PREPARATION AND CHARACTERIZATION OF TOLTERODINE TARTRATE  PRONIOSOMES

Adim Ekene Ugochukwu¹, Obeta Judith Nnedimkpa², Ngwu Ogochukwu Rita³

Department of Biochemistry, ¹Ahmadu Bello University Zaria, Nigeria.

²University of Nigeria Nsukka, Nigeria, ³Caritas University Enugu, Nigeria.

*Corresponding Author’s Email: bruceallino@gmail.com

DOI: http://doi.org/10.22270/ujpr.v2i2.R1

ABSTRACT

The present work deals with the preparation of Tolterodine tartrate proniosome formulations by coacervation phase separation method by using different surfactants in different ratios.  The prepared proniosomal formulations were evaluated for vesicle size, rate of spontaneity, encapsulation efficiency, drug content etc. In vitro release study was conducted and it indicated that, increases in liphophilicity of surfactants decreases release of Tolterodine tartrate from proniosomal formulations. Stability studies were performed at optimized formulation PG4, indicated that, the prepared formulations remain stable at room and refrigeration temperature.

Keywords: In vitro release, proniosomes, Tolterodine tartrate.

INTRODUCTION

At present scenario vesicular systems have been receiving a lot of interest as a carrier for advanced drug delivery¹. Encapsulation of the drug in vesicular structures is one such system, which can be expected to prolong the duration of the drug in systemic circulation². 

Proniosomes are water soluble carrier particles that are coated with surfactants and can be hydrated to form niosomal dispersion immediately before use in hot aqueous media. Proniosome is a dry free flowing, granular product that could be hydrated immediately before use and would avoid many of the problems associated with aqueous noisome dispersions and problem of physical stability³. Proniosome technology offers novel solution for poorly soluble drugs.

Proniosomes avoid many of the problems associated with aqueous niosome dispersions, and problems of physical stability (aggregation, fusion, leaking) could be minimized. The additional convenience of the transportation, distribution, storage, and dosing would make ‘dry niosomes’ a promising industrial product⁴.

Tolterodine tartrate is used for the treatment of overactive bladder with symptoms of urge urinary in continence, urgency and frequency⁵. Use of Tolterodine tartrate is associated with side effects like dry mouth and other side effects like constipation, headache, stomach pain and blurred vision, often leading to discontinuation of therapy⁶. The aim of present study includes development of proniosomes of Tolterodine tartrate to reduce dosing frequency and avoid side effects.

MATERIALS AND METHODS

Tolterodine tartrate was obtained as gift sample from Churchbells Pharma Nigeria Limited. Span 60, Tween 40 and cholesterol were procured from Drugfield Pharmaceuticals Limited, Nigeria.  Ethyl alcohol and lecithin was procured from Interpharma Industries Nigeria Limited. All other reagents used were of analytical grades.

Preparation of proniosomal gel

Tolterodine tartrate proniosomal gel formulations were prepared by coacervation phase separation method. Precisely weighed amounts of surfactant, lipid phase and drug were taken in a clean and dry wide mouthed glass vial of 5.0 ml capacity and alcohol was added to it.

All the ingredients were mixed well with a glass rod; the open end of the glass vial was covered with a lid to prevent the loss of solvent from it and warmed over water bath at 50-60°C for about 5 minutes until the drug is dissolved completely in surfactant mixture. Then the aqueous phase 1.6ml phosphate buffer (pH 7.4) was added and warmed on a water bath until a clear solution was formed.

Preliminary the composition of these formulations is reported in Table 1 and they are referred as PG1 to PG4⁷.

EVALUATION OF PRONIOSOME FORMULATIONS

Vesicle size analysis

Hydration of Tolterodine tartrate proniosomal gel (100 mg) was done by adding saline solution (0.9% solution) in a small glass vial with occasional shaking for 10 min. The dispersion was observed under optical microscope at 45 x magnification. The sizes of 200-300 vesicles were measured using a calibrated ocular and stage micrometer (Erma, Tokyo) fitted in the optical microscope⁸.

