Relative bioavailability of paracetamol from tablets and suppositories as well as of paracetamol and codeine in a combination tablet

Eight healthy male volunteers took part in this study to determine the relative bioavailability of Treuphadol oblong tablets (500 mg paracetamol), Treuphadol Plus oblong tablets (500 mg paracetamol, 30 mg codeine phosphate) and Treuphadol suppositories (750 mg paracetamol) against commercial tablets (500 mg paracetamol). Plasma levels of paracetamol and codeine, plus saliva levels of paracetamol for the two paracetamol only formulations, were determined by HPLC and the pharmacokinetic parameters established. The AUC data for paracetamol showed that all four preparations were bioequivalent. The saliva levels of paracetamol demonstrated a good correlation to the corresponding plasma levels. The pharmacokinetic data of codeine from the Treuphadol Plus tablet were compared with corresponding data from the literature. The bioequivalence of codeine when based on this comparison can also be assured.     

Bioavailability of two new formulations of paracetamol, compared with three marketed formulations, in healthy volunteers

The aim of this study was to compare the main pharmacokinetic characteristics of two new paracetamol formulations, powder sachet and tablet, with that of three commercially available paracetamol formulations: two conventional solid tablets and one effervescent tablet. Twelve healthy volunteers participated in an open, single dose (paracetamol 1,000 mg), randomized, five-way, crossover study. Formulations studied included: formulation A: 2 x 500 mg paracetamol tablets (Laboratorios Belmac S.A.); formulation B: 1 x 1,000 mg paracetamol powder sachets (Laboratorios Belmac, S.A.); formulation C: 2 x 500 mg paracetamol film-coated tablets (Panadol, SmithKline Beecham); formulation D: 2 x 500 mg paracetamol tablets (Tylenol, McNeil); and formulation E: 1 x 1,000 mg effervescent paracetamol tablets (Efferalgan, UPSA). The primary variables were area under the plasma concentration time curve extrapolated to infinity (AUC(0-infinity)), maximum plasma concentration (Cmax), and time to maximum plasma concentration (tmax). Mean AUC(0-infinity) ranged from 52.6 (B) to 56.3 microg x h/ml (D); mean Cmax varied between 17.98 (C) and 20.73 microg/ml (E); mean tmax ranged from 0.40 (E) to 0.88 h (C); and median t(1/2) varied between 2.65 (C) and 2.81 h (A). Formulations A, B and E showed significantly shorter tmax than formulation C. The tmax and Cmax values found for formulations A and B were very similar to that found for E, an effervescent tablet formulation. In conclusion, the two new formulations of paracetamol tested in this study were absorbed rapidly after a single oral dose in healthy volunteers, similar to an effervescent paracetamol formulation and significantly faster than two ordinary commercialized paracetamol tablets.     

Absorption of effervescent paracetamol tablets relative to ordinary paracetamol tablets in healthy volunteers

Objectives: The aim of this study was to compare the rate of absorption between ordinary paracetamol tablets and effervescent paracetamol tablets. Methods: Twenty healthy volunteers participated in an open randomised crossover study and were given a 1000-mg dose of either ordinary paracetamol tablets (2 × 500 mg Panodil tablets, SmithKline Beecham) or effervescent paracetamol tablets (2 × 500 mg Pinex Brusetablett, Alpharma AS) with a 3-week washout period in between. Blood samples were collected for 3 h. Maximum serum concentration (C_max) and the time to maximum serum concentration (t_max) were recorded and the area under the concentration versus time curve (AUC) was calculated. Results: The mean t_max was significantly shorter when paracetamol effervescent tablets were taken (27 min) rather than ordinary paracetamol tablets (45 min) (P=0.004). There was no significant difference between the mean C_max of 143 μmol/l with effervescent tablets and that of 131 μmol/l with ordinary tablets. The mean AUC_0–3 h was significantly higher with paracetamol effervescent tablets (223.8 μmol · h · l⁻¹) than with ordinary tablets (198.2 μmol · h · l⁻¹; P=0.003). After 15 min, 17 (85%) subjects in the effervescent group had a serum concentration of 70 μmol/l (lower therapeutic serum concentration) or higher relative to only 2 (10%) subjects in the ordinary tablet group (P=0.001). Conclusion: Paracetamol effervescent tablets are absorbed significantly faster than ordinary paracetamol. Thus, effervescent tablets might offer significantly faster pain relief when paracetamol is used. Received: 4 October 1999 ;/ Accepted in revised form: 15 February 2000     

