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At least 379 records · Page 21Linked to original sources
PubMed2005

Cold response of the bladder in guinea pig: involvement of transient receptor potential channel, TRPM8.

OBJECTIVES: To address the physiologic role of TRPM8, one of the transient receptor potential channels, we investigated the bladder cooling reflex and the effect of menthol on it in the guinea pig. METHODS: Single cystometry in female Hartley guinea pigs was performed with high-speed infusion (60 mL/hr) under urethane anesthesia (1 g/kg intraperitoneally). The volume threshold for micturition (VT) and micturition pressure were determined. The distribution of TRPM8 in the S1 dorsal root ganglion (DRG) was also examined by immunostaining. RESULTS: Intravesical infusion of saline containing menthol (0.6 mM) at 38 degrees C markedly decreased the VT and increased micturition pressure. Although cold saline itself (4 degrees C) had little effect on VT or micturition pressure, the VT was significantly decreased in a temperature-dependent manner when the bladder was pretreated with menthol. This decrease in the VT was not observed in animals that received hexamethonium pretreatment (10 mg/kg intravenously), which blocks the spinal reflex, or capsaicin (1 mM intravesically), which causes deafferentation of capsaicin-sensitive C-fiber afferent. Immunohistochemical analysis revealed that TRPM8 is expressed in small-diameter neurons in guinea pig S1 dorsal root ganglions. CONCLUSIONS: The results of our study showed that the bladder cooling reflex is observed in guinea pigs if the animals were pretreated with menthol. This reflex was sensitive to ganglion blockade or capsaicin-sensitive C-fiber deafferentation and might be mediated by C-fiber activation through TRPM8.

Afferent Pathways↗
PubMedDate not supplied

Smoke constituent exposure and stage of change in black and white women cigarette smokers.

Differences in smoke constituent exposure by ethnicity and menthol preference and differences in decisional balance and habit strength by stage of change, ethnicity, and menthol preference were examined in this 2-factor study design. Ninety-five women, half of whom were Black and half of who smoked menthol cigarettes, participated in a cigarette smoking bout in the Clinical Research Center. Measures of smoking topography, plasma cotinine and nicotine, and expired carbon monoxide were obtained in addition to self-report of the pros and cons of smoking, time to first cigarette, and smoking history. Black women smoked significantly fewer cigarettes per day, but had higher cotinine levels compared to White women. Menthol smokers (n = 49) had significantly larger puff volumes, higher cotinine levels, and shorter time to first cigarette compared to nonmenthol smokers (n = 46). Precontemplators (n = 44) were significantly lower on beliefs about the negative aspects of smoking compared to contemplators and those in preparation stage. Black women, all stages combined, had higher negative beliefs about smoking than did White women. Implications for assessment of smoking patterns and intervention are discussed.

Adult↗
PubMed2004

Flavor release and perception in hard candy: influence of flavor compound-compound interactions.

The influence of flavor compound-compound interactions on flavor release properties and flavor perception in hard candy was investigated. Hard candies made with two different modes of binary flavor delivery, (1) L-menthol and 1,8-cineole added as a mixture and (2) L-menthol and 1,8-cineole added separate from one another, were analyzed via breath analysis and sensory time-intensity testing. Single-flavor candy containing only L-menthol or 1,8-cineole was also investigated via breath analysis for comparison. The release rates of both L-menthol and 1,8-cineole in the breath were more rapid and at a higher concentration when the compounds were added to hard candy separate from one another in comparison to their addition as a mixture (conventional protocol). Additionally, the time-intensity study indicated a significantly increased flavor intensity (measured as overall cooling) for hard candy made with separate addition of these flavor compounds. In conclusion, the flavor properties of hard candy can be controlled, at least in part, by flavor compound-compound interactions and may be altered by the method of flavor delivery.

Adult↗
PubMedDate not supplied

Effect of penetration enhancers on the transdermal delivery of bupranolol through rat skin.