Drug content

In a 100 ml volumetric flask, 20 mg of proniosomal gel formulations were taken, and volume was made up to mark with pH 7.4. The flask was shaken for 12 hours using an orbital shaker incubator (Finlab, Nigeria). Then the solution was filtered and from the filtrate appropriate dilutions were made and absorbance was measured at 261 nm⁸.

Encapsulation efficiency

To evaluate the loading capacity of proniosomal systems for Tolterodine tartrate gel (100 mg) was dispersed in distilled water and warmed a little for the formation of niosomes. Then the dispersion was centrifuged at 18000 rpm for 40 min the clear fraction was used for the determination of free drug at 281 nm spectrophotometrically. The percentage encapsulation efficiency was calculated from following equation ^{9, 10}.

pH and Viscosity

Accurately weighed gel was taken and then diluted with the pH 7.4 phosphate buffer and
checked the pH by using pH meter (Finlab, Nigeria)  and Brook field viscometer is used to determine the viscosity of the gel¹¹.

In vitro release study

In vitro release studies on proniosomal gel of Tolterodine tartrate were performed using locally manufactured Franz-diffusion cell. The capacity of receptor compartment was 15 ml. The area of donor compartment exposed to receptor compartment was 1.41cm². The dialysis cellophane membrane (MMCO 14KDC) was mounted be Tween the donor and receptor compartment¹². A weighed amount of proniosomal gel was placed on one side of the dialysis membrane. The receptor medium was phosphate saline buffer pH 7.4. The receptor compartment was surrounded by a water jacket to maintain the temperature at 37±1^oC. Samples were withdrawn and were replaced by equal volumes of fresh receptor fluid on each occasion. Samples withdrawn were analyzed spectrophotometrically (Finlab, Nigeria) at 281 nm¹³.

Stability Studies

The ability of vesicles to retain the drug  was assessed by keeping the proniosomal gel at three different temperature conditions, i.e., refrigeration temperature (4-8⁰C), room temperature (25±2⁰C) and oven (45±2⁰C) for 12 weeks (60% relative humidity). Throughout the study, proniosomal formulations of Tolterodine tartrate were stored in aluminium foil-sealed glass vials. The samples were withdrawn at different time intervals and drug leakage from the formulations was analyzed for drug content spectrophotometrically at 281 nm¹⁴.

RESULTS AND DISCUSSION

Results of vesicle size of Tolterodine tartrate proniosome formulations are presented in Table 2, which indicated that vesicle formed with Span 60 is smaller in size than vesicle formed with Tween 40. The reason for this may be higher hydrophobicity of Spans as compared to Tweens¹⁵. As hydrophobicity increases, surface energy of surfactants decreases, resulting in smaller vesicle size¹⁶. The size range was found to be 15.28±0.33 to 16.43±0.22 µm. Viscosity of all formulations lies in the range of 7244-9314 cp.

Drug content is important parameter to maintain the minimum effective concentration and it is also used to estimate the drug release profile. The percent drug content was higher for PG4 that is 99±0.47% and lower for PG2 (88±0.12%).

In vitro release studies (Figure 1) are often performed to predict how a delivery system might work in an ideal situation. The amount of drug released from different proniosomal  formulations was found in the order of PG4 > PG3 > PG2> PG1. In vitro release study were performed on different proniosomal gel formulations shows maximum release for formulations of batch PG4 (87.45 %), and minimum for formulations of batch PG4 (50%), after 12 h.

Stability studies performed on optimized formulations PG4 shows 96.74% drug content at refrigeration condition, 94.74% drug content at oven condition and 99.59% drug content at room temperature during the studies performed for 12 weeks on the formulations (Figure 2). Thus the room temperature is the favorable storage condition for storage of proniosomes.

CONCLUSION

The results of investigation demonstrated that proniosomes offers an alternative colloidal carrier approach. The results obtained from the present study clearly revealed that Tolterodine tartrate proniosome formulations prepared by using coacervation phase separation method are capable of releasing drug for the extended period of time. Results of the present work have shown that surfactant type affect the encapsulation efficiency and drug release rate from proniosomes. Based on different parameters formulation of batch PG4 was considered as an optimum formulation. 

