Comparison of simple Eudragit microparticles loaded with prednisolone and Eudragit-coated chitosan-succinyl-prednisolone conjugate microparticles: Part I. Particle characteristics and in vitro evaluation as a colonic delivery system.

OBJECTIVE: Simple Eudragit microparticles loaded with prednisolone and chitosan-succinyl-prednisolone conjugate microparticles coated with Eudragit were prepared and characterized in vitro in order to obtain their basic features as a colonic delivery system. MATERIALS AND METHODS: Both types of microparticles were prepared by the emulsification-solvent evaporation modified somewhat from the previous one. Their particle size, shape and their drug content were investigated, and in vitro release profiles were examined using JP-15 1st fluid (pH 1.2), JP-15 2nd fluid (pH 6.8) and PBS (pH 7.4) as release media. Furthermore, the regeneration of conjugate microparticles from Eudragit-coated microparticles was investigated under the same incubation conditions. RESULTS: Simple Eudragit S100 (EuS) microparticles (ES-M) were almost spherical, ca. 1.2 µm diameter, and PD content ca. 3.7% (w/w). Conjugate microparticles (CS-M1) and EuS-coated conjugate microparticles (CS-M1/S) had particle sizes of ca. 2.8 and 15.3 µm, respectively, and PD contents of 5.4 and 2.1% (w/w), respectively. ES-M exhibited suppressed release at pH 1.2, gradual release at pH 6.8 and rapid release at pH 7.4. CS-M1 showed no release at pH 1.2, and very slow release at pH 6.8 and 7.4. CS-M1 regenerated poorly from CS-M1/S at pH 6.8. CONCLUSIONS: Simple Eudragit micrparticles and Eudragit-caoted conjugate microparticles, prepared by the present methods, were found in vitro to be possibly useful as the delivery systems of PD to the lower intestine, although there were differences in their release rate and morphological features.

Semi-solid dosage form of clonazepam for rapid oral mucosal absorption.

BACKGROUND: In order to obtain an alternative to the intravenous (i.v.) dosage form of clonazepam (CZ), an oral droplet formulation of CZ was developed previously; however, the droplet was physically unstable. Therefore, in the present study, it was attempted to develop an easily-handled dosage form, which was more physically stable and allowed rapid drug absorption from oral mucosa. METHOD: A semi-solid dosage form, composed of polyethylene glycol 1500 (PEG), CZ, and oleic acid (OA) at 37/1/2 (w/w) and named PEG/CZ/OA, and a semi-solid dosage form containing PEG and CZ at 39/1 (w/w), called PEG/CZ, were prepared. Their physical stability in air at room temperature and oral mucosal absorption in rats were investigated. RESULTS: The semi-solid dosage forms were much more stable physically than the droplet, that is, no recrystallization of CZ was observed for at least 8 days. The effective concentration for humans and rats (20 ng/mL or more) was achieved within 30 min after buccal administration for both PEG/CZ/OA and PEG/CZ. The plasma concentration increased gradually and less varied at each time point for PEG/CZ/OA. PEG/CZ/OA was found to show more rapid and higher absorption of CZ in buccal administration than in sublingual administration. CONCLUSION: Buccal administration with the semi-solid dosage PEG/CZ with or without OA was suggested to be a possibly useful novel dosage form as an alternative to i.v. injection.

Preparation and evaluation of medicinal carbon oral films.

