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 Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 9  |  Issue : 1  |  Page : 21-24

Comparison of nicotine concentration and pH of commercially available smokeless tobacco products


Department of Public Health Dentistry, A.J. Institute of Dental Sciences, Mangalore, Karnataka, India

Date of Web Publication2-Mar-2017

Correspondence Address:
Ambili Nanukuttan
Department of Public Health Dentistry, A.J. Institute of Dental Sciences, NH 17, Kuntikhana, Mangalore - 575 004, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jorr.jorr_39_16

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  Abstract 

Aim: This study aims to compare the nicotine concentration and pH in commercially available smokeless tobacco (ST) products.
Materials and Methods: The pH level and nicotine concentration were determined in five ST products which were obtained from local markets. The pure form of nicotine was used as a standard which was obtained from Sigma-Aldrich Chemicals, Bengaluru. An extract of each product was prepared and the nicotine concentration was determined in triplicates by spectrophotometric method. The estimation of pH was done using digital pH meter.
Results: The analysis showed that nicotine concentration was highest in plain tobacco followed by ghutka, khaini, pan masala, and supari, respectively. The pH was highest in khaini followed by pan masala, supari, ghutka, and plain tobacco, respectively.
Conclusion: The study results showed that there is a difference in nicotine concentration and pH among ST products. Although other factors could influence the rate of nicotine absorption from ST, manipulating tobacco pH appears to be the primary means by which the speed of nicotine absorption is determined in ST products.

Keywords: Nicotine, pH, smokeless tobacco


How to cite this article:
Hegde V, Nanukuttan A. Comparison of nicotine concentration and pH of commercially available smokeless tobacco products. J Oral Res Rev 2017;9:21-4

How to cite this URL:
Hegde V, Nanukuttan A. Comparison of nicotine concentration and pH of commercially available smokeless tobacco products. J Oral Res Rev [serial online] 2017 [cited 2017 Sep 25];9:21-4. Available from: http://www.jorr.org/text.asp?2017/9/1/21/201407


  Introduction Top


The use of smokeless tobacco (ST) is a worldwide practice with variations in its nature and customs associated with its use.[1] Unlike smoked tobacco, which is burnt or heated and then inhaled in products such as cigarettes, cigars, and hookahs, ST is predominantly used orally or nasally, which results in absorption of nicotine and other chemicals across mucous membranes.[2] Global Adult Tobacco Survey India revealed that more than one-third (35%) of adults in India use tobacco. Among them, 21% adults use only ST, 9% only smoke and 5% smoke as well as use ST.[3] The prevalence of ST use in India is 26% with the prevalence being 33% in males and 18% in females and 29% in rural areas compared to 18% in urban areas.[3]

People who use tobacco are at risk for several cancers.[4] Chronic use of ST can result in harmful effects on soft tissues of oral cavity such as cancer.[5],[6] The systemic effects of ST are due to its long-term use caused by nicotine dependence.[7],[8] Mouth cancer is one of the most common cancers in India due to the use of ST.[4] A number of toxicants and carcinogens present in ST are believed to be responsible for these negative health effects (Brunnemann and Hoffmann, 1992; Hoffmann and Djordjevic, 1997; NCI, 1992).[9] Among 28 known carcinogens in ST (NCI, 1992), tobacco-specific nitrosamines are considered to be the most important due to the combination of abundance and strong carcinogenicity.[9]

In manufacturing ST products, tobacco leaves, and other ingredients are blended to achieve specific nicotine content, pH, taste, flavor, and aroma.[10] Nicotine is the substance in ST that causes addiction and is directly related to difficulty in quitting and to symptoms of withdrawal.[8],[11] Unionized nicotine is rapidly absorbed in the mouth.[11] Nicotine dosage of ST is primarily controlled by pH level of the product.[12] Increasing the pH of nicotine transforms this drug to an un-ionized or free base form that moves easily through biological membranes.[8]

