Vaginal suppository formulations of metronidazole were prepared using six different bases as Witepsol H15, Cremao, Ovucire WL2944, Ovucire WL3264, PEG 1500, PEG 6000. Three different dissolution methods were used to evaluate the in vitro drug release from the suppositories. The diffusion studies were performed through synthetic (cellophane) and natural membrane (rabbit vagina), but the drug did not show good permeation characteristics from natural membrane. Ovucire WL3264 suppositories of metronidazole labeled with 99mTc (Tecnetium-99m) were used for the vaginal absorption and biodistribution studies in the rabbits. Scintigraphic images were collected after vaginal administration of the labeled suppositories using SPECT gamma fitted with a low energy, high-resolution parallel hole collimator. The labeled drug showed high biodistribution in urine beside vaginal site. The results of this study suggested that the Ovucire WL3264 suppository of metronidazole prepared for vaginal infections could also be effective in the urinary infections.

Diffusion rates of testosterone from various suppository bases with and without surfactants were determined. In a limited study, selected suppository formulations were evaluated for efficiency of rectal absorption of testosterone in three male volunteers ranging in age from 25 to 30 years. Significant reductions in the ratios of urinary metabolites to free testosterone were observed with polyethylene glycol 1000, esterified (C10-C18) fatty acids, and theobroma oil-based samples.

BACKGROUND Nesiritide is approved in the United States for early relief of dyspnea in patients with acute heart failure. Previous meta-analyses have raised questions regarding renal toxicity and the mortality associated with this agent. METHODS We randomly assigned 7141 patients who were hospitalized with acute heart failure to receive either nesiritide or placebo for 24 to 168 hours in addition to standard care. Coprimary end points were the change in dyspnea at 6 and 24 hours, as measured on a 7-point Likert scale, and the composite end point of rehospitalization for heart failure or death within 30 days. RESULTS Patients randomly assigned to nesiritide, as compared with those assigned to placebo, more frequently reported markedly or moderately improved dyspnea at 6 hours (44.5% vs. 42.1%, P=0.03) and 24 hours (68.2% vs. 66.1%, P=0.007), but the prespecified level for significance (P≤0.005 for both assessments or P≤0.0025 for either) was not met. The rate of rehospitalization for heart failure or death from any cause within 30 days was 9.4% in the nesiritide group versus 10.1% in the placebo group (absolute difference,-0.7 percentage points; 95% confidence interval [CI],-2.1 to 0.7; P=0.31). There were no significant differences in rates of death from any cause at 30 days (3.6% with nesiritide vs. 4.0% with placebo; absolute difference,-0.4 percentage points; 95% CI,-1.3 to 0.5) or rates of worsening renal function, defined by more than a 25% decrease in the estimated glomerular filtration rate (31.4% vs. 29.5%; odds ratio, 1.09; 95% CI, 0.98 to 1.21; P=0.11). CONCLUSIONS Nesiritide was not associated with an increase or a decrease in the rate of death and rehospitalization and had a small, nonsignificant effect on dyspnea when used in combination with other therapies. It was not associated with a worsening of renal function, but it was associated with an increase in rates of hypotension. On the basis of these results, nesiritide cannot be recommended for routine use in the broad population of patients with acute heart failure.(Funded by Scios; ClinicalTrials.gov number, NCT00475852.).

(-)Epicatechin (EC) is a major antioxidant component of grape seed extract which has become increasingly popular in topical skin preparations. This study assessed the following:(1) the permeability through cellulose membranes of EC in three different gel formulations (Carbopol 940, Klucel, and Ultrez 10);(2) the effect of three different antioxidants (butylated hydroxytoluene (BHT), alpha-tocopherol (VE), and ascorbic acid (AA)) on the stability and penetration properties of EC; and (3) the permeability and retention of EC in Ultrez 10 gels, supplemented with BHT or VE, on human cadaver skin. Permeability studies through cellulose membranes showed that different gelling agents do not significantly affect the permeability of EC (n = 7/gel; p > 0.05). BHT and VE have antioxidant properties superior to AA (p < 0.05) and preserve 100% of the initial content of EC for 28 days. Permeation studies on cadaver human skin, following application of two anhydrous gel formulations (0.5% EC in Ultrez 10 containing BHT or VE), showed that EC was not detectable in the receiving solution. However, the EC amount in viable skin increased with time, indicating that EC penetrated and was retained in the upper part of the skin for approximately 1% and 3% of the dose for the formulations containing BHT and VE, respectively.