Medicinal carbon (MC) films, which can be taken more easily than other dosage forms, were prepared using sodium carboxymethyl cellulose (CMC), hydroxypropylmethyl cellulose (HPMC) and alginic acid sodium (ALG) as film base materials. Brilliant blue FCF (BB) was used as a model drug. The films containing MC had sufficient strength and disintegration time, but their ability to adsorb BB was clearly inhibited compared to that of MC in powder form. When ALG was used as the film base, the BB adsorption capacity of MC film was approximately 50% of that of MC powder. In an attempt to improve this adsorption ability, two saccharides, sorbitol (SOR) and maltitol (MT), were separately added to MC at a mixing ratio of 1 : 1 by weight. When ALG was the film base, MC films containing SOR or MT showed rapid adsorption profiles and had greatly increased capacities for BB adsorption compared with films containing MC alone. SOR was superior to MT as an additive, though both gave MC-containing films a BB adsorption capacity almost equal to that of MC powder after 24 h, and physical mixtures tended to have better BB adsorption capacities than pre-treatment mixture. In addition, both SOR and MT tended to increase vertical strength of films, but neither additive in either type of mixture had a clear effect on disintegration time. When CMC or HPMC was used as the film base, on the other hand, the addition of SOR or MT caused hardly any improvement in adsorption ability. The above results demonstrate that ALG is useful as a film base material for the preparation of MC films, and that MC films with sufficient strength and adsorption capacities equal to those of MC powders can be produced using a physical mixture of MC and SOR on an ALG base.

Preparation of chitosan/alginate/calcium complex microparticles loaded with lactoferrin and their efficacy on carrageenan-induced edema in rats.

BACKGROUND: Although lactoferrin (LF) possesses useful functions such as antitumor, antiviral, and anti-inflammatory acitivities, it is subject to gastric digestion, resulting in the reduction of efficacy. Therefore, it is important to develop a system delivering LF efficiently to intestinal mucosa or gut-associated lymphoid tissue. METHOD: Chitosan/alginate/calcium complex microparticles containing LF at a high loading were prepared using alginate, LF, and calcium chloride at the ratio of 6:3:8 (w/w). The release test was performed using Japanese Pharmacopoeia, Fifteenth Edition (JP15) first fluid (pH 1.2) for initial 2 hours, followed by JP15 second fluid (pH 6.8) for another 5 hours. Furthermore, the in vivo efficacy was evaluated from anti-inflammatory effect using rats with carrageenan-induced edema, in which dosing was performed intragastrically at 50 mg LF eq./kg 5, 3, and 1 days before carrageenan injection. RESULTS: Microparticles have 20-30 % (w/w) LF content and 1-3 mm size. Nearly 60 % of LF was released at pH 1.2 at the first 1 hour, and then slowly released up to 80% at 7 hours. Suppressive effect against the edema was greater in the order of microparticles LF solution control (saline). Initial burst of LF from microparticles was not associated with their promoted efficacy. CONCLUSION: Chitosan/alginate/calcium complex microparticles are suggested to be useful for promotion of efficacy of LF at oral administration.

[Preparation of orally disintegrating tablets for masking of unpleasant taste: comparison with corrective-adding methods].

Many orally disintegrating tablets have recently been developed to improve oral ingestion and usability and are widely administered clinically, resulting in improved quality of life for patients. Since orally disintegrating tablets rapidly disintegrate in the mouth, the masking of unpleasant taste is important. We investigated the masking of the taste of furosemide (FU) as a model drug with correctives and prepared orally disintegrating tablets. Using maltitol (MA) as a corrective, granules were prepared employing mixing, coating, and mixing/coating methods using a desktop granulator. Each preparation was subjected to tasting. The taste was masked well when granules were prepared by the mixing and mixing/coating methods. Tablets were prepared from these granules with mannitol and crystalline cellulose added as fillers. Tablets made from granules prepared by the mixing and mixing/coating methods showed appropriate strength and disintegrated rapidly. When the amount of MA was increased in the mixing method, the disintegration time was prolonged, and thus the amount should be determined considering both taste masking and disintegration property. The results showed that orally disintegrating tablets of insoluble drugs with an unpleasant taste such as FU should be prepared with the taste masked employing the methods used in this study.

Preparation of orally disintegrating tablets with taste-masking function: masking effect in granules prepared with correctives using the dry granulation method and evaluation of tablets prepared using the taste-masked granules.