Relative bioavailability of new formulation of paracetamol effervescent powder containing sodium bicarbonate versus paracetamol tablets: a comparative pharmacokinetic study in fed subjects

Objective: the aim of this relative bioavailability study was to determine the rate and extent of absorption of Alikal Dolor^® (effervescent powder containing paracetamol 500 mg/sodium bicarbonate 2318 mg) – test formulation (T) in relation to Parageniol^® (paracetamol 500 mg coated tablets) – reference formulation (R). Methods: 18 healthy volunteers (10 male and 8 female aged between 21 and 46 years) received, after 2 h of standardized breakfast, a single oral dose with 220 ml of water, in an open, randomized, crossover study, with a 7-day wash-out period. Paracetamol concentrations were established at 0, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 75, 90 min and at 2, 4, 6, 8 and 10 h postdose by HPLC with an ultraviolet detector. Results: the regression coefficient determined for paracetamol calibration curves was 0.9983 ± 0.0034 and the working range was from 0.2 to 50 μg/ml. The quantification limit was 0.2 μg/ml. The rate of absorption was significantly greater (p < 0.03) for T (T_max = 20.4 min) compared with R (T_max = 38.4 min). Extent of absorption over the first 30 min postdose AUC_{(0-30 min)} was 4.21-fold greater (p < 0.03) for T compared with R, without differences between C_max. The 90% CI on the geometric mean for C_max, AUC_{(0-10 h)} and AUC_(0-∞) ratios (T/R) were within the limits of 0.80 – 1.25, indicating both formulations were bioequivalent with respect to these parameters. Conclusion: paracetamol was absorbed at least twice as fast from T-containing sodium bicarbonate compared with R. This pharmacokinetic feature could prove crucial from the therapeutic point of view as it would allow a lower latency in the action time of paracetamol in producing its analgesic and antithermal effect.     

Comparison of the pharmacokinetic profiles of soluble aspirin and solid paracetamol tablets in fed and fasted volunteers

The aim of this study was to investigate the absorption of popular preparations of two common analgesics--soluble aspirin and solid paracetamol tablets. An open, randomised, crossover study design was used to compare the pharmacokinetic parameters of soluble aspirin and solid paracetamol tablets in 16 healthy, male volunteers from the University of the Witwatersrand, South Africa, in both fed and fasted states. Plasma concentrations of paracetamol, aspirin and salicylic acid were measured. It was found that the rate of absorption was significantly faster for soluble aspirin than for solid paracetamol, regardless of fed or fasting state, considering time to maximum concentration (p < 0.01), time to first quantifiable concentrations (p < 0.05) and absorption rate (p < 0.01). Absorption rate was significantly affected by food for both soluble aspirin (p = 0.028) and for solid paracetamol (p = 0.0003). Time to maximum concentration was not significantly affected by food for soluble aspirin (p = 0.17) but significantly lengthened for solid paracetamol (p = 0.0003). The extent of absorption was affected by food in terms of maximum concentration for both drugs (p = 0.0001), with a reduction of 49% in the fed state for solid paracetamol compared to 18% for soluble aspirin, the difference between the drugs being statistically significant (p = 0.0024). The overall bioavailability of soluble aspirin was unaffected by food and the bioavailability of salicylic acid was increased in the fed state, whereas that of solid paracetamol was lowered in the fed state. Greater inter-individual variation was seen in paracetamol concentrations compared with aspirin or salicylic acid levels. In conclusion, these results show that the absorption of soluble aspirin is largely unaffected by food, whereas, in the same volunteers, the absorption of solid paracetamol tablets is greatly affected. In some volunteers, maximum plasma concentrations of paracetamol following food did not reach levels previously reported to be required for effective analgesia, and this may have implications for pain relief in some individuals. The practice in some individuals of taking aspirin tablets after food to minimise potential gastric disturbance should not affect the level of analgesia.     