BACKGROUND Chronic low back pain (LBP) is a growing health problem. Non-steroidal anti-inflammatory drugs (NSAIDs) are used to treat this condition, but have not demonstrated efficacy beyond 2 weeks, and no studies have shown that NSAIDs produce durable improvements in disability. METHODS To evaluate the efficacy and durability of effect of etoricoxib for chronic LBP, a randomized, double blind, placebo-controlled trial was conducted at 46 centres. Three hundred and twenty-five patients with chronic LBP requiring treatment with an NSAID or paracetamol were randomized 1:1:1 to etoricoxib 60 mg (n=109), 90 mg (n=106), or placebo (n=110), daily for 3 months. Pre-specified endpoints over 3 months included LBP intensity scale (visual analog scale 0-100 mm) time-weighted average change from baseline, the Roland-Morris Disability Questionnaire (RMDQ), the LBP bothersomeness scale, patient and investigator global assessments, and measures of quality of life. RESULTS Both etoricoxib groups experienced significant reductions in LBP intensity at 4 weeks versus placebo [-15.15 mm and -13.03 mm for 60 and 90 mg, respectively, probability (p)<0.001 for each], which was maintained over 3 months. Treatment resulted in significant improvement from baseline compared to placebo in RMDQ scores (etoricoxib 60 mg,-2.82 and 90 mg,-2.38, p<0.001 for each) over 12 weeks and most other efficacy endpoints. There were no significant differences between treatments in incidence of adverse events (AEs) or discontinuations due to AEs. CONCLUSION Etoricoxib provided significant relief of symptoms and disability associated with chronic LBP detected at 1 week, confirmed at 4 weeks, and maintained over 3 months. Reductions in chronic LBP severity corresponded to improvements in physical functioning and quality of life. All treatments were generally well tolerated.

Rofecoxib (VIOXX(R)) is a selective inhibitor of cyclo-oxygenase-2 and is indicated for the treatment of acute pain. Prior acute pain studies showed similar analgesic efficacy of rofecoxib 50 mg compared with analgesics doses of non-selective NSAIDs. We performed a randomized, double-blind trial to evaluate the efficacy and safety of rofecoxib, a standard fixed formulation of codeine with acetaminophen, and placebo in the treatment of acute pain. Three-hundred ninety-three patients with moderate or severe pain after surgical extraction of at least two 3rd molars were randomized to receive a single dose of rofecoxib 50 mg (n = 182), codeine 60 mg with acetaminophen 600 mg (n = 180), or placebo (n = 31). Efficacy was assessed at 11 pre-specified time points after dosing by pain relief and pain intensity scores. Patient global assessment of study medication was also performed. Baseline characteristics were similar among the groups. The mean age was 21 years; 69.0% were female; and 78.6% had a pain intensity score of "moderate." For the primary endpoint, total pain relief over 6 hours, rofecoxib was more effective than codeine/acetaminophen (p < 0.001) and placebo (p < 0.001). Proportion of patients who rated the study medication as good, very good, or excellent at 6 hours was 64.6% on rofecoxib, 36.4% on codeine/acetaminophen, and 10.3% on placebo (rofecoxib> codeine/acetaminophen; p < 0.001). The time to rescue medication was longer for rofecoxib compared to codeine/acetaminophen (p < 0.001). More patients on codeine/acetaminophen experienced clinical adverse events than rofecoxib (p < 0.05). Patients receiving codeine/acetaminophen versus rofecoxib had higher incidences of nausea (25.0% vs 6.0%; p < 0.001) and vomiting (18.3% vs 3.8%; p < 0.001). In this study, rofecoxib had superior efficacy and gastrointestinal safety compared to codeine/acetaminophen, which provides support for the use of rofecoxib as an alternative option to opioid analgesics in the treatment of acute post-surgical pain.

