Biopharmaceutical insights of particulate emulsified systems - a prospective overview.

During the twenty-first century, drug discovery is expanding rapidly and a large number of chemical moieties are recognized. Many of them are poorly soluble and hence related biopharmaceutical constraints are to be addressed systematically. Among novel approaches to resolving biopharmaceutical issues, micro- and nano-emulsified systems serve as the best strategy for delivering both hydrophobic and hydrophilic drugs owing to their greater solubilization and transportation capabilities. Of late, the unique physical and biopharmaceutical properties of these liquid isotropic homogenous systems have gained substantive research importance. In addition nano/micro lipid systems share structural and functional similarity with that of the physiological lipids which offer better tolerance ability in the body. In this context, this article provides information on the historical emergence of particulate emulsified systems, importance and rationale of selection of carriers. It also encompasses the physicochemical principles that are responsible for the elevation of therapeutic outcomes of delivery systems. Detailed and schematic absorption of these drug delivery systems is explained here. Gastro-intestinal biochemistry necessary in the understanding of digestion process, lipolytic products formed, micellar structures, enzymes, transporters, mechanism of cell uptake involved after subsequent oral absorption are also emphasized. In addition, this article also explains disposition and pharmacokinetic properties of emulsified systems with real-time therapeutic research outcomes. The influence of biochemical compositions and biopharmaceutical principles on absorption and disposition patterns of ME/NEs was described in the article for the interest of readers and young researchers.

Biopharmaceutical Process of Diclofenac Multi-particulate Systems for Chronotherapy of Rheumatoid Arthritis.

OBJECTIVES: Diclofenac exhibits limited solubility, low bioabsorption and gastric toxicity. The objective of the study was to address the above limitations and to design a multi-particulate formulation for the chronotherapy of RA. MATERIALS AND METHODS: Solid dispersions of DC with SSG and GG were prepared. Uniform-sized (∼400 µm) non-pareil seeds were coated with solid dispersions to produce immediate-release pellets (DMP-1 and DMP-2) and controlled-release pellets (DMP-3 and DMP-4). The resultant controlled-release pellets were further layered with methacrylate polymers to obtain pulsatile-release pellets (DMPP). Solubility, FTIR, DSC, micrometrics, SEM, drug content, drug release, pharmacokinetics, and stability studies were performed for DMPP. RESULTS: The solubility of DC was improved by 164-folds due to the presence of hydrophilic carriers in the solid dispersions. No chemical and physical interactions were noticed in FTIR spectra and also in thermograms. A fluidized bed processor facilitated the production of high-quality, circular, and regular pellets with an angle of repose less than 19.5 degrees and DC content between 95.18% and 98.87%. The maximum drug was released from DMPP at the end of 12 hours. DMP-1 and DMP-2 pellets had 2 hr of drug release and pulsatile, controlled-release pellets had a 6 hr lag phase followed by 12 hr controlled release. Both DMP-1 and DMP-2-immediate showed first-order release followed by Hixson-Crowell kinetics, whereas DMPP pellets followed zero-order release with Higuchi's kinetics. The maximum concentration of DC in plasma was 400.8 ng/mL at 5 hr for DMP-2 and 381.1 ng/mL at 14 hr for DMPP-5. The solubility of DC was increased with the application of solid dispersion and in turn increased the pharmacokinetics. The pellets were plausibly stable over a period of 90 days. CONCLUSION: Thus, multi-particulate pulsatile systems of DC were as effective as chronotherapeutics in the treatment of circadian rhythm-based ailments such as RA.

Chronopharmacokinetic Evaluation of Budesonide Multiparticulate Systems.

BACKGROUND: Poor oral absorption of budesonide limits the design of its solid oral dosage form. With this context, multiparticulate pulsatile system of budesonide for chronotherapy of nocturnal asthma was aimed in this study. METHODS: Initially, solid dispersions of budesonide (BD) using sodium starch glycolate (SSG) and guar gum (GG) were developed and characterized. Uniform sized non-pareil seeds (~400 µm) were coated with solid dispersions to obtain immediate (BMP) and controlled release pellets by solution layering technique. Rationale of selection of BD in this research was based on recent patents such as diltiazem HCl (US5914134) and multipar-ticulate systems (US5017381). Pulsatile drug release pellets (BMPP) of BD were obtained by coating the controlled release pellets with Eudragit L100 and RS 100. Pellets were assessed by saturation sol-ubility, FTIR, DSC, micromeritic, SEM, drug content, drug release, pharmacokinetic and stability studies. RESULTS: Solubility of BD was increased by 22 folds due to inter-particle distribution of BD and polymers in solid dispersions. No changes in characteristic functional groups of BD had indicated the compatibility of drug with polymers as noticed in FTIR and DSC. Fluidized bed processor enabled the production of spherical and uniformly distributed pellets with optimum angle of repose (12-19°) and friability (<1%). Solution layering technique employed in preparation of pellets had facilitated with moderately high BD content (91.5-99.6%) and 100% drug release at the end of 12hr. The pulsatile release pellets (BMPP) produced 6hr lag phase followed by 12hr controlled release. Promised pharmacokinetics was resulted as Cmax of 380ng/ml for BMP-2 and 162ng/ml for BMPP-5 and Tmax of 5 hr for BMP-2 and 12hr for BMPP-5. Increased pharmacokinetics was the direct results of increased solubility of BD due to application of solid dispersion and solution layering on pellets. CONCLUSIONS: Chronopharmacokinetics of BD were achieved with the help of Eudragit coatings on pellets. The BMP and BMPP formulations were found to be reasonably stable over a period of time. Thus, optimal chronopharmacokinetics of BD was achieved successfully by multiparticulate pulsatile technology.