Bupranolol (BPL) is a suitable drug candidate for transdermal drug delivery system development based on its favorable physicochemical and pharmacokinetic properties. The effect of different penetration enhancers on the permeation of BPL across rat skin was studied using side-by-side diffusion cells. 2-Pyrrolidone (PY), 1-methyl-2-pyrrolidone (MPY), and propylene glycol (PG) at various concentrations were used as penetration enhancers along with 0.4% w/v aqueous suspension of BPL. Menthol at different concentrations in isopropanol-water (6:4) mixture also was used as an enhancer wherein BPL at 0.4% w/v was completely solubilized. Skin pretreatment studies were carried out with all the above enhancers to understand their role in the penetration enhancement effect. PY and MPY at 5% w/v concentrations increased the permeation of BPL by 3.8- and 2.4-fold, respectively, versus control (p < .01). PG at 10% and 30 w/v concentrations increased the flux of BPL by 2.5- and 5.0-fold, respectively, versus control (p < .001). Menthol at 2% w/v concentration increased the flux of BPL by 3.8-fold (p < .01) and further increase in menthol concentration significantly decreased the flux of BPL. Overall, pyrrolidones and menthol at low concentrations (5% w/v or less) and PG at 30% w/v concentration were effective as penetration enhancers for BPL.

2-Propanol↗
PubMed2004

Two-phase melt systems of ibuprofen for enhanced membrane permeation.

A novel method to convert S- and racemic (RS-) ibuprofen (Ibu) into an oily state at ambient temperature (25 degrees C) was developed. Using menthol and aqueous isopropanol (IPA) as melting point depressing agents, the two-phase melt systems (TMSs) of Ibu consisting of a homogeneous oily phase and a homogeneous aqueous phase were obtained. In TMS with a high S-Ibu: menthol ratio and a low IPA content, the oily phase primarily consisted of Ibu and menthol, whereas the majority of the aqueous phase was IPA and buffer. Using this method, the S-Ibu concentration in the oily phase reached as high as 70% (w/w). The compositional phase diagram was obtained using a titration method to study the relationship between the melting states of the solid components and system composition. S- and RS-Ibu showed different phase diagrams, and the maximum concentration of S-Ibu measured in the oily phase of TMS was much greater than that of RS-Ibu. The permeation study of a series of TMS and non-TMS systems showed that S-Ibu penetrated through shed snake skin faster than RS-Ibu, and the contents of IPA and menthol significantly affected the permeation rates of ibuprofen across shed snake skin, which may be attributed to the higher lipophilicity, and thus, higher solubility of S-Ibu in the skin than RS-Ibu. Such results support the use of S-Ibu TMS for topical formulation development.

Administration, Cutaneous↗
PubMed2004

Two populations of cold-sensitive neurons in rat dorsal root ganglia and their modulation by nerve growth factor.

Cold sensing in mammals is not completely understood, although significant progress has been made recently with the cloning of two cold-activated ion channels, TRPM8 and TRPA1. We have used rat DRG neurons in primary culture and calcium fluorimetry to identify distinct populations of cold-sensitive neurons, which may underlie different functions. Menthol sensitivity clearly separated two classes of cold-responding neurons. One group was menthol-sensitive (MS), was activated at warmer temperatures and responded faster and with a larger increase in intracellular calcium concentration during cooling; the fraction of MS neurons in culture and their cold sensitivity were both increased in the presence of nerve growth factor. Neurons in the menthol-insensitive (MI) group required stronger cooling for activation than MS cells and neither their proportion nor their cold sensitivity were significantly altered by nerve growth factor. The two groups of cold-sensitive neurons also had different pharmacology. A larger fraction of MS cells were capsaicin-sensitive and coexpression of menthol and capsaicin sensitivity was observed in the absence of NGF. MI neurons were not stimulated by the super-cooling agent icilin or by the irritant mustard oil. Taken together these findings support a picture in which TRPM8 is the major player in detecting gentle cooling, while TRPA1 does not seem to be involved in cold sensing by MI neurons, at least in the temperature range between 32 and 12 degrees C.