BACKGROUND In recent studies of acute pain and primary dysmenorrhea, rofecoxib, a nonsteroidal anti-inflammatory drug that selectively targets the cyclooxygenase-2 enzyme, was found to be similar in efficacy to ibuprofen and naproxen sodium. OBJECTIVE The purpose of this study was to determine the analgesic efficacy of a single oral dose of rofecoxib 50 mg compared with the combination of codeine 60 mg/acetaminophen 600 mg in a model of postsurgical dental pain. METHODS In this double-blind, placebo- and active comparator-controlled, parallel-group study, patients experiencing moderate or severe pain after the surgical extraction of > or = 2 third molars, at least 1 of which was a mandibular impaction, were randomized to receive placebo, rofecoxib 50 mg, or codeine 60 mg/acetaminophen 600 mg. Patient evaluations of pain intensity, pain relief, and global assessments were recorded throughout the 24-hour period after dosing. The 2-stopwatch method was used to determine time to confirmed perceptible pain relief. The primary end point assessing overall analgesic effect was total pain relief over 6 hours (TOPAR6). Secondary end points were patient global assessment of response to therapy (PGART) at 6 hours, onset of analgesia, peak analgesic effect, and duration of analgesia. RESULTS A total of 393 patients were enrolled; 182 received rofecoxib, 180 received codeine/acetaminophen, and 31 received placebo. The overall analgesic effect of rofecoxib 50 mg was greater than that of codeine 60 mg/acetaminophen 600 mg for TOPAR6 (12.4 vs 7.0; P < 0.001) and PGART at 6 hours (P < 0.001). The onset of analgesic effect was similar for rofecoxib and codeine/acetaminophen. Peak analgesic effect as measured by peak pain relief scores during the first 6 hours was significantly greater in the rofecoxib group compared with the codeine/acetaminophen group (P < 0.001), as was the duration of analgesic effect measured by the time to rescue analgesia (9.6 hours vs 2.3 hours, P < 0.001). Adverse events were reported in 33.0%, 46.1%, and 32.3% of patients treated with rofecoxib, codeine/acetaminophen, and placebo, respectively. The most common adverse events were nausea (6.0%, 25.0%, and 9.7%, respectively) and vomiting (3.8%, 18.3%, and 6.5%, respectively). Significantly more patients in the codeine/acetaminophen group than in the rofecoxib group experienced adverse events overall (P < 0.050) and nausea in particular (P < 0.001). CONCLUSION In this study of moderate to severe postoperative dental pain, the analgesic efficacy of rofecoxib 50 mg was greater than that of codeine/acetaminophen, with a lower incidence of adverse events and nausea.

A new controlled-release technology that is based on electrorheological fluids (ERF) is described, and a model system is investigated. Humidified starch (duration of humidification is 30-35 minutes) was used as a filler material (approximately 20% w/w) in olive oil to make the ER system, and benzocaine (BZN) was used as the model drug. The average particle size of starch in the olive oil was approximately 200 nm. 1N HCl was used as the receiver medium and BZN was assayed by UV spectroscopy at 226 nm. A series of studies was done at five temperatures (25 degrees, 30 degrees, 35 degrees, 40 degrees, and 45 degrees C) and two external electric fields (E-fields) that were generated by applying potential drops across the diffusion apparatus of 0 V and 290 V. Control studies of BZN release from olive oil without filler showed little or no increase in release rates resulting from application of E-fields. In addition, while reversing the polarity for BZN in olive oil caused differences in release rates, these differences were too small to explain the results obtained for the ER systems. It was found that release of BZN increased significantly with the application of the electric field (approximately 53% increase at 25 degrees C). A plot of the log of the release rate vs 1/T was linear for the 0 V data but deviated from linearity for the 290 V data. The increase in release rates due to the E-field became smaller as the temperature was increased. The results are consistent with (but are not sufficient to prove) the hypothesis that the increased release rate is due to a small amount of ordering of the cornstarch filler particles in response to the applied E-field, which results in a reduction in the tortuosity of the system.

