Plasma Concentrations Of Indomethacin Research Articles

Development of an Intrauterine Device Releasing Both Indomethacin and Levonorgestrel During the First Months of Use: Pharmacokinetic Characterization in Healthy Women.

Post-placement menstrual bleeding pattern changes with intrauterine contraceptives (IUCs), including levonorgestrel-releasing intrauterine systems (LNG-IUS), can be a reason for avoidance or early discontinuation. Prostaglandins play an important role in menstrual bleeding and pain. The key drivers of prostaglandin synthesis are cyclooxygenase (COX) enzymes, which are inhibited by non-steroidal anti-inflammatory drugs. In this study, we report the findings from pharmacokinetic (PK) analyses undertaken with an LNG-IUS (LNG-IUS8) modified with an additional reservoir containing indomethacin (IND). The IND/LNG-IUS8 is a proof-of-concept device studied in a phase II proof-of-concept/dose-finding study. IND/LNG-IUS8 contains the same LNG content as the unmodified LNG-IUS8 (13.5 mg) but was prepared with three different IND doses (low, 6.5 mg; middle, 12.5 mg; and high, 15.4 mg), resulting in different daily release rates. Overall, 174 healthy, premenopausal women were randomized to one of the four treatment arms (low-, middle-, high-dose IND/LNG-IUS8 or LNG-IUS 8). Initial and residual IND and LNG content were collected and the amount of IND and LNG released in vivo over the period of use was calculated. A subset of 62 participants underwent dense blood sampling for PK analysis. Concentrations of IND and LNG in plasma were determined by validated liquid chromatography-tandem mass spectrometry methods and plotted over time. Descriptive statistics were calculated for plasma drug concentrations and PK parameters. High-dose IND/LNG-IUS8 initially released much higher levels of IND than expected based on in vitro release data, followed by a steep decline, with the reservoir emptied by 4.5 months. Middle- and low-dose IND/LNG-IUS8 demonstrated steady sustained release of IND over time, emptying after 7.4 and 8.4 months, respectively. Peak plasma concentrations of IND for low- and middle-dose IND/LNG-IUS8 remained below the 20% maximal inhibitory concentration (IC20) values for COX enzymes. The average daily IND release rate in vivo was 49 µg/day for low-dose and 112 µg/day for middle-dose IND/LNG-IUS8. The IND release rate profile and IND plasma concentrations in vitro both decreased steadily over time with low- and middle-dose IND/LNG-IUS8. The LNG release rate profile was comparable for all IND/LNG-IUS8 dose groups and LNG-IUS8. This PK study demonstrates that two different drugs can be released at different rates from an IUS designed with two drug reservoirs. Inclusion of IND does not impact the LNG PK profile. Low- and middle-dose IND/LNG-IUS8 were associated with a systemic IND exposure that should preclude the occurrence of adverse events typically observed after oral IND dosing. ClinicalTrials.gov identifier number: NCT03562624.

Gastroprotective Effect of Enteral Nutrition Formula in Mice Injected Subcutaneously with Indomethacin.

We have previously shown that two enteral nutrition formulas suppressed gastric lesions induced by the oral administration of indomethacin (IND) in mice. However, the mechanism of their protective effect is unknown. In this study, the effect of the two enteral nutrition formulas on gastric lesions induced by subcutaneous IND injection was investigated, with the objective of exploring the possibility that they may interact directly with IND in the gastrointestinal tract. Ten-week-old, male, ICR mice were fasted, then orally given either purified water, Mermed® One, or 2-fold diluted Terumeal® 2.0α as enteral nutrition formula (25 mL/kg). IND was injected subcutaneously at 20 mg/kg after 30 min, and the stomach was removed 6 h later and fixed in formalin. The number and area of lesions in the stomachs of mice given enteral nutrition formula was reduced to 56–89% and 34–61%, respectively, compared with the mice given purified water. The time courses of plasma IND concentrations were comparable among the three groups. These results suggested that the effect of these enteral nutrition formulas on gastric lesions did not originate from their direct interaction with IND in the gastrointestinal tract or their effect on the disposition of IND.

