Optimization and validation of high performance liquid chromatography-ultra violet method for quantitation of metoprolol in rabbit plasma: application to pharmacokinetic studies

Purpose: To develop a sensitive, simple and validated high performance liquid chromatography (HPLC) analytical method for the determination of metoprolol tartrate in rabbit plasma.Methods: Mobile phase of methanol and 50 mM ammonium dihydrogen phosphate solution (50:50) at pH 3.05 was used for separation of metoprolol on BDS hypersil C18 column at a wavelength of 223 nm. Flow rate and retention time were 0.6 mL/min and 7.4 min, respectively. For pharmacokinetic study, rabbits were given an oral dose of 8 mg/kg of metoprolol in solution form. Blood samples were taken from jugular vein of the rabbits after drug administration and analysed by HPLC.Results: Separation of metoprolol was not interfered with other components in plasma. The calibration curve was linear in the range of 25 - 1000 ng/mL (r2 = 0.997). Lower limits of detection (LLOD) and quantitation (LLOQ) were 8.87 and 25 ng/mL, respectively. Relative standard deviation (RSD) of intraday and inter-day precision was < 14.27 and 7.61 %, respectively. Relative error of accuracy was between 4.85 and 14.37 %. Maximum plasma concentration (Cmax), time to maximum plasma concentration (Tmax) and half-life (t½) after metoprolol oral administration in rabbits were 186.29 ng/mL, 0.50 h and 2.27 h, respectively.Conclusion: A simple, accurate and precise HPLC-UV method for metoprolol determination in rabbit plasma has been successfully developed and applied to a pharmacokinetic study.Keywords: HPLC-UV, Metoprolol, Pharmacokinetics, Rabbit plasma, Liquid-liquid extraction, Validatio

Fabrication and Evaluation of Rosuvastatin Calcium Fast- Disintegrating Tablets Using β-Cyclodextrin and Superdisintegrants

Purpose: To formulate fast-disintegrating tablets (FDT) of rosuvastatin calcium (RST) using β- cyclodextrin (CD) and different superdisintegrants to enhance their solubility.Methods: A total of 15 FDT formulations of RST were prepared using three different techniques. The FDTs were evaluated for micromeritic properties, as well as by Fourier transform infrared spectroscopy (FTIR), thermal analysis, disintegration time (DT), dissolution rate, powder x-ray diffraction (XRDP), scanning electron microscopy (SEM) and stability studies.Results: XRDP showed that RST was changed from crystalline to amorphous form. SEM images revealed the presence of small microscopic pores that enhanced water penetration and provided rapid dissolution rate compared with the pure drug. There was maximum release of drug (99 %) from F4 formulation containing solid dispersion of RST, CD and superdisintegrants. DT and wetting time were 25 s (p = 0.032) and 33 s (p = 0.023), respectively, for F4 formulation. In vitro dispersion time was also lowest for F4 at 23 s (p = 0.023). FTIR and DSC studies also confirmed complex formation of drug with CD and superdisintegrants.Conclusion: FDT is a suitable strategy to enhance the dissolution rate of RST and thus is an effective tool to improve bioavailability of poorly water soluble drugs.Keywords: Solubility, β-cyclodextrin, Kyron, Polymer, Rosuvastatin, Fast-disintegrating tablet

Development and in vitro characterization of 5-flurouracilloaded, colon-targeted drug delivery system

Purpose: To prepare chondroitin sulphate–polyvinyl alcohol cross-linked microcapsules (miCAPs) for controlled delivery of 5-flurouracil (5-FU) in cancer patients.Method: Nine different miCAP formulations were prepared using emulsion cross-linking procedure. The formulations were evaluated for their physicochemical properties, complex formation, stability at variable temperatures, safety, as well as drug-loading and drug-release characteristics. The effects of glutaraldehyde (GA), polymer concentration and stirring speed on 5-FU release at various pH were also assessed.Results: One of the miCAP formulations (miCAP-1) was adjudged the most suitable based on its particle size, high drug loading (75.3 %, p = 0.034), and high entrapment efficiency (85.2 %, p = 0.031). Best-fit drug release model was Higuchi model based on regression coefficient value (R2) while drug release mechanism was Fickian.Conclusion: Highly stable, crosslinked, amorphous and drug delivery system has been successfully developed. The delivery system is potentially suitable for acid-sensitive therapeutic moieties and where controlled release is desired.Keywords: Emulsion cross-linking, Colon-specific delivery, 5-Flurouracil, Glutaraldehyde, Kinetic model