We investigated several methods of taste masking in the preparation of orally disintegrating tablets (ODTs), using furosemide (FU) as a model drug. Four types of FU preparations were prepared: granules with maltitol (MA), granules with yogurt powder (YO), a physical mixture of FU and MA, and a physical mixture of FU and YO. All taste-masking granules were prepared using the dry granulation method. The taste of each type of preparation was evaluated. All four preparations markedly improved the taste of the FU tablets, but the mixing ratios of the correctives did not affect the masking effect. No difference in masking effect was found between MA and YO in the physical mixtures, but the masking effect in the granules with YO was superior to that of the granules with MA. Taste-masked FU tablets were prepared using the direct compression method; crystalline cellulose (Avicel PH-302) and mannitol were added as excipients at the mixing ratio of 1/1. All four types of tablets displayed sufficient hardness, but MA-containing tablets were harder than YO-containing tablets. The hardness of the tablets prepared from YO granules increased as the YO content increased. The most rapidly disintegrating tablets were those of YO granules prepared at a mixing ratio of FU/YO=1/1, which disintegrated within 20 s, followed by the tablets of MA granules prepared at a mixing ratio of FU/MA=1/1. The disintegration times of the tablets made from physical mixtures, in contrast, were longer than 200 s. Disintegration time lengthened as the mixing ratio of YO or MA increased. The hardness and disintegration time of these tablets could be controlled by varying the compression pressure. We found that YO is more useful than MA in masking unpleasant tastes and confirmed that orally disintegrating tablets with taste-masking function can be prepared using granules of YO prepared using the dry granulation method as a new corrective.

[Development of semisolid dosage form of clonazepam for oral cavity administration].

A semisolid dosage form of clonazepam (CZP), administered to the oral cavity between the lower gum and bottom lip with small volume of saline, was developed to obtain the stable dosage which can replace the injection dosage form. Semisolid dosage forms were prepared using a mixture of CZP/(polyethylene glycol 1500 (PEG))/(oleic acid (OA)) at the ratios of 1/39/0, 1/37/2 and 2/36/2 (w/w), named CZP1-PEG, CZP1-PEG-OA and CZP2-PEG-OA, respectively, and were evaluated in vitro and in vivo. No crystal of CZP was observed in CZP1-PEG-OA for at least 8 days, while CZP crystal appeared before administration for CZP2-PEG-OA. When a small volume of saline was added to CZP1-PEG-OA just before the oral cavity administration, more than 80% (w/w) was found to exist in the soluble form. Each semisolid dosage form (40 mg) was administered to the oral cavity in rats, and CZP 1 mg suspension in 0.5% (w/v) sodium carboxymethylcellulose aqueous solution was administered into rat stomach as a control. CZP1-PEG-OA gave the plasma concentrations of more than 5 ng/ml and 12 ng/ml at 30 min and 1 h after administration, respectively, which might be near the plasma levels effective for the suppression of epileptic seizures in human, while the plasma concentration was less than 5 ng/ml at 30 min or did not reach 10 ng/ml at 1 h for the other formulations. It is proposed that the semisolid dosage form CZP1-PEG-OA should be a possibly useful preparation for the antiepileptic or sedative medication.

[Preparation and evaluation of taste masked orally disintegrating tablets with granules made by the wet granulation method].

Using furosemide (FU) as a model drug, we examined the wet granulation method as a way to improve the taste masking and physical characteristics of orally disintegrating tablets (ODTs). In the wet granulation method, yogurt powder (YO) was used as a corrective and maltitol (MA) was used as a binding agent. The taste masked FU tablets were prepared using the direct compression method. Microcrystalline cellulose (Avicel® PH-302) and mannitol were added as excipients at a mixing ratio of 1/1 by weight. Based on the results of sensory test on taste, the prepared granules markedly improved the taste of FU, and a sufficient masking effect was obtained at the YO/FU ratio of 1 or more. Furthermore, it was found that the masking effect achieved by YO granules made with the wet granulation method was similar to or better than that produced by the granules made with dry granulation method. All types of tablets displayed sufficient hardness (over 3.5×10(-2) kN), and rapidly disintegrating tablets were obtained with YO granules produced at a mixing ratio of FU/YO=1/1, which disintegrated within 20 s. Disintegration time lengthened as the mixing ratio of YO to FU increased. In the mixing ratio of FU/YO=1/1, the hardness of tablets with granules made by the wet granulation method exceeded that of tablets with granules made by the dry granulation method, with minimal differences in disintegration time. The hardness and disintegration time of the tablets with granules made by the wet granulation method could be controlled by varying the compression force. In conclusion, YO was found to be a useful additive for masking unpleasant tastes. FU ODTs with improved taste, rapid disintegration and greater hardness could be prepared with YO-containing granules made by the wet granulation method using MA as a binding agent.