In addition to pH other factors could modulate nicotine absorption, such as local blood flow, “wettability” of the product, size and surface area of the tobacco mixture, buffering capacity to hold the pH constant, and the nicotine content of the tobacco.[13] Although there are other factors which may also influence the speed of nicotine release from the tobacco such as chemicals that coat tobacco cuttings or bind them and size of tobacco cuttings, products with higher pH delivered more nicotine than those with lower pH.[12],[13] Unfortunately, there are only a few data available on actual dosing capabilities of ST products. A recent study reported the nicotine concentrations of several products but did not report the pH levels.[12] Hence, the purpose of this study was to compare the pH level and nicotine concentrations of several ST products.[12]

The aim of this study is to compare the pH and nicotine concentration in commercially available ST products, which may contribute new basic information to evaluate tobacco on oral health with an objective to estimate the nicotine content and pH of the extract of various commercially available ST products.


  Materials and Methods Top


The commercially available ST products available with the local vendors of Mangalore city, Karnataka was used in the study. The ST products prepared by the vendors were not used as there were intervariability in its composition.

The commercially available ST products used in the study were:

  • Plain tobacco: Sundried tobacco leaves without any additives [4]
  • Khaini: The powdered sun-dried tobacco, slaked lime menthol [4]
  • Gutkha: Consists of areca nut (betel nut) pieces coated with powdered tobacco, flavoring agents, and other “secret” ingredients that increase the addiction potential [4]
  • Pan masala: Pan masala is a commercial preparation containing the areca nut, slaked lime, catechu, and condiments, with or without powdered tobacco [4]
  • Supari: Naturally occurred areca nut without adding other ingredients.[14]


Popular brand of plain tobacco, khaini, gutkha, pan masala, supari available in local markets of Mangalore city, Karnataka were used for the study.

Preparation of smokeless tobacco extract

An extract of each of the ST was prepared using 10 g of the product in 100 ml of distilled water at 37°C for 2 h. The mixture was stirred immediately. After 2 h, the mixture was centrifuged at 2500 rpm for 5 min and supernatant obtained was filtered.

Determination of pH of smokeless tobacco extracts

The pH of the aqueous extract of different ST products was determined in triplicates for each extract using digital pH meter, 0.5 g sample was ground using a pestle and mortar and made to 10 ml with distilled water. pH measurements were conducted at room temperature and were measured to a precision of at least two decimal places.

Estimation of nicotine concentration of smokeless tobacco extracts

The samples were weighed, and 0.1–0.2 g of each was taken, 2 ml of ammonia was added and kept for 45 min. Further, 3 ml of chloroform was added and mixed well and kept on shaker at 200 rpm for 45 min. The chloroform layer was aspirated and filtered through Whatman no 1 into a fresh tube. The second round of extraction was carried out by the addition of 2 ml of chloroform into the tube containing the extracted tobacco leaves, mixed well, and the chloroform layer was filtered through the same filter paper. The third round of extraction was also carried out, chloroform layer was filtered, and finally the entire content was passed through filter paper. The filtrate obtained was dispensed into separating funnel and the lower chloroform layer was separated and evaporated to dryness in a water bath maintained at around 80°C. The dried layer was reconstituted in 1 ml methanol and mixed well. Further 1 ml of 0.05M hydrochloric acid was added. Appropriate dilution was made in 0.05M HCl, and the absorbance was read at 260 nm using Genesys 10S ultraviolet-visible spectrophotometer. For calibration, 8.5 mg of nicotine (standard) in 0.2 ml of D/W was taken; 2 ml of ammonia was added and extracted using chloroform as given above. Appropriate dilutions (containing 10–100 µg of nicotine per ml) of the nicotine extract were read at 260 nm. Calibration curve was plotted and was used for determining the nicotine concentration in the test samples.

Reagents used

Standard nicotine was obtained from Sigma-Aldrich Chemicals.


