Progestogen-releasing intrauterine systems for heavy menstrual bleeding.

BACKGROUND: Heavy menstrual bleeding (HMB) impacts the quality of life of otherwise healthy women. The perception of HMB is subjective and management depends upon, among other factors, the severity of the symptoms, a woman's age, her wish to get pregnant, and the presence of other pathologies. Heavy menstrual bleeding was classically defined as greater than or equal to 80 mL of blood loss per menstrual cycle. Currently the definition is based on the woman's perception of excessive bleeding which is affecting her quality of life. The intrauterine device was originally developed as a contraceptive but the addition of progestogens to these devices resulted in a large reduction in menstrual blood loss: users of the levonorgestrel-releasing intrauterine system (LNG-IUS) reported reductions of up to 90%. Insertion may, however, be regarded as invasive by some women, which affects its acceptability. OBJECTIVES: To determine the effectiveness, acceptability and safety of progestogen-releasing intrauterine devices in reducing heavy menstrual bleeding. SEARCH METHODS: We searched the Cochrane Gynaecology and Fertility Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO and CINAHL (from inception to June 2019); and we searched grey literature and for unpublished trials in trial registers. SELECTION CRITERIA: We included randomised controlled trials (RCTs) in women of reproductive age treated with LNG-IUS devices versus no treatment, placebo, or other medical or surgical therapy for heavy menstrual bleeding. DATA COLLECTION AND ANALYSIS: Two authors independently extracted data, assessed risk of bias and conducted GRADE assessments of the certainty of evidence. MAIN RESULTS: We included 25 RCTs (2511 women). Limitations in the evidence included risk of attrition bias and low numbers of participants. The studies compared the following interventions. LNG-IUS versus other medical therapy The other medical therapies were norethisterone acetate, medroxyprogesterone acetate, oral contraceptive pill, mefenamic acid, tranexamic acid or usual medical treatment (where participants could choose the oral treatment that was most suitable). The LNG-IUS may improve HMB, lowering menstrual blood loss according to the alkaline haematin method (mean difference (MD) 66.91 mL, 95% confidence interval (CI) 42.61 to 91.20; 2 studies, 170 women; low-certainty evidence); and the Pictorial Bleeding Assessment Chart (MD 55.05, 95% CI 27.83 to 82.28; 3 studies, 335 women; low-certainty evidence). We are uncertain whether the LNG-IUS may have any effect on women's satisfaction up to one year (RR 1.28, 95% CI 1.01 to 1.63; 3 studies, 141 women; I² = 0%, very low-certainty evidence). The LNG-IUS probably leads to slightly higher quality of life measured with the SF-36 compared with other medical therapy if (MD 2.90, 95% CI 0.06 to 5.74; 1 study: 571 women; moderate-certainty evidence) or with the Menorrhagia Multi-Attribute Scale (MD 13.40, 95% CI 9.89 to 16.91; 1 trial, 571 women; moderate-certainty evidence). The LNG-IUS and other medical therapies probably give rise to similar numbers of women with serious adverse events (RR 0.91, 95% CI 0.63 to 1.30; 1 study, 571 women; moderate-certainty evidence). Women using other medical therapy are probably more likely to withdraw from treatment for any reason (RR 0.49, 95% CI 0.39 to 0.60; 1 study, 571 women, moderate-certainty evidence) and to experience treatment failure than women with LNG-IUS (RR 0.34, 95% CI 0.26 to 0.44; 6 studies, 535 women; moderate-certainty evidence). LNG-IUS versus endometrial resection or ablation (EA) Bleeding outcome results are inconsistent. We are uncertain of the effect of the LNG-IUS compared to EA on rates of amenorrhoea (RR 1.21, 95% CI 0.85 to 1.72; 8 studies, 431 women; I² = 21%; low-certainty evidence) and hypomenorrhoea (RR 0.98, 95% CI 0.73 to 1.33; 4 studies, 200 women; low-certainty evidence) and eumenorrhoea (RR 0.55, 95% CI 0.30 to 1.00; 3 studies, 160 women; very low-certainty evidence). We are uncertain whether both treatments may have similar rates of satisfaction with treatment at 12 months (RR 0.95, 95% CI 0.85 to 1.07; 5 studies, 317 women; low-certainty evidence). We are uncertain if the LNG-IUS compared to EA has any effect on quality of life, measured with SF-36 (MD -14.40, 95% CI -22.63 to -6.17; 1 study, 33 women; very low-certainty evidence). Women with the LNG-IUS compared with EA are probably more likely to have any adverse event (RR 2.06, 95% CI 1.44 to 2.94; 3 studies, 201 women; moderate-certainty evidence). Women with the LNG-IUS may experience more treatment failure compared to EA at one year follow up (persistent HMB or requirement of additional treatment) (RR 1.78, 95% CI 1.09 to 2.90; 5 studies, 320 women; low-certainty evidence); or requirement of hysterectomy may be higher at one year follow up (RR 2.56, 95% CI 1.48 to 4.42; 3 studies, 400 women; low-certainty evidence). LNG-IUS versus hysterectomy We are uncertain whether the LNG-IUS has any effect on HMB compared with hysterectomy (RR for amenorrhoea 0.52, 95% CI 0.39 to 0.70; 1 study, 75 women; very low-certainty evidence). We are uncertain whether there is difference between LNG-IUS and hysterectomy in satisfaction at five years (RR 1.01, 95% CI 0.94 to 1.08; 1 study, 232 women; low-certainty evidence) and quality of life (SF-36 MD 2.20, 95% CI -2.93 to 7.33; 1 study, 221 women; low-certainty evidence). Women in the LNG-IUS group may be more likely to have treatment failure requiring hysterectomy for HMB at 1-year follow-up compared to the hysterectomy group (RR 48.18, 95% CI 2.96 to 783.22; 1 study, 236 women; low-certainty evidence). None of the studies reported cost data suitable for meta-analysis. AUTHORS' CONCLUSIONS: The LNG-IUS may improve HMB and quality of life compared to other medical therapy; the LNG-IUS is probably similar for HMB compared to endometrial destruction techniques; and we are uncertain if it is better or worse than hysterectomy. The LNG-IUS probably has similar serious adverse events to other medical therapy and it is more likely to have any adverse events than EA.

