Nigerian Journal of Pharmaceutical and Applied Science Research, 2012, 1(2): 91-97 QUALITY ASSESSMENT OF SOME BRANDS OF PIROXICAM CAPSULES Igboasoiyi A.C.*, Eseyin O.A., Oladimeji H.O., and Akpan R.J. Department of Pharmaceutical and Medicinal Chemistry, Faculty of Pharmacy, University of Uyo.
*Author for correspondence; E-mail: [email protected] Phone: +2348033228771 Abstract
The quality assessment of eleven brands of piroxicam capsules marketed in Nigeria, which included confirmation of their label claims were carried out. Non-aqueous titrimetric evaluation showed that all but two of the brands contained a chemical equivalent of piroxicam within limits of official compendia specifications. However, one of the brands failed the weight uniformity determination as specified by both the British and United States Pharmacopoeia for enteric coated capsules. The dissolution test results were subjected to statistical analyses using a model independent approach employing difference factor (f1) and similarity factor (f2) to compare the dissolution profiles of the brands. The outcome indicated that five out of the eleven brands tested.
Keywords: Piroxicam; quality assessment; physicochemical; non-aqueous titrimetric evaluation.
Introduction
oral parenteral and topical administration Moghimipour, 2009). The drug inhibits the
Piroxicam is a non-steroidal anti-inflammatory
synthesis of prostaglandins in inflammation
drug (NSAID) with antipyretic and analgesic
(Hardman and Limbrid, 2001; Moffat et al,
properties (Florey, 1986). It is the prototype
drug in the class of Oxicam group of NSAIDs. It
makes a daily dose administration of the drug
is official in the British Pharmacopoeia (B.P.
possible (Katzung, 2001; Sweetman, 2005).
1988) and United States Pharmacopoeia (USP
The once-daily dosing feature of the drug
1988). One of the popular brands of piroxicam
makes it attractive to patients as it affords
in the Nigerian market is Feldene by Pfizer
Inc. New York, U.S.A. manufactured and sold
recommend it for their patients and quite
However, in addition to this brand, there are
counter (OTC) drugs. The high demand has
also Feldene made in Pakistan and Feldene
made it a regular stock in most pharmacies
made in China which are also passed off as
and drug stores, with various brands being
Feldene made in Nigeria to the unsuspecting
displayed for sales. Some of these brands
have comparatively high prices despite having
similar label claims with the cheaper brands.
lipophilic anti-inflammatory drug available for
Igboasoiyi et al. NIJOPHASR, 2012, 1(2):91-97 Nigerian Journal of Pharmaceutical and Applied Science Research, 2012, 1(2): 91-97
All the samples monitored bore brand names.
first weighed with the shell and then the shell
Unbranded piroxicam preparations are few in
content (that is the powder alone). The mean
the market place. Manufacturers seem to be
weight and the standard deviation of each
products. This probably could be to enable them sell their products at higher prices than
Dissolution Test: The B.P. 1988 method (B.P.,
they would have done if the products were
1988) was used. The dissolution medium was
positioned as generics, in line with, perhaps,
0.1N HCl maintained at 37⁰C±0.5⁰C. The
the erroneous perception by many consumers
that the more expensive the drug is, the more
Non-aqueous tirimetric analysis: The contents
effective (Stock, 1997). Some of the brands
of 20 capsules (theoretically containing
had very high prices, 2900-3650% higher than
the least expensive brands. High prices could
not easily be attributed to possession of
thoroughly mixed. This mixture was weighed
superior physicochemical properties. The
to determine the total weight of the powder.
relevant properties of various brands of
eoretically equivalent to 250mg piroxicam
piroxicam with a view to ascertaining whether
conical flask. The piroxicam in the powdered
Experimental
filtered. The filtrate was evaporated to
99.48%w/w piroxicam USP was collected from
dryness and dried at 110⁰C using the oven
(U.S.P./N.F., 1995). A 60 ml mixture of equal
volumes of acetic anhydride and anhydrous
acetic acid solution were poured into the
circulating in Nigeria were purchased within
conical flask to dissolve the dried powder. The
their expiry period and coded A-K. Each of the
solution was titrated with 0.1M standardized
brands had label indicating 20mg piroxicam
perchloric (Olaniyi and Ogundaini, 1998) using
crystal violet as indicator. Average of three determinations was recorded for each
sample. The blank titration was carried out.
The results obtained were applied to calculate the percentage content of the various brands.
Weight analysis of capsules: Ten (10) capsules of each brand were selected at random and
separately weighed on a Mettler UBROR-EB 330H analytical balance. Each capsule was
Igboasoiyi et al. NIJOPHASR, 2012, 1(2):91-97 Nigerian Journal of Pharmaceutical and Applied Science Research, 2012, 1(2): 91-97 Results and Discussion
States Pharmacopoeia 1988 specification for capsule uniformity test. The permissible
Only one of the brands, sample I, failed the
deviation is ±10%. Sample I failed the test
with percentage deviation of 20.2% (Table 2).