Effect of beta-cyclodextrin on the degradation rate of amoxicillin in acidic solution.

The formation of an inclusion complex of amoxicillin (AMX) with beta-cyclodextrin (beta-CD) in aqueous solution was confirmed by a solubility method and proton nuclear magnetic resonance (1H-NMR) spectroscopy. The apparent stability constant for the inclusion complex was 10.72 M(-1) in water at 25 degrees C. The effect of alpha-CD, beta-CD, and gamma-CD on the degradation of AMX in a pH 1.2 solution at 37 degrees C was investigated. beta-CD and gamma-CD reduced the rate of degradation. alpha-CD had no effect. These results were consistent with those of 1H-NMR spectroscopy. The effect of beta-CD on the degradation rate was studied in more detail. The apparent first order rate constant for the degradation of AMX in the pH 1.2 solution at 37 degrees C was 0.1121 h(-1) (t(1/2)=6.18 h), which decreased with the addition of beta-CD. The rate constants and t(1/2) values for the concentrations of beta-CD added, corresponding to molar ratios of AMX to beta-CD of 1:0.5, 1:1, 1:2, 1:5, and 1:10, were 0.1051 h(-1) and 6.59 h, 0.0992 h(-1) and 6.98 h, 0.0893 h(-1) and 7.76 h, 0.0697 h(-1) and 9.95 h, and 0.0509 h(-1) and 13.61 h, respectively. The activation energy for the degradation of AMX in the pH 1.2 solution was increased from 6.9 x 10(4) J/mol (AMX alone) to 8.0 x 10(4) J/mol (AMX:beta-CD=1:10).

Preparation and evaluation of medicinal carbon tablets with different saccharides as binders.

Medicinal carbon (MC) tablets were prepared with several saccharides to improve the formability and absorption ability of MC tablets made with maltitol (MT). The MC tablets were made by the wet granule compression method, in which maltitol, xylitol (XYL), mannitol (MAN), and sorbitol (SOR) were used as binders. Granule and tablet formability, tablet strength, disintegration, and MC adsorption potential were evaluated for each formulation. Acetaminophen (AA) was used in checking effect of binders on adsorption. Due to low water solubility, MAN was added only up to 30% (w/w) of MC; in greater concentrations, the tablet could not be formed. However, tablets formed easily when using XYL or SOR at 120% (w/w) of the MC amount. This result was similar for MT. The XYL, SOR, and MT tablets displayed sufficient hardness and rapid disintegration. The tensile strength of the SOR tablets exceeded that of the MT tablets, which in turn had greater tensile strength than the XYL tablets. In addition, the XYL tablets disintegrated more quickly than the MT tablets, which disintegrated more quickly than the SOR tablets. The MC adsorption capacity was slightly decreased by XYL and SOR, but to a lesser extent than the decrease caused by MT. Overall, XYL and SOR were superior to MT as binding agents for preparation of MC tablets. Therefore, we recommend preparing the tablets with XYL or SOR as a binder using the wet granule compression method to produce a compact dosage form of MC.

Preparation of medicinal carbon tablets by modified wet compression method.

BACKGROUND: Although medicinal carbon (MC) is useful to treat intoxications caused by orally taken toxic chemicals or toxins, high dose of MC is a burden on patients and sticks to oral mucosa or throat. A tablet dosage form of MC is useful to solve such problems. Fast-disintegration, adequate hardness, and quick and high-adsorption potential are required for MC tablets. METHOD: A modified wet compression method using carboxymethylcellulose sodium (CMC-Na) solution as binder solution was newly developed. Croscarmellose sodium (CC-Na) was used as a disintegration agent. MC granules, binder solution, and MC granules were placed in the cylinder in that order, and the resultant mass was compressed. The obtained tablets were examined for hardness, disintegration rate, and acetaminophen adsorption profiles. RESULTS: The tablets, produced with MC granules containing CMC-Na and CC-Na at 10% each and using 280 microL of 2.5% (w/w) CMC-Na binder solution in compression, showed adequate hardness (more than 4 kg), short disintegration time (less than 6 min), and almost the same acetaminophen adsorption profile as intact MC powder. CONCLUSION: The modified wet compression with CMC-Na and CC-Na is suggested to be useful to obtain MC tablets with good quality.