Diclofenac (DCLF) is a nonsteroidal anti-inflammatory drug that is widely used for the treatment of osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, and acute muscle pain conditions. Toxic doses of DCLF can cause nephrotoxicity in humans and experimental animals. However, whether this DCLF-induced nephrotoxicity involves apoptotic cell death in addition to necrosis is unknown. The goals of this investigation were to determine whether DCLF-induced nephrotoxicity involves oxidative stress and apoptotic type genomic DNA fragmentation, and if so, whether DCLF-induced oxidative stress and DNA fragmentation cause apoptotic cell death in mouse kidneys. Male ICR mice (CD-1; 25-45 g), fed ad libitum, were administered nephrotoxic doses of DCLF (100, 200, 300 mg/Kg, po) and sacrificed 24 h later. Blood was collected to evaluate renal injury (BUN), lipid peroxidation (MDA: malondialdehyde levels), and superoxide dismutase (SOD) activity (a marker of oxidative stress). Kidney tissues were analyzed both quantitatively and qualitatively to determine the degree and type of DNA damage, and evaluated histopathologically for the presence of apoptotic characteristics in the nucleus of diverse types of kidney cells. Results show that diclofenac is a powerful nephrotoxicant (at 100, 200, and 300 mg/kg: 4.7-, 4.9-, and 5.0-fold increases in BUN compared to the control, respectively) and a strong inducer of oxidative stress (significant increase in MDA levels). Oxidative stress induced by DCLF was also coupled with massive kidney DNA fragmentation (100, 200, and 300 mg/kg: 3-, 8-, and 10-fold increases compared to control, respectively). A dose-dependent increase in MDA levels and SOD activity was also observed, which indicated a link between oxidative stress and nephrotoxicity. Qualitative analysis of DNA fragmentation by gel electrophoresis showed a DNA ladder indicative of Ca2+-Mg2+-endonuclease activation. Histopathological examination of kidney sections revealed numerous apoptotic nuclei across proximal and distal tubular cell linings. Collectively, these data for the first time suggest that DCLF-induced nephrotoxicity may involve production of reactive oxygen species leading to oxidative stress and massive genomic DNA fragmentation, and these two free radical mediated events may ultimately translate into apoptotic cell death of kidney cells in vivo, and reveal a DNA-active role for DCLF.

In vitro release of ketoprofen from suppository bases and in vivo absorption in rabbits were studied. Suppositories containing 50 mg of ketoprofen were prepared using theobroma oil, esterified (c10-c18) fatty acids, and polyethylene glycol 1000 bases. The displacement values of the drug were determined and found to be of the order of theobroma oil > esterified (c10-c18) fatty acids and polyethylene glycol 1000 bases. The suppository hardness data revealed that the theobroma oil base produced relatively brittle suppositories. Using the USP dissolution method, the release of ketoprofen was observed to be greatest from polyethylene glycol 1000 suppositories. With the dialysis technique, the maximum release of drug was obtained from theobroma oil suppository containing polysorbate 40 at a 6% level. Selected suppository formulations were evaluated for rectal absorption studies in rabbits. The in vivo data showed that the optimum drug absorption took place from the polyethylene glycol 1000 base and theobroma oil formulation containing 6% polysorbate 40.

