Table 2: Commercially marketed bilayer tablets [19]

Product Name

Chemical Name



Metformin hydrochloride, Glimepiride

USV Limited


Sertraline, Alprazolam

Torrent Pharmaceutcals Ltd.


Gliclazide, Metformin hydrochloride

Sedia® Pharmaceuticals (India) Pvt. Ltd.

Newcold Plus

Levocetrizine             hydrochloride,          Phenylpropanolamine, Paracetamol

Piramol Healthcare Ltd.


Nevirapine, Lamivudine, Stavudine

Cipla Ltd.


Furosemide, Potassium chloride

T.C. Health Care Pvt. Ltd.


Glimepiride,            Pioglitazone               hydrochloride,          Metformin                  hydrochloride

Abbott Healthcare Pvt. Ltd.


Pioglitazone, metformine hydrochloride

Psychotropics India Ltd.

Revelol®-Am 25/5

Metoprolol succinate, Amlodipine besilate

Ipca Laboratories Ltd.


1.      Tablet Thickness and Size
Thickness and diameter of tablets were important foruniformity of tablet size. Thickness and diameter was measuredusing venire caliper.

2.      Tablet Hardness
The resistance of tablets to shipping or breakage underconditions of storage, transportation and handling before usagedepends on its hardness. The hardness of tablet of each formulationwas measured by Monsanto hardness tester. The hardness wasmeasured in kg/cm2.

3.      Friability
Friability is the measure of tablet strength. Electrolab EF- 2 friabilator (USP) was used for testing the friability using the following procedure. Twenty tablets were weighed accurately and placed in the tumbling apparatus that revolves at 25 rpm dropping the tablets through a distance of six inches with each revolution. After 4 min, the tablets were weighed and the percentage loss in tablet weight was determined.

% loss = [(Initial wt. of tablets – Final wt. of tablets)/ Initial wt. of tablets] ×100

4.      Uniformity of weight
Twenty tablets were selected at random and the average weight was calculated. Weight Variation was calculated and was compared with I. P. standards.

5.      Dissolution Studies
Bilayer tablets were subjected to in vitro drug release studies in simulated gastric and intestinal fluids to assess their ability in providing the desired controlled drug delivery. Drug release studies were carried out using USP dissolution test apparatus I at 100 rpm, 37±0.5°C, and pH 1.2 buffer (900 ml) (i.e. 0.1 N HCl) for 2 hours, since the average gastric emptying time is about 2 hours. The dissolution medium was replaced with pH 6.8 phosphate buffer (900ml) and experiment continued for another 10 hours. At different time intervals, 5ml of the samples were withdrawn and replaced with 5ml of drug-free dissolution medium. The samples withdrawn were analyzed by UV spectrophotometer using multi component mode of analysis.

Bilayer tablet is suitable for sequential release of two drugs in combination, separate two incompatible substances and also for sustained release tablet in which one Layer is immediate release as initial dose and second layer is maintenance dose. Compression Force-controlled presses are clearly limited when a quality bi-layer tablet needs to be produced in conjunction with accurate weight control of both layers. Low pre-compression forces are necessary to secure interlayer bonding. But at low forces, the compression force control system is not sufficiently sensitive and therefore lacks in accuracy. The use of higher compression forces may rapidly result in separation and hardness problems when compressing bi-layer tablets. Such problems become even more apparent when the tableting speed is high or increased.