Renal ultrastructural alterations induced by various preparations of mefenamic acid.

Mefenamic acid (MFA) treatment is associated with a number of cellular effects that potentiate the incidence of renal toxicity. The aim of this study is to investigate the potential ultrastructural alterations induced by various preparations of MFA (free MFA, MFA-Tween 80 liposomes, and MFA-DDC liposomes) on the renal tissues. Sprague-Dawley rats were subjected to a daily dose of MFA preparations for 28 days. Renal biopsies from all groups of rats under study were processed for transmission electron microscopic examination. The findings revealed that MFA preparations induced various ultrastructural alterations including mitochondrial injury, nuclear and lysosomal alterations, tubular cells steatosis, apoptotic activity, autophagy, and nucleophagy. These alterations were more clear in rats received free MFA, and MFA-Tween 80 liposomes than those received MFA-DDC liposomes. It is concluded that MFA-DDC liposomes are less potential to induce renal damage than free MFA and MFA-Tween 80 liposomes. Thus, MFA-DDC liposomes may offer an advantage of safe drug delivery.

Effect of alpha-lipoic acid at the combination with mefenamic acid in girls with primary dysmenorrhea: randomized, double-blind, placebo-controlled clinical trial.

Primary dysmenorrhea is a common gynecologic disorder and is one of the main causes for referral to the gynecology clinic. This study aimed to determine the effects of alpha-lipoic acid (ALA) and mefenamic acid and a combination compared with placebo on the girls with primary dysmenorrhea. This double-blind, placebo-controlled clinical trial done on population consisted of female students living in dormitories of Qazvin University of Medical Sciences who had moderate to severe dysmenorrhea using the Visual Analog Scale (VAS) questionnaire. Participants were randomly divided into four groups (n = 100): ALA, mefenamic acid, ALA + mefenamic acid and placebo groups. ALA and mefenamic acid were administrated in 600 mg and 250 mg, respectively. The severity of the pain was measured in the beginning and the end of the study. Statistical analysis was performed using SPSS software (SPSS Inc., Chicago, IL). Our final results suggested that, although mefenamic acid significantly decreased the menstrual pain, ALA supplementation, 600 mg, would be more efficient than mefenamic acid in 250 mg. Also, the combination of ALA and mefenamic acid significantly has been far. Considering the ALA supplementation effect on pain relief in patients with primary dysmenorrhea, this antioxidant can be recommended for the healing of symptoms of these patients.

