Chinna Reddy Palem

Enhanced bioavailability of lacidipine via microemulsion based transdermal gels: Formulation optimization, ex vivo and in vivo characterization

The purpose of the present study was to develop and optimize the microemulsion based transdermal therapeutic system for lacidipine (LCDP), a poorly water soluble and low bioavailable drug. The pseudo-ternary phase diagrams were developed for various microemulsion formulations composed of isopropyl myristate, Tween 80 and Labrasol. The microemulsion was optimized using a three-factor, three-level Box-Behnken design, the independent variables selected were isopropyl myristate, surfactant mixture (Tween 80 and Labrasol) and water; dependent variables (responses) were cumulative amount permeated across rat abdominal skin in 24h (Q(24); Y(1)), flux (Y(2)), and lag time (Y(3)). Mathematical equations and response surface plots were used to relate the dependent and independent variables. The regression equations were generated for responses Y(1), Y(2) and Y(3). The statistical validity of the polynomials was established, and optimized formulation factors were selected by feasibility and grid search. Validation of the optimization study with 10 confirmatory runs indicated high degree of prognostic ability of response surface methodology. The gel of optimized formulation (ME-OPT) showed a flux of 43.7microgcm(-2)h(-1), which could meet the target flux (12.16microgcm(-2)h(-1)). The bioavailability studies in rabbits showed that about 3.5 times statistically significant (p<0.05) improvement in bioavailability, after transdermal administration of microemulsion gel compared to oral suspension. The ex vivo-in vivo correlation was found to have biphasic pattern and followed type A correlation. Microemulsion based transdermal therapeutic system of LCDP was developed and optimized using Box-Behnken statistical design and could provide an effective treatment in the management of hypertension.

Oral transmucosal delivery of domperidone from immediate release films produced via hot-melt extrusion technology

The objective of the study was to prepare and characterize the domperidone (DOM) hot-melt extruded (HME) buccal films by both in vitro and in vivo techniques. The HME film formulations contained PEO N10 and/or its combination with HPMC E5 LV or Eudragit RL100 as polymeric carriers, and PEG3350 as a plasticizer. The blends were co-processed at a screw speed of 50 rpm with the barrel temperatures ranging from 120–160°C utilizing a bench top co-rotating twin-screw hot-melt extruder using a transverse-slit die. The HME films were evaluated for drug content, drug excipient interaction, in vitro drug release, mechanical properties, in vivo residence time, in vitro bioadhesion, swelling and erosion, ex vivo permeation from HME films and the selected optimal formulation was subjected for bioavailability studies in healthy human volunteers. The extruded films demonstrated no drug excipient interaction and excellent content uniformity. The selected HME film formulation (DOM2) exhibited a tensile strength (0.72 Kg/mm2), elongation at break (28.4% mm2), in vivo residence time (120 min), peak detachment force (1.55 N), work of adhesion (1.49 mJ), swelling index (210.2%), erosion (10.5%) and in vitro drug release of 84.8% in 2 h. Bioavailability from the optimized HME buccal films was 1.5 times higher than the oral dosage form and the results showed statistically significant (p < 0.05) difference. The ex vivo–in vivo correlation was found to have biphasic pattern and followed type A correlation. The results indicate that HME is a viable technique for the preparation of DOM buccal-adhesive films with improved bioavailability characteristics.

Transmucosal delivery of domperidone from bilayered buccal patches: in vitro, ex vivo and in vivo characterization.

Bilayered mucoadhesive buccal patches for systemic administration of domperidone (DOM), a dopamine-receptor (D2) antagonist, were developed using hydroxy propyl methyl cellulose and PVPK30 as a primary layer and Eudragit RLPO and PEO as a secondary layer. Ex vivo drug permeation through porcine buccal membrane was performed. Bilayered buccal patches were developed by solvent casting technique and evaluated for in vitro drug release, moisture absorption, mechanical properties, surface pH, in vitro bioadhesion, in vivo residence time and ex vivo permeation of DOM through porcine buccal membrane from a bilayered buccal patch. Formulation DB4 was associated with 99.5% drug release with a higuchi model release profile and 53.9% of the drug had permeated in 6 h, with a flux of 0.492 mg/h/cm2 through porcine buccal membrane. DB4 showed 5.58 N and 3.28 mJ peak detachment force and work of adhesion, respectively. The physicochemical interactions between DOM and the polymer were investigated by differential scanning calorimetry (DSC) and fourier transform infrared (FTIR) Spectroscopy. DSC and FTIR studies revealed no interaction between drug and polymer. Stability studies for optimized patch DB4 was carried out at 40°C/75% relative humidity. The formulations were found to be stable over a period of 3 months with respect to drug content, in vitro release and ex vivo permeation through porcine buccal membrane. The results indicate that suitable bilayered mucoadhesive buccal patches with desired permeability could be prepared.