Effect of supersaturation on absorption of indomethacin and tadalafil in a single pass intestinal perfusion rat model, in the absence and presence of a precipitation inhibitor

The effect of the degree of supersaturation (DS) on absorption of the model drugs indomethacin and tadalafil was elucidated in a single-pass intestinal perfusion (SPIP) model in rats. In addition, the performance of the precipitation inhibitor (PI) hydroxypropylmethylcellulose (HPMC) was evaluated when added at a concentration of 0.1% (w/v) to fasted state simulated intestinal fluid (FaSSIF and FaSSIFHPMC) used as perfusion medium.A supersaturated state was created by a solvent shift method where indomethacin or tadalafil dissolved in dimethyl sulfoxide (DMSO) were administered to a segment of the small intestine, which subsequently was perfused with FaSSIF or FaSSIFHPMC. The perfusate was collected for 60 min, and for one group of rats dosed with 30 mg tadalafil, for 120 min. Blood samples were drawn every 15 min. The solubility of indomethacin and tadalafil in the perfusate was determined. The DS of each drug in the perfusate was calculated by dividing the concentration in the perfusate at selected time points with the solubility. The DS was above one for all timepoints for both drugs, thus showing supersaturation during the time of perfusion. For indomethacin, no improvement of the DS was seen when perfusing with FaSSIFHPMC, compared to FaSSIF. For tadalafil, a higher DS was achieved when perfusing with FaSSIFHPMC compared to FaSSIF. Perfusing the drugs with FaSSIFHPMC resulted in a significantly lower area under the curve (AUC0-60 min) for plasma concentrations of indomethacin, and no increase in the AUC0-60 min of plasma concentrations of tadalafil compared to perfusion with FaSSIF.The importance of simultaneously estimating the intraluminal DS and absorption of a drug was demonstrated by the SPIP model in the present study. Further, the study highlights the discrepancy between optimal in vitro supersaturation, intraluminal supersaturation and in vivo performance of two poorly soluble drugs, and further emphasizes the importance of optimization of in vitro methods in order to predict in vivo supersaturation and precipitation of drugs.

Study of the Inhibitory Effects of Enteral Nutrition Formula on Indomethacin-Induced Gastric Lesions in Mice.

We investigated the effects of enteral nutrition formula on non-steroidal anti-inflammatory drug (NSAID)-induced gastric lesions in mice. Male ICR mice aged 7–9 weeks old were fasted, then orally given either purified water, Mermed® One, or 2-fold diluted Terumeal® 2.0α as enteral nutrition (25 or 50 mL/kg each). Indomethacin (IND) was orally administered at 20 mg/kg after 30 min, and the stomach was removed 6 h later and fixed in formalin. The number and area of lesions in the stomachs of the mice given enteral nutrition showed a significant, dose-dependent decrease compared to the purified water-treated group, and no significant difference was seen between the two enteral nutrition-treated groups. Comparable time courses of plasma IND concentrations suggest that enteral nutrition does not inhibit gastrointestinal absorption of IND. Our findings indicate that administering enteral nutrition could inhibit the onset of NSAID-induced gastric ulcers.

Topical therapies for rheumatoid arthritis by gel ointments containing indomethacin nanoparticles in adjuvant-induced arthritis rat.

Indomethacin (IMC), a nonsteroidal anti-inflammatory drug, has been used in the treatment of rheumatoid arthritis (RA), although its clinical use has been limited by its systemic side effects that include gastrointestinal lesions. Therefore, the development of IMC formulations that do not cause gastrointestinal lesions is highly anticipated. In this study, we designed new topical formulations containing IMC solid nanoparticles (IMCnano gel ointment), and investigated their pharmacokinetics. In addition, we demonstrate the preventive effects of this topical application of IMC nanoparticles on inflammation in adjuvant-induced arthritis rat (AA rat). The IMCnano gel ointment was prepared using Bead Smash 12 (a bead mill) and additives including 2-hydroxypropyl-β-cyclodextrin, methylcellulose and Carbopol 934; the mean particle size of the IMC nanoparticles was 173 ± 91 nm (means ± S.D.). The application of the IMCnano gel ointment attenuated the increase in paw edema of the hind feet of AA rats in comparison with AA rats treated with gel ointment containing IMC microparticles (IMCmicro gel ointment, particle diameter 17.1 ± 11.6 mm, means ± S.D). In addition, the accumulation of IMC from the IMCnano gel ointment in skin tissue was significantly large than for the IMCmicro gel ointment; however, the plasma IMC concentrations were similar for the IMCmicro and IMCnano gel ointments. Our findings suggest that the dermal application of nanoparticles may enable a medication to be applied without high-systemic drug levels, which could provide efficient and effective therapy that spares patients from unwanted side effects. A formulation of a topical drug delivery system using IMC nanoparticles may provide a delivery option for the clinical treatment of RA.