Comparison of Intra-Socket Bupivacaine Administration Versus Oral Mefenamic Acid Capsule for Postoperative Pain Management Following Removal of Impacted Mandibular Third Molars.

PURPOSE: Surgical removal of impacted third molar teeth is one of the most common surgical procedures performed in oral and maxillofacial surgery. Postoperative pain is a common and predictable occurrence after maxillofacial surgery. MATERIALS AND METHODS: This randomized double-blind clinical trial was conducted with a crossover design in which each patient served as his or her own control. Forty-six patients with similar bilateral impacted lower third molars were selected. In each patient, the intervention and control sides of the mandible were randomly determined at the end of surgery. If the removed tooth was in the intervention side, then the patient would receive bupivacaine and a placebo of mefenamic acid. If the impacted tooth was in the control side, then the patient would receive a mefenamic acid capsule and a placebo of bupivacaine. Pain severity was assessed using a visual analog scale. Data were analyzed using paired-sample t test and a P value less than .05 was considered statistically significant. RESULTS: Of 46 participants originally recruited, 43 were included in the present study. The mean postoperative pain score in patients who received bupivacaine was increased to a maximum 4 hours, with marked improvements after this time. The mean intensity of pain after administration of bupivacaine was lower than that of mefenamic acid capsules at different time points. Statistical analysis showed a relevant difference in pain intensity between the 2 study groups. CONCLUSION: The results of the present study showed that local administration of bupivacaine relieves postoperative pain after surgical removal of impacted third molar teeth.

Central nervous system toxicity of mefenamic acid overdose compared with other NSAIDs: an analysis of cases reported to the United Kingdom National Poisons Information Service.

AIMS: Case reports and small case series suggest increased central nervous system (CNS) toxicity, especially convulsions, after overdose of mefenamic acid, compared with other nonsteroidal anti-inflammatory drugs (NSAIDs), although comparative epidemiological studies have not been conducted. The current study compared rates of CNS toxicity after overdose between mefenamic acid, ibuprofen, diclofenac and naproxen, as reported in telephone enquiries to the UK National Poisons Information Service (NPIS). METHODS: NPIS telephone enquiries related to the four NSAIDs, received between January 2007 and December 2013, were analysed, comparing the frequency of reported CNS toxicity (convulsions, altered conscious level, agitation or aggression, confusion or disorientation) using multivariable logistic regression. RESULTS: Of 22 937 patient-specific telephone enquiries, 10 398 did not involve co-ingestion of other substances (mefenamic acid 461, ibuprofen 8090, diclofenac 1300, naproxen 547). Patients taking mefenamic acid were younger and more commonly female than those using other NSAIDs. Those ingesting mefenamic acid were more likely to experience CNS toxicity than those ingesting the other NSAIDs combined [adjusted odds ratio (OR) 7.77, 95% confidence interval (CI) 5.68, 10.62], especially convulsions (adjusted OR 81.5, 95% CI 27.8, 238.8). Predictors of CNS toxicity included reported dose and age, but not gender. CONCLUSIONS: Mefenamic acid overdose is associated with a much larger and dose-related risk of CNS toxicity, especially convulsions, compared with overdose of other NSAIDs. The benefit-risk profile of mefenamic acid should now be re-evaluated in light of effective and less toxic alternatives.

ASSESSMENT OF GUAR AND XANTHAN GUM BASED FLOATING DRUG DELIVERY SYSTEM CONTAINING MEFENAMIC ACID.

We aimed to assess guar and xantban gum based floating drug delivery system containing mefenamic acid. Floating tablets of nefenamic acid were formulated with different concentrations of guar and xanthan gum via wet granulation method. The flow properties of granules that is: bulk density, tapped density, flow rate, Carr index, Hausner's ratio, compressibility index and angle of repose as well as physical parameters of the compressed tablets including: hardness, friability, thickness and swelling indices were determined and found to be good. Xanthan gum was superior to guar gum in maintaining drug release, but a combination of polymers was found to be the best for achieving sustained release up to 12 h due to the synergistic effect of both gums. Drug release mechanism was best explained by Korsmeyer-Peppas model. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) studies showed absence of any visible interaction. Stability studies at 40°C (75% RH) showed that the formulation was stable at elevated temperature. It can be concluded that floating tablets can be used as a sustained release matrix due to their superior characteristics.