1.    Wilding IR, Coupe AJ, Davis SS. The role of gamma scintigraphy in oral drug delivery. Adv. Drug Deliv. Rev.1991; 7:87–117.
2.    Chien YW. Fundamentals of controlled-release of drug administration in: J. Swarbrick (Ed.), Novel Drug Delivery System Marcel Dekker, New York, 1982, pp. 465–574.
3.    Lee L. Diffusion-controlled matrix systems, in: A. Kydonieus (Ed.), Treatise on Controlled Drug Delivery, Marcel Dekker, New York, 1992, pp. 155– 198.
4.    Kumar KK, Mahesh M, Sasikanth K. Design, development and characterization of sustained release of Metformin hydrochloride and Gliclazide bilayered tablets by wet granulation method. Int J Biopharm 2010; 1(2):67-71.
5.    Shiyani B, Gattani S, Surana S. Formulation and evaluation of bi-layer tablet of Metoclopramide hydrochloride and Ibuprofen. AAPS Pharm Sci Tech 2008 ; 9(3):818-27.
6.    Deshpande RD, Gowda DV, Mahammed N, Deepak N. Maramwar. Bi-layer tablets- An emerging trend: a review. IJPSR 2011; 2(10): 2534-2544.  
7.    Panchal HA, Tiwari AK. Novel Approach of Bilayer tablet Technology: An Review. Journal of Pharmaceutical Science and Technology 2012; 4(4): 892–904.         
8.    Divya A, Kavitha K, Kumar MR, Dakshayani S, Jagadeesh SSD. Bilayer tablet technology: An overview. Journal of Applied Pharmaceutical Science 2011; 01(08): 43-47.  
9.    Patel M, Ganesh NS, Kavitha, Tamizh M. Challenges in the formulation of bilayered tablets: A review. IJPRD 2010; 2(10): 30–42.  
10.    Panchal HA, Tiwari AK. Novel Approach of Bilayer tablet Technology: An Review. Journal of Pharmaceutical Science and Technology 2012; 4(4), 892–904
11.    Vinayagamkannan, Ragupathikandarapu, Garg S. Optimization techniquies for the design and development of novel drug delivery systems- part I. Pharm. Technol 2003; 27(2): 74–90.
12.    Davis SS, Hardy JG, Fara JW. Transit of pharmaceutical dosage forms through the small intestine. Gut 1986; 27: 886–92.
13.    Ahmed SI, Mangamoori LN, Rao YM. Formulation and characterization of matrix and triple-layer matrix tablets for oral controlled drug delivery. International Journal of Pharmacy and Pharmaceutical Sciences 2010; 2(3): 137–43.
14.    Rane AB, Gattani SG, Kadam VD, Tekade AR. Formulation and evaluation of press coated tablets for pulsatile drug delivery using hydrophilic and hydrophobic polymers. Chem Pharm Bull 2009; 57(11): 1213–7.
15.    Fell JT, Newton JM. Determination of tablets strength by the diametral-compression test. J. Pharm. Sci 1970; 59: 688–91.
16.    Fukui E, Miyamura N, Kobayashi M. An in vitro investigation of the suitability of press-coated tablets with hydroxypropylmethylcellulose acetate succinate (HPMCAS) and hydrophobic additives in the outer shell for colon targeting. J. Control. Release 2001; 70: 97–107.
17.    Cremer K, Asmussen B. Novel Controlled-release tablet with erodible layers. Proc. Int. Control. Release Bioact. Mater 1995; 22: 732–3.
18.    Verma RK, Garg S. Current Status of Drug Delivery Technologies and Future Directions. Pharmaceutical Technology On-Line 2001; 25(2): 1–14.
19.    Sanjay D, Sanhati SR, Amitava G, Bhaskar M. Bilayer Table Technology: A Suitable Approach for Bimodal Release and Co-administration of Drug(s) Through Oral Route. Available on:
20.    Naeem MA, Mahmood A, Khan SA, Shahiq Z. Development and evaluation of controlled release bilayer tablets containing microencapsulated tramadol and acetaminophen. Trop J Pharm Res 2010; 9(4): 347-54.
21.    Pattanayak DP, Dinda SC. Bilayer tablet formulation of metformin HCl and glimepiride: A novel approach to improve therapeutic efficacy. Int J Drug Discovery Herb Res 2011; 1(1): 1-4.
22.    Ramesh DS, Guruvaiah, Harani A. Formulation and evaluation of bilayer sustained release matrix tablets of metformin Hcl and pioglitazone. Amer-Euras J Sci Res 2010; 5(3): 176-82.
23.    Gohel MC, Parikh RK, Nagori SA, Jethwa BA. Fabrication and evaluation of bilayer tablet containing conventional paracetamol and modified release diclofenac sodium. Ind J Pharm Sci 2010; 72(2): 191-6.
24.    Nirmal J, Sasivam S, Peddanna C, Muralidharan S, Kumar SG, Nagarajan M. Formulation and evaluation of bilayer tablets of atorvastatin calcium and nicotinic acid. Chem Pharm Bull (Tokyo) 2008; 56(10): 1455-58.
25.    Atram SC, Udavant YK, Salunke RJ, Neb GB, Shahi SR, Gulecha BS, Padalkar AN. Formulation and evaluation of bilayer tablet containing metoprolol succinate and amlodipine besylate as a model drug for anti hypertensive therapy. J Pharm Res 2009; 2(8): 1335-47.
26.    Kulkarni AS, Manish S. Design and floating bilayer tablets of diltiazen HCl and lovastatin. PDA J Pharm Sci Technol 2008; 62(5): 344-52.
27.    Nagaraju R, Kaza R. Formulation and evaluation of bilayer sustained release tablet of salbutamol and theophylline. Int J Pharm Sci Nanotechno 2009; 2(3): 638-46.



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