Preparation and Comparative Bioavailability Studies of Indomethacin-Loaded Cetyl Alcohol Microspheres.

The purpose of the present study was to compare the in vitro release and to find out whether the bioavailability of a 75 mg indomethacin capsule (Microcid SR) was equivalent to optimized formulation (indomethacin-loaded cetyl alcohol microspheres). Indomethacin-loaded cetyl alcohol microspheres were prepared by meltable emulsified cooling-induced technique. Surface morphology of microspheres has been evaluated using scanning electron microscopy. A single dose, randomized, complete cross over study of IM microspheres was carried out on 10 healthy male and female Albino sheep's under fasting conditions. The plasma was separated and the concentrations of the drug were determined by HPLC-UV method. Plasma indomethacin concentrations and other pharmacokinetic parameters obtained were statistically analyzed. The SEM images revealed the spherical shape of fat microspheres, and more than 98.0% of the isolated microspheres were in the size range 12–32 μm. DSC, FTIR spectroscopy and stability studies indicated that the drug after encapsulation with fat microspheres was stable and compatible. Both formulations were found to be bioequivalent as evidenced by in vivo studies. Based on this study, it can be concluded that cetyl alcohol microspheres and Microcid SR capsule are bioequivalent in terms of the rate and extent of absorption.

Coating of Indomethacin with Glycyrrhiza Derivatives Provides Protection Against Gastric Ulceration when Orally Administered to Rats

Liquorice has been shown to be effective in the treatment of gastric ulcer and in this study we have examined the protective effect of liquorice and its derivatives against gastric ulcer induced by indomethacin in rat. Animals were treated with a granular mixture of indomethacin alone or coated with glycyrrhiza derivatives including liquorice, deglycyrrhized liquorice, high glycyrrhized liquorice, carbenoxolone and enoxolone. The results show that indomethacin coated with these derivatives reduced the number and sizes of ulcers; decreasing the ulcer index from 2·9 to 0·75 and the incidence from 90% to 48% without reduction of plasma concentration of indomethacin.

Comparative Bioavailability Studies of Two Indomethacin Controlled Release Formulations in Healthy Albino Sheep's

The purpose of the present study was to compare the in vitro release and to findout the bioavailability of a 75 mg indomethacin capsule (Microcid®SR - reference - product A) was equivalent to optimized formulation (indomethacin loaded microspheres – test – product B). Indomethacin (IM) loaded carnauba wax fat microspheres were prepared by using meltable emulsified dispersion cooling induced solidification technique utilizing a wetting agent. Solid, discrete, reproducible free flowing microspheres were prepared. The yield of the microspheres was up to 92%, having smooth surfaces, with free flowing and good packing properties, angle of repose, % Carr’s index and tapped density values were within the limit. More than 98.0% of the isolated spherical microspheres were in the particle size range of 1135 - 1360 mm were confirmed by scanning electron microscopy (SEM). The drug loaded in microspheres was stable and compatible, as confirmed by DSC and FTIR studies. A single dose, randomized, complete cross over study of IM (75 mg) microspheres was carried out on 10 healthy male and female Albino sheep’s under fasting conditions. The plasma was separated and the concentrations of IM were determined by HPLC-UV method. Plasma IM concentrations and other pharmacokinetic parameters obtained were statistically analyzed. Based on this study, is it possible to conclude that drug loaded microspheres and Microcid®SR capsule are bioequivalent in terms of the rate and extent of absorption.