Animals↗
PubMed2003

Combination strategies to enhance transdermal permeation of zidovudine (AZT).

The objective of this study was to evaluate the effect of simultaneous application of two penetration enhancers of different chemical classes or a chemical penetration enhancer and current application on permeation of zidovudine (AZT) across rat skin. Ex vivo permeation of AZT using combinations of cineole or menthol in vehicle with either oleic acid/linolenic acid or 0.5 mA/cm2 anodal current application for 6 h was studied. Penetration enhancers were significantly different in enhancing the permeability of AZT across rat skin and are in the decreasing order of activity: linolenic acid > menthol > oleic acid > cineole > vehicle. The combination of cineole and oleic acid synergistically enhanced transdermal flux of AZT in addition to reducing lag time. However, this was not observed for combinations of menthol with oleic or linolenic acid. On the other hand, the simultaneous application of current with menthol and cineole significantly increased cumulative amounts of AZT permeating during the course of current application and reduced the lag time but failed to further increase steady state flux of AZT. These results suggest that a combination of two penetration enhancers of different classes or the simultaneous use of iontophoresis and a penetration enhancer may be advantageous to achieve permeation enhancement with low risk of skin damage.

Administration, Cutaneous↗
PubMed2001

Evaluation of percutaneous absorption and skin irritation of ketoprofen through rat skin: in vitro and in vivo study.

The influences of different mechanisms of penetration enhancers (such as menthol, azone, ethanol and nonivarnide) regarding the percutaneous absorption and skin irritation of ketoprofen formulations through rat skin were investigated by in vitro and in vivo study. The skin irritation degree at the end of the experiment (10 h) was deterinined by pathologic biopsy and colorimetry methods. In vitro, the menthol showed the most potent enhancing effect. Furthermore, the enhancement effect of a combination of menthol and nonivamide was higher than that of their individual use alone. In vivo the formulation containing 0.05% nonivantide, 5% menthol and 20% ethanol showed a higher penetration rate and an acceptable degree of skin irritation compared to a commercial product (Formax plus gel containing 3% ketoprofen), indicating that it could be used in the clinical situation.

Animals↗
PubMed2001

Effect of melting point of chiral terpenes on human stratum corneum uptake.

The effect of melting point of chiral penetration enhancers on their stratum corneum uptake was investigated. The pure enantiomers of a chiral compound often possess different melting points, and therefore dissimilar solubilities, to the racemate because of variations in their crystal structure. Two terpenes, menthol and neomenthol, saturated in propylene glycol/water, were applied to stratum corneum. Racemic menthol melts at approximately 33 degrees C, some 9 degrees C lower than the pure enantiomers, whereas racemic neomenthol melts at 26 degrees C higher than the study temperature, considered as the theoretical melting point of its enantiomers, which are both liquids. Terpene solubility increased with the propylene glycol content of the vehicle. The lower melting forms of both penetration enhancers possessed the highest solubility in every vehicle. Maximum stratum corneum uptake was obtained from formulations containing the lower melting forms of each enhancer in 60% w/w propylene glycol systems (highest concentration used). Compared with menthol, the larger melting point difference between optical forms of neomenthol produced bigger differences in their uptake. Thus melting point depression of menthol and neomenthol, by selection of the appropriate optical form, increased the amount of terpene delivered to the stratum corneum, in agreement with theoretical predictions.

Calorimetry, Differential Scanning↗
PubMed2001

Molecular-imprinted, polymer-coated quartz crystal microbalances for the detection of terpenes.

A piezoelectric sensor coated with an artificial biomimetic recognition element has been developed for the determination of L-menthol in the liquid phase. A highly specific noncovalently imprinted polymer (MIP) was cast in situ on to the surface of a gold-coated quartz crystal microbalance (QCM) electrode as a thin permeable film. Selective rebinding of the target analyte was observed as a frequency shift quantified by piezoelectric microgravimetry with the QCM. The detectability of L-menthol was 200 ppb with a response range of 0-1.0 ppm. The response of the MIP-QCM to a range of monoterpenes was investigated with the sensor binding menthol in favor of analogous compounds. The sensor was able to distinguish between the D- and L-enantiomers of menthol owing to the enantioselectivity of the imprinted sites. To our knowledge, this is the first report describing enantiomeric resolution within an MIP utilizing a single monomer-functional moiety interaction. It is envisaged that this technique could be employed to determine the concentration of terpenes in the atmosphere.

