This paper reviews the developments of drug delivery with special attention on its controlled release and drug targeting. Finally, the importance of multidisciplinary informations and how they are integrated in a systematically meaningful manner to achieve an optimization of cancer drug delivery are discussed by taking lipophilic prodrugs and dextran-conjugated macromolecular prodrugs of mitomycin C as an example.
From the leaves of Pertya glabrescens SCH. BIP. (Compositae) a new germacranolide, 3-epipertilide (III), C15H16O4, [α]17D+52°and a new glycoside (VIII), C12H22O6, [α]24D-36.5°were isolated in addition to pertic acid (Ib), 3α-hydroxypertic acid (IIb), benzoic acid, p-coumaric acid and methyl caffeate. On the basis of chemical and physicochemical evidence, III was determined to be stereoisomeric to pertilide (VI) at C-3, namely [1 (10) Z, 4E]-(3S, 7R, 8S)-germacra-1 (10), 4, 11 (13)-triene-12, 8; 14, 3-diolide, and VIII, to be the β-D-glucopyranoside of (Z)-3-hexen-1-ol (leaf alcohol). The conformation of III was assigned from the examination of its derivatives IV, Va and Vb in nuclear Overhouser effect and circular dichroism. A new bitter principle, glucohaageanolide (X), C21H30O8·H2O, mp 155-165°C (dec.), [α]20D+51.2°was isolated from the leaves of P. scandens (THUNB.) SCH. BIP. On hydrolysis X gave D-glucose and a known sesquiterpene haageanolide (XI). In order to make clear the exact structure of X including its absolute streorchemistry, an X-ray structure analysis of X monohydrate was undertaken, resulting in determination of X to be [1 (10) E, 4E]-(6S, 7S, 9S)-9-β-D-glucopyranosyloxygermacra-1 (10), 4, 11 (13)-trien-12, 6-olide.
Administration of various 3H-labeled monoterpenes to Catharanthus roseus and Lonicera morrowii demonstrated that secoiridoid glucosides and indole alkaloids of these plants are formed through cyclization of 10-oxoneral or 10-oxogeranial to iridodial followed by further elaboration. This result is contradictory with the report by Kurz et al. which indicated the intermediacy of 9, 10-dihydroxygeraniol and its oxo-derivatives for the biosynthesis of secologanin and indole alkaloids of C. roseus suspension cultures.
Gallotannins (tetra-undecagalloylglucose) in Paeoniae Radix were separated according to the degree of galloylation (number of galloyl groups per glucose) by normal phase high performance liquid chromatography and quantitiatively determined. Total gallotannin contents of Paeoniae Radix produced in Hokkaido, Nara prefecture and China were shown to be in the range of 0.52-1.16%, and there was no difference among three groups of samples. The average degree of galloylation was calculated from the contents of tetra-undecagalloylglucose, and those of Paeoneae Radix produced in Hokkaido (5.88-7.36) appeared to be higher than those in Nara prefecture (5.30-5.72) and China (5.10-5.75). The total gallotannin contents and the average degree of galloylation varied according to the preparation methods of Paeoniae Radix, and the total gallotannin contents in the aerial parts of peony were found to be 5-15 times higher than that of root on fresh weight basis. In the decoction of two Kanpo prescriptions, Shakuyaku-kanzo-to ( ?? ?? ?? ?? ?? ) and Keishi-ka-shakuyaku-to ( ?? ?? ?? ?? ?? ?? ), only tetra and pentagalloylglucoses were detected as gallotannin.
A rapid fluorescent labeling method of imides with 4-bromomethyl-7-methoxycoumarin (Br-Mmc) is described. Mmc-derivatives of imides are prepared by adding 10 mg of Br-Mmc to a solution containing 1 mg of imides (pyrimidine nucleobases or barbitals) and 10 mg potassium carbonate in 5 ml dimethylsulfoxide (DMSO). The reaction is completed for 5 min at room temperature when Br-Mmc concentration in the mixture is 2 mg/ml. The excess Br-Mmc is treated with p-nitrobenzoic acid, which gives Mmc-derivative with no fluorescence. High performance liquid chromatographic separation of Mmc-derivatives of imides are obtained on a C18 column. With this method the reaction time for labeling is dramatically reduced without catalyst such as crown ether. The reaction system is discussed according to donor-acceptor theory.
The enzymatic study on an angiotensin I converting enzyme (ACE) inhibitor of (2R, 4R)-2-(2-hydroxyphenyl)-3-(3-mercaptopropionyl)-4-thiazolidinecarboxylic acid (SA 446) was described. ACE was purified from rabbit lung, and the specific activity of final preparation was 22.5 U/mg protein with Hip-His-Leu as substrate. The concentration of SA 446 producing 50% inhibition of ACE activity was 6 nM. The inhibition mode was competitive with K1 of 2.2 nM. The inhibitory potency did not change even in the presence of a relatively large amount of Zn2+ or Co2+. SA 446 in the concentration of 0.1 mM did not produce 50% inhibition on the other enzymes including zinc-enzyme such as carboxypeptidase A, B, N, leucine aminopeptidase and alkaline phosphatase. These results indicated that SA 446 was an extremely potent and specific inhibitor of ACE. The structural characteristics of SA 446 were also demonstrated by the study on analogous compounds.