The effect of mefenamic acid and ginger on pain relief in primary dysmenorrhea: a randomized clinical trial.

PURPOSE: The aim of the study was to compare the effect of mefenamic acid and ginger on pain management in primary dysmenorrhea. METHODS: One hundred and twenty-two female students with moderate to severe primary dysmenorrhea were randomly allocated to the ginger and mefenamic groups in a randomized clinical trial. The mefenamic group received 250 mg capsules every 8 h, and the ginger group received 250 mg capsules (zintoma) every 6 h from the onset of menstruation until pain relief lasted 2 cycles. The intensity of pain was assessed by the visual analog scale. Data were analyzed by descriptive statistics, t test, Chi-square, Fisher exact test and repeated measurement. RESULTS: The pain intensity in the mefenamic and ginger group was 39.01 ± 17.77 and 43.49 ± 19.99, respectively, in the first month, and 33.75 ± 17.71 and 38.19 ± 20.47, respectively, in the second month (p > 0.05). The severity of dysmenorrhea, pain duration, cycle duration and bleeding volume was not significantly different between groups during the study. The menstrual days were more in the ginger group in the first (p = 0.01) and second cycle (p = 0.04). Repeated measurement showed a significant difference in pain intensity within the groups by time, but not between groups. CONCLUSION: Ginger is as effective as mefenamic acid on pain relief in primary dysmenorrhea. Ginger does not have adverse effects and is an alternative treatment for primary dysmenorrhea.

Cryomilling-induced solid dispersion of poor glass forming/poorly water-soluble mefenamic acid with polyvinylpyrrolidone K12.

The effect of mechanical impact on the polymorphic transformation of mefenamic acid (MFA) and the formation of a solid dispersion of mefenamic acid, a poor glass forming/poorly-water soluble compound, with polyvinylpyrrolidone (PVP) K12 was investigated. The implication of solid dispersion formation on solubility enhancement of MFA, prepared by cryomilling, was investigated. Solid state characterization was conducted using powder X-ray diffraction (PXRD) and Fourier-transform infrared (FTIR) spectroscopy combined with crystal structure analysis. Apparent solubility of the mixtures in pH 7.4 buffer was measured. A calculation to compare the powder patterns and FTIR spectra of solid dispersions with the corresponding physical mixtures was conducted. Solid state characterization showed that (1) MFA I transformed to MFA II when pure MFA I was cryogenically milled (CM); and (2) MFA forms a solid dispersion when MFA was cryogenically milled with PVP K12. FTIR spectral analysis showed that hydrogen bonding facilitated by mechanical impact played a major role in forming solid dispersions. The apparent solubility of MFA was significantly improved by making a solid dispersion with PVP K12 via cryomilling. This study highlights the importance of cryomilling with a good hydrogen bond forming excipient as a technique to prepare solid dispersion, especially when a compound shows a poor glass forming ability and therefore, is not easy to form amorphous forms by conventional method.

Nano-proniosomes enhancing the transdermal delivery of mefenamic acid.

Mefenamic acid (MA) is a BCS II class NSAID drug. It is available only in the form of tablets, capsules, and pediatric suspensions. Oral administration of MA is associated with severe gastrointestinal side effects. The aim of this study was to develop a convenient and low-cost transdermal drug delivery system for MA using proniosome as a novel carrier without the addition of penetration enhancers. The formulation factors, such as the presence of cholesterol, types of lecithin, and surfactants were investigated for their influence on the entrapment efficiency, rate of hydration, vesicle size, and zeta potential, in vitro drug release and skin permeation in order to optimize the proniosomal formulations with the minimum dose of the drug. Furthermore, the in vivo anti-inflammatory effect was evaluated on a formalin-induced rat paw edema model. The results showed that the type of surfactants had higher impact on the entrapment efficiency than the type of lecithins, with the highest in Span 80 (82.84%). The release of MA from Span 80 proniosomal gel was significantly affected by the type of lecithin used. The addition of cholesterol significantly increased both the drug release and the skin permeation flux of MA. Zeta potential showed a stable A4 noisomal suspension. DSC revealed the molecular dispersion of MA into the loaded proniosomes. In vivo study of the treatment group with MA proniosome gel showed a significant inhibition of rat paw edema compared with the same gel without the drug (control). The results of this study suggest that proniosomes are promising nano vesicular carriers and safe alternatives to enhance the transdermal delivery of MA.

