the effect of various types of chitosan used as...

Progress on Chemistry and Application of Chitin and Its ..., Volume XIV, 2009 145

THE EFFECT OF VARIOUS TYPES OF CHITOSAN USED AS DIETARY SUPPLEMENTS ON BIOAVAILABILITY OF CERTAIN

H-2 HISTAMINE RECEPTOR INHIBITORS

Jan Meler, Janusz Pluta

Departament of Drug Form Technology, Medical University of Wrocław,

ul. Szewska 38/39 50-139 Wrocław, PolandE-mail: [email protected]

AbstraktThe clinical practice of obesity treatment uses many natural macromolecular compounds which assist in slimming. Chitosan is used in the treatment of obesity due to its lipid, cholesterol, fatty acids, triglycerides and bile acids binding capacity. It is indigestible; it dissolves in the acid environment in the stomach, where it binds many water molecules, forming stable adsorptive gel. A molecule of cationic polymer, such as chitosan, is capable of binding acid drugs. The aim of the study was to determine the capability of binding H-2 receptors antagonists by chitosans present in slimming drugs. The phenomenon of H-2 antagonist receptors absorption was investigated by means of a dynamic method on a biopharmaceutical model which imitated the conditions in vitro. The amount of drug absorbed by chitosan was calculated from the difference in concentrations of the investigated drug before and after sorption. The results of measurements of the bounded drug were used to calculate the mean percentage of the absorbed dose. The obtained findings demonstrate that drugs such as Famotidine and Ranitidine are absorbed by chitosans at applied pH ranges, and the binding capability depends on environmental pH, concentration of the applied drug and the kind of chitosan. Mean absorption of drugs by chitosans ranged from 0.866 g to 2.449 g per 1 g of chitosan. The highest absorption was observed at pH above 7.

Key words: H-2 receptors antagonists; chitosans; Ranitidine hydrochloride; Famotidine hydrochloride; adsorption

Progress on Chemistry and Application of Chitin and Its ..., Volume XIV, 2009146

J. Meler, J. Pluta

1. IntroductionThe clinical practice of obesity treatment uses many natural macromolecular com-

pounds which assist in slimming. Chitosan is used in the treatment of obesity due to its lipid, cholesterol, fatty acids, triglycerides and bile acids binding capacity. It is an effective source of soluble dietary fibres. It is indigestible; it dissolves in the acid environment in the stomach, where it binds many water molecules, forming stable adsorptive gel. A molecule of cationic polymer, such as chitosan, is capable of binding acid drugs [1].

The aim of the study was to determine the capability of binding H-2 receptors an-tagonists by chitosans present in slimming drugs. H-2 receptors antagonists strongly affect basal secretion, what is manifested, among others, by very strong inhibition of nocturnal secretion. They stimulate the secretion of gastrin, but they do not affect gastric emptying, the tonus of the cardiac sphincter, or pancreatic secretion. The drugs are well absorbed from the gastrointestinal tract, while neutralizing drugs and food delay absorption [2 - 4].

2. Materials and methodHigh purity natural krill chitosans with deacetylation of 85% to 95%, not degraded

and degraded by 5 to 30 kGy radiation dose were used in the study.

The investigations were performed in an imitated gastrointestinal tract, which met the standards of Polish Pharmacopoeia VIII [5].

The studies were carried out at 37 °C. 0.03 g portions of chitosan were weighed and put to 5 ml glass centrifuge vials. Next 2 ml of 0.05 M HCl were added to achieve pH 2 of the solution, what corresponds to natural fasting gastric pH.

Next 0.1 M Na2CO3 were added to the vials to achieve pH 6.4 (pH in the duo-denum) and stirred for 0.5 hour (300 rpm). The mixture was then alkalized with sodium carbonate to achieve pH 7.0 - 7.6, corresponding to pH of the intestinal juice. The samples were incubated at 37 °C in a shaker (300 r.p.m.) for 2.5 hours.

Next the samples were brought to room temperature and centrifuged (2100 ×g) for 20 minutes. The vials were then left for 30 minutes to stabilize and next, depending on the kind of investigated drug, certain amount of the solution was collected from over the sedi-ment and determined spectrophotometric analysis.n In case of ranitidine hydrochloride, 0.01 ml of the solution was transferred to a 10 ml test

tube and completed to 10 ml with 0.1 M HCl.n In case of famotidine, 0.05 ml of the solution was collected, transferred to a test tube and

completed to 5 ml with 0.1 M HCl.

The investigations were performed with the use of generally accepted doses of drugs (0.1 mg/10 ml; 0.15 mg/10 ml; 0.2 mg/10 ml – for Ranitidine (1), and 0.02 mg/5 ml; 0.04 mg/5 ml ; 0.05 mg/5 ml – for Famotidine (2)).


