Determination and quality evaluation of some imported drugs in Iraqi kurdistan region

Some of important drugs in Kurdistan Region are planned to be determined such as analgesics and antibiotics from different available companies. For the first stages Paracetamol, Aspirin, Chloramphenicol, Ibuprofen and Tetracycline drugs were examined and the real quantities determined were compared with that reported on a commercial labels. Mean recoveries 99.2,95.9,99.2,99 and 102.8 respectively, and have percentage errors (%E) 0.80, -4.07,-0.80, 2.80 and -1.00 respectively and the best companies for these drugs.


Introduction
Paracetamol Prior to its' spectrophotometric determination, acetaminophen was separated from combination with other antipyretic-analgesics by column chromatography using purified siliceous earth a cation exchange resine [1][2], or an anion-exchange resine [3].
Recently, high-performance liquid chromatography [4] was utilised in the determination of an acetaminophen-methaqualone(2-methyl-3-otolylquinazolin-4-one) mixture. Spectrophotometric methods [5], for the determination of acetaminophen in combination with acetylsaliclic acid (aspirin) have been proposed. In biological fluids,acetaminophen was extracted and determined by spectrophotometry [6], fluorimetry [7], differential spectrophotometry [8] and gas-liquidchromatography [9]. It was concluded that oxidative coupling organic reactions took an important role in the determination of paracetamol [10].Another method is developed in order to improve sensitivity, selectivity and accuracy of the determination of paracetamol.It is based on the oxidative coupling reaction between paracetamol and sodiumperiodate-aniline leading to the formation of a yellow-orange colour [11]. Aspirin The plasma half-life of aspirin is only about 20 minute because it is readily hydrolyzed to salicylic acid(SAL) [12] its' principal metabolite. An anlytical method that measure ASA in biological fluids should, therefore,be capable of measuring SAL also.Such assays are required for many reasons in case of aspirin poisoning, in tolerance reactions, side effects, and for metabolic and pharmacokinetic studies. Lowlevel determination of thse compounds is usually carried out using HPLC methods, many of which have been described in a review by kwong in 1987.The mobile phase usually contain methanol or acetonitrile and have a low pH (normally 2.5-3.0), with UV. Detection in the range 225-240 nm. Small improvements in validation results (e.g. sensitivity) have been made over the years, but since 1980, HPLC methodology for ASA and SAL has only really charged in terms of applications, at the latter determination of aspirin and salicylic acid in human plasma by column-switching liquid chromatography using on line solid-phase extraction was done [13].
Chloramphenicol has strong UV. Absorption and can be determined directly by LC. It has a maximam absorption at 278 nm. [14]. A comprehensive review of methods for the determination of chloramphenicol residues in food, which included eight GC methods and six LC methods for chloramphenicol in milk, has been reported by Nagata [14]. Since this report provides a detailed review of methods, only additional developments, will be reviewed here. Pfenning et al.
[15] developed a GC method for the determination of chloramphenicol in raw milk. The milk is extracted with acetonitrile, then followed by a C 18 SpE clean-up, derivatization with sylon BFT and GC determination with electron-capture detection. Average recoveries ranged from 92-104% at levels ranging from 5-80 ng/ml. Kijal [16] presented a GC-Ms method for the confirmation of chloramphenicol residuse in bovine milk. Meta -nitrochloramphenicol was added as a surrogate standard. Chlorampenicol residues were extracted from the milk by mixing the milk with ethyl acetate using a diatomaceous earth SPE column clean-up. This was followed a C 18 SPE clean-up and derivatization with sylon HTP. Chloramphinicol was determined using GC with a 30 m methylsilicone column and negative ion chemical ionization mass spectrometric determination. The method was validated at levels of .5-2.0 ng/ml. Bayo et al [17] used diphasic dialysis to extract chloramphenicol from milk. Ethyl acetate was added to a piece of hydrated dialysis tubing, The tubing was placed into a flask of milk and mixed with an orbital shaker for 5 hr. The ethyl acetate in the dialysis tubing was dried with sodium sulfate and evaporated. Determination was by LC using a Novapak C 18 column and UV. Detection. The limit of quantitation was 5 ng/ml. Keeukens et.al [18] presented preliminary studies on the determination of chloramphenicol in milk by modifying a previously reported LC method for chloramphenicol in meat [5]. Extraction and clean-up of the milk was with an extrelut diatomaceous earth SPE column and watertoluene partitioning. The limit of detection was 0.5 ng/ml. Clark et al. [19] presented a GC method for the determination of trace levels of chloramphenicol in milk. Milk was partially defatted by centrifugation.

