Development of a lip vermilion epithelium reconstruction model using keratinocytes from skin and oral mucosa.

Lip vermilion is unique and can be distinguished from the adjacent skin and oral mucosa. However, because of the lack of appropriate evaluation tools, skin and/or oral mucosa substitutes such as in vitro vermilion epithelial models have been used for lip product testing. We aimed to develop and characterize a lip vermilion epithelium reconstruction model (LVERM) using skin and oral keratinocytes. LVERM was manufactured by co-culturing primary skin and oral keratinocytes, using a device that allowed the separation of cell seeding, and created an intercalated cell-free zone, referred to as the vermilion part. After removing the device, LVERM construction was completed in 8 days, in a submerged condition. Subsequently, they were placed in an air-liquid interface for 7 days. To determine the epithelial characteristics of LVERM, keratin 2e (KRT2) and small proline-rich protein 3 (SPRR3) expression patterns were examined. The in vivo expression profiles of KRT2 and SPRR3 genes in vermilion were also examined. We found that a continuous multi-layered epithelium was generated in the LVERM that exhibited ortho- and para-keratinization in the skin and oral mucosa parts, respectively. Although an intermediate keratinization pattern was observed in the vermilion part, KRT2 and SPRR3 were co-expressed in the suprabasal layer, consistent with the expression pattern of a single vermilion epithelial model. Clustering analysis revealed that KRT2 and SPRR3 gene expression in vermilion was location-dependent within the sample. Therefore, LVERM can be used as an evaluation tool for lip products and has great importance in innovative approaches for cosmetic testing.

Distribution of Domains Formed by Lateral Packing of Intercellular Lipid in the Stratum Corneum.

Intercellular lipids fill the interstices of corneocytes and serve a barrier function. The amount of transdermal water evaporation varies depending on the packing structure of intercellular lipids, as this structure is important for maintaining barrier efficacy. This packing structure consists of a mixture of crystals (orthorhombic and hexagonal) and liquid crystals (fluid phase), and the proportion of these phases is thought to affect barrier function. However, there have been no methods to visualize the actual distribution of the domains formed by packing structure in intercellular lipids. In this study, the planar distribution of intercellular lipid structures was determined using focal plane array (FPA)-based Fourier transform (FT) IR imaging analysis of stratum corneum cell units obtained by grid stripping. The lipid composition of ceramides was revealed by electrospray ionization tandem mass spectrometry (ESI-MS/MS)-based shotgun lipidomics. The distribution of domains formed by packing structures and the lipid composition of ceramides was compared in skin with high- or low-transepidermal water loss (TEWL). The orthorhombic proportion was lower in high-TEWL skin than in low-TEWL skin. ESI-MS/MS-based shotgun lipidomics analysis showed that the alpha-hydroxyceramide content in the low- and high-TEWL groups differed regarding the distribution of fatty acid chain lengths. The evaluation of stratum corneum cell units using FPA-based FTIR imaging is an innovative technology that can visualize the distribution of domains formed by intercellular lipid-packing structures. Increased proportions of alpha-hydroxyceramide subclasses such as alpha-hydroxy-sphingosine ceramide and alpha-hydroxy-phytosphingosine ceramide were associated with a reduced proportion of the orthorhombic packing structure domain.

Evaluation of Perioperative Intestinal Motility Using a Newly Developed Real-Time Monitoring System During Surgery.