When slightly soluble drugs were dissolved or suspended in O/W type ointments, some drugs were crystallized or grew up in these preparations during storage for several months. In these cases, the efficacy and physical properties of these ointments were decayed. Therefore, the method to foretell the possibility of crystallization in various ointments in short time were investigated. Dequalinium chloride was used as a test drug and dissolved in the model preparations as 0.3% concentration. These preparations were stored at room temperature, constant temperatures of 5, 25, and 40°C and cyclizing temperatures from 5 to 25°C or 5 to 40°C everyday. The crystallization of the test drug in these preparations stored at various temperatures was observed by a polarizing microscope. After being stored at room temperature for six months, the crystallization of the test drug was slightly recognized, while, in the drug stored at constant temperatures of 20 and 40°C, the crystallization was not recognized. After a week, in the drug stored at 5°C and cyclizing temperature, the crystallization was recognized, and the crystals in these preparations stored at cyclizing temperature were bigger than those stored at 5°C.
The growth rate of cephalothin sodium (KF) after seeding in frozen solution was measured. Crystal growth of KF followed equation (1) untill α=0.98. 1-(1-α)1/3=(1/3N) (Kt)N……(1) where α is crystallinity, K is rate constant, t is time, and N is parameter depending on the freezing temperature and the amount of seed. Crystal growth of KF in the frozen solution hardly changed when the concentration of KF was in the range of 19.4% to 28.6% but it was remarkably dependent on the amount of seed at the constant freezing temperature. According to the decrease in the amount of seed at the constant freezing temperature, the value of N increased and the rate constant (K) decreased. The growth rate increased with a rise of freezing temperature, and had the maximum value at a temperature little below the eutectic temperature. The activation energy of crystal growth of KF in the range of -5°C to -14°C was 49 kcal/mol.
Atherosclerotic lesions were induced in the aorta, particularly aortic arch, of rats fed a 1.5% cholesterol diet supplemented with 0.15% β-aminopropionitrile (BAPN) for six weeks. BAPN is a chemical lathyrogen known to interfere with the formation of elastin and collagen cross-links. Histopathological observation revealed the dissecting aneurysm in the lesions of the aorta. Intense fibrous proliferation in the media and foam cells in the media as well as adventitia were also observed. Aortic cholesterol levels (mainly esterified cholesterol) remarkably increased. The serum cholesterol levels markedly increased while the serum high density lipoprotein (HDL)-cholesterol level markedly decreased. Lecithin : cholesterol acyltransferase (LCAT) activity also notably decreased. A distinct decrease in very low density lipoprotein and HDL, particularly HDL2, was demonstrated by the electrophoretic technique on polyacrylamide gel. These changes in the aorta and serum cholesterol levels and LCAT activity were not as great in rats fed a diet supplemented with 0.15% BAPN or 1.5% cholesterol alone. These studies suggest that synergism of the arterial wall injury by BAPN and the abnormal lipid metabolism by cholesterol feeding induces a lipid accumulation in the aorta, which leads to the development of atherosclerotic lesions.
The effect of extract of calf blood (SS-094) on developing granuloma tissue was investigated in normal and alloxan diabetic rats. Results obtained were as follows : (1) SS-094 dose-dependently increased in the weight of granuloma tissue induced by croton oil in normal and alloxan diabetic rats. (2) The fluid exudation and the weight of granuloma tissue induced by croton oil were inhibited in alloxan diabetic rats and then were recovered to normal level by SS-094 and insulin, but not by fibroblast growth factor. (3) In normal rats SS-094 increased as compared with control group both in the fluid exudation and in the weight of granuloma tissue up to the 10th days, but at the 15th and 20th days it increased only in the weight of granuloma tissue by means of croton oil method. Total amount of hydroxyproline in the granuloma tissue was increased as compared with control group by SS-094 throughout all the period in parallel with granuloma tissue, though there was no difference from the control group in terms of collagen content (%). (4) In alloxan diabetic rats SS-094 showed no different effect on the fluid exudation from the control group, whereas it increased in the weight of granuloma tissue throughout all the period by means of croton oil method. From these results we concluded that SS-094 increases the granuloma tissue and suggested that its mechanism may be dependent on the increase of collagen, but other factors of cell growth also related to it.