Preparation and in vitro evaluation of chitosan-coated alginate/calcium complex microparticles loaded with fluorescein-labeled lactoferrin.

An attempt was made to prepare FITC-labeled-lactoferrin (LF-FTC)-loaded microparticles, durable under gastrointestinal conditions, first by the combination of alginate/calcium complexation and emulsification-evaporation and next by treatment with chitosan solution. The obtained microparticles were examined for particle characteristics, in vitro release profiles and physical stability in solutions of pH 1.2 and 6.8. The obtained chitosan-coated alginate/calcium complex microparticles (Ch/Al/Ca-MP) showed almost uniform size of 1-2 microm and a spherical shape with a non-smooth surface. The content and recovery of LF-FTC in Ch/Al/Ca-MP fell as the concentration of chitosan solution used in chitosan coating increased. The release rate of LF-FTC was faster in Ch/Al/Ca-MP prepared with more chitosan at pH 1.2 and 6.8. Ch/Al/Ca-MP coated with 0.25 and 0.5% (w/v) chitosan solution showed good gradual release characteristics in vitro. Furthermore, they were durable at pH 1.2 and 6.8, though swelling and softening of the microparticles occurred at pH 6.8. It is suggested that alginate/calcium complex microparticles coated with 0.25-0.5% (w/v) chitosan solution would be useful for the intestinal delivery of LF.

Novel preparation of enteric-coated chitosan-prednisolone conjugate microspheres and in vitro evaluation of their potential as a colonic delivery system.

After chitosan-succinyl-prednisolone conjugate (Ch-SP) was synthesized, conjugate microspheres (Ch-SP-MS), Eudragit L100-coated Ch-SP-MS and Eudragit S100-coated Ch-SP-MS, were prepared under novel preparative conditions. Namely, sonication was utilized to prepare finer Ch-SP-MS, and the addition ratio of Eudragit was reduced to yield Eudragit-coated Ch-SP-MS with higher drug content. Ch-SP-MS and Eudragit-coated Ch-SP-MS had mean sizes of 1.3microm and approximately 30microm, respectively, and showed prednisolone (PD) contents of 4.6% (w/w) and approximately 3% (w/w), respectively. Morphological changes of all the types of microparticles in different pH media were observed by scanning electron microscopy and confocal laser scanning microscopy. Both methods gave similar results. Both types of Eudragit-coated Ch-SP-MS protected Ch-SP-MS from morphological change at pH 1.2, and regenerated Ch-SP-MS fast at pH 6.8 and 7.4. For all types of microparticles, release of PD was suppressed at pH 1.2, but caused gradually at pH 6.8. These particle characteristics and in vitro behaviors demonstrated that the present Eudragit-coated Ch-SP-MS were considered potentially suitable for in vivo or practical application as a specific delivery system of PD to IBD sites.

Preparation and biodisposition of methoxypolyethylene glycol amine-poly(DL-lactic acid) copolymer nanoparticles loaded with pyrene-ended poly(DL-lactic acid).