BACKGROUND: This study aimed to investigate perioperative intestinal motility using a novel bowel sound monitoring system in patients undergoing breast and neck surgery. MATERIALS AND METHODS: This study enrolled 52 patients who underwent surgery for breast cancer, thyroid tumor, and parathyroid tumor at Kochi Medical School from May 2019 to June 2020. Perioperative bowel sound counts (BSCs) were recorded using a newly developed real-time analysis system in the operating theater. Clinical information and BSC per minute (cpm) data during the preanesthetic, preoperative, operative, postoperative periods, and period in recovery room were obtained to compare between each period. The Mann-Whitney U and Pearson Chi-square tests were used in data analysis. RESULTS: The BSCs during the intraoperative period and postoperative period were significantly decreased compared to those during the preanesthetic period (0.07 cpm versus [vs.]. 1.4 cpm, P = 0.002 and 0.1 cpm vs. 1.4 cpm, P = 0.025, respectively). The preoperative BSC with a preanesthetic BSC < 1.4 was significantly lower than that with a preanesthetic BSC ≥ 1.4 (0.40 cpm vs. 1.78 cpm, P = 0.006). The preanesthetic, preoperative, and postoperative BSCs with an intraoperative BSC < 0.07 were significantly lower than those with an intraoperative BSC ≥ 0.07 (0.48 cpm vs. 2.83 cpm, P = 0.007; 0.40 cpm vs. 1.81 cpm, P = 0.008; and 0.07 cpm vs. 0.42 cpm, P = 0.006, respectively). CONCLUSION: The real-time bowel sound analysis system demonstrated an inhibitory effect associated with anesthetic and surgical stress on intestinal motility as the BSC sequentially.

Amino Acids and Their N-Acetylated Derivatives Maintain the Skin's Barrier Function.

The hydrocarbon-chain packing structure of intercellular lipids in the stratum corneum (SC) is critical to the skin's barrier function. We previously found that formation of V-shaped ceramide reduces the barrier function of skin. There are few agents, apart from ceramides and fatty acids that can improve the orthorhombic packing (Orth) ratio of the intercellular lipid packing structure. In this study, we investigated agents that directly increase the Orth ratio. We selected an intercellular lipid model consisting of ceramide, cholesterol, and palmitic acid and performed differential scanning calorimetry. We focused on natural moisturizing factor components in the SC, and therefore investigated amino acids and their derivatives. The results of our intercellular lipid model-based study indicate that N-acetyl-L-hydroxyproline (AHYP), remarkably, maintains the lamellar structure. We verified the effect of AHYP on the lamellar structure and hydrocarbon chain packing structure of intercellular lipids using time-resolved X-ray diffraction measurements of human SC. We also determined the direct physicochemical effects of AHYP on the Orth ratio of the hydrocarbon-chain packing structure. Hence, the results of our human SC study suggest that AHYP preserves skin barrier function by maintaining the hydrocarbon-chain packing structure of intercellular lipids via electrostatic repulsion. These findings will facilitate the development of skincare formulation that can maintain the skin's barrier function.

Phase Separation in Lipid Lamellae Result from Ceramide Conformations and Lateral Packing Structure.

Intercellular lipids in the stratum corneum protect the living body from invasion by allergens and pathogens, and also suppresses water evaporation within the body. It is important to understand how differences in the microstructure of intercellular lipids arise. This microstructure is affected by lipid composition. Studies using intercellular lipid models have reported the formation of two phases with different short lamellar periodicities. However, the details of the packing structure characteristics of the two phases observed in these intercellular lipid models are unclear. Our previous report revealed that different short periodicity phases coexist in the N-(α-hydroxyoctadecanoyl)-dihydrosphingosine (CER[ADS]), cholesterol (CHOL), and palmitic acid (PA) complex model. In this study, the characteristics of the packing structure of two phases with different short lamellar periodicities, which were observed in the intercellular lipid model (CER[ADS]/CHOL/PA) that we used previously, were adjusted for models with different lipid compositions. The characteristics of the packed and lamellar structures have been determined by temperature-scanning small-angle X-ray scattering and wide-angle X-ray diffraction measurements simultaneously. These differences in lamellar structure were thought to be caused by differences in ceramides (CER) conformation between the hairpin and the V-shape type. The lamellar structure of the V-shaped CER conformation has a low orthorhombic ratio. The above results suggest that an increase in the ratio of CER with the V-shaped structure causes the lamellar structure to have low orthorhombic ratio, thereby contributing to a decrease in the bilayer's barrier function.

Preparation and evaluation of fast-dissolving films of etilefrine hydrochloride for practical buccal dosing.