  Results Top


[Table 1] and [Graph 1] show the mean nicotine concentration of ST products. The analysis showed that nicotine concentration was highest in plain tobacco (2.22 mg/g) followed by ghutka (1.85 mg/g), khaini (0.53 mg/g), pan masala (0.10 mg/g), and supari (0.06 mg/g), respectively.
Table 1: The mean nicotine concentration of smokeless tobacco products

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[Table 2] and [Graph 2] show the mean pH of ST products, as analyzed using digital pH meter which revealed that the pH of ST products varies from 9.47 to 5.24, which was highest for khaini (9.47) followed by pan masala (8.71), supari (5.70), gutkha (5.24), and plain tobacco (5.24).
Table 2: The mean pH of smokeless tobacco products

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  Discussion Top


The present study was conducted to compare the nicotine concentration and pH of different commercially available ST products available in the local market. The products used were plain tobacco, ghutka, pan masala, supari, and khaini.

Plain tobacco is sun-dried tobacco leaves without any additives. Khaini is a mixture of powdered sun-dried tobacco, slaked lime, and menthol. Gutkha consists of areca nut (betel nut) pieces coated with powdered tobacco, flavoring agents, and other “secret” ingredients that increase the addiction potential. Pan masala is a commercial preparation containing areca nut, slaked lime, catechu, and condiments, with or without powdered tobacco.[4] Supari is natural crude areca nut without adding other ingredients.[14]

Tobacco use has not been considered as a good habit by many communities, right from its introduction. Toxic emissions and pattern of use have made tobacco use to be very harmful. Patterns of use, in turn, are related to addictiveness and consumer appeal.[15] Nicotine is an addictive drug present in tobacco products that increase the expression of nicotine receptors in the nervous system.[8] The main actions of nicotine involve activation of the sympathetic nervous system resulting in acceleration of heart beat (from 10 to 20 beats per min) and increased blood pressure (from 5 to 10 mm Hg).[16] Nicotine occurs in ionized and unionized form with a pKa (dissociation constant) of 8.02. The total concentration of nicotine is divided equally to ionized and unionized at pKa 8.02.[8] An unionized form of nicotine is immediately free for absorption than ionized nicotine.[12]

In the present study, nicotine concentration of five ST products was estimated. The analysis showed that nicotine concentration was highest in plain tobacco (2.22 mg/g) followed by ghutka, khaini, pan masala and supari, respectively. The variation in nicotine concentration of these products depends on the difference in their manufacturing, size of tobacco cuttings.[12]

The pH of ST products is a crucial determinant of nicotine absorption through the nose and mouth.[8] In an alkaline pH, nicotine is unionized and rapidly absorbed whereas in an acidic (low) pH, nicotine is ionized and does not cross biological membranes.[13] The pH of ST products varies from 9.47 to 5.24, which was highest for khaini and lowest for plain tobacco. This discrepancy in pH is associated with the fact that tobacco naturally occurs in an acidic form and therefore is slow to release free-base nicotine unless buffered to alkaline levels.[12] The difference in pH could be attributed to different manufacturing methods, additives used and moisture contamination.[17]


  Conclusion Top


Nicotine concentration varies amoung various forms of tobacco products. This study results proved that there is a difference in nicotine concentration and pH among smokeless tobacco products. Although other factors could influence the rate of nicotine absorption from smokeless tobacco, manipulating tobacco pH appears to be the primary means by which the speed of nicotine absorption is determined in smokeless tobacco products.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
U.S. Department of Health and Human Services. The Health Consequences of Using Smokeless Tobacco. A Report of the Advisory Committee to the Surgeon General. A NIH Publication; 1986. Available from: https://www.profiles.nlm.nih.gov/ps/access/NNBBFC.pdf. [Last accessed on 2016 Jun 02].  Back to cited text no. 1
    
2.
National Cancer Institute Centers for Disease Control and Prevention U.S. Department of Health and Human Services. Smokeless Tobacco and Public Health: A Global Perspective. A Global View of Smokeless Tobacco Products. Available from: http://www.cancercontrol.cancer.gov/brp/tcrb/global-perspective/SmokelessTobaccoAndPublicHealth.pdf. [Last accessed on 2016 Aug 02].  Back to cited text no. 2
    