Determination of Free Indomethacin in Human Plasma Using HPLC with UV Detection

Determination of free indomethacin concentration in human plasma is an issue of great importance for the drug safety monitoring and the efficiency of the drug therapy, especially in the case of patent ductus arteriosus treatment (PDA) in neonates. The presented study describes a simple and sensitive method of free indomethacin analysis in plasma samples using high performance liquid chromatography (HPLC) combined with ultraviolet (UV) detection. In the developed method the unbound drug separation was performed by means of the ultrafiltration method on Amicon MPS units, utilizing the YM-10 membranes of 10 kDa molecular mass cutoff. The sample preparation step involved liquid–liquid extraction with ethyl acetate, providing very good absolute recovery of the analyte (ca. 97%, n = 7). Chromatographic separation was achieved on a C18 column using 63% acetonitrile and 37% water (pH = 2.0, adjusted with 0.2% orthophosphoric acid) as the mobile phase. The external standard calibration curves showed good linearity (R2 > 0.9995) in the concentration range from 10 to 5000 ng/mL (total drug determination) and from 10 to 200 ng/mL (free drug determination). The intra-day and inter-day precision and accuracy were satisfactory, with relative standard deviations not exceeding 10%. The limit of detection (LOD) and the limit of quantitation (LOQ) were 3 ng/mL and 10 ng/mL, respectively. The presented analytical approach constitutes substantial improvement over previously reported methods for indomethacin analysis and thus seems to be the method of choice for determination of free indomethacin in plasma.

Soluble Dietary Fiber Protects Against Nonsteroidal Anti-inflammatory Drug-Induced Damage to the Small Intestine in Cats

Nonsteroidal anti-inflammatory drugs (NSAIDs) often cause ulcers in the small intestine in humans, but there are few effective agents for treatment of small intestinal ulcers. We found that soluble dietary fibers (SDFs), such as pectin, could prevent the formation of small intestinal lesions induced by indomethacin (IND) in cats. To elucidate the mechanism of protection by SDFs, we examined the viscosities of SDFs and the effects of pectin on gastrointestinal absorption of IND and intestinal hypermotility induced by IND. Cats were given regular dry food (RFD-Dry) or RFD-Dry supplemented with pectin, guar gum, polydextrose, or mucin twice daily. IND was administered orally once daily for 3 days. Mucosal lesions in the small intestine were examined 24 h after the final dosing of IND. Plasma concentrations of IND were measured by HPLC. GI motilities were measured using a telemetry system in conscious cats implanted with force transducers. Viscosities of the SDFs were measured using a viscosimeter. In cats given RFD-Dry, IND (3 mg/kg) increased motility and produced many lesions in the lower half of the small intestine; the total lesion area (TLA) was 7.5 +/- 2.6 cm(2) (n = 4). Lesions induced by IND were markedly decreased in cats given RFD-Dry supplemented with 3% pectin, guar gum, polydextrose or mucin; TLAs were 0.6 +/- 0.3, 0.0 +/- 0.0, 1.3 +/- 0.8 and 1.6 +/- 0.5 cm(2) (n = 4) (P < 0.05 vs. RFD-Dry alone), respectively. The viscosity (mPa-S) of pectin, guar gum, polydextrose and mucin (3% concentration) was 414, >1,200, 1 and 4, respectively. Pectin did not affect the absorption of IND nor did it inhibit IND-induced intestinal hypermotility. SDFs protect the small intestine against NSAID-induced damage, probably by compensating a barrier function of the mucin decreased by IND. Viscosities of the SDFs play a role, at least in part, in the protective effects of the SDFs on the small intestine.

Preparation, evaluation and bioavailability studies of indomethacin-bees wax microspheres

The present study envisages the preparation of microspheres containing indomethacin (IM) as model drug and bees wax as carrier, and to compare the in vitro release and pharmacokinetics of prepared IM formulation with commercially available oral formulation MicrocidSR. The microsphere formulations were prepared by meltable emulsified dispersion and cooling induced solidification. Surface morphology of microspheres has been evaluated using scanning electron microscopy (SEM). The SEM images revealed the spherical shape of microspheres and more than 98.0% of the isolated microspheres were in the size range 115-855 mum. Differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy studies indicated that the drug after encapsulation with bees wax was stable and compatible. A single dose randomized complete cross over study of IM (75 mg) microspheres was carried out on 8 healthy Albino sheeps. Plasma IM concentrations and other pharmacokinetic parameters obtained were statistically analyzed. The T (max), C (max), AUC(O-24) and T (1/2) values of MicrocidSR and optimized formulation were 3.0 h, 2038 +/- 51.31 ng/ml, 9528 +/- 129.65 ng/ml h(-1), and 2.59 +/- 0.02 h(-1); and 3.2 h, 1940 +/- 22.61 ng/ml, 8751 +/- 41.32 ng/ml h(-1), and 2.68 +/- 0.02 h(-1), respectively. Beeswax microspheres showed controlled release and it can be concluded that both the prepared formulation and MicrocidSR are bioequivalent.