Journal Article↗
PubMed2003

Topical capsaicin--a novel and effective treatment for idiopathic intractable pruritus ani: a randomised, placebo controlled, crossover study.

PURPOSE: Pruritus ani is a common and embarrassing proctological condition which can be very difficult to treat. We report the results of a double blind placebo controlled study of treatment with capsaicin. METHODS: Firstly, a pilot open study was carried out on five patients to establish which of two doses was the most acceptable by comparing effectiveness and side effects. Secondly, a double blind, placebo controlled, crossover study of topical capsaicin was performed. This study involved two four week treatment phases separated by a one week washout phase. Forty four patients were randomised to receive locally either active capsaicin (0.006%) or placebo (menthol 1%) ointment over a four week period (22 patients per group). After four weeks of treatment and a one week washout period, the placebo group began to receive capsaicin while the treated group received placebo (menthol 1%) for another four weeks. At the end of the controlled study, responders from both groups continued with capsaicin treatment in an open labelled manner. RESULTS: Thirty one of 44 patients experienced relief during capsaicin treatment periods and did not respond to menthol; all patients not responding to capsaicin also failed on menthol (p<0.0001). In 13 patients, treatment with capsaicin was unsuccessful: eight patients did not respond to capsaicin treatment, one responded equally to capsaicin and placebo, and four others dropped out because of side effects. During the follow up period (mean 10.9 (SD 5.8) months), 29 "responders" needed a mean application of capsaicin every day (1.6 (SD 1.2); range 0.5-7 days) to remain symptom free (or nearly symptom free). CONCLUSION: Capsaicin is a new, safe, and highly effective treatment for severe intractable idiopathic pruritus ani.

Administration, Topical↗
PubMed2000

A sequential sampling scheme for detecting infestation levels of tracheal mites (Heterostigmata: Tarsonemidae) in honey bee (Hymenoptera: Apidae) colonies.

The introduction of parasitic honey bee mites, the tracheal mite, Acarapis woodi (Rennie) in 1984 and the Varroa mite, Varroa jacobsoni, in 1987, has dramatically increased the winter mortality of honey bee, Apis mellifera L., colonies in many areas of the United States. Some beekeepers have minimized their losses by routinely treating their colonies with menthol, currently the only Environmental Protection Agency-approved and available chemical for tracheal mite control. Menthol is also expensive and can interfere with honey harvesting. Because of inadequate sampling techniques and a lack of information concerning treatment, this routine treatment strategy has increased the possibility that tracheal mites will develop resistance to menthol. It is important to establish economic thresholds and treat colonies with menthol only when treatment is warranted rather than treating all colonies regardless of infestation level. The use of sequential sampling may reduce the amount of time and effort expended in examining individual colonies and determining if treatment is necessary. Sequential sampling also allows statistically based estimates of the percentage of bees in standard Langstroth hives infested with mites while controlling for the possibility of incorrectly assessing the amount of infestation. On the average, sequential sampling plans require fewer observations (bees) to reach a decision for specified probabilities of type I and type II errors than are required for fixed sampling plans, especially when the proportion of infested bees is either very low or very high. We developed a sequential sampling decision plan to allow the user to choose specific economic injury levels and the probability of making type I and type II errors which can result inconsiderable savings in time, labor and expense.

Animals↗
PubMed2004

Heart rate and blood pressure responses to tobacco smoking among African-American adolescents.