The dissolution of paracetamol tablets and the in vitro transfer of paracetamol with and without sorbitol

MANY adjuvants such as sorbitol, glucosamine hydrochloride and sodium hexametaphosphate, have been added to oral dosage forms to improve the absorption of drugs, but Wagner (1961) emphasizes that the attribution of beneficial results to them is not always unequivocal. With sorbitol in paracetamol tablets, it has been suggested that the improved absorption is due to the sorbitol acting on the metabolism of paracetamol and as a dispersing agent (Gwilt, Robertson & others, 1963). The combination of paracetamol and sorbitol provides a readily assayable system with which to examine the role of the adjuvant. I have examined the effect of sorbitol on the aqueous solubility and partitioning of paracetamol and have studied the dissolution rate of paracetamol from commercial tablets containing paracetamol with or without sorbitol with the aim of evaluating the effect of the adjuvant on the availability of the drug.     

Absolute bioavailability and absorption characteristics of divalproex sodium extended-release tablets in healthy volunteers

Conventional delayed-release, enteric-coated divalproex sodium tablet has an absolute bioavailability of approximately 100%. Divalproex sodium extended-release (ER) tablet is a novel formulation of valproic acid (VPA) designed to release the drug slowly at a constant zero-order rate. The purpose of this study was to evaluate the absolute bioavailability and absorption characteristics of divalproex ER. Healthy adult volunteers (n = 16) received divalproex ER and intravenous VPA in crossover fashion. Absolute bioavailability was calculated as the divalproex ER/intravenous VPA ratio of area under the curve extrapolated to infinity. The duration and rate of absorption of VPA from divalproex ER tablets were determined by deconvolution analysis. The geometric mean absolute bioavailability of divalproex ER was 0.896. The mean (coefficient of variation) duration of drug absorption from divalproex ER was 21.8 (17%) hours, and the zero-order absorption rate was 21.6 (24%) mg/h for a 500-mg tablet. Divalproex ER has a lower absolute bioavailability than conventional divalproex tablets but exhibits good extended-release characteristics without any dose dumping.     

Tramadol/paracetamol

The orally administered fixed combination tablet of tramadol (centrally-acting opiate) plus paracetamol (acetaminophen; nonopiate, nonsalicylate analgesic) [37.5/325 mg] provides effective analgesia in patients with moderate to severe acute pain and those with chronic painful conditions characterised by intermittent exacerbations of pain. Two tramadol/paracetamol 37.5/325 mg tablets provided greater relief of dental pain over an 8-hour period than either agent alone, with a faster onset of action than tramadol alone and a longer duration of action than either agent as monotherapy. In patients with postoperative dental pain, two tramadol/paracetamol tablets (37.5/325 mg) provided similar analgesia to hydrocodone/paracetamol 10/650 mg over an 8-hour period. The addition of one or two tramadol/paracetamol 37.5/32 5mg tablets (up to four times daily) for 5 days to existing NSAID or cyclo-oxygenase-2 inhibitor analgesic therapy provided effective pain relief in patients with osteoarthritis flare pain. Tramadol/paracetamol 37.5/325 mg provided similar efficacy to that of codeine/paracetamol 30/300 mg in patients with chronic back pain in a 4-week, randomised, double-blind trial (a maximum of 10 tablets or capsules per day of the active drug).     

Multiple-dose pharmacokinetics of naproxen from a controlled-release tablet in healthy volunteers

The pharmacokinetics of a new controlled-release tablet of naproxen (750 mg) given once daily has been studied in healthy volunteers, in comparison with two doses of the conventional naproxen tablets (375 and 500 mg) administered twice daily. Steady-state plasma concentrations of naproxen were achieved after two days of repeated administration of both the controlled-release and the conventional tablets. On day seven, peak concentration, cowest concentration and the steady-state average plasma concentration values of the controlled-release tablet were significantly higher than those of 375 mg conventional tablet and comparable to those of 500 mg conventional tablet. Areas under the plasma concentration-time curve indicated an equal extent of absorption between the new and the conventional formulation. Overall the controlled-release tablet administered once daily mimicked a twice daily regimen so suggesting that the new formulation could be suitable for once daily dosing.     

Flow-injection spectrophotometric determination of paracetamol in tablets and oral solutions

A flow injection method is proposed for the determination of paracetamol in pharmaceutical dosage forms. The method is based on the nitration of paracetamol with sodium nitrite, and the absorption of the reaction product is measured at 430 nm in alkaline medium. Unlike other colorimetric methods used for determination of paracetamol, this method does not require the use of heat. The influence of several operating parameters is studied. The method was applied to the determination of paracetamol in oral solutions and in tablets, alone or associated with caffeine. When the results were compared with those obtained by the official HPLC method (USP 24) the relative differences found were from 0.4 to 2.3%, with relative standard deviations below 1%.     