Orogastric and Intravenous Indomethacin Administration to Very Premature Neonates With Patent Ductus Arteriosus: Population Pharmacokinetics, Absolute Bioavailability, and Treatment Outcome

A population pharmacokinetic model was developed after administration of orogastric and/or intravenous indomethacin for the treatment of patent ductus arteriosus in preterm infants. Plasma indomethacin concentrations (n=227) were obtained from 90 preterm infants of median gestational age 27 weeks, mean postnatal age of 12 days, and a mean current weight (WT) of 1010 g. Infants received one to three courses of indomethacin (0.1 mg/kg per day for 6 days). A one-compartment model was fitted to the data to obtain estimates of clearance (CL), volume of distribution (V), absorption rate constant (Ka) and orogastric bioavailability (F), using NONMEM. Model robustness was assessed by bootstrapping with replacement (500 samples). The structural model was: CL (L/h)=0.0166 (WT / 0.936)1.54; V (L)=0.484 (WT / 0.936)1.41; F=0.986; Ka (h(-1))=0.786. The interindividual variability for CL and V was 57.7% and 45.6%, respectively. There remained considerable residual unexplained variability (45.4%). Mean (range) conditional estimates from individual infants for CL, V, and elimination half-life were 18.9 (4.7-45.5) mL/h/kg, 509 (191-1120) mL/kg, and 20.0 (12.0-37.3) hours, respectively. Complete ductus closure occurred in 67% of patients. Infants of lower gestational age or birth weight had less chance of successful ductal closure. There was no obvious dose-response relationship between systemic exposure to varying plasma indomethacin concentrations and ductus closure, which does not support individualized indomethacin dosing based on monitoring to a target plasma concentration.

In vitro drug interaction between diflunisal and indomethacin via glucuronidation in humans

It was reported that the plasma concentration of indomethacin was increased with concomitant oral dosages of diflunisal in humans. Both indomethacin and diflunisal are glucuronidated in humans. The effects of diflunisal on the indomethacin glucuronidation were thus investigated in vitro using human liver microsomes (HLM) and human intestine microsomes (HIM) in order to assess the drug-drug interaction. The glucuronidation of indomethacin in HLM showed atypical kinetics with Km and Ksi values of 210 and 89.5 microM, respectively, while HIM exhibited Michaelis-Menten kinetics with a Km value of 17.4 microM. Diflunisal inhibited the indomethacin glucuronidation in HLM with IC50 values ranging from 100 to 231 microM. In HIM, inhibition of the indomethacin glucuronidation by diflunisal was more potent with IC50 values of 15.2-48.7 microM. When the clinical dose of diflunisal (250 mg b.i.d.) is taken into consideration, it is expected that the diflunisal concentration in the intestine would be higher than the IC50 values for indomethacin glucuronidation in the intestine. These findings suggest that the clinical drug-drug interaction between diflunisal and indomethacin may be at least partly attributable to the inhibition of indomethacin glucuronidation by diflunisal in the intestine.

Comparative bioavailability studies of indomethacin from two-controlled release formulations in healthy albino sheep

The objective of the study was to obtain the pharmacokinetic data of two controlled release formulations of (75 mg) indomethacin and to compare the relative bioavailability of the test formulation (product B cetostearyl alcohol microspheres) with standard formulation (product A-Microcid®SR 75 mg capsule). A single dose randomized (4×2) complete cross over study of the indomethacin (75 mg) was carried out on 8 healthy albino sheep. The study was carried out on two separate occasions with a washout period of 2 weeks. Blood samples were collected at pre-determined time intervals. Plasma indomethacin concentrations and other pharmacokinetic parameters obtained were statistically analyzed. The results of the paired t-test for the comparison of pharmacokinetic data showed that there was no significant variation between the products A and B. Products did not show any significant difference between them with regard to the T max , C max , AUC 0-24 , AUCo-oo, MRT, Ka, Kel , K 1/2 , 3.0 h, 2054 ± 55.78 ng/ml, 9637 ± 132.87 ng h/ml, 9870 ± 129.22 ng h/ml, 4.76 ± 0.10 h, 0.3812 ± 0.002 h -1, 0.2713 ± 0.004 h -1, 2.55 ± 0.03 h -1, respectively for product A and 3.5 h, 1929 ± 20.32 ng/ml, 8343 ± 40.04 ng h/ml, 8617 ± 46.88 ng h/ml, 4.98 ± 0.02 h, 0.3648 ± 0.002 h -1, 0.2427 ± 0.010 h -1, 2.86 ± 0.20 h -1 for product B. From the dissolution studies and in vivo bioavailability studies, it was concluded that the products A and B are bioequivalent.