Development of high performance liquid chromatography method for buspirone in rabbit serum: Application to pharmacokinetic study

A simple and sensitive high performance liquid chromatographic (HPLC) method for quantification of lacidipine (LCDP) in rabbit serum was developed and validated. LCDP and internal standard (IS), felodipine were extracted into n-hexane and dichloromethane (70:30) solvent system and separated using an isocratic mobile phase, on an Inertsil C18 column. The effluent was monitored by UV detector at 240 nm and at a flow rate of 1.0 mL min(-1). The linearity range of proposed method was 1-500 ng mL(-1). The intra-day and inter-day coefficient of variation and percent error values of the assay method were less than 15% and mean recovery was more than 94 and 95% for LCDP and IS, respectively and the method was found to be precise, accurate, and specific during the study. The method was successfully applied for pharmacokinetic study of lacidipine after application of LCDP microemulsion gel in rabbits.

Role of cyclodextrin complexation in felodipine-sustained release matrix tablets intended for oral transmucosal delivery: in vitro and ex vivo characterization.

The objective of the present research was two-fold: To characterize the produced inclusion complex of felodipine (FDP)-hydroxypropyl-β-cyclodextrin (HPβCD) utilizing lyophilization, and to develop and characterize a complexed sustained-release polymeric matrix tablets intended for buccal delivery. The phase-solubility diagram suggested an AL type system with 1:1 stoichiometry. Solid complexes prepared by physical mixing and lyophilization were characterized by thermal and non-thermal analytical techniques to corroborate the fact of complex formation. The sustained-release FDP tablets were produced by direct compression, and these drug or complex-loaded hydrophilic matrices were assessed for in vitro bioadhesion and release modulation, ex vivo permeation, and in vivo residence time. The in vitro drug release and ex vivo permeation across the porcine buccal membrane demonstrated that the matrix tablets containing FDP-HPβCD (FH5) solid complex exhibited a complete and sustained drug release pattern, and a significantly higher drug permeation (p < 0.05) compared to all of the other formulations tested. This could be attributed to both, the FDP-HPβCD complexation phenomenon, and the presence of hydrophilic polymer in the formulation. All of the formulations tested, demonstrated good stability in human saliva. Additionally, in vivo mucoadhesive behavior of the optimized formulations was studied in healthy human volunteers and subjective parameters were evaluated.

Development of bioadhesive buccal tablets for felodipine and pioglitazone in combined dosage form: in vitro, ex vivo, and in vivo characterization.

The purpose of the present research was to develop bioadhesive buccal tablets for Felodipine (FDP) and Pioglitazone (PIO), low bioavailability drugs, in a combined dosage form for the management of diabetes and hypertension. Buccal tablets were prepared by direct compression method using bioadhesive polymers hydroxypropyl methyl cellulose, sodium carboxymethyl cellulose, and carbopol, alone or in combination of two polymers, and were evaluated for physicochemical properties, swelling index, in vitro bioadhesion, in vivo residence time, in vitro drug release, and ex vivo permeation through porcine buccal membrane. Formulation (PF6) showed peak detachment force (3.12 N), work of adhesion (0.72 mJ), swelling index (196%), erosion (10.8%), in vivo residence time of 280 min, in vitro drug release (99.65% and 98.96% in 6 h for FDP and PIO, respectively) with higuchi model release profile and permeated 66.1 and 64.6 % with a flux of 0.118 and 0.331 mg/h/cm2 of FDP and PIO through porcine buccal membrane. The bioavailability study for optimized formulation (PF6) in pigs showed 2.05- and 2.13-times statistically significant (p < 0.05) improvement in bioavailability for FDP and PIO, respectively, after administration of buccal tablets compared to oral suspension. The ex vivo–in vivo correlation was found to have a biphasic pattern and followed type A correlation. The stability of the PF6 was studied and no significant changes were detected in drug content and in vitro release and ex vivo permeation through porcine buccal membrane after 6 months.

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

Abstract 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/mm2), 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% mm2), 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.