Etilefrine hydrochloride (ET) is an important drug in the treatment of hypotension, and parenteral injections and oral tablets are the conventional dosage forms. However, parenteral injections may cause abnormally high plasma levels as well as pain and necrosis, and oral tablets undergo first-pass metabolism. Although fast-dissolving buccal tablets were previously reported, the initial absorption rate was a little slow and the plasma levels were varied extensively. Recently, many films have been developed as novel dosage forms. Therefore, in the present study, film dosage forms containing ET were produced using water-soluble polymers and glycerin (GLY) as excipients to obtain a practical buccal dosage form. Films composed of ET, GLY, and sodium alginate (AL) exhibited good physical characteristics and rapid release in vitro (more than 70% at 2 min). The compacted AL film containing 2 mg ET (1 × 1 cm) exhibited rapid absorption (>19 ng/mL at 0.5 h), maintained an effective plasma level (>7 ng/mL) for a long time period (0.5-4 h), and had an adequate plasma concentration-time profile with a smaller standard error (<15.3 ng/mL). These results suggest that the present compacted buccal film is a superior dosage form of ET for practical use.

Higher Accumulation of Docosahexaenoic Acid in the Vermilion of the Human Lip than in the Skin.

The vermilion of the human lip is a unique facial area because of certain distinguishing features from the adjacent tissues such as the white lip (skin) and oral mucosa. However, the distinction in terms of molecular distribution between the vermilion and skin has remained unexplored. Therefore, we aimed to map the human lip by mass spectrometry imaging to gain understanding of the free fatty acid distribution in the vermilion. The lip specimens trimmed off during cheiloplasty were analyzed using desorption electrospray ionization-mass spectrometry imaging. Distributions of two monounsaturated fatty acids and three polyunsaturated fatty acids were observed in the human lip tissue: palmitoleic acid (POA) and oleic acid (OA) and linoleic acid (LA), arachidonic acid (AA), and docosahexaenoic acid (DHA), respectively. Although POA, OA, LA, and AA were differentially distributed across the vermilion and skin, DHA showed a higher accumulation in the epithelium of the vermilion compared to that in the skin. Our results clearly demonstrated the difference in fatty acid distributions between the vermilion and skin. The highly abundant DHA in the epithelium of the vermilion may have an antioxidant role and may thus protect the lip from aging. Our findings can provide a novel strategy for treating lip disorders.

Preparation of orally fast-dissolving tablets of etilefrine hydrochloride to achieve efficient absorption.

Etilefrine hydrochloride (ET) is commonly used in the treatment of hypotension in dosage forms of oral tablets and parenteral injections. However, oral tablets only temporarily achieve high plasma levels and have low bioavailability (BA), while intravenous injections may cause pain and necrosis around administration sites. In an attempt to overcome these limitations, the buccal delivery of ET using oral droplets has been investigated. In this study, a buccal tablet as an alternative dosage form was developed for practical use. Buccal tablets were prepared by the direct compression method with sodium alginate (AL) and mannitol (MA) as excipients. Their disintegration and in vitro drug release were rapid (more than 50% being released after 3 min). Furthermore, effective plasma levels (> 5-7 ng/mL) were reached within 0.5 h of buccal administration in rats. The systemic absorption of these tablets was similar to that of buccal droplets. Therefore, the ET buccal tablets developed herein have potential as an alternative dosage form for hypotension therapy.

In vitro and in vivo evaluations of buccal tablet formulations of ritodrine hydrochloride.

Buccal tablets of ritodrine (RD) hydrochloride (HCl), called RD-HCl, were prepared using the direct compression method with alginate (AL), lactose (LC), magnesium stearate (ST), and microcrystalline cellulose (MC) as excipients. The tablets were evaluated based on hardness, and tablets weighing 80 mg and with hardness of greater than 30 N were chosen as appropriate ones. As a result, tablets composed of RD-HCl (4 mg)/LC (38.5 mg)/ST (0.5 mg)/MC (37 mg) and RD-HCl (4 mg)/AL(7 mg)/LC (28.5 mg)/ST (0.5 mg)/MC (37 mg), called D9 and D10, respectively, were selected. These tablets were further evaluated based on in vitro dissolution and in vivo absorption studies in rats. D9 rapidly released RD, achieved an effective plasma concentration from 15 min to 7 h after its buccal administration, and did not exceed the toxic plasma level of 80 ng/mL. D10 gradually released RD, and maintained an effective concentration from 1 h to 7 h after its buccal administration, without exceeding the toxic plasma level. The absorption was more prolonged in D10 than D9. Their in vivo release was considered to be caused gradually from the amount of RD remaining in the oral cavity at 7 h, in particular D10. The superior retention of D10 in plasma and oral cavity appeared to be related to its higher mucoadhesive properties. Although these results were obtained using rats, they suggest that the chosen tablets should have adequate characteristics from the viewpoints of plasma levels.