The study was designed to investigate the feasibility of developing a transdermal drug dosage form of promethazine hydrochloride (PMH). The in vitro release and diffusion characteristics of PMH from various dermatological polymeric bases were studied using cellulose membrane and hairless mouse skin as the diffusion barriers. These included polyethylene glycol (PEG), hydroxypropyl methylcellulose (HPMC), cross-linked microcrystalline cellulose, and carboxyl methyl cellulose sodium (Avicel CL-611), and a modified hydrophilic ointment USP. In addition, the effects of several additive ingredients known to enhance the drug release from topical formulations were evaluated. The general rank order for the drug release from these formulations using cellulose membrane was observed to be PEG > HMPC > Avicel CL-611 > hydrophilic ointment base. The inclusion of the additives had little or no effect on the drug diffusion from these bases, except for the hydrophilic ointment formulation containing 15% ethanol, which provided a significant increase in the drug release. However, when these formulations were studied for drug diffusion through the hairless mouse skin, the Avicel CL-611 base containing 15% ethanol exhibited the optimum drug release. The data also revealed that this formulation gave the highest steady-state flux, diffusion, and permeability coefficient values and correlated well with the amount of drug release.

The in vitro permeation rates of metaproterenol sulfate (MPS) across hairless mouse skin and TESTSKIN living skin equivalent were very low unless skin permeation enhancers were included in the vehicle. An optimum balance should be established between the chain length of the fatty acid and its molar ratio to MPS in order to enhance its penetration through the skin. Thus, the best flux values were shown by capric acid: MPS, 3:1 molar ratio, and lauric acid:MPS, 1:1 and 2:1 molar ratio, while myristic acid:MPS, 1:1 molar ratio, was the optimum under the experimental conditions used. The mechanism of the enhancing effect was examined by measuring 1H NMR spectra and the apparent partition coefficient of MPS, lauric acid, and the mixture. The apparent partition coefficient of MPS between n-octanol and water was higher for the mixture with lauric acid than for MPS alone. A 1:1 molar ratio formulation of MPS and lauric acid was selected for the in vivo permeation study. The data indicated that lauric acid increased the diffusivity of MPS in the skin by forming a complex and by affecting its partition coefficient between the skin and the delivery system.

Fenoterol HBr is a bronchodilator known to be subject to first pass effect after oral administration. The aim of this study was to prepare and evaluate fenoterol HBr suppositories. Suppositories were prepared by a fusion method using different fatty bases, viz. Witepsol H15, Witepsol E75, Suppocire AP, and Suppocire BM, as well as different hydrophilic bases, viz. polyethylene glycol and poloxamer bases. In vitro release studies revealed a greater release of the drug from hydrophilic bases than from fatty bases. The effect of incorporating different types and concentrations of non-ionic surfactants (Tween 60 and Span 20) on the release rate of the drug from Witepsol H15, as a model fatty base, was investigated. Results showed an enhanced release at low surfactant concentrations. A very fast 100% drug release was achieved when the drug was incorporated as an aqueous solution in Witepsol H15 (F17). This formula was selected to test the effect of fenoterol HBr suppositories on histamine-induced bronchospasms in Guinea pigs. No dyspnea of the animals was recorded for up to 30 min. In addition, thermogel liquid suppositories of different poloxamer 188 and poloxamer 407 proportions in the presence of sodium alginate as a mucoadhesive polymer were prepared. The different formulations behaved similarly concerning sustainment of drug release, however, only the formula containing 15% poloxamer 188 and 25% poloxamer 407 (F20) showed optimal gelation at body temperature. In conclusion, among the studied suppository bases there are bases suitable for fast release of the drug like F17 and hydrophilic bases especially polyethylene glycol, as well as other bases for sustained release applications of fenoterol HBr like fatty and thermogel bases.

