinal pH 6.8 as compared to acidic pH 1.2. The fluoroscopic study revealed the retention of MUS in GIT for more than 5 hours. The pharmacokinetic parameters C(max), T(max), mean residence time (MRT) and area under curve (AUC) of developed MUS were found to be improved significantly (p<0.05) when compared with marketed immediate release tablets each containing 500 mg of drug. This study demonstrates that the MUS could be a good alternative to immediate release tablets to deliver ornidazole and expected to be less irritant to gastric and intestinal mucosa.

P-Glycoprotein- and cytochrome P-450-mediated herbal drug interactions.

P-Glycoprotein (P-gp), the most extensively studied ATP-binding cassette transporter, functions as a biological barrier by extruding toxic substances and xenobiotics out of cells. Drug efflux pumps such as P-gp play a functional role in determining the pharmacokinetics of drugs administered by oral and parenteral routes. Determining the activity of drug efflux transport proteins has important implications in the identification of substrates and/or inhibitors. The significant role of the small intestine in reducing the oral bioavailability of drugs is due to metabolic enzymes and efflux transporters. The role of cytochrome P-450 3A (CYP3A) and P-gp in intestinal drug disposition has been highlighted. This review examines the structure, localisation and functional role of P-gp, the mechanism of drug efflux and drug-herb interactions.

Lipid nanoparticles for transdermal delivery of flurbiprofen: formulation, in vitro, ex vivo and in vivo studies.

The aim of the study is to prepare aqueous dispersions of lipid nanoparticles--flurbiprofen solid lipid nanoparticles (FLUSLN) and flurbiprofen nanostructured lipid carriers (FLUNLC) by hot homogenization followed by sonication technique and then incorporated into the freshly prepared hydrogels for transdermal delivery. They are characterized for particle size, for all the formulations, more than 50% of the particles were below 300 nm after 90 days of storage at RT. DSC analyses were performed to characterize the state of drug and lipid modification. Shape and surface morphology were determined by TEM which revealed fairly spherical shape of the formulations. Further they were evaluated for in vitro drug release characteristics, rheological behaviour, pharmacokinetic and pharmacodynamic studies. The pharmacokinetics of flurbiprofen in rats following application of SLN gel (A1) and NLC gel (B1) for 24 h were evaluated. The Cmax of the B1 formulation was 38.67 +/- 2.77 microg/ml, which was significantly higher than the A1 formulation (Cmax = 21.79 +/- 2.96 microg/ml). The Cmax and AUC of the B1 formulation were 1.8 and 2.5 times higher than the A1 gel formulation respectively. The bioavailability of flurbiprofen with reference to oral administration was found to increase by 4.4 times when gel formulations were applied. Anti-inflammatory effect in the Carrageenan-induced paw edema in rat was significantly higher for B1 and A1 formulation than the orally administered flurbiprofen. Both the SLN and NLC dispersions and gels enriched with SLN and NLC possessed a sustained drug release over period of 24 h but the sustained effect was more pronounced with the SLN and NLC gel.

Development and evaluation of nitrendipine loaded solid lipid nanoparticles: influence of wax and glyceride lipids on plasma pharmacokinetics.

Nitrendipine is an antihypertensive drug with poor oral bioavailability ranging from 10 to 20% due to the first pass metabolism. For improving the oral bioavailability of nitrendipine, nitrendipine loaded solid lipid nanoparticles have been developed using triglyceride (tripalmitin), monoglyceride (glyceryl monostearate) and wax (cetyl palmitate). Poloxamer 188 was used as surfactant. Hot homogenization of melted lipids and aqueous phase followed by ultrasonication at temperature above the melting point of lipid was used to prepare SLN dispersions. SLN were characterized for particle size, zeta potential, entrapment efficiency and crystallinity of lipid and drug. In vitro release studies were performed in phosphate buffer of pH 6.8 using Franz diffusion cell. Pharmacokinetics of nitrendipine loaded solid lipid nanoparticles after intraduodenal administration to conscious male Wistar rats was studied. Bioavailability of nitrendipine was increased three- to four-fold after intraduodenal administration compared to that of nitrendipine suspension. The obtained results are indicative of solid lipid nanoparticles as carriers for improving the bioavailability of lipophilic drugs such as nitrendipine by minimizing first pass metabolism.

Effect of ketoconazole on the pharmacokinetics of ornidazole--a possible role of p-glycoprotein and CYP3A.

The influence of ketoconazole, a modulator of P-glycoprotein (P-gp), on the exsorption of ornidazole from everted sacs of rat intestine (duodenum, jejunum and ileum) was investigated. The effect of ketoconazole pretreatment on the pharmacokinetics of ornidazole was also studied in eight healthy human volunteers. After overnight fasting ornidazole 500 mg was administered before and after pretreatment with ketoconazole 200 mg once daily for 7 days. Serum samples were analyzed by reversed phase HPLC. Significant differences were observed in pharmacokinetic parameters C(max), AUC(0-t), AUC(0-infinity), T(max) and clearance. Ornidazole is believed to be metabolized through CYP3A and it has considerable intestinal efflux, which was observed from the in vitro study. The altered pharmacokinetic parameters can be attributed to ornidazole efflux from the blood to the intestine and its metabolism by CYP3A in the intestine.