Formulation and evaluation of time-controlled triple-concentric mefenamic acid tablets for rheumatoid arthritis.

A triple-concentric time-controlled release mefenamic acid (MA) tablet was developed using Carbopol and Ethocel polymers. The burst dose was programed to release immediately after an ingestion of tablet to be followed by a lag period of 2-4 h, and thereafter an 8 h controlled release of MA from core tablet. Core tablets were prepared using Carbopols 971P, 974P, 71G or 907 at various concentrations. The core tablet provided a controlled release of MA and the release rate decreased with increasing polymer concentration. Highly cross-linked Carbopol 974P released MA at a faster rate compared to release from Carbopol 971P with medium degree of cross-linking. Carbopols 71G and 971P exhibited essentially similar release rates. Carbopol 907, a linear polymer, showed fastest release of MA. The extent of uptake of dissolution medium by core tablets was inversely related to the rate of release of MA from the tablets. Compression coating of core tablet with Ethocel provided the lag period to delay release of MA from core tablet. Increase in lateral coating thickness decreased MA release and increased lag period. Compression forces applied during compression coating with Ethocel for lag period, and immediate-release MA coating for burst release did not affect the integrity of core tablet.

Multiple drug-delivery strategies to enhance the pharmacological and toxicological properties of Mefenamic acid.

OBJECTIVE: To improve the biological and toxicological properties of Mefenamic acid (MA), the galactosylated prodrug of MA named MefeGAL was included in polymeric solid dispersions (PSs) composed of poly(glycerol adipate) (PGA) and Pluronic® F68 (MefeGAL-PS). MefeGAL-PS was compared with polymeric solid formulations of MA (MA-PS) or a mixture of equal ratio of MefeGAL/MA (Mix-PS). METHODS: The in vitro and in vivo pharmacological and toxicological profiles of PSs have been investigated. In detail, we evaluated the anti-inflammatory (carrageenan-induced paw edema test), analgesic (acetic acid-induced writhing test) and ulcerogenic activity in mice after oral treatment. Additionally, the antiproliferative activity of PSs was assessed on in vitro models of colorectal and non-small cell lung cancer. RESULTS: When the PSs were resuspended in water, MefeGAL's, MA's and their mixture's apparent solubilities improved due to the interaction with the polymeric formulation. By comparing the in-vivo biological performance of MefeGAL-PS with that of MA, MefeGAL and MA-PS, it was seen that MefeGAL-PS exhibited the same sustained and delayed analgesic and anti-inflammatory profile as MefeGAL but did not cause gastrointestinal irritation. The pharmacological effect of Mix-PS was present from the first hours after administration, lasting about 44 hours with only slight gastric mucosa irritation. In-vitro evaluation indicated that Mix-PS had statistically significant higher cytotoxicity than MA-PS and MefeGAL-PS. CONCLUSIONS: These preliminary data are promising evidence that the galactosylated prodrug approach in tandem with a polymer-drug solid dispersion formulation strategy could represent a new drug delivery route to improve the solubility and biological activity of NSAIDs.

Investigation of the rat model for preclinical evaluation of pH-dependent oral absorption in humans.

Many pharmaceutically active compounds are weak electrolytes and are ionizable in the pH range experienced throughout the gastrointestinal tract. Changes in protonation state due to pH changes in the gut can have dramatic effects on solubility, dissolution, and permeation through biological barriers. Preclinical assessment of the pH-dependence of oral absorption is critical for compounds possessing pH-dependent solubility. Here we examine pH-dependent solubility and oral exposure in rat for three model compounds, dasatinib, ketoconazole, and mefenamic acid. Dasatinib and ketoconazole are both weak bases, while mefenamic acid is a carboxylic acid. The effects of gastric pH modulators, pentagastrin and famotidine, were investigated in rat PK studies to assess the applicability of using the rat to evaluate the risk of pH-dependent oral exposure for ionizable compounds. Dasatinib showed similar exposure between control and pentagastrin-pretreated groups, and 4.5-fold lower AUC in famotidine-pretreated rats. Ketoconazole showed a 2-fold increase in AUC in pentagastrin-treated rats relative to control, and 4.5-fold lower AUC in famotidine treated rats, relative to the pentagastrin group. Mefenamic acid showed highly similar exposures among control, pentagastrin-pretreated, and famotidine-pretreated groups. The rat model was shown to be useful for compounds displaying pH-dependent solubility and oral absorption that may be affected by gastric pH modulators.