Myrrh has long been used for its circulatory, disinfectant, analgesic, antirheumatic, antidiabetic, and schistosomicidal properties. Myrrh essential oil (MEO) was extracted from the oleo-gum resin of Commiphora molmol and formulated into emulsions and suppositories to mask/avoid its bitter taste. Three oil-in-water emulsions (E1-E3) were formulated and taste was evaluated by 10 volunteers. Particle size distribution was measured and correlated with excipients and the method of preparation. Physical and chemical stability testing was carried out for the optimum formulation (E2). Seven suppository formulations were investigated (F1-F7). Suppocire AML (F1) and Suppocire CM (F2) were chosen as fatty bases, and polyethylene glycol (PEG) 1500 (F3), PEG 4000 (F4), and a PEG blend (50% PEG 6000 + 30% PEG 1500 + 20% PEG 400)(F5) were chosen as water-soluble bases. A blend of PEG 1500 and Suppocire CM was also used (F7). Camphor (5%) was added to PEG 1500 (F6). Disintegration time, release rate, DSC, fracture points, and weight uniformity were evaluated. The overall average bitterness for formulations E1, E2, and E3 was 6.44, 4.15, and 3.45, respectively. Suppositories containing Suppocire AML had the fastest disintegration time (1.5 min) with dissolution efficiency (DE) of 56.8%. F3 containing PEG 1500 had a fast disintegration time of 2.5 min and maximum DE of 93.5%. The PEG blend had satisfactory release:(DE = 90.9%). A mixed fatty and water-soluble base (F7) had a disintegration time of 5 min and low DE (33.4%). A stable MEO emulsion with acceptable taste was formulated to improve patient acceptance and compliance. F3 suppositories yielded satisfactory results, while formulations containing fatsoluble bases exhibited poor release.

In this study, the lipophilic matrix tablets of metronidazole were prepared with Cutina HR (hydrogenated castor oil), stearic acid, Compritol ATO 888 (glyceryl behenate) and Precirol ATO 5 (glycerol palmitostearate) in two different shapes; cylinder and hexagonal. Our first aim was to investigate the influence of the lipid excipients and geometric shape on the release behavior of metronidazole, and the second aim was to investigate the influence of tablet surface area/volume (SA/V) ratio on drug release from controlled release matrix tablets. In vitro release test was performed using a standard USP dissolution apparatus I. Hardness, surface/volume ratio and friability were determined. The hexagonal tablets were harder than the cylinder tablets. Stearic acid showed the highest release rates for both geometric shapes reflecting the highest surface area and the lowest SA/V ratio. According to power law analysis, the diffusion mechanism was expressed as a Fickian diffusion for all lipid matrix tablets. The square root of time relationship was operative for all tablets. Higuchi kinetic constants obtained with hexagonal tablets were higher than the cylinder tablets. As the type of lipid matrix, the geometric shape of the tablets was also effective on the diffusion and release kinetics. From the present study, it was shown that surface area and volume ratio may be used as parameters for the evaluation of the drug release profile.

An acetyl salicylic acid-caffeine complex was prepared and evaluated for the potential use in rectal administration. The results revealed the formation of a complex between acetyl salicylic acid and caffeine in a 1:1 molar ratio by a charge transfer mechanism. The effects of acetyl salicylic acid and complex on the rectal tissues showed destruction in the mucosal epithelium in case of acetyl salicylic acid; however, no change in the rectal tissues was noticed upon the administration of the complex. The effect of suppository bases on the release of the complex was studied using Witepsol H15 as fatty base and polyethylene glycols (PEG) 1000 and 4000 as a water soluble suppository base. The release profiles of acetyl salicylic acid and the complex were faster from PEG than from that of Witepsol H15. The percent release for the complex and acetyl salicylic acid from PEG base were 45.8, and 34.9%, respectively. However, it was 8.7 and 7.8%, respectively, from Witepsol H15 fatty base. The release kinetic was found to follow the non-Fickian diffusion model for complex from the suppository bases. It was concluded that acetyl salicylic acid caffeine complex can be used safely for rectal administration.