Comparative bioavailability of aspirin and paracetamol following single dose administration of soluble and plain tablets

Summary

In this study, the bioavailability of aspirin and paracetamol was compared in plain and soluble combination formulations in fasting, healthy volunteers. Blood samples were taken and C_max, T_max and AUC measured at various times following administration of single doses of the two formulations in 12 subjects.

The rapidity of uptake of aspirin following administration of a soluble formulation suggests significant absorption from the stomach. There was no significant difference in the pharmacokinetic parameters of paracetamol derived from a soluble or plain formulation. A comparison of the uptake of aspirin from the soluble aspirin formulation with paracetamol from either plain or soluble tablets showed that aspirin entered the plasma and achieved peak levels significantly more quickly. However, the half life of paracetamol was significantly longer than that of aspirin.

These findings suggest that onset of analgesia should be more rapid following dosing with soluble aspirin, a conclusion supported by comparative efficacy studies conducted with differing formulations of aspirin.     

Formulation design and optimization of fast disintegrating Lorazepam tablets by effervescent method

Fast disintegrating tablets of lorazepam were prepared by effervescent method with a view to enhance patient compliance. A 3(2) full factorial design was applied to investigate the combined effect of two formulation variables: amount of crospovidone and mixture of sodium bicarbonate, citric acid and tartaric acid (effervescent material) on in vitro dispersion time. Crospovidone (2-8% w/w) was used as superdisintegrant and mixture of sodium bicarbonate, citric acid and tartaric acid (6-18% w/w) was used as effervescent material, along with directly compressible mannitol to enhance mouth feel. The tablets were evaluated for hardness, friability, thickness, drug content uniformity and in vitro dispersion time. Based on in vitro dispersion time (approximately 13 s); the formulation containing 8% w/w crospovidone and 18% w/w mixture of sodium bicarbonate, citric acid and tartaric acid was found to be promising and tested for in vitro drug release pattern (in pH 6.8 phosphate buffer), short-term stability and drug-excipient interaction. Surface response plots are presented to graphically represent the effect of independent variables (concentrations of crospovidone and effervescent material) on the in vitro dispersion time. The validity of the generated mathematical model was tested by preparing two extra-design check point formulations. The optimized tablet formulation was compared with conventional marketed tablet for drug release profiles. This formulation showed nearly eleven-fold faster drug release (t(50%) 2.8 min) compared to the conventional commercial tablet formulation (t(50%) >30 min). Short-term stability studies on the formulation indicated that there were no significant changes in drug content and in vitro dispersion time (P<0.05).     

A study of powder adhesion to metal surfaces during compression of effervescent pharmaceutical tablets

Effervescent tablets were produced using four different formulations containing citric and/or tartaric acid and sodium bicarbonate with povidone and macrogol 6000. The same formulations were prepared with the addition of 1% sucrose ester powder. The adhesion of each formulation to the metal faces of tableting machine punch tips was determined using electron microscopy, surface roughness measurements and quantification of punch weight variations during tablet production. The basic formulations were inherently adhesive and produced tablets with a weak, porous structure which were qualitatively and quantitatively rougher than conventional, non-effervescent compressed tablets. Both formulations containing tartaric acid produced tablets with a lower surface roughness and with less tendency to stick to tablet punch faces than the two formulations containing citric acid alone. The addition of a water-soluble sucrose ester had a beneficial effect especially on the formulations with inherently high adhesive tendencies.     

Bioavailability of hydrochlorothiazide from isomalt-based moulded tablets

The bioavailability of hydrochlorothiazide (HCT) from moulded isomalt-based tablets was evaluated after oral administration of 50 mg HCT to healthy volunteers as an oral moulded tablet and as a lozenge, in comparison with a conventional tablet formulation (Dichlotride 50 mg). Moulded tablets had a high relative bioavailability (F(rel)) as the pharmacokinetic parameters (C(max), t(max), t(1/2), AUC(0-->24 h)) determined from HCT plasma concentration versus time profiles were not significantly different (P>0.05; two-way ANOVA) in comparison with the conventional tablet. The relative bioavailability of the moulded tablet administered as a lozenge and as an oral tablet was 106.2+/-30.9% and 89.4+/-25.9%, respectively, in relation to the conventional tablet formulation. Direct moulding of isomalt tablets proved to be a suitable technique to administer a poorly soluble drug either as a conventional tablet or as a lozenge.     

