In vitro Evaluation of Commercially Available ... - ResearchGate

International Journal of Research in Pharmaceutical and Biomedical Sciences ISSN: 2229-3701spectrophotometer at 276nm. The drug content ofeach sample was estimated from their previouslyprepared standard curve.Statistical analysisBy one-way analysis of variance the differences inphysicochemical properties were evaluated usingGraphpad Instart software. When P is < 0.05 thedifferences were considered significant.RESULT AND DISCUSSIONSFour brands of diclofenac sodium tablets having 50mg potency were purchased from local retailpharmacy. All the brands of diclofenac sodiumtablets used were within their self life during thestudy period. Weight variation, drug content,disintegration time and dissolution are compendialstandards. Hardness and friability are referred to asnon compendia standards. However, friability is nowincluded in the United States Pharmacopeia (USP,1995). Tablets were subject to weight variation study(Table 2) for uniformity of weight. All brandsshowed different mean weight which indicates theuse of different excipients in the different brands.It is evident that the deviations from the averageweight are within limits in all brands since all brandshaving uniform weight. Crown thickness anddiameter uniformity of tablets are necessary not onlyfor consumer requirements but also for packaging. ±5% variation is permissible. The thickness anddiameter values of the branded tablets (Table 2) werewithin limit.The weight variation test is clearly not sufficient toassure uniform potency of tablets. The potency oftablets is expressed in terms of grams, milligrams, ormicrograms of drug per tablet and is given as thelabel strength of the product. The BP specification isthat the content of drug should not be less than 95%and not more than 105%. The potency of the tabletswas found to be 95.90 – 99.42% (Table 3). The resultascertains the presence and compendia quantity ofdiclofenac sodium in all the brands and so could notbe judged as counterfeits without activepharmaceutical ingredients. However, statisticallysignificant difference (P < 0.05) of drug content wasobserved in different tablet brands. The hardness ofthe tablets is an essential criterion in thedetermination of the ability of the tablets to resistchipping, abrasion or breakage under conditions ofstorage, transportation and handling. The hardness ofthe tablet was found to be 2.5 – 5 kg/cm 2 (Table 3).Brand C required the least pressure before fracturewhile brand A required highest pressure. The resultsof the analysis of variance revealed significantdifference (P < 0.05) in hardness of all the fourbrands at 95% confidence interval. Tablet hardness isnot an absolute indicator of strength since someformulations, when compressed into very hardtablets, tend to cap on attrition, losing their, crownportions. Therefore, another measure of tabletsstrength, its friability, is often measured.Conventional compressed tablets that lose less than1% of their weight are generally consideredacceptable. The friability of the tablets (determinedusing Friabilator) was found between 0.012 – 0.102%(Table 3) that was below 1% indicating sufficientmechanical integrity and strength of the tablets.Analysis of variance revealed significant differencein friability (F calculated > F tabulated at 95% level) ofbranded tablets.For most tablets, the first important step towardsolution is breakdown or disintegration of the tabletsinto smaller particles or granules. Variousformulations factors are known to affectdisintegration time of tablets. Disintegration time is anecessary condition and could be the rate determiningstep in the process of drug absorption. The type andamount of excipients used in the tablet formulation aswell as the manufacturing process are all known toaffect the disintegration time of all tablets. Thedisintegration time of enteric coated diclofenacsodium 50mg tablets were determined according tothe procedure reported in USP (USP 2007). Theenteric coated tablets pass the disintegration test ifeach of the six tablets does not disintegrates in 2hours in the simulated gastric fluid and tablets shoulddisintegrate in not more than 60 minutes in thesimulated intestinal fluid. The results of thedisintegration test are presented in Table 4. Theresults showed that all the brands passed thedisintegration test. However, analysis of variancerevealed significant difference in disintegration time (F calculated > F tabulated at 95% level ) of branded tablets.The drug release study is a measure of the amount ofthe drug released into the dissolution medium withtime. This study gives an idea of amount of drugavailable for absorption after oral administration.Drugs with poor dissolution profile will not beavailable in the body system to elicit therapeuticeffect. The results of dissolution tests in terms ofdissolution efficiency and time to dissolve 50% drug(t 50% ) are collected in Table 5, whereas thedissolution curves of diclofenac sodium tablets fromdifferent manufactures are shown in Figure 3.The dissolution efficiency (DE) is defined as the areaunder the dissolution curve up to a certain time, t,expressed as a percentage of the area of rectangledescribed by 100% dissolution in the same time 27 .Vol. 3 (2) Apr – Jun2012 www.ijrpbsonline.com 877