Effects of rifampin and mefenamic acid on the pharmacokinetics and pharmacodynamics of dapagliflozin.

AIMS: Dapagliflozin is a selective sodium glucose cotransporter 2 (SGLT2) inhibitor that decreases serum glucose by reducing renal glucose reabsorption, thereby promoting urinary glucose excretion. Dapagliflozin is primarily metabolized via the uridine diphosphate-glucuronosyltransferase (UGT)1A9 pathway to its major inactive metabolite, dapagliflozin 3-O-glucuronide. The aim of this study was to evaluate the potential for drug-drug interaction between dapagliflozin and two potential UGT1A9 modulators. METHODS: The results of two open-label, non-randomized, single-sequence studies are reported in which the effects of rifampin (a pleiotropic drug-metabolizing enzyme inducer; study 1) and mefenamic acid (a strong UGT1A9 inhibitor; study 2) were evaluated on the pharmacokinetics and pharmacodynamics (assessed by urinary glucose excretion [UGE]) of dapagliflozin in healthy subjects. In study 1, 14 subjects received single doses of dapagliflozin 10 mg alone and in the presence of rifampin 600 mg QD (6 days). In study 2, 16 subjects received single doses of dapagliflozin 10 mg alone and in the presence of mefenamic acid 250 mg q6h (5 days). RESULTS: Rifampin reduced total exposure (area under the concentration-time curve from time 0 to infinity [AUC0-inf]) to dapagliflozin by 22% and mefenamic acid increased dapagliflozin AUC0-inf by 51%. No clinically meaningful effect of rifampin or mefenamic acid on the pharmacokinetics of dapagliflozin or on dapagliflozin-mediated urinary glucose excretion was observed. CONCLUSION: Modest changes in dapagliflozin exposure were seen with rifampin and mefenamic acid with minor changes in UGE, none of which were considered clinically meaningful.

Compounded ointment results in severe toxicity in a pediatric patient.

BACKGROUND: Dermal drug delivery is becoming more common, as evidenced by the increased numbers of compounding pharmacies preparing topical products for chronic pain management. Consumers may not appreciate the potency or dangers associated with some of the drugs in these preparations. Pediatric patients are especially at risk for significant toxicity with accidental exposures. We report a case of severe toxicity in an 18-month-old boy from exposure to his father's compounded pain ointment. CASE: An 18-month-old previously healthy child had an ointment applied topically to a diaper rash by his mother, consisting of a single pump of a prescription ointment that her husband received from a compounding pharmacy for neck pain. Approximately 20 minutes later, when the child had been put down for a nap, he had gasping respiration but was otherwise unresponsive. Emergency medical services was called, and the child was unresponsive. In the ED, vital signs were pulse of 57 beats/min, blood pressure 74/35 mm Hg, respiratory rate 21 breaths/min, and O2 saturation 98% on a nonrebreather. Fingerstick glucose was 105 mg/dL. In the ED, physical examination was significant for unresponsiveness, pinpoint pupils, and hyporeflexia. The patient's mental status continued to deteriorate with depressed respirations, and he was intubated. Laboratory results were noncontributory. Electrocardiogram revealed only sinus bradycardia. The patient was transported to a pediatric intensive care unit. He did well over the next several hours with supportive care and had return to normal vital signs over the following 12 hours. He was extubated the following morning without problems. Blood taken at the time of ED presentation had a serum clonidine level of 9.2 ng/mL (reference range, 0.5-4.5 ng/mL) and a norketamine level of 41 ng/mL (reporting limit, >20 ng/mL). CONCLUSIONS: Dermal absorption of drugs leading to significant toxicity in children is well known. Our patient had toxicity from a topical pain medication compounded with several potent drugs known to cause central nervous system depression. There has been an increase in the use of this drug delivery system for management of chronic painful conditions. The popularity and attractiveness of such preparations may be the perception that they are somehow safer and more natural than taking pills. This perception and the fact that these are not dispensed in child-proof containers and are often mailed to the patients without pharmacist counseling can lead to increased inadvertent exposures in the pediatric population.