The Effect of Various Types of Chitosan Used as Dietary Supplements on Bioavailability of Certain H-2 ...

, HCl

(1)

Scheme 1. Ranitidine HCl

(2)

Scheme 2. Famotidine

The findings were thoroughly evaluated statistically, standard deviations and rela-tivity coefficient were determined.

Measurements were led at constant temperature of 25 °C in automatic Ubbelohde viscometer. Water solution of 0.1 M acetic acids was employed and it was filtered to sepa-rate insoluble fraction of 0.2 M sodium chloride. The time of outflow through the viscom-eter gauge was measured for all the solutions and their dilutions. At least five measurements were executed for each concentration. Since the Mark-Houwink parameters used to recal-culate intrinsic viscosity into viscosity-average molecular weight are known for chitosan, it was calculated for this solvent composition (K = 1.81 × 10-6 dm3 g-1, α = 0.93) [2].

3. Results and discussion3.1. The effect of radiation degradation rate on intrinsic viscosity of chitosans

The analysis of the effect of radiation degradation rate on intrinsic viscosity shows that a decrease in mean molecular weight of chitosan causes a decrease of this parameter (Table 1).


J. Meler, J. Pluta

Table 1. Intrinsic viscosity and viscosity-average molecular weight of investigated chitosans and chitosan preparations.

Kind of chitosan Dose of degradation radiation, kGy

Intrinsic viscosity[h], dm3 g-1

Viscosity-average molecular weight M[η], kDa

Chito Clear TM 10150 0.5100 7255 0.4172 584

30 0.2550 344

Chitosan 6520 0.3132 4295 0.2725 369

30 0.1615 210

Chitosan 3430 0.6402 9255 0.4588 647

30 0.2700 366

Chitosan 3520 0.2117 2825 0.1949 258

30 0.1497 194

Chitosan HUASU0 0.7437 10875 0.5843 839

30 0.2986 407Vitana® Sample 0.1774 229Chromadiet® Sample 0.1872 242Chitosan Nutrisearch® Sample 0.1576 205Bio-Active® Sample 0.1576 205

The highest decrease in intrinsic viscosity under the effect of an increased dose of degradation radiation (0 - 30 kGy) was observed in case of Huasu chitosan and it was 0.4451 dm3g-1.

The lowest change in intrinsic viscosity was observed for chitosan 352, and it was 0.062 dm3g-1 . The remaining chitosans demonstrated a moderate decrease in viscosity with increased dose of degradation radiation 0 - 30 kGy, which in case of chitosan Chito Clear TM 1015 was 0.2550 dm3g-1, for chitosan 652 - 0.1517 dm3g-1 and for chitosan 343 - 0.3702 dm3g-1 (Figure 1).

3.2. Investigation of Ranitidine and Famotodine binding by degraded and non-degraded chitosans

The investigation of ranitidine and famotidine binding by radiation degraded and non-degraded chitosan confirmed the hypothesis that it depends on the radiation dose and the origin of the polymer.

The analysis of the effect of intrinsic viscosity on absorption capability of the in-vestigated drugs by chitosans demonstrates nonlinearity of the drug binding. In case of ra-



nitidine hydrochloride, an increased quantity of absorbed drug with an increase in intrinsic viscosity was observed for chitosan Chito Clear and chitosan Huasu. On the other hand, the amount of bounded drug decreases with an increased intrinsic viscosity for chitosan 652 and chitosan 352. Chitosan 343 with increasing viscosity absorbs initially increased and then decreased amounts of ranitidine hydrochloride. The relation was observed for all ivestigated doses of ranitidine hydrochloride: 0.1 g; 0.15 g and 0.2 g (Figure 2 - 6).

Figure 1. Dependence from intrinsic viscosity in dm3g-1 chitosans from degradation rate in kGy.

Figure 2. The relation between Ranitidine binding by 1 gram chitosans Chito Clear and viscosity average molecular weight M in kDa.


J. Meler, J. Pluta

Figure 3. The relation between Ranitidine binding by 1 gram chitosans 652 and viscosity aver-age molecular weight M in kDa.





Figure 6. The relation between Ranitidine binding by 1 gram chitosans Huasu and viscosity average molecular weight M in kDa.

Standard deviation for Ranitidine ranged from 0.006 to 0.042. Determined relativ-ity coefficient ranged form 0.53% to 4.82%, what confirms high accuracy of measurements.