Usefulness of a real-time bowel sound analysis system in patients with severe sepsis (pilot study).

Healthy bowel function is an important factor when judging the advisability of early enteral nutrition in critically ill patients, but long-term observation and objective evaluation of gastrointestinal motility are difficult. In the study, real-time continuous measurement of gastrointestinal motility was performed in patients with severe sepsis using a developed bowel sound analysis system, and the correlation between bowel sounds and changes over time in blood concentrations of interleukin (IL)-6, which is associated with sepsis severity, was evaluated. The subjects were five adult patients in the acute phase of severe sepsis on a mechanical ventilator, with IL-6 blood concentrations ≥100 pg/mL, who had consented to participate in the study. Gastrointestinal motility was measured for a total of 62,399 min: 31,544 min in 3 subjects in the no-steroids group and 30,855 min in 2 subjects in the steroid treatment group. In the no-steroids group, the bowel sound counts were negatively correlated with IL-6 blood concentration, suggesting that gastrointestinal motility was suppressed as IL-6 blood concentration increased. However, in the steroid treatment group, gastrointestinal motility showed no correlation with IL-6 blood concentration (r = -0.25, p = 0.27). The IL-6 blood concentration appears to have decreased with steroid treatment irrespective of changes in the state of sepsis, whereas bowel sound counts with the monitoring system reflected the changes in the state of sepsis, resulting in no correlation. This monitoring system provides a useful method of continuously, quantitatively, and non-invasively evaluating gastrointestinal motility in patients with severe sepsis. Gastrointestinal motility might be useful as a parameter reflecting disease severity, particularly in patients treated with steroids.

Effects of oils and emulsifiers on the skin penetration of stearyl glycyrrhetinate in oil-in-water emulsions.

We investigated whether an emulsifier or an emulsified oil affects the skin penetration of stearyl glycyrrhetinate (SG) when it is applied in an oil-in-water (O/W)-type emulsion under finite dose conditions in vitro. SG has a high molecular weight (MW: 723) and high lipophilicity (log P: 15.6). Skin penetration of SG applied with O/W emulsions was evaluated using 6 types of emulsifiers that are commonly used in cosmetics; however, no significant differences were observed between these emulsifiers. When applied with liquid paraffins in oil phase, SG skin penetration increased significantly as the molecular weight of the liquid paraffin decreased. The skin penetration of the fluorescent dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI; MW: 834, log P: 23.2) also increased with O/W-type emulsions containing liquid paraffins of lower molecular weights. These results indicate that use of O/W-type emulsions with an appropriate oil phase can improve SG skin penetration.

Temporal changes in occurrence frequency of bowel sounds both in fasting state and after eating.

Food evaluation technology that takes into account the constitutional predisposition and health of an individual's digestive system should aid in the development of value-added foods for patients and people who require health care. Based on the assumption that the degree of bowel activity changes depending on each individual's constitutional predisposition, health, and tolerance of the consumed foods, we investigated bowel sounds as an index of bowel activity. We have developed a method for investigating changes in bowel activity by performing long-term continuous recording of bowel sounds and observing changes in the occurrence frequency of bowel sounds per unit of time. In order to obtain basic data, we made recordings of eight healthy adults. We observed that bowel sounds continued even after the most recently consumed food had been nearly completely digested. In addition, we found that the occurrence frequency of bowel sounds of normal intensity (stethoscope audible) did not synchronize with that of minimal intensity (amplifier audible) in the fasting state. In contrast, the former did synchronize with the latter during digestion.