Stabilization of a supersaturated solution of mefenamic acid from a solid dispersion with EUDRAGIT(®) EPO.

PURPOSE: The stabilization mechanism of a supersaturated solution of mefenamic acid (MFA) from a solid dispersion with EUDRAGIT(®) EPO (EPO) was investigated. METHODS: The solid dispersions were prepared by cryogenic grinding method. Powder X-ray diffractometry, in vitro dissolution test, in vivo oral absorption study, infrared spectroscopy, and solid- and solution-state NMR spectroscopies were used to characterize the solid dispersions. RESULTS: Dissolution tests in acetate buffer (pH 5.5) revealed that solid dispersion showed > 200-fold higher concentration of MFA. Supersaturated solution was stable over 1 month and exhibited improved oral bioavailability of MFA in rats, with a 7.8-fold higher area under the plasma concentration-versus-time curve. Solid-state (1)H spin-lattice relaxation time (T(1)) measurement showed that MFA was almost monomolecularly dispersed in the EPO polymer matrix. Intermolecular interaction between MFA and EPO was indicated by solid-state infrared and (13)C-T(1) measurements. Solution-state (1)H-NMR measurement demonstrated that MFA existed in monomolecular state in supersaturated solution. (1)H-T(1) and difference nuclear Overhauser effect measurements indicated that cross relaxation occurred between MFA and EPO due to the small distance between them. CONCLUSIONS: The formation and high stability of the supersaturated solution were attributable to the specifically formed intermolecular interactions between MFA and EPO.

Sustained release spherical agglomerates of polymethacrylates containing mefenamic acid: in vitro release, micromeritic properties and histological studies.

Mefenamic acid (MA) spherical agglomerates (SAs) were prepared with various polymethacrylates having different permeability characteristics (Eudragit RS 100, Eudragit RL 100 and Eudragit L 100) and also with combination of Eudragit RS 100 and Eudragit L 100 in different ratios. SAs were prepared by spherical crystallization method using ethanol/dichloromethane solvent (crystallization) system. The influence of various formulation factors on the encapsulation efficiency, as in vitro drug release, and micromeritic properties was investigated. Target release profile of MA was also drawn. The yields of preparation and the encapsulation efficiencies were high for all formulations. The shape and surface characteristics of SAs were observed by a scanning electron microscope. The particle sizes are in the range of 0.219 ± 0.1 to 0.482 ± 0.25 mm (mean ± confidence interval t(95%)). In addition, histological studies showed that the administration of MA in SAs containing Eudragit RS/L provided a distinct tissue protection in the stomach and duodenum. Differential scanning calorimetry and X-ray diffraction of powder studies showed that MA particles crystallized in the presence of polymethacrylates did not undergo structural modifications.

In vitro/in vivo correlation of fast release mephenamic acid microspheres in humans.

OBJECTIVES: The objectives of this study were to assess the bioavailability of an optimized mephenamic acid (MFA) microspheres (test) against a Ponstan® capsule (reference) in healthy volunteers, and to establish a correlation with in vitro parameters. SUBJECTS AND METHODS: Four subjects received the test and reference (250 mg MFA each) in a randomized crossover design, separated by a 1-week washout period. The drug was analyzed in plasma by a specific high-performance liquid chromatographic method. The relevant pharmacokinetic parameters [maximum plasma concentration (C(max)), time of peak concentration (T(max)), area under plasma concentration-time curves from 0 to 12 h (AUC(0-12)) and area under plasma concentration-time curves from zero to ∞ (AUC(0-)∞)] were calculated from the plasma drug concentration-time data. RESULTS: The test product exhibited faster absorption (T(max) of 1.87 ± 0.482 vs. 2.14 ± 0.20 h; C(max) of 5.91 ± 0.604 vs. 3.58 ± 0.671 µg/ml) when compared to the reference. The relative bioavailability of the test compared to the reference capsule was 172%. Good correlations were established between the in vitro 90% dissolution (T90) and each of the AUC(0-12) and T(max), as well as between the percentage of drug released and plasma concentrations. CONCLUSION: The formulation of MFA microsphere with polyethylene glycol improved the dissolution rate and bioavailability of MFA, as evidenced by a higher C(max), AUC(0-12) and AUC(0-)∞, and shorter T(max) values. Good correlations between T90 and both AUC(0-12) and T(max) as well as between the percentage of drug released and plasma concentrations were achieved.