Ethnic differences in both physiological response to and health consequences of tobacco smoking-some of which have been attributed to ethnic preferences for menthol cigarettes-have been described in the literature. We compared acute physiological responses to smoking in African-American and European-American adolescent menthol cigarette smokers seeking smoking cessation treatment. One-hundred- twenty-eight adolescents (32% African-American, 71% female; mean age 15.16 +/- 1.32 years, mean Fagerström Test of Nicotine Dependence (FTND) score 6.73 +/- 1.53, cigarettes per day (CPD) 16.9 +/- 2.64) participated in an experimental session during which they smoked one menthol cigarette of their usual brand. Blood pressure, heart rate, and exhaled carbon monoxide (CO) concentrations were measured before and after smoking; mean puff volume (mL), puff duration (sec) and maximal puff velocity (mL/sec) during smoking were also determined. Two sample t-tests were performed to assess ethnic differences in smoking topography; analysis of covariance was used to determine whether heart rate and blood pressure after smoking one menthol cigarette varied by ethnicity, after controlling for baseline physiological measures. No significant ethnic differences were observed in either smoking topography or acute cardiovascular response to smoking. These preliminary findings warrant extension to a broader group of nontreatment-seeking adolescent smokers of both ethnicities.

Adolescent↗
PubMed2005

Cigarette advertising in Black, Latino, and White magazines, 1998-2002: an exploratory investigation.

OBJECTIVE: To examine the number, type (menthol vs non-menthol), brand (Black, White, Women's, Other), and size of cigarette ads in Black, Latino, and White magazines. METHOD: Analysis of digital photographs of 274 cigarette ads appearing in Ebony (Black), People (White), and People in Spanish (Latino) for the 4.5-year period of January 1998 to August 2002. RESULTS: Black magazines were 9.8 times and Latino magazines 2.6 times more likely than White magazines to contain ads for menthol cigarettes. Black and Latino magazines also contained significantly more ads for brands (Virginia Slims) that target women. CONCLUSIONS: The tobacco industry continues to target Blacks with menthol cigarette ads, appears now to be targeting Latinos similarly, and targets Black and Latino women with additional, tailored cigarette ads.

Advertising↗
PubMedDate not supplied

Cigarette advertising and black-white differences in brand preference.

Anecdotal evidence indicates that the cigarette industry is targeting the sale of specific brands, notably menthol cigarettes, to black consumers. This paper presents data on the types of cigarettes smoked by white and black smokers. The cigarette brand preferences of two populations of smokers were examined. The first comprised 70 white and 365 black adult smokers seen at the Deaconness Family Medicine Center located in Buffalo, NY. The second population included 1,070 white and 92 black smokers who called a Stop Smoking Hotline in Buffalo. The results showed that, in both populations, blacks were twice as likely to smoke mentholated cigarettes compared with whites. In an attempt to evaluate the targeting of cigarette ads to black smokers as a possible explanation for black-white differences in brand preferences, cigarette ads appearing in magazines targeted to predominantly white or black readers were compared. Cigarette ads appearing in seven magazines were reviewed, four directed to predominantly white readers (Newsweek, Time, People, Mademoiselle) and three with wide circulation among black audiences (Jet, Ebony, Essence). The results showed that the magazines targeted to black readers contained significantly more cigarette ads and more ads for menthol brand cigarettes than magazines similar in content but targeted to white readers. The observation that a higher percentage of blacks smoke menthol cigarettes than do whites is consistent with the findings regarding differences in the type of cigarette ads appearing in magazines intended for black or white readers. However, it is not possible to determine from this study whether cigarette advertising is the cause of the differences in preference of cigarette brands between white and black smokers. Future research focusing on understanding the reasons for cigarette brand preferences may provide ideas for anti smoking campaigns aimed at specific target groups.

Adolescent↗
PubMed2001

Fumigant toxicity of volatile natural products from Korean spices and medicinal plants towards the rice weevil, Sitophilus oryzae (L).