Defining a quantitative and reliable relationship between in vitro drug release and in vivo absorption is highly desired for rational development, optimization, and evaluation of controlled-release dosage forms and manufacturing process. During the development of once daily extended-release (ER) tablet of glipizide, a predictive in vitro drug release method was designed and statistically evaluated using three formulations with varying release rates. In order to establish internally and externally validated level A in vitro-in vivo correlation (IVIVC), a total of three different ER formulations of glipizide were used to evaluate a linear IVIVC model based on the in vitro test method. For internal validation, a single-dose four-way cross over study (n=6) was performed using fast-, moderate-, and slow-releasing ER formulations and an immediate-release (IR) of glipizide as reference. In vitro release rate data were obtained for each formulation using the United States Pharmacopeia (USP) apparatus II, paddle stirrer at 50 and 100 rev. min(-1) in 0.1 M hydrochloric acid (HCl) and pH 6.8 phosphate buffer. The f(2) metric (similarity factor) was used to analyze the dissolution data. The formulations were compared using area under the plasma concentration-time curve, AUC(0-infinity), time to reach peak plasma concentration, T(max), and peak plasma concentration, C(max), while correlation was determined between in vitro release and in vivo absorption. A linear correlation model was developed using percent absorbed data versus percent dissolved from the three formulations. Predicted glipizide concentrations were obtained by convolution of the in vivo absorption rates. Prediction errors were estimated for C(max) and AUC(0-infinity) to determine the validity of the correlation. Apparatus II, pH 6.8 at 100 rev. min(-1) was found to be the most discriminating dissolution method. Linear regression analysis of the mean percentage of dose absorbed versus the mean percentage of in vitro release resulted in a significant correlation (r(2)>or=0.9) for the three formulations.

Prednisolone suppositories have been used successfully for the treatment of ulcerative colitis in hospital settings. However, the raw material of prednisolone suppository, JP prednisolone powder (JP Powder), was recently removed from the market. Therefore we studied the effects of raw material and suppository base on the release of prednisolone suppository for the purpose of designing a new suppository with similar effects to those of suppository prepared using JP powder (old suppository). New suppositories consisting of the powder of pulverized tablet as raw material and Witepsol H-15 and Witepsol E-75 as suppository base were prepared according to the fusion method. Suppository release test was performed by reciprocating dialysis tube method with tapping (RDT method) and dialysis tubing method (DT method). Both RDT method and DT method were performed using a suppository dissolution apparatus (modified JP disintegration apparatus) and a JP15 paddle apparatus, respectively. The test fluid was 50 mM phosphate buffer solution (pH 7.4) maintained at 37+/-0.5 degrees C. The results of release test by RDT method were similar to those of DT method. Release rate of prednisolone from the new suppository was much faster than that of old suppository. The addition of Witepsol E-75 to new suppository base markedly delayed the release of prednisolone from the new suppository. Release rate of prednisolone from the new suppository, consisting of pulverized tablet and Witepsol H-15 and Witepsol E-75 (76:24), corresponded well with that of the old suppository. It was suggested that this suppository could be used as incoming preparation of suppository prepared using JP powder.

The aim of this work was to improve the rectal bioavailability of quinine hydrochloride by designing thermosensitive and mucoadhesive gels intended for rectal delivery. The rheological and mucoadhesive properties of poloxamer 407 solutions have been modulated by addition of hydroxypropylmethycellulose (HPMC) and propanediol-1,2. In vitro release and rectal absorption of quinine have been highlighted by a dialysis dissolution testing method and by the determination of bioavailability of the different formulations in rabbits. Increasing the proportions of HPMC and poloxamer in the formulations resulted in a prolonged release of quinine. Indeed, compared to the DT 50% of a rectal solution and a simple HPMC gel (27 and 65min, respectively) the DT 50% of thermosensitive ternary systems was increased and ranged between 80 and 138min, depending on the system composition. The release rate depended strongly on the elasticity of the gels after thermogelation. The absolute rectal bioavailability of quinine determined in rabbits was significantly improved with these thermosensitive and adhesive systems. It increased from 62% for the rectal solution to 98% for a ternary system 16/0.5/30 (poloxamer (16%)/HPMC (0.5%)/propanediol-1,2 (30%)). As a result of combined bioadhesion and prolonged release of quinine in vivo, higher average values of MRT and t(max)(9.1+/-0.2h and 30min, respectively) were obtained compared to the rectal solution (6.9+/-0.9h and 15min, respectively). Moreover, these formulations presented a very good rectal tolerance. Modulation by HPMC of the viscoelastic and mucoadhesive properties of poloxamer 407 thermogelling solutions allowed a prolonged release of quinine hydrochloride and an improvement of bioavailability in rabbit.