Table 1. Particulars of brands analyzed.
This brand will likely have wide variation in
the content of active ingredient of various
capsules (Aulton, 1999; Aulton, 2002) with
similar comparison could be made between
some having too much and others having too
samples B or K with sample G. Yet, each brand
little. Analysis of variance of the different
contained 20mg of piroxicam by the label
brands.This could be as a result of remarkably
different quantities of excepients used in
brands may not be as critical as variation of
bulking the capsules of different brands. For
weight within a brand as typified by sample I.
example, the average weight of sample E was
Igboasoiyi et al. NIJOPHASR, 2012, 1(2):91-97 Nigerian Journal of Pharmaceutical and Applied Science Research, 2012, 1(2): 91-97
Table 2. Weight uniformity analysis of piroxicam 20mg capsules
Permissible percentage deviation is ±10
Table 3.f1 and f2 values of the various brands of piroxicam compared with innovator product (Sample G)
56.46 39.61 55.96 55.18 44.47 47.98 41.82 57.58 76.14 36.64
Content of piroxicam 95.7 73.8 96.9 101.5 61.1 95.7 99.2 93.5 95.7 95.7 93.5
Significant variation in the weight of capsules
relatively small number of medicines such as
within a brand invariably suggests significant
variation in the content of active ingredient
between capsules. Weight variation should be
variation among individual patients much
larger than the variations among products of
attribute for all pharmaceutical preparations
is the requirement for a constant dose of the
Dartness, 1998), variations as seen with
drug between individual preparations (Aulton,
sample I could be critical when products with
2002). Though it has been suggested that
effectiveness is clinically relevant for only a
Igboasoiyi et al. NIJOPHASR, 2012, 1(2):91-97 Nigerian Journal of Pharmaceutical and Applied Science Research, 2012, 1(2): 91-97
Figure 1 shows a graphical representation of
bioequivalent if f1 is between 0 and 15 and f2
the dissolution profile of the different brands
is between 50 and 100 (FDA, 1997). Table 3
shows f1 and f2 values of different brands
dissolution rate test having dissolved more
innovator product. Brands A,C,D, and J gave
45minutes. The U.S.P.-prescribed standard is
f1 values less than 15 and f2 values more than
a dissolution of not less than 75% of the label
claim within 45 minutes. Difference factor (f1)
interchangeably. Though sample I had f1 and
and similarity factor (f2) were calculated to
respectively, it failed the capsule uniformity
dissolution profiles are considered similar and
test and, therefore cannot be recommended.
Dissolution Test Result Time Interval (minutes)
Figure 1. Graph of dissolution test result of different brands of piroxicam 20mg
Table 4, shows that only samples B and E
brands are comparatively higher than those of
failed the test on percentage purity. Sample E,
in spite of its comparatively high price did not
higher than the cheapest brand, in spite of its
meet the standard specification of purity.
From the price evaluation data published in
Table 2, it could be seen that prices of some
Igboasoiyi et al. NIJOPHASR, 2012, 1(2):91-97 Nigerian Journal of Pharmaceutical and Applied Science Research, 2012, 1(2): 91-97
comparatively high price, could be adjudged a
narrows the range of error in delivering the
good product from all parameters monitored,
required level of active ingredient, whether
such cannot be said of sample E. The variation
the same brand is used or whether in the
in the weight of capsules between brands
course of treatment the patient is constrained
It is advisable for regulatory agencies to
regulate capsule weight for a preparation like
application of this result is that prescribers
piroxicam for ease of comparison between
and patients should be cautious of switching
Furthermore, NAFDAC registration number is
except it is absolutely necessary. When a
a mark of authenticity and quality and aptly
patient is stabilized on a brand or a generic
suggests that the preparation is not only fit
product by a particular manufacturer it is
for use but could be switched with other
advisable to stick to that brand or generic for
brands of similar preparation. Thus, insisting
Conclusion
Five of the eleven brands tested (A, C, D, G
Aulton M.E. (2002). Pharmaceutics.The Science of Dosage Form Design. Churchill.
British Pharmacopoeia (1988) `Her Majesty’s
Acknowledgement
The authors gratefully acknowledge Neimeth
British Pharmacopoeia (1998). Her Majesty’s
Pharmaceutical International Lagos for kindly
Stationary Office ,London, vol.1, pp.1050.
supplying the reference (piroxicam) standard used in this work.
Dartness J., (1998) Essential Drugs Monitor. Managing Drugs Supply, WHO, Geneva 25(6),
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