Controlled Systemic Delivery of Indomethacin Using Membrane-Moderated, Cream Formulation–Based Transdermal Devices

The present study was carried out to design a viable and practically effective transdermal systems of indomethacin using cream-based drug reservoirs and suitable rate controlling membranes. As vehicles, a more lipophilic base (F1) and a cream formulation containing predominant aqueous phase (F2) were chosen to study the influence of vehicle nature and role of permeation enhancers that increases thermodynamic activity and to provide diffusible species of drug to skin. Rate controlling membranes of cellulose acetate (CA) and ethyl cellulose (EC) with polyvinyl pyrollidine and hydroxypropyl methyl cellulose were used to design transdermal devices. In vivo, effective plasma concentrations of indomethacin are maintained up to 24 hr whereas oral formulation showed only up to 8 hr. Although the plasma drug levels between both EC films differ insignificantly, PVP film showed a better pharmacokinetic profile. The pharmacodynamic performance of the transdermal devices exhibited good anti-inflammatory activity over 24 hr compared with orally administered indomethacin. In vivo studies indicate the superiority of CA films over the EC films. Further, enhancement may be achieved with other classic enhancers/enhancement strategies with such devices containing aqueous cream vehicle and the optimum membranes.

Effect of Chitosan on Gastrointestinal Absorption of Water-Insoluble Drugs Following Oral Administration in Rats

Chitosan is widely used as a dietary weight-loss supplement in Japan. In the present study, we examined the effect of chitosan on the gastrointestinal absorption profiles of the water-insoluble drugs, indomethacin and griseofulvin, and the water-soluble drugs, acetaminophen and cephalexin, after oral administration in rats. Rats received oral administration of chitosan (5 mg/kg or 25 mg/kg) dissolved in 5% acetic acid or vehicle 15 min before oral administration of each drug. Chitosan at a dose of 25 mg/kg, but not 5 mg/kg, significantly decreased the plasma concentrations of indomethacin and griseofulvin after administration as a suspension with a significant delay of the time to reach maximum concentration compared to the corresponding control values (vehicle-pretreated rats). However, pretreatment of chitosan (25 mg/kg) did not change the pharmacokinetics of indomethacin administered as a solution. Further, the same dose of chitosan had no effect on the pharmacokinetics of acetaminophen. The gastrointestinal absorption profile of an amino-beta-lactam antibiotic, cephalexin, which is actively absorbed via carrier-mediated transport system, was also unchanged. The present findings at least suggest the possibility that chitosan at high dose reduces the gastrointestinal absorption of water-insoluble drugs such as indomethacin and griseofulvin, but not water-soluble drugs, by diminishing the surfactant-like effect of bile acids.

Indomethacin‐loaded methoxy poly(ethylene glycol)/poly(D,L‐lactide) amphiphilic diblock copolymeric nanospheres: Pharmacokinetic and toxicity studies in rodents

Biodegradable methoxy poly(ethylene glycol)/poly(D,L-lactide) amphiphilic block copolymeric nanospheres were prepared for application as a particulate drug carrier. Drug-loaded nanospheres (ML50) showed a narrow size distribution with the average diameter of <200 nm. When the feed weight ratio of indomethacin (IMC) to polymer was 1:1, the ML50 nanosphere having a relatively high drug-loading efficiency of about 33.0% could be obtained. To investigate pharmacokinetic characteristics of IMC in rats, the IMC concentration in plasma was analyzed using a high-performance liquid chromatography system after intravenous bolus injection of free IMC and IMC-loaded ML50 nanospheres. ML50 nanosphere system exhibited a significant potential for sustained release of drug and showed slow clearance of IMC, but there was no significant effect on metabolism of IMC in the rats. Median lethal dose (LD50) and major organs (e.g., heart, lung, liver, and kidney) toxicities were determined using ICR mice to estimate the acute toxicity of ML50 nanospheres. The LD50 of ML50 nanospheres determined by Litchfield-Wilcoxon method was about 1.54 g/kg. After the mice were intraperitoneally administered with a half dose of LD50 for 7 days, no significant histopathologic changes were observed in ML50-treated mice compared with normal mice in the light and electron microscopic observations of major organs. This indicates that ML50 nanospheres might be a useful candidate as a novel sustained drug carrier for hydrophobic drugs.