A formyl group-ended poly(DL-lactic acid) (PLA-aldehyde), synthesized in the same manner as reported previously, was utilized to produce the polymeric marker for PLA-related nanoparticles. Namely, pyrene-ended poly(DL-lactic acid) (PLA-pyrene) was prepared as a polymeric marker by the reductive amination of PLA-aldehyde and aminopyrene. Methoxypolyethylene glycol amine-poly(DL-lactic acid) block copolymer (PLA-(MeO-PEG) nanoparticles loaded with PLA-pyrene were prepared, and examined on retention of PLA-pyrene in the nanoparticles, and biodisposition in normal and sarcoma-180 solid tumor-bearing mice. PLA-pyrene was retained stably in PLA-(MeO-PEG) nanoparticles in a PBS-ethanol (7:3, v/v) mixture and a plasma-PBS (1:1, v/v) mixture, indicating that PLA-pyrene might be a useful marker of PLA-(MeO-PEG) nanoparticles themselves. After i.v. injection in normal rats, the plasma level of PLA-pyrene was very high for initial 8h, and accumulated gradually into organs, especially spleen and liver. After i.v. injection in tumor-bearing mice, similar biodistribution profiles of PLA-pyrene were observed, and PLA-pyrene was accumulated well in tumor, suggesting that PLA-(MeO-PEG) nanoparticles should be delivered efficiently to solid tumors. It is suggested that PLA-pyrene might be a useful probe of the nanoparticles themselves. In addition, it was demonstrated that PLA-(MeO-PEG) nanoparticles should be a useful drug carrier for passive tumor targeting.

Efficacy and toxicity of Eudragit-coated chitosan-succinyl-prednisolone conjugate microspheres using rats with 2,4,6-trinitrobenzenesulfonic acid-induced colitis.

A targeted delivery system for inflammatory bowel disease (IBD), Eudragit L100 (EuL)-coated chitosan (Ch)-succinyl-prednisolone (SP) conjugate microspheres (Ch-SP-MS/EuL), were designed and examined in vivo for efficacy and toxicity. Their preparation was conducted in the same manner as previously; that is, by synthesis of the conjugate by carbodiimide coupling of Ch and SP, conversion into microspheres (Ch-SP-MS), and coating of Ch-SP-MS with EuL. Experimental colitis was induced by instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS) into the colon in rats. Drugs were administered once or twice a day intragastrically for three consecutive days. Visible colitis severity, colon/body weight ratio and myeloperoxidase activity were measured as inflammatory indices. Toxicity was examined from the decrease in the thymus/body weight ratio. Efficacy was dose-dependent and the greatest in the order Ch-SP-MS/EuL>Ch-SP-MS>prednisolone (PD) alone, and Ch-SP-MS/EuL showed excellent recovery of colitis states. Toxicity was the greatest in the order PD>>Ch-SP-MS>Ch-SP-MS/EuL. Ch-SP-MS and Ch-SP-MS/EuL reduced significantly the thymic atrophy caused by PD. It was demonstrated that Ch-SP-MS/EuL enhanced effectiveness of PD and reduced toxic side effects of PD greatly. Also, these results established the prediction by previous in vitro and in vivo studies.

Gastrointestinal distribution and absorption behavior of Eudragit-coated chitosan-prednisolone conjugate microspheres in rats with TNBS-induced colitis.

Conjugate of chitosan and succinyl-prednisolone, termed Ch-SP, was synthesized, and Ch-SP microspheres (Ch-SP-MS) and Eudragit L100-coated Ch-SP-MS (Ch-SP-MS/EuL) were prepared using Ch-SP. Ch-SP-MS and Ch-SP-MS/EuL had a mean size of 1.5 and 26.6microm, respectively, and a drug content of 4.6 and 3% (w/w), respectively. Prednisolone (PD) was released very slow in JP 14 first fluid (pH 1.2), and gradually in JP 14 second fluid (pH 6.8). The addition of cecal or colonic content did not accelerate the release. Rats with 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis were used in animal studies. Gastrointestinal distribution and plasma concentration were investigated by oral administration of PD alone and Ch-SP-MS/EuL. For PD alone, PD was distributed at the stomach and small intestine, and disappeared from the gastrointestinal tracts within 8h. When administering Ch-SP-MS/EuL, the drug was distributed mainly in the lower intestine between 3 and 24h. Plasma concentration was much lower in Ch-SP-MS/EuL than in PD alone, suggesting lower toxic side effects of Ch-SP-MS/EuL. Thus, Ch-SP-MS/EuL delivered PD specifically near the diseased site and PD was released gradually, with much less plasma concentration of PD. Ch-SP-MS/EuL are suggested as a useful delivery system to the site of inflammatory bowel disease.

Particle characteristics and biodistribution of camptothecin-loaded PLA/(PEG-PPG-PEG) nanoparticles.