Investigations on mefenamic acid sustained release tablets with water-insoluble gel

Mefenamic acid (MA) has analgesic, anti-inflammatory and antipyretic properties. Available conventional dosage forms are capsules and film-coated tablets. No commercial sustained release preparation of MA exists in the market. The usual oral dose is 250 or 500 mg and reported half-life is 2 h. Sodium alginate (NaAL) is the sodium salt of alginic acid, a natural polysaccharide extracted from marine brown algae. It has the ability to form a water-insoluble gel with a bivalent metal ions as calcium. Therefore, NaAL has been studied for preparing sustained release formulations in pharmaceutical technology. In this study, tablet formulations containing different ratios of NaAL and calcium gluconate (CaGL) were prepared by direct compression method. In vitro release studies were carried out using USP 23 basket method and release data were kinetically evaluated. According to release studies, it can be emphasized that NaAL and CaGL can be used for design of sustained release preparation of MA.     

Exploration of Intestinal Calcium Precipitation as a Barrier to Absorption at High Calcium Doses

Purpose  To investigate the hypothesis that intestinal bicarbonate secretions precipitate calcium as the carbonate salt, thereby resulting in poor absorption (20–40%) from calcium supplements. Methods  The in vitro effect of calcium dose and bicarbonate secretion rate on soluble calcium was determined by neutralizing elemental Ca²⁺(250, 475, and 630 mg) in 0.1 N HCl to pH 7 with a bicarbonate secretion rate of 0.12 or 1.2 mEq/min. P _CO2 and pH of the solutions were monitored. Soluble calcium was analyzed using atomic absorption spectrometry. Additionally, the transport of calcium across Caco-2 cell monolayers was determined. Results  Calcium from a 250 mg dose remained soluble during bicarbonate secretion, regardless of rate. Once the dose increased, the calcium remaining in solution decreased during neutralization with bicarbonate. The Ca²⁺/CaHCO₃ ⁺ ratio had no effect on calcium permeation across Caco-2 cell monolayers. Conclusions  The physicochemical mechanism of intestinal calcium precipitation supports published clinical data by suggesting that once the solubility product of calcium carbonate is reached, increasing the calcium dose results in significant precipitation at intestinal pH values.     

The influence of morphine on the absorption of paracetamol from various formulations in subjects in the supine position, as assessed by TDx measurement of salivary paracetamol concentrations

The aim of this study was to determine the influence of the type of paracetamol formulation on the rate of absorption when subjects are in the supine position, with or without taking concomitant morphine. Two groups of healthy volunteers were used, who were in the fasting state and remained in the supine position during the study. One group took 1,500 mg of paracetamol on three occasions as conventional tablets, dispersible tablets or a suspension in a randomized crossover design. Seventeen saliva samples per subject were obtained (time zero to 360 min post-dose), which were then centrifuged and kept at -20 degrees C prior to analysis. The second group repeated the study following four doses of morphine syrup (10 mg 4 hourly) in the 12 h preceding paracetamol ingestion. In this phase of the study, paracetamol absorption from suspension was not investigated. A TDx assay was used to determine salivary paracetamol concentrations. The tmax for conventional tablets when taken concomitantly with morphine was 160 (+/- 81) min compared to 51 (+/- 58) min for subjects not taking morphine. For dispersible tablets the tmax in the morphine group was 14 (+/- 9) min compared to 15 (+/- 12) min without morphine. The results suggest that patients who are confined to bed and taking morphine will have an unacceptably long delay between taking conventional paracetamol tablets and the paracetamol reaching therapeutic plasma concentrations. Conversely, there is little effect on the absorption of dispersible paracetamol under the same conditions.     