Tikrit Journal of Pure Science 21 (3) 2016 ISSN: 1813 -1662 (Print) E-ISSN: 2415 -1726 (On Line)
This was followed by a C 18 SPE clea-up and derivatization with sylon-HTP. GC was with 2m x 4mm column packed with 3% dimethyl silicon (OV-101) on gas chrom  and electron-capture detection. The method was validated at levels of 0.5-1.5 ng/ml chloramphenicol in milk. Ibuprofen: Colorimetric determination of ibuprofen in tablets [20], a simple extraction and colorimetric method for the determination of ibuprofen in its' dosage form based on the conversion of carboxylic acid into an acid chloride and its' coupling with hydroxylamine to get hydroxamic acid which forms a violet coloured complex with vanadium in acidic medium. Ibuprofen and novocaine hydrochloride were determined with the use of water-micellar solutions of surfactants [21]. Simultaneous determination of several antalgic drugs based on their interactions with b-cyclodextrin by capillary zone electrophoresis was done by Wei et al. [22]. The binding constants of b-cyclodextrin (b-CD) with antalgic drugs such as ibuprofen and aspirin are determined by affinity capillary electrophoresis, based on these interactions,a reliable method for separation and simultaneous determinations of these compounds in the presence of 5.0 mM b-CD in phosphate buffer solution is presented by capillary zone electrophoresis with UV. detection at 200 nm for ibuprofen and aspirin. The linear ranges for ibuprofen and aspirin are from 2.5-700 and 2-800 g/ml. Respectively. Their detection limits are 0.5 and 1.5g/ml. at a signal to noise ratio of 3 respectively. This method has been successfully applied to the detections of these drugs in the pharmaceutical formulations(tablets or capsules) and urine samples. Tetracycline : The FDA has set levels of concern for residues of chlortetracycline, oxytetracycline and tetracycline in milk of 30, 30 and 80 ng/ml. Respectively [23]. Oka and Patterson [24], Shaikh and Moats [25], Barker and Walker [26] reviewed chromatographic methods for the determination of tetracyclines in food products. Since these reports provide a detailed review of methods for tetracyclines in milk, additional developments since then will be reviewed here. Nazol et al. [27], reviewed a rapid determination of trace levels tetracycline in surface water using continuous flow manifold coupled to a capillary electrophoresis system. Tetracyclines are widely used as bacterio static and antibiotic drugs. Ttetracycline (TC) and its' derivatives oxytetracycline (OTC), chlortetracycline (CTC), doxycycline (DC) and demeclocycline (DMCC) have been employed extensively in veterinary medicine animal nutrition and feed additives. However, many health authorities do not allow antibiotic residues in foods because of allergic reactions, paricularly hypertensive people [ procedure. Capillary electrophoretic methods also have been used to analyze other tetracycline [46][47][48]. Our preliminary investigations throughout consultants and pharmacies reveal that some of these drugs may be ineffective and the patients already gain little advantages even when they take a high dose of such drugs. Therefore it was decided to analyze such drugs through a long program according to the procedures reported in British Pharmacopoeia Monographs [49], which are alone authoritative and the results will compare with pure compounds which will be analyse in the first stage of the work. For the time being it was possible to obtain five of such pure drugs namely Paracetamol, Aspirin, Chloramphenicol, Ibuprofen and Tetracycline. It was hoped in the next stage more pure drugs would be obtained.

Apparatus:
A PU 8000 UV/VISIBLE double beam scanning spectrophotometry was used to measure the absorbance of both pure and sample of the analysed drugs.

Procedures:
The procedures followed in accordance to British Pharmacopoeia as following [50]. Paracetamol: 0.3 g of the sample was dissolved in a mixture of 10 ml of water and 30 ml of 1M sulphuric acid. Boiled under reflux for one hour, cooled and diluted to 100 ml with water. To 20 ml of the solution 40 ml of water; 4 g of ice, 15 ml of 2M HCl and 0.1 ml of ferroine sulphate solution. The final solution was titrated with 0.1M ammonium cerium (IV) sulphate until a yellow colour is obtained. The procedure was repeated without the substance being examined. Aspirin: 0.5 g of the drug is dissolved in 10 ml of ethanol (96%), 0.2 ml of dilute phenolaphthaline solution and titrated with 0.1M sodium hydroxide. Each ml of 0.1M sodium hydroxide is equivalent to 0.01802 g of C 9 H 8 O 4 .

Tikrit Journal of Pure Science 21 (3) 2016 ISSN: 1813 -1662 (Print) E-ISSN: 2415 -1726 (On Line)
A 50 ml of 0.1M NaOH is added to the neutral solution so obtained and the mixture was boiled under reflux for 15 minutes. The mixture was allowed to cool in a fume cupboard to preclude CO 2 absorption and then titrated with 0.1M HCl. The difference between the volumes of 0.1M NaOH used in the first and second titration was not more than 0.4 ml. Calculated with reference to 0.5 g of the substance. Chloramphenicol: 1 g of the substance was dissolved in sufficient water to produce 500 ml. 10 ml was diluted to 100 ml with water and the absorbance of the resulting solution was measured at the a maximum at 278 nm. The content of chloraphenicol C 11 H 12 Cl 2 N 2 O 5 was calculated. Taking 297 on the value of A (1%, 1 cm) at the maximum at 278 nm. Ibuprofen: Dissolve 0.18g. in 100ml. Of ethanol(98%) and titrate with 0.1M sodium hydroxide using 0.2 ml. Of phenolaphthaline solution RI (retention index) as indicator until a red colour is produced. Repeat the procedure without the substance being examined. The difference between the titrations represents the amounts of sodium hydroxide required. Each ml. Of 0.1M sodium hydroxide is equivalent to 20.63 mg. Of C 13 H 18 O 2 .
Tetracycline: 10 mg of the substance was dissolved in 0.01M Hydrochloric acid solution to produce 100 ml solution. To 10 ml of the resulting solution add 75 ml of water, 5 ml of 5M sodium hydroxide and sufficient water to produce 100 ml, and mix immediately. The absorbance was taken at 380 nm six minutes after the addition of the NaOH solution.

Reagents:
Pure reagents of the drug examined obtained from sammara drugs institute/ Iraq (SDI).Commercial drugs are purchased from local farmacies in Erbil city, Table(1) illustrate the details.