The fumigant toxicity of various volatile constituents of essential oils extracted from sixteen Korean spices and medicinal plants towards the rice weevil, Sitophilus oryzae L (Coleoptera: Curculionidae), was determined. The most potent toxicity was found in the essential oil from Mentha arvensis L. var piperascens (LC50 = 45.5 microliters litre-1 air). GC-MS analysis of essential oil from M arvensis showed it to be rich in menthol (63.2%), menthone (13.1%) and limonene (1.5%), followed in abundance by beta-pinene (0.7%), alpha-pinene (0.6%) and linalool (0.2%). Treatment of S oryzae with each of these terpenes showed menthone to be most active (LC50 = 12.7 microliters litre-1 air) followed by linalool (LC50 = 39.2 microliters litre-1 air) and alpha-pinene (LC50 = 54.9 microliters litre-1 air). Studies on inhibition of acetylcholinesterase activity of S oryzae showed menthone to have a nine-fold lower inhibitory effect than menthol, despite menthone being 8.1-fold more toxic than menthol to the rice weevil. Different modes of toxicity of these monoterpenes towards S oryzae are discussed.

Acetylcholinesterase↗
PubMed2005

Formation of phenytoin nanoparticles using rapid expansion of supercritical solution with solid cosolvent (RESS-SC) process.

Nanoparticles are of significant importance in drug delivery. Rapid expansion of supercritical solution (RESS) process can produce pure and high-quality drug particles. However, due to extremely low solubility of polar drugs in supercritical CO(2) (sc CO(2)), RESS has limited commercial applicability. To overcome this major limitation, a modified process rapid expansion of supercritical solution with solid cosolvent (RESS-SC) is proposed which uses a solid cosolvent. Here, the new process is tested for phenytoin drug using menthol solid cosolvent. Phenytoin solubility in pure sc CO(2) is only 3 micromol/mol but when menthol solid cosolvent is used the solubility is enhanced to 1,302 micromol/mol, at 196 bar and 45 degrees C. This 400-fold increase in the solubility can be attributed to the interaction between phenytoin and menthol. Particle agglomeration in expansion zone is another major issue with conventional RESS process. In proposed RESS-SC process solid cosolvent hinders the particle growth resulting in the formation of small nanoparticles. For example, the average particle size of phenytoin in conventional RESS process is 200 nm whereas, with RESS-SC process, the average particle size is 120 nm, at 96 bar and 45 degrees C. Similarly at 196 bar and 45 degrees C, 105 nm average particles were obtained by RESS and 75 nm average particles were obtained in RESS-SC process. The particles obtained were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS) and differential scanning calorimetery (DSC) analyses. Phenytoin nanoparticle production rate in RESS-SC is about 400-fold more in comparison to that in RESS process.

Anticonvulsants↗
PubMed2006

Effect of DC/mDC iontophoresis and terpenes on transdermal permeation of methotrexate: in vitro study.

The systemic toxicity caused by methotrexate limits its use and transdermal delivery would be a possible alternative. Transdermal permeation of methotrexate loaded into polyacrylamide-based hydrogel patch, across mice skin was studied in vitro after pretreatment with terpenes and ethanol, alone or in combination with iontophoresis (DC/mDC). Polyacrylamide patches gave the maximum flux as compared to the copolymers of acrylamide and acrylic acid. Of the terpenes used, pure menthol showed maximum enhancement (38%), whereas pure limonene elicited a minimum of 9.9% enhancement. Binary combination of menthol and ethanol increased the permeation to 54.9%, which was further enhanced to 93.69% and 117% when used in combination with DC and square wave (mDC) iontophoresis, respectively. ATR-FTIR of the stratum corneum treated with terpenes showed a split in the asymmetric C-H stretching vibrations along with decrease in peak heights and areas of asymmetric, symmetric C-H stretching, C=O stretching and amide bands. A split in amide II band was observed with iontophoresis. ATR-FTIR studies suggest conformational changes in the lipid-protein domains thereby increasing permeation. Histopathological studies on treated skin samples, gave an insight about the anatomical changes brought by the application of various enhancers. Binary mixture of menthol and ethanol in combination with square wave gave best results.

Acrylic Resins↗