3.
Global Adult Tobacco Survey India Report 2009-2010. Ministry of Health and Family Welfare, New Delhi. Government of India; 2010. Available from: http://www.searo.who.int/tobacco/documents/2010-pub2.pdf. [Last accessed on 2016 Aug 01].  Back to cited text no. 3
    
4.
Tobacco Use in India: An Evil with Many Faces. American Cancer Society. Available from: http://www.cpaaindia.org/infocentre/acs/eng/Tobacco%20Abuse.pdf. [Last accessed on 2016 Aug 02].  Back to cited text no. 4
    
5.
Reddy KS, Gupta PC, editors. Report on Tobacco Control in India. Ministry of Health and Family Welfare, New Delhi: Government of India; 2004. Available from: http://www.who.int/fctc/reporting/Annex6_Report_on_Tobacco_Control_in_India_2004.pdf. [Last accessed on 2016 Jan 01].  Back to cited text no. 5
    
6.
Greer RO Jr. Oral manifestations of smokeless tobacco use. Otolaryngol Clin North Am 2011;44:31-56, v.  Back to cited text no. 6
    
7.
Fact Sheet: SPIT TOBACCO KILLS. Statistics & Facts on Smokeless Tobacco. Available from: http://www.lassencoe.org/tfree/4-6/SPIT%20TOBACCO%20KILLS.pdf. [Last accessed on 2016 Aug 01].  Back to cited text no. 7
    
8.
Tomar SL, Henningfield JE. Review of the evidence that pH is a determinant of nicotine dosage from oral use of smokeless tobacco. Tob Control 1997;6:219-25.  Back to cited text no. 8
    
9.
Stepanov I, Jensen J, Hatsukami D, Hecht SS. New and traditional smokeless tobacco: Comparison of toxicant and carcinogen levels. Nicotine Tob Res 2008;10:1773-82.  Back to cited text no. 9
    
10.
Determination of pH of Smokeless Tobacco Products. CORESTA Recommended Method No. 69. June, 2010. Available from: https://www.coresta.org/Recommended_Methods/CRM_69.pdf. [Last accessed on 2016 Jan 03].  Back to cited text no. 10
    
11.
Richter P, Hodge K, Stanfill S, Zhang L, Watson C. Surveillance of moist snuff: Total nicotine, moisture, pH, un-ionized nicotine, and tobacco-specific nitrosamines. Nicotine Tob Res 2008;10:1645-52.  Back to cited text no. 11
    
12.
Henningfield JE, Radzius A, Cone EJ. Estimation of available nicotine concentration of six smokeless tobacco products. Tob Control 1994;4:57-61.  Back to cited text no. 12
    
13.
Pickworth WB, Rosenberry ZR, Gold W, Koszowski B. Nicotine absorption from smokeless tobacco modified to adjust pH. J Addict Res and Ther 2014;5:1-11.  Back to cited text no. 13
    
14.
Madani AH, Dikshit M, Bhaduri D. Risk for oral cancer associated to smoking, smokeless and oral dip products. Indian J Public Health 2012;56:57-60.  Back to cited text no. 14
  Medknow Journal  
15.
Hegde V, Panchmal GS. A study to determine the nicotine concentration and pH in commercially available brands of cigarettes and bidis. J Indian Assoc Public Health Dent 2010;14:185-7.  Back to cited text no. 15
    
16.
Benowitz NL. Systemic absorption and effects of nicotine from smokeless tobacco. Adv Dent Res 1997;11:336-41.  Back to cited text no. 16
    
17.
Smokeless Tobacco. Available from: http://www.monographs.iarc.fr/Eng/Monographs/vol189/mono89-6.pdf. [Last accessed on 2016 Apr 01].  Back to cited text no. 17
    



 
 
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