In vivo absorption study of ritodrine hydrochloride in the buccal administration to rats.

BACKGROUND: Although ritodrine (RD)-hydrochloride (HCl), named RD-HCl, is widely used in the treatment of premature labor by intravenous prolonged infusion or frequent oral dosing of tablets, those administrations often lower patients' quality of life (QOL) or cause undesirable side effects, such as tachycardia; therefore, in this study, the potential usefulness of buccal administration as a novel administration method was examined in vivo. METHOD: First, the HPLC method was assessed for the determination of plasma RD concentration. Then, after RD-HCl solution in saline was administered intravenously (1 mg/kg), intragastrically (10 mg/kg) or buccally (10 mg/kg) in rats, the plasma concentration-time profiles were investigated, and the absorption extent and rate compared. RESULTS: The present modified determination method by HPLC with fluorescence detection (Ex. 278 nm, Em. 306 nm) was suitable to analyze the plasma level at 8-200 ng/mL. Buccal administration gave the best plasma concentration-time profile for maintenance of an effective plasma level and fewer side effects. Absorption rates calculated by deconvolution also supported better sustained absorption in buccal dosing. CONCLUSION: Buccal application of RD-HCl was demonstrated to be a potentially useful dosing method in the treatment of premature labor with RD-HCl.

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.

Linoleic acid and squalene are oxidized by discrete oxidation mechanisms in human sebum.

Previous studies suggest that squalene (SQ) in sebum is oxidized by a photooxidation mechanism (i.e., singlet oxygen oxidation) to create SQ hydroperoxide (SQOOH), a compound that causes adverse skin conditions. However, oxidation of other lipids in sebum, such as linoleic acid (LA), has not been fully understood. Elucidating their oxidation, especially its mechanisms, may lead to a further understanding of the relationship between sebum oxidation and skin conditions. In this study, using HPLC-MS/MS, we aimed to detect LA hydroperoxide (LAOOH) directly from sebum and identify the oxidation mechanism of LA in sebum through analysis of LAOOH isomers. We developed extraction and HPLC-MS/MS analysis conditions that can sufficiently quantify each LAOOH isomer in sebum. Using this method, LAOOH was detected in samples from healthy individuals, demonstrating the presence of LAOOH in human sebum. Moreover, isomer analysis of LAOOH and SQOOH indicated that LA and SQ are oxidized in sebum by discrete oxidation mechanisms (LA oxidized by free radical oxidation, whereas SQ oxidized by singlet oxygen oxidation). Such results may further lead to the development of mechanism-specific ways to prevent oxidation of sebum via a selection of appropriate antioxidants, ultimately leading to the promotion of skin health.

The human vermilion surface contains a rich amount of cholesterol sulfate than the skin.

BACKGROUND: The vermilion of the human lip presents characteristic features and undergoes aging faster than the skin. Therefore, knowledge of the vermilion surface-specific functional molecules is important to understand lip aging and formulate lip care products. Previously, we analyzed the free fatty acids distributions and showed that docosahexaenoic acid highly accumulated in the vermilion's epithelium than in the skin. OBJECTIVE: We aimed to explore the functional molecules other than the free fatty acids on the vermilion's surface. METHODS: Human lip tissues from children and tape-stripped samples from smooth and rough lips of adults were measured by desorption electrospray ionization-mass spectrometry imaging (DESI-MSI). RESULTS: DESI-MSI of children's lip sections revealed a major distribution of five phospholipid species in the viable layer, but not in the superficial area, of both the vermilion and the skin than that in the underlying tissue. Interestingly, a remarkably higher distribution of cholesterol sulfate was observed in the vermilion's superficial area compared to that in the skin in all subjects under this study. Furthermore, DESI-MSI of tape-stripped lip samples showed an overall higher accumulation of cholesterol sulfate in the stratum corneum of the rough lips than that in the smooth lips. CONCLUSION: Our study concluded that cholesterol sulfate has a characteristic distribution to the vermilion's surface and showed an association with the roughness of the lip.

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.

[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 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.

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.