Plasticiser-free 3D printed hydrophilic matrices: Quantitative 3D surface texture, mechanical, swelling, erosion, drug release and pharmacokinetic studies

Hydroxypropyl methyl cellulose, HPMC, a hydrophilic polymer, is widely used for the development of extended release hydrophilic matrices and it is also considered as a good contender for the fabrication of 3D printing of matrix tablets. It is often combined with plasticisers to enable extrusion. The aim of the current project was to develop plasticizer-free 3D printed hydrophilic matrices using drug loaded filaments prepared via HME to achieve an in vitro (swelling, erosion and drug release) and in vivo (drug absorption) performance which is analogous to hydrophilic matrix tablets developed through conventional approaches. Additionally, the morphology of the printed tablets was studied using quantitative 3D surface texture studies and the porosity calculated. Filaments were produced successfully and used to produce matrix tablets with acceptable drug loading (95–105%), mechanical and surface texture properties regardless of the employed HPMC grade. The viscosity of HPMC had a discernible impact on the swelling, erosion, HPMC dissolution, drug release and pharmacokinetic findings. The highest viscosity grade (K100M) results in higher degree of swelling, decreased HPMC dissolution, low matrix erosion, decreased drug release and extended drug absorption profile. Overall, this study demonstrated that the drug loaded (glipizide) filaments and matrix tablets of medium to high viscosity grades of HPMC, without the aid of plasticisers, can be successfully prepared. Furthermore, the in vitro and in vivo studies have revealed the successful fabrication of extended release matrices

Novel Black Seed Polysaccharide Extract-g-Poly (Acrylate) pH-Responsive Hydrogel Nanocomposites for Safe Oral Insulin Delivery: Development, In Vitro, In Vivo and Toxicological Evaluation

Oral delivery of insulin has always been a challenging task due to harsh gut environment involving variable pH and peptidase actions. Currently, no Food and Drug Administration (FDA) approved oral insulin formulation is commercially available, only intravenous (IV) or subcutaneous (SC) routes. Therefore, it is really cumbersome for diabetic patients to go through invasive approaches for insulin delivery on daily basis. In the present study, a novel pH-responsive hydrogel nanocomposite (NC) system was developed and optimized for safe oral delivery of insulin. Black seed polysaccharide extract-based hydrogel (BA hydrogel) was formulated by free radical polymerization and loaded with insulin. Blank BA hydrogel was also incorporated with insulin-loaded montmorillonite nanoclay (Ins-Mmt) to form an Ins-Mmt-BA hydrogel NC and compared with the insulin-loaded hydrogel. Swelling, sol-gel analysis and in vitro release studies proved that Ins-Mmt-BA6 hydrogel NC has the best formulation, with 96.17% maximum insulin released in 24 h. Kinetic modeling applied on insulin release data showed the Korsemeyer-Peppas model (R2 = 0.9637) as the best fit model with a super case II transport mechanism for insulin transport (n > 0.89). Energy Dispersive X-ray (EDX) Spectroscopy, Fourier Transformed Infrared (FTIR) spectroscopy and Powdered X-ray diffraction (PXRD) analysis results also confirmed successful development of a hydrogel NC with no significant denaturation of insulin. Toxicity results confirmed the safety profile and biocompatibility of the developed NC. In vivo studies showed a maximum decrease in blood glucose levels of 52.61% and percentage relative bioavailability (% RBA) of 26.3% for an Ins-Mmt-BA hydrogel NC as compared to BA hydrogels and insulin administered through the SC route

Simvastatin Loaded Dissolvable Microneedle Patches with Improved Pharmacokinetic Performance