CONFLICT OF INTEREST

The authors have declared that there is no conflict of interest related to this work.

REFERENCES

1. Kakkar R, Rao R, Dahiya NK, Nanda S. Formulation and characterization of valsartan proniosomes. Int J Sci Technol. 2011; 5(01):146-158.
2. Mahmoud M, Omaima A. Sammour, Mohammed A. Hammad, Nagia A. Megrab. Effect of some formulation parameters on flurbiprofen encapsulation and release rates of niosomes prepared from proniosomes. Int. J   2008; 361: 104–111.
3. Gamal M. Mahrous. Pronisomes as a drug carrier for transdermal delivery of Meloxicam. Bull Pharm Sci. Assiut University. 2010; 33 (2): 131-140.
4. Chavan P, Jain B, Jain P. Proniosomal gel: a novel approach for transdermal drug delivery-a review. Int J Pharm. Res Dev. 2012; 4(03): 158-170.
5. Shaik RP, Srinivasa BP, Kothapalli CB, Zayed B, Challa BR. A validated LC–MS/MS method for the determination of tolterodine and its metabolite in rat plasma and application to pharmacokinetic study. J Pharm Anal. 2013; 3(6):489–499.
6. Zhang B, Zhang Z, Tian Y, Xu F. High performance liquid chromatography-electrospray ionization mass spectrometric determination of tolterodine tartrate in human plasma. J Chromat. B Analyt. Techn. Biomed. Life Sci. 2005; 25: 824(1-2):92-8.
7. Patil HN, Hardikar SR, Bhosale AV. Formulation development and evaluation of proniosomal gel of carvedilol. Int J Pharm Pharm Sci. 2012; 4 (1): 191-197.
8. Trupti AU, Wankhade VP, Latika MI, Atram S, Tapar KK. Proniosomes- a novel approach to vesicular drug delivery system. Int J Pharm  Pharm Sci Res. 2013; 3(1): 1-6.
9. Ibrahim MM, Sammour OA, Hammad MA, Megrab NA, In vitro evaluation of proniosomes as a drug carrier for flurbiprofen, AAPS Pharm. Sci. Tech. 2008; 9(3): 782–790.
10. Thakur R, Anwer MK, Shams MS, Ali A, Khar RK, Shakeel F, Taha EI. Proniosomal transdermal therapeutic system of losartan potassium: development and pharmacokinetic evaluation. J Drug Target. 2009; 17(6): 449.
11. Kumar K, Rai AK. Development and Evaluation of Proniosomes as a promising drug carrier to improve transdermal drug delivery. Int Res J Pharm. 2011; 2 (11): 71-74.
12. Melike U,   Benek C. Design of hydralazine hydrochloride matrix tablets based on various polymers and lipids. Ind J Pharm Ed Res. 2012; 46(1).
13. Varshosaz J, Pardakhty A, Mohsen S, Baharanchi H. Sorbitan monopalmitate-based proniosomes for transdermal delivery of chlorpheniramine maleate. Informa Health Care. 2005; 12(2): 75-82.
14. Hazel G, Dubey A, Prabhakara P, Kamath J. Development and evaluation of norfloxacin loaded maltodextrin based proniosomes. Int Res J Pharm. 2012; 3(6):176-79.
15. Csoka G, Marton S, Zelko R, Otomo N, Antal I. Application of sucrose fatty acid esters in transdermal therapeutic systems. Eur J Pharm Biopharm. 2007; 65(2): 233–237.
16. Varshosaz J, Pardakhty A, Baharanchi SM, Sorbitan monopalmitate-based proniosomes for transdermal delivery of chlorpheniramine maleate. Drug Deliv. 2005; 12(2): 75–82.

Table 1: Composition of Tolterodine tartrate pronisomal gel formulations.

Table 2: Characterization of the proniosomal formulations of Tolterodine tartrate.

Figure 1: Comparative in-vitro release study of different proniosome formulations of Tolterodine tartrate

Figure 2: Stability study of optimized gel formulation (PG4) at different temperature conditions