The relationship between the intracellular accumulation of vinblastine (VBL) and the effect of reserpine in four rat ascites hepatoma cell lines having different sensitivities to VBL was investigated. The order of the sensitivity to VBL was AH66 cells<AH109A cells<AH44 cells<AH13 cells. The intracellular VBL content for 30 min incubation was higher in sensitive cells than in natural resistant cells and after washing out extracellular VBL, VBL retained in sensitive cells was more than that in resistant cells. Reserpine suppressed the extrusion of VBL, accumulated VBL in all cells, and enhanced VBL sensitivity of the cells. These effects of reserpine were significant in VBL resistant cell lines, AH66 cells and AH109A cells, rather than in sensitive cell lines, AH13 cells and AH44 cells, and the VBL resistance was completely overcome by reserpine. The activities of adenosine triphosphatase (ATPase), especially Mg2+ ATPase, in the plasma membrane of VBL resistant cells were higher than those of sensitive cells. Reserpine markedly suppressed the activities of Mg2+ ATPase and Ca2+ ATPase but had no effect on (Na+-K+) ATPase activity. From these results, it was indicated that rat ascites hepatoma cells possessing higher ATPase activities in the plasma membrane were more resistant to VBL and reserpine overcame the natural resistance to VBL suppressing the active efflux of VBL.
The effect of six Rauwolfia alkaloids on the growth inhibitory effect of vinblastine (VBL) in rat ascites hepatoma AH66 cells was investigated. When cells were treated with VBL and each alkaloid for 30 min, reserpine, rescinnamine, syrosingopine, and ajmaline markedly potentiated the effect of VBL, but dimethylaminoethylreserplinate hydrochloride (DMAR) and yohimbine did not influence. On the other hand, in the continuous treatment for 2 d, DMAR and yohimbine also potentiated the effect of VBL. All of alkaloids increased the intracellular VBL content. Among these alkaloids, reserpine markedly suppressed the activities of Mg2+ATPase and Ca2+ATPase in the plasma membrane and DMAR suppressed the activities of adenosine triphosphatase (ATPase) except (Na+-K+) ATPase. Reserpine and DMAR did not affect the VBL binding to microtubules. Reserpine inhibited the microtubule polymerization by itself and synergistically acted with VBL on microtubules but DMAR did not affect the polymerization and the effect of VBL. From the results, it was indicated that all of Rauwolfia alkaloids suppressed the active extrusion of VBL, increased the intracellular VBL content, and potentiated the effect of VBL on AH66 cells. Moreover, it was suggested that some of alkaloids including reserppine could enhance the effect of VBL even by a short term treatment because of their synergistical interaction with VBL on microtubules.
The influence of Ca2+ antagonists and metabolic inhibitors on the membrane transport of vinblastine (VBL) in rat ascites hepatoma AH66 cells was investigated. Such Ca2+ antagonists as ruthenium red (RR) and lanthanum chloride (La) decreased the uptake of VBL but did not influence the intracellular retention of VBL. In contrast, verapamil markedly increased the uptake and decreased the efflux of VBL. Since AH66 cells are not excitable cells, it was considered that verapamil which is a Ca2+ channel antagonist showed a different action from other Ca2+ antagonists. Iodoacetic acid increased the uptake of VBL and suppressed the extrusion of VBL but dinitrophenol and ouabain did not influence the intracellular content of VBL in the glucose rich medium. On the other hand, RR and La specifically inhibited the activity of (Ca2+-Mg2+) ATPase. Ouabain also specifically inhibited the activity of (Na+-K+) ATPase. Iodoacetic acid suppressed the activities of ATPase except (Na+-K+) ATPase. Therefore, in the influx of VBL, the presence of Ca2+ on the plasma membrane or in the cell seemed to be necessary. Moreover, it was suggested that VBL was not extruded by neither (Na+-K+) ATPase nor (Ca2+-Mg2+) ATPase in the plasma membrane and a different active transport system might be concerned with the efflux of VBL.
A new preparation of flavones was discussed. Dehydrogenation of some 2'-hydroxychalcones with 2, 3-dichloro-5, 6-dicyano-1, 4-benzoquinone (DDQ) in boiling dioxane furnished the corresponding flavones and small amount of aurones.
The stability of porcine insulin (PI) in various concentrations of hydrochloric acid was investigated by use of high-performance liquid chromatographic (HPLC) method. Separation and determination of PI and its degradation products were achieved on a column of LiChrosorb RP-18 with a mixture of acetonitrile and 0.1 M phosphate buffer (pH 5.0) (29 : 71) containing 50mM sodium sulfate and 0.2mM cethyltrimethylammonium bromide as a mobile phase at 30°C. The decomposition of PI in hydrochloric acid was greatly affected by the concentration of hydrochloric acid and temperature, and followed a good pseudo-first order reaction. In 0.001 and 0.01 N hydrochloric acid, PI was stable at 0°C for 28 d, but it decomposed quickly at 30 and 60°C, and gave almost one degradation product. In 0.1 and 0.3 N hydrochloric acid, PI was slightly decomposed at 0°C, but decomposed rapidly at 30°C and gave many degradation products. HPLC method was very useful for the mutual separation of PI and its degradation products in various concentrations of hydrochloric acid.