Single dose oral mefenamic acid for acute postoperative pain in adults.

BACKGROUND: Mefenamic acid is a non-steroidal anti-inflammatory drug (NSAID). It is most often used for treating pain of dysmenorrhoea in the short term (seven days or less), as well as mild to moderate pain including headache, dental pain, postoperative and postpartum pain. It is widely available in many countries worldwide. OBJECTIVES: To assess the efficacy of single dose oral mefenamic acid in acute postoperative pain, and any associated adverse events. SEARCH STRATEGY: We searched Cochrane CENTRAL, MEDLINE, EMBASE and the Oxford Pain Relief Database for studies to December 2010. SELECTION CRITERIA: Single oral dose, randomised, double-blind, placebo-controlled trials of mefenamic acid for relief of established moderate to severe postoperative pain in adults. DATA COLLECTION AND ANALYSIS: Studies were assessed for methodological quality and the data extracted by two review authors independently. Summed total pain relief (TOTPAR) or pain intensity difference (SPID) over 4 to 6 hours was used to calculate the number of participants achieving at least 50% pain relief. These derived results were used to calculate, with 95% confidence intervals, the relative benefit compared to placebo, and the number needed to treat (NNT) for one participant to experience at least 50% pain relief over 4 to 6 hours. Numbers of participants using rescue medication over specified time periods, and time to use of rescue medication, were sought as additional measures of efficacy. Information on adverse events and withdrawals was collected. MAIN RESULTS: Four studies with 842 participants met the inclusion criteria; 126 participants were treated with mefenamic acid 500 mg, 67 with mefenamic acid 250 mg, 197 with placebo, and 452 with lignocaine, aspirin, zomepirac or nimesulide. Participants had pain following third molar extraction, episiotomy and orthopaedic surgery. The NNT for at least 50% pain relief over 6 hours with a single dose of mefenamic acid 500 mg compared to placebo was 4.0 (2.7 to 7.1), and the NNT to prevent use of rescue medication over 6 hours was 6.5 (3.6 to 29). There were insufficient data to analyse other doses or active comparators, or numbers of participants experiencing any adverse events. No serious adverse events or adverse event withdrawals were reported in these studies. AUTHORS' CONCLUSIONS: Oral mefenamic acid 500 mg was effective at treating moderate to severe acute postoperative pain, based on limited data. Efficacy of other doses, and safety and tolerability could not be assessed.

Physiologically-Based Pharmacokinetic Modeling of the Drug-Drug Interaction of the UGT Substrate Ertugliflozin Following Co-Administration with the UGT Inhibitor Mefenamic Acid.

The sodium-glucose cotransporter 2 inhibitor ertugliflozin is metabolized by the uridine 5'-diphospho-glucuronosyltransferase (UGT) isozymes UGT1A9 and UGT2B4/2B7. This analysis evaluated the drug-drug interaction (DDI) following co-administration of ertugliflozin with the UGT inhibitor mefenamic acid (MFA) using physiologically-based pharmacokinetic (PBPK) modeling. The ertugliflozin modeling assumptions and parameters were verified using clinical data from single-dose and multiple-dose studies of ertugliflozin in healthy volunteers, and the PBPK fraction metabolized assignments were consistent with human absorption, distribution, metabolism, and excretion results. The model for MFA was developed using clinical data, and in vivo UGT inhibitory constant values were estimated using the results from a clinical DDI study with MFA and dapagliflozin, a UGT1A9 and UGT2B4/2B7 substrate in the same chemical class as ertugliflozin. Using the verified compound files, PBPK modeling predicted an ertugliflozin ratio of area under the plasma concentration-time curves (AUCR ) of 1.51 when co-administered with MFA. ClinicalTrials.gov identifier: NCT00989079.