In case of famotidine, the amount of bounded drug increases with an increased viscosity for chitosans 343 and Huasu, and decreases for chitosans Chito Clear and 652. Chitosan 352 reveals a significant differentiation of the findings in relation to the dose; the absorption increases for doses 0.02 g and 0.05 g, and falls down slightly with 0.04 g (Fig-ure 7 - 11).

Figure 7. The relation between Famotidine binding by 1 gram chitosans Chito Clear and viscos-ity average molecular weight M in kDa.


J. Meler, J. Pluta

Figure 8. The relation between Famotidine binding by 1 gram chitosans 652 and viscosity aver-age molecular weight M in kDa.





Figure 11. The relation between Famotidine binding by 1 gram chitosans Huasu and viscosity average molecular weight M in kDa.

The significante of relation between the total percentage of mean adsorption inves-tigate drugs on chitosans evaluated statistically by means of a uni-factorial Anova?Manova analysis,post hoc Nir test,confirmed statistically significant differences in the percentage of value adsorption of drugs on chitosans. Standard deviations of mean adsorbance levels for Famotidine were in the limits from 0.006 to 0.52 and variation coefficients were from 0.46% to 4.39%.

3.3. Investigation of Ranitidine and Famotidine binding by chitosans present in di-etary supplements

The binding of ranitidine and famotidine by chitosans present in dietary supple-ments confirms the hypothesis of aggregative character of chitosans in relation to these drugs. The chitosans used in the study present in dietary supplements available on the slim-ming products market are capable of binding on an average of 1.26 g per 1 g of chitosan. The obtained results of absorption of the investigated drugs by chitosans from dietary sup-plements were presented in a graph.

The least amounts of ranitidine hydrochloride are absorbed absorbed by Chro-madiet®, while Vitana® demonstrated the highest absorption. Bio-Active® absorbs much more ranitidine hydrochloride than Nutrisearch® (Figure 12).

Famotidine is best absorbed by Nutrisearch®, while the remaining investigated preparations reveal a similar level of famotidine absorption (Figure 13).


J. Meler, J. Pluta

Figure 12. The amount of ranitidine hydrochloride bound by 1 g of chitosans present in dietary supplements.

Figure 13. The amount of Famotidine hydrochloride bound by 1 g of chitosans present in dietary supplements.



Standard deviation ranged from 0.006 to 0.042. Determined relativity coefficient ranged form 0.53% to 4.89%, what confirms high accuracy of measurements [7]. Mean absorption of drugs by chitosans ranged from 0.866 g to 2.449 g per 1 g of chitosan. The highest absorption was observed at pH above 7.

4. ConclusionA interaction between famotidine, ranitidine and chitosan can be confirmed, what

affects the bioavailability of the drugs.

5. References 1. Harish Prashanth K. V., Tharanathan R. N.; Chitin/chitosan: modifications and their unlimited

applcation potential- on overview, Trends in Food Science & Technology, 18, pp. 117-131, 2007.2. Roberts G. A. F., Domszy J. G. : Determination of the viscosimetric constants for chitosan. Int.

J. Biol. Macromol. 4, p. 374, 1982.3. Meler J., Pluta

J., Ulanski P., Krotkiewski M.; Fat- binding capacity of non-modified and mo-

dified chitosans. In: Progress he Chemistry and Application of Chitin and its Derivatives. Vol. IX (ed.: H. Struszczyk), Polish Chitin Society, Łódź, pp. 129-136, 2003.

4. Meler J., Pluta J.; The effect of auxiliary substances the activity of lipase pancreatic biophar-maceutical patternel of digestive tract. In: Progress of Chemistry and Application of Chitin and its Derivatives. Vol. X (ed.: H. Struszczyk), Polish Chitin Society, Łódź, pp. 131-137, 2004.

5. Meler J, Pluta J, Ulański P., Krotkiewski M.; Vozdejstvie raznych form chitozana na sposobnost’ svjazyvanija žirov.Modern perspectives in chitin and chitosan studies : Proceedings of the VIIth

International Conference. St. Petersburg - Repino, Moscow VNIRO Publishing, pp. 258-260, 2003.6. Meler J.: Influence of different change on bioavailability of medicine chitosans antiphlogistic

drugs W:Progress on chemistry and application of chitin and its derivatives. Monograph Volume 13; ed. by Małgorzata M. Jaworska: Polish Chitin Society, Łódź pp. 81-88, 2008.

7. Meler J., Pluta J.; Influence of factor on ownership in model - chemical absorption of chitosans in vitro W:Progress on chemistry and application of chitin and its derivatives. Monograph Volume 13; ed. by Małgorzata M. Jaworska; Polish Chitin Society, Łódź, pp. 75-80, 2008.


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