Poly(DL-lactic acid) (PLA)/poly(ethylene glycol)-block-poly (propylene glycol)-block-poly(ethylene glycol) copolymer (PEG-PPG-PEG) nanoparticles loaded with camptothecin (CPT), called CPT-NP, were prepared and examined for particle size change and drug release in phosphate-buffered saline, pH 7.4, (PBS), and drug biodistribution profiles in mice bearing sarcoma 180 solid tumor. CPT-NP kept an almost constant mean size and exhibited an initial rapid release of approximately 20%, following by very slow release. As compared with CPT solution, CPT-NP showed higher tissue accumulation and better tumor localization, which were considered essentially associated with the better efficacy of CPT-NP reported in the previous study.

Clonazepam oral droplets for the treatment of acute epileptic seizures.

Oral droplet formulations of clonazepam (CZ) were developed to examine their potentials as an alternative to i.v. administration for the treatment of acute epileptic seizures. Propylene glycol containing 2.5% (wt/wt) CZ with or without 5.0% (wt/wt) oleic acid (OA) was prepared as a solution by heating at 90 degrees C and subsequently lowering the temperature to 30 degrees C. The droplet (20 microL) was administered to the oral cavity between the lower gum and bottom lip before CZ precipitation started. With a droplet of propylene glycol loaded with 2.5% (wt/wt) CZ and 5.0% (wt/wt) OA, the plasma concentration reached 20 ng/mL (minimal effective concentration) within 10 min and was maintained between 20 and 60 ng/mL, less than a toxic level, for a period of 60 min. For a droplet of propylene glycol loaded only with CZ at 2.5% (wt/wt), it took more than 15 min for the plasma concentration to reach 20 ng/mL. It is suggested that a droplet of CZ/OA/propylene glycol (2.5:5.0:92.5, wt/wt) might be useful as an alternative to i.v. injection of CZ for the treatment of acute epileptic seizures.

In vitro and in vivo evaluation of microparticulate drug delivery systems composed of macromolecular prodrugs.

Macromolecular prodrugs are very useful systems for achieving controlled drug release and drug targeting. In particular, various macromolecule-antitumor drug conjugates enhance the effectiveness and improve the toxic side effects. Also, polymeric micro- and nanoparticles have been actively examined and their in vivo behaviors elucidated, and it has been realized that their particle characteristics are very useful to control drug behavior. Recently, researches based on the combination of the concepts of macromolecular prodrugs and micro- or nanoparticles have been reported, although they are limited. Macromolecular prodrugs enable drugs to be released at a certain controlled release rate based on the features of the macromolecule-drug linkage. Micro- and nanoparticles can control in vivo behavior based on their size, surface charge and surface structure. These merits are expected for systems produced by the combination of each concept. In this review, several micro- or nanoparticles composed of macromolecule-drug conjugates are described for their preparation, in vitro properties and/or in vivo behavior.

[In-vitro evaluation of cinnarizine as a competing agent to beta-cyclodextrin inclusion complexes: effect of cinnarizine on the membrane permeation rate of progesterone from its beta-cyclodextrin inclusion complex].

The use of competing agents is considered a powerful tool for the development of a drug-delivery system with drug/cyclodextrin inclusion complexes. However, there are very few studies examining this issue. To explain this phenomenon, it was thought that a competing agent with a sufficiently high stability constant had not yet been reported. In this study, cinnarizine (CN), which has a high stability constant with beta-cyclodextrin (beta-CD) and unique solubility characteristics, was selected, and its ability as a competing agent was examined in a membrane permeability study. The permeability study showed that the permeation rates of the drugs flurbiprofen, progesterone, and spironolactone decreased with their stability constants with the addition of beta-CD. In one of the drugs, progesterone (Pro), the decrease was restored by the addition of CN. The amount of CN added was a 1:1 molar ratio to the amount of Pro. However, no similar action was induced with the addition of DL-phenylalanine (Phe) in the permeation study at the 1:5 (Pro:Phe) molar ratio. These finding indicate that CN acts as a competing agent, and its action is much stronger than that of Phe.