Essential Oils from Sweet Basil (Ocimum basilicum) as Novel Enhancers to Accelerate Transdermal Drug Delivery

The purpose of this study was to evaluate the essential oils from sweet basil (Ocimum basilicum, OB) as skin permeation enhancers to promote the percutaneous absorption of drugs. The in vitro and in vivo irritancy of the essential oils was also examined. Terpenes with various carbon numbers (mono-, sesqui-, di-, and tri-) were identified in both the lower-polarity fraction (OB-1) and higher-polarity fraction (OB-2). In vitro skin permeation and deposition of indomethacin were significantly enhanced after treatment with OB essential oils. The enhancing effect of OB-1 was greater than that of OB-2 in the in vitro permeation and in vivo cutaneous microdialysis analyses as well as in the plasma concentration of indomethacin. On the other hand, the in vivo study showed that OB-2 had a greater ability to retain the drug within the skin than did OB-1. Enhancement of the skin permeation of drugs by OB essential oils might be mainly due to improvement in the partitioning of the drugs to the stratum corneum. Both in vitro cell cultures (keratinocytes and skin fibroblasts) and in vivo transepidermal water loss showed no or only negligible irritation to skin by OB essential oils.

Indomethacin-loaded methoxy poly(ethylene glycol)/poly( ε-caprolactone) diblock copolymeric nanosphere: pharmacokinetic characteristics of indomethacin in the normal Sprague–Dawley rats

We prepared the drug-loaded polymeric nanospheres composed of the methoxy poly(ethylene glycol) (MePEG) and poly( ε-caprolactone) (PCL) that showed a narrow size distribution and average diameter of less than 200 nm. We could obtain the nanosphere having a relatively high drug-loading efficiency of about 42% when the feed weight ratio of indomethacin (IMC) to polymer was 1:1. To investigate the IMC pharmacokinetics in the IMC-loaded MePEG/PCL nanosphere (DMEP70) using the rats as animal model, we analyzed the IMC concentration in plasma with HPLC after i.v. bolus administered at a dose of 10 mg/kg in free IMC (control) and IMC-loaded MePEG/PCL nanosphere (DMEP70) groups via tail vein. Pharmacokinetics parameters (mean±s.d.) such as the mean residence time (MRT, h), the steady-state volume of distribution ( V dss, l), the terminal half-time ( t 1/2, h) and the plasma clearance (CL, l/h) of IMC in each groups (control vs. DMEP70) were determined; MRT (16.97±4.83 vs. 28.69±11.28, p<0.01); V dss (14.26±4.86 vs. 20.37±12.04, p<0.05); t 1/2 (15.12±4.77 vs. 23.1±8.24, p<0.01); CL (0.84±0.27 vs. 0.71±0.41). From these results, we could concluded that MEP70 has a significant potential for sustained release and the enhancement of circulation time of loaded drug by prolonging terminal half-life, increasing MRT and V dss of IMC. Therefore, The MePEG/PCL block copolymeric nanosphere system is being considered as promising biodegradable and biocompatible drug carrier vehicles for parentral use and may be useful as sustained release injectable delivery systems for hydrophobic drugs.

Thermally reversible xyloglucan gels as vehicles for oral drug delivery

The potential, as sustained release vehicles, of gels formed in situ following the oral administration of dilute aqueous solutions of a xyloglucan polysaccharide derived from tamarind seed has been assessed by in vitro and in vivo studies. Aqueous solutions of xyloglucan that had been partially degraded by β-galactosidase to eliminate 44% of galactose residues formed rigid gels at concentrations of 1.0 and 1.5% w/w at 37°C. The in vitro release of indomethacin and diltiazem from the enzyme-degraded xyloglucan gels followed root-time kinetics over a period of 5 h at 37°C at pH 6.8. Plasma concentrations of indomethacin and diltiazem, after oral administration to rats of chilled 1% w/w aqueous solutions of the enzyme-degraded xyloglucan containing dissolved drug, and a suspension of indomethacin of the same concentration were compared. Constant indomethacin plasma concentrations were noted from both formulations after 2 h and were maintained over a period of at least 7 h. Bioavailability of indomethacin from xyloglucan gels formed in situ was increased approximately threefold compared with that from the suspension. The results of this study suggest the potential of the enzyme-degraded xyloglucan gels as vehicles for oral delivery of drugs.