Formulation and evaluation of famotidine floating tablets

The purpose of this investigation was to prepare a gastroretentive drug delivery system of famotidine. Floating tablets of famotidine were prepared employing two different grades of methocel K100 and methocel K15M by effervescent technique; these grades of methocel were evaluated for their gel forming properties. Sodium bicarbonate was incorporated as a gas-generating agent. The floating tablets were evaluated for uniformity of weight, hardness, friability, drug content, in vitro buoyancy and dissolution studies. The effect of citric acid on drug release profile and floating properties was investigated. The prepared tablets exhibited satisfactory physico-chemical characteristics. All the prepared batches showed good in vitro buoyancy. The tablet swelled radially and axially during in vitro buoyancy studies. It was observed that the tablet remained buoyant for 6-10 hours. Decrease in the citric acid level increased the floating lag time but tablets floated for longer duration. A combination of sodium bicarbonate (130mg) and citric acid (10mg) was found to achieve optimum in vitro buoyancy. The tablets with methocel K100 were found to float for longer duration as compared with formulations containing methocel K15M. The drug release from the tablets was sufficiently sustained and non-Fickian transport of the drug from tablets was confirmed.     

Pharmacokinetic profile of a new form of sumatriptan tablets in healthy volunteers

OBJECTIVE: Rapid delivery of migraine-specific medication to its site(s) of action is thought to be crucial in preventing or minimizing sensitization of central pain pathways and thereby in optimizing pain-free outcomes in patients with migraine. Sumatriptan has been developed as a new tablet formulation to enhance the rate of systemic drug delivery by improving tablet disintegration and drug dispersion relative to those of conventional tablets. These enhanced formulation characteristics may be beneficial during occurrences of the gastric stasis that can accompany migraine. METHODS: This randomized, open-label, 4-way crossover study (n = 32) was conducted to determine whether the new formulation of sumatriptan 50 and 100 mg is bioequivalent to sumatriptan conventional tablets and to compare the pharmacokinetic profiles of the new formulation and the conventional tablet during the early (0-2 h) postdose interval in healthy volunteers. Pharmacokinetics during the early post-dose interval are important in determining a drug's onset of action, an important parameter to patients with migraine. RESULTS: The results confirm that the new formulation of sumatriptan and sumatriptan conventional tablets are bioequivalent as demonstrated by the finding that the 90% confidence intervals for the sumatriptan area under the concentration time curve to infinity and to the last evaluable time point (AUC(0- infinity ) and AUC(0-t), respectively) and maximum plasma concentration (C(max)) fell within the predetermined bounds defining bioequivalence (0.80-1.25) for both doses. Pharmacokinetic parameters measured early (0-2 h) after dosing reveal slightly faster absorption, on average, of the new sumatriptan formulation than sumatriptan conventional tablets although high intersubject variability was observed. For the new sumatriptan formulation, AUC(0-2) (AUC up to 2 h post dose) was, on average, 1% greater (50 mg) and 8% greater (100 mg) and maximal sumatriptan levels were attained, on average, 10 min earlier (50 mg) and 15 min earlier (100 mg) compared with the conventional tablet. Other measures including AUC(0-0.5) (AUC to 30 min post-dose), times to achieve sumatriptan concentrations of 5 and 10 ng/mL, and mean percentage C(max) 15, 20 and 30 min post-dose demonstrate an observable improvement in rate of drug absorption for the new form of sumatriptan compared with conventional tablets. CONCLUSION: The new form of sumatriptan is bioequivalent to sumatriptan conventional tablets and is absorbed more quickly than conventional tablets.     

Design and in vitro testing of a floatable gastroretentive tablet of metformin hydrochloride

Metformin hydrochloride, which is better absorbed in the upper intestine, was formulated as a floating (buoyant) matrix tablet using a gas generating agent (sodium bicarbonate) and a gel forming hydrophilic polymer (hydroxypropyl methylcellulose). The formulation was optimized on the basis of floating ability and in vitro drug release. The resulting formulation produced robust tablets with optimum hardness, consistent weight uniformity and low tablet friability. All tablets but one exhibited satisfactory (gradual and near complete) drug release and buoyancy. In vitro drug release tests of these tablets indicated controlled sustained release of metformin hydrochloride and 96-99% released at the end of 8 h. Two formulations of fabricated tablets containing metformin hydrochloride (500 mg), sodium bicarbonate (75 mg), hydroxypropyl methylcellulose-K 4M (170-180 mg), citric acid (between 15 and 20 mg) and polyvinyl pyrrolidone K90 (32-40 mg) with hardness between 6.8 to 7.5 kg/cm2 showed a floating time of more than 8 h and promising drug release results. The release followed the Higuchi kinetic model, indicating diffusion dominated drug release.