Controlled-release morphine suppositories were prepared by utilizing polyglycerol ester of fatty acid (PGEF). The addition of PGEF to fatty suppository base Witepsol H15 resulted in a decrease of morphine release rate from suppositories. Among PGEFs examined, decaglycerol heptabehenate (HB750) was the most effective additive for the controlled-release of morphine from fatty suppositories. The apparent viscosity of suppository bases increased with the increase in HB750 content, and good correlation was observed between the apparent viscosity of suppository bases at 37 degrees C and the amount of HB750 added in the mixed base. The in vitro release rate of morphine was decreased by the addition of HB750 and the release rate constant (Higuchi's rate constant) for morphine release was significantly correlated with the HB750 content in the mixed bases as well as the apparent viscosity of mixed bases, indicating that the release of morphine from the mixed bases could be regulated by the HB750 content in the mixed bases. After rectal administration of Witepsol H-15-HB750 mixed suppositories to dogs, plasma concentrations of morphine did not increase rapidly at early time periods, but relatively high levels of morphine in plasma were sustained for longer time periods. Mean residence time of morphine was considerably prolonged without changing relative bioavailability in the case of the mixed base suppositories containing 15-17% HB750, compared with the Witepsol H15 suppository, clearly indicating that the mixed bases containing HB750 are expected to be useful for the design of controlled-release morphine suppositories.

Localized fluoride delivery to the oral cavity is important in caries prevention. However, no current marketed dosage forms deliver fluoride for an extended period. This work describes the effect of poly (methyl vinyl ether-co-maleic anhydride) mixed calcium/sodium salt (Gantrez MS), sodium carboxymethylcellulose (NaCMC), polyethylene glycol 8000 (PEG8000) and Carbopol 934 (C934) on the in vitro dissolution and ex vivo bioadhesion of sodium fluoride matrix tablets. Dissolution was studied using USP Apparatus 2 and a low volume (3.1 ml), low flow (0.5 ml/min) dissolution apparatus. In both apparatus, the percent drug dissolved at 2, 4 and 8 h was found to be statistically dependent on the fractions of Gantrez MS and NaCMC. The interaction term was significant at 2 and 4 h (probability >(t) of less than 0.05). Ex vivo bioadhesion was studied using excised bovine gingiva and a TA.XT2i Texture Analyzer. Peak bioadhesive force and work of bioadhesion were found to be statistically dependent on the fractions of Gantrez MS and NaCMC with no interaction (probability >(t) of less than 0.01). Results indicate that bioadhesive matrix fluoride tablets of these mixtures can be designed to exhibit both bioadhesive and extended release properties.

The purpose of this study was to evaluate the effect of pH on the dissolution behavior of metaxalone in the marketed product Skelaxin tablets. The dissolution was evaluated using United States Pharmacopeia (USP) dissolution Apparatus 2 and 3 at pHs ranging from 1.5 to 7.4. Results from these studies show that the dissolution of this product is pH dependent. At low pH (simulated gastric fluid, pH 1.5), the dissolution of metaxalone from Skelaxin tablets was less than 10% over 75 minutes; whereas, dissolution at pH 4.5 showed greater than 90% release in the same time period. These results were consistent for both Apparatus 2 and 3. This suggests that Skelaxin Tablets should be considered a delayed release dosage form.