Microneedle patches (MNPs) are one of the emerging approaches for drug delivery involving minimal invasion and improved skin penetration of macro- and micro-entities. Herein, we report dissolvable microneedle patches (dMNPs) as a novel tool for better systemic delivery of Simvastatin in the management of hypocholesteremia. Thiolated chitosan (TC), polyvinyl pyrolidone (PVP) and polyvinyl alcohol (PVA) were employed in the development of dMNPs. Developed patches were characterized through SEM, FTIR, DSC, TGA, PXRD, dissolution testing, tensile strength, elongation (%), skin irritation studies, moisture content and pharmacokinetic evaluation. dMNP F26 exhibited excellent tensile strength (9.85 MPa), penetration potential (~700 µm), moisture content (5.95%), elongation (35.54%) and Simvastatin release of 77.92%. Pharmacokinetic properties were also improved, i.e., Cmax 1.97 µg/mL, tmax 9 h, MRT 19.9 h and AUC 46.24 µg·h/mL as compared to Simvastatin solution displaying Cmax 2.55 µg/mL, tmax 3 h, MRT 5.91 h and AUC 14.20 µg·h/mL thus confirming higher and improved bioavailability. Kinetic modelling revealed zero order as the best fit model based on regression coefficient. Histopathological findings proved the biocompatibility of the developed dMNPs

Orally Administered, Biodegradable and Biocompatible Hydroxypropyl–β–Cyclodextrin Grafted Poly(methacrylic acid) Hydrogel for pH Sensitive Sustained Anticancer Drug Delivery

In the current study, a pH sensitive intelligent hydroxypropyl–β–cyclodextrin-based polymeric network (HP-β-CD-g-MAA) was developed through a solution polymerization technique for site specific delivery of cytarabine in the colonic region. Prepared hydrogel formulations were characterized through cytarabine loading (%), ingredient’s compatibility, structural evaluation, thermal integrity, swelling pattern, release behavior and toxicological profiling in rabbits. Moreover, the pharmacokinetic profile of cytarabine was also determined in rabbits. New polymer formation was evident from FTIR findings. The percentage loaded into the hydrogels was in the range of 37.17–79.3%. Optimum swelling ratio of 44.56 was obtained at pH 7.4. Cytarabine release was persistent and in a controlled manner up to 24 h. In vitro degradation of hydrogels was more pronounced at intestinal pH as compared to acidic pH. Toxicity studies proved absence of any ocular, skin and oral toxicity, thus proving biocompatibility of the fabricated network. Hydrogels exhibited longer plasma half-life (8.75 h) and AUC (45.35 μg.h/mL) with respect to oral cytarabine solution. Thus, the developed hydrogel networks proved to be excellent and biocompatible cargo for prolonged and site-specific delivery of cytarabine in the management of colon cancer

Press-Coated Aceclofenac Tablets for Pulsatile Drug Delivery: Formulation and In Vitro Evaluations

The symptoms of some diseases show circadian rhythms, such as the morning stiffness associated with pain at the time of awakening in rheumatoid arthritis. Therapy for such diseases doesn’t require immediate release or sustained release of medicament. In such therapies, pulsatile drug release is more suitable with a programmed drug release. The purpose of this research was to formulate press-coated aceclofenac tablets for pulsatile drug delivery with a distinct delay time of no drug release and release of the drug when it is more likely desired (i.e., after 5 to 6 h). Immediate release core tablets having aceclofenac were formulated. Three formulations, F1, F2, and F3, were prepared with variable concentrations of sodium croscarmellose. Pre- and post-compression tests were performed on the core tablets. The selection criteria included the lowest disintegration time as a requirement of pulsatile drug delivery with an immediate release core and a delayed release coat. The disintegration times of F1, F2, and F3 were 120 s, 60 s, and 15 s, respectively. Therefore, the F3 formulation was selected as the core tablet formulation because it had the shortest disintegration time (15 s). The core tablets were press-coated using different polymers, such as HPMC K100M, Eudragit L100, HEC, and HPMC E5. The polymers were used in the coatings to hinder the release of the core for the desired time. 36 formulations of polymer were prepared: A1 to A10 had HPMC K100M and Avicel PH102; formulations B1 to B6 had HPMC K100M, Eudragit L100, and Avicel PH102; formulations C1 to C7 had HPMC K100M and hydroxyethyl cellulose; formulations D1 to D7 had HPMC K100M and HPMC E5; and formulations E1 to E6 had changed the coating weight of the formulation used for D6 (having HPMC K100M and HPMC E5 in the ratio of 12.5% to 87.5%). Evaluations of the press-coated tablets were carried out through thickness, hardness, weight variation, friability, and in vitro dissolution tests. These parameters concluded that the formulation of E6, having HPMC K100M and HPMC E5 in the ratio of 12.5% to 87.5% at 600 mg weight, was the most optimum formulation as it showed 3.5% drug release after 4 h, 21.4% drug release after 5 h, and 99.27% drug release after 6 h