“Oleoscience” is very useful and important in formulation research and development, and the associated technologies are now often employed during the pharmaceutical formulation development stage. In this review, some “Oleoscience” based methods used in recent pharmaceutical formulation development studies are illustrated and evaluated. The following experiments are described : measuring the degree of self-assembly between the molecules of a drug by using the physicochemical method; analyzing the relationship between orally administered dose in human and capacity factor determined from liposome chromatography; estimating the physicochemical stability of liposomes by osmometry; determination of the thickness of the hydration layer around liposomes by measuring zeta-potentials; estimating the degree of aggregation in water/oil emulsions using dielectric relaxation measurement; particle size determination of perfluorocarbon/water emulsions by phase doppler particle analysis; analysis of an immuno-reaction between drug-antibody complex and antigen expressed by tumor cells using surface plasmon resonance method; molecular weight determination of macromolecular drugs by using light-scattering, and so on. The number of poorly or less water-soluble and macromolecular drugs is increasing, providing fresh challenges for pharmaceutical formulation research. New drug delivery technology is expected to provide novel solutions to some of the problems often encountered when developing suitable formulations for these new types of products. The methods described in this review demonstrate some of the basic and important technologies for drug delivery, which are required to support this rapidly growing area of pharmaceutical research.

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A review is given on electrokinetic phenomena in dispersions of colloidal particles. Relationships between electrophoretic mobility and zeta potential (or particle charge) are given for various types of particles including hard particles, polyelectrolytes and soft particles. Static and dynamic electrophoresis in dilute and concentrated suspensions are discussed with particular emphasis on dynamic measurements in concentrated suspensions (that is, colloid vibration potential (CVP) method and electrokinetic sonic amplitude (ESA) method).

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A novel gel (Microemulsion-based-organogel, MEBG) prepared by the addition of gelatin to W/O microemulsion, was first reported by Luisi et al. and Eicke et al. in 1986. The conditions and mechanism for MEBG formation and MEBG structures have extensively been investigated by methods. MEBGs are a transparent and thermally reversible and in which, water phase and oil phase domain were present together. Therefore, MEBGs are materials which enable us to solubilize mutually many more reactive molecules. Consequently, MEBGs are very interesting materials for the chemical and pharmaceutical applications, and also applied studies have been started. In this review, first, studies of the conditions and mechanism for MEBG formation and MEBG structures, next, physico-chemical properties for MEBGs, furthermore, examples for applied studies for MEBG and fundamental study toward application, were described.

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Low molecular weight drugs are loaded into polymeric particles to enable the targeting and concentration of drugs at the aimed spaces, controlled and sustained release of drugs, maintaining of drug activity, etc. The particles should not be toxic and residuary in the body. To prepare the particles which satisfy these conditions, materials employed are restricted and, in most cases, natural and/or biodegradable polymers are preferred. The preparative methods are classified into two categories, fabrication of existing polymers into particulate forms and particle-forming polymerizations. The former includes precipitation of polymers from saturated solution, coacervation of polymer solution, self-assembling of amphiphilic polymers, emulsification followed by solidification via crosslinking, solvent evaporation, solvent extraction, spray drying, etc. The latter, particle-forming polymerization, includes emulsion polymerization, modified emulsion polymerization, dispersion polymerization, sedimentation polymerization, etc. In most cases, attention is paid on the conditions of particle surfaces not only during the particle formation but also in the time when they are applied. Polyethyleneglycol (PEG) is one of the most popular polymers which lowers the interfacial energy between polymer and aqueous phase and, therefore, they or their graft/block polymers have been used widely in drug carrying systems. PEG-block-lyophilic polymers construct polymer micelles and well-designed dendrimers are developed. They are expected to be the leading materials in fine chemistry.

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It is well known that many factors affecting the phamcokinetic parameters fluctuate dur-ing one day, because of the circadian rhythm. That is, blood flow rate, blood pressure, or hormone con-centration in blood varies depending on the time of day. For these 50 years, many studies have been done for many types of drugs about the relationship between the time of day at which the drug is administered and the therapeutic effects of the drug in the field of chronopharmacology. Then, it has been made clear that now “the flatter the better ”for the drug blood level is not desirable for a certain kind of drug, but“time-of-day”plays an increasing role in drug treatment. For such kind of drug therapy, a new drug delivery system, that is, pulsatile drug delivery system, is useful. In this review article, pulsatile drug delivery systems, such as a sigmoidal-drug release system, a time-controlled explosion system, PULSINCAP, a OROS delayed push pull system, will be introduced together with three-dimen-sional printing as a new pharmaceutical technology to prepare tablets.

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