SIMULTANEOUS DETERMINATION OF GLIMEPIRIDE AND ATORVASTATIN IN HUMAN SERUM BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY: APPLICATION TO PHARMACOKINETIC STUDY

A simple and sensitive high performance liquid chromatographic method for simultaneous quantification of glimepiride (GMP) and atorvastatin (ATN) in human serum was developed and validated. GMP, ATN, and internal standard (IS), pioglitazone (PG) were extracted into dichloromethane and methanol solvent system and separated using an isocratic mobile phase on an Inertsil C18 column. The eluent was monitored by UV detector at 230 nm. The linearity range of proposed method was 1–1600 ng mL−1 for each analyte. The retention times for GMP, ATN, and IS were found to be 9.8, 6.92, and 7.96 min, respectively. The intra-day and inter-day coefficient of variation and percentage error values of the assay method were less than 15% and mean recovery was more than 96, 93, and 95% for GMP, ATN, and IS, respectively, and the method was found to be precise, accurate, and specific. The method was successfully applied for pharmacokinetic study of GMP and ATN after oral administration to patients. The CMax, TMax, and AUC0–12 of GMP and ATN were found to be 355.3 ng mL−1, 3.1 hr, 2167.5 ng h mL−l and 12.6 ng mL−1, 2.6 hr, 80.8 ng h mL−l, respectively.

Development of a high-performance liquid chromatography method for simultaneous determination of pioglitazone and felodipine in pig serum: application to pharmacokinetic study

A simple and sensitive high-performance liquid chromatographic method was developed and validated for simultaneous estimation of pioglitazone and felodipine in pig serum. The present method consists of protein precipitation, extraction of analytes from pig serum into dichloromethane and separation using reversed-phase C(18) column. Nitrendipine was used as an internal standard and the eluent was monitored by UV detector at 240 nm. The mobile phase used was acetonitrile and 50 mm ammonium acetate buffer at a flow rate of 1 mL/min. The retention times for pioglitazone, felodipine and nitrendipine were found to be 5.12, 10.53 and 7.14 min, respectively. The intraday and inter-day coefficient of variation and percent error values of assay method were less than 7% and mean recovery was more than 94% for each analyte, and the method was found to be precise, accurate and specific during study. The method was successfully applied for pharmacokinetic study of pioglitazone and felodipine from bioadhesive buccal tablet after buccal administration to pigs. The C(Max) , T(Max) , and AUC(0-24) of pioglitazone and felodipine from buccal tablet were found to be 394.6 ng/mL, 5.6 h, 2624.2 ng h/mL and 44.4 ng/mL, 5.5 h, 275.8 ng h/mL, respectively.

Iontophoretic delivery of lisinopril: Optimization of process variables by Box-Behnken statistical design

The objective of the investigation was to optimize the iontophoresis process parameters of lisinopril (LSP) by 3 x 3 factorial design, Box-Behnken statistical design. LSP is an ideal candidate for iontophoretic delivery to avoid the incomplete absorption problem associated after its oral administration. Independent variables selected were current (X(1)), salt (sodium chloride) concentration (X(2)) and medium/pH (X(3)). The dependent variables studied were amount of LSP permeated in 4 h (Y(1): Q(4)), 24 h (Y(2): Q(24)) and lag time (Y(3)). Mathematical equations and response surface plots were used to relate the dependent and independent variables. The regression equation generated for the iontophoretic permeation was Y(1) = 1.98 + 1.23X(1) - 0.49X(2) + 0.025X(3) - 0.49X(1)X(2) + 0.040X(1)X(3) - 0.010X(2)X(3) + 0.58X(1)(2) - 0.17X(2)(2) - 0.18X(3)(2); Y(2) = 7.28 + 3.32X(1) - 1.52X(2) + 0.22X(3) - 1.30X(1)X(2) + 0.49X(1)X(3) - 0.090X(2)X(3) + 0.79X(1)(2) - 0.62X(2)(2) - 0.33X(3)(2) and Y(3) = 0.60 + 0.0038X(1) + 0.12X(2) - 0.011X(3) + 0.005X(1)X(2) - 0.018X(1)X(3) - 0.015X(2)X(3) - 0.00075X(1)(2) + 0.017X(2)(2) - 0.11X(3)(2). The statistical validity of the polynomials was established and optimized process parameters were selected by feasibility and grid search. Validation of the optimization study with 8 confirmatory runs indicated high degree of prognostic ability of response surface methodology. The use of Box-Behnken design approach helped in identifying the critical process parameters in the iontophoretic delivery of lisinopril.