1. INTRODUCTION:

Rectal suppositories are one of the conventional dosage forms which are favorable and alternative to oral dosage forms in cases such as elderly and pediatric patients who have difficulties in swallowing or in unconscious cases. As expected, age has a noticeablenegative impact on the function and physiology of the body systems such as immunological and metabolic systems. This increases the incidence of many gastrointestinal diseases.[1-3]. Also, different drugs can be loaded in rectal suppositories for treatment of nausea, vomiting, inflammation of bowel and hemorrhoids [4], Additionally, it was noticeable, the growing interest in formulating painkillers by using suppositories such as the morphine suppository to control the pain of anal cancer patients [5]. Moreover, many studies showed the importance of painkiller suppositories for pre or postoperative patients like Lee et al reveled a reduced in pain for patients of prior ureteroscopy by using opium rectal suppository [6], and opium suppository in a different study was used for patients undergoing the laparoscopic hysterectomy operation [7]. Also, Jones et al formulated prochlorperazine as rectal suppository and their formulation showed within 2 hours an exceptional pain relief for migraine treatment [8]. Moreover and the most significant advantage to the rectal suppository is the guarantee of partial avoidance of the hepatic first pass effect as this helps to increase the bioavailability of drugs. This incomplete avoidance is due to the high vascularity of the rectum and the direct contact to the systemic circulation by the inferior and middle veins whereas just the superior vein is joined directly to the portal system [9-11]. The decision for present work was to formulate triflu suppositories for prolonged action using cocoa butter with different additives: span 60, tween 80, and PEG 400 separately and this was partially similar to another previous work as swiader et al formulated paracetamol suppository in cocoa butter using span 60 that helped to delay the release of paracetamol [12]. The new addition in this work considered triflu the hydrophilic drug to be formulated in a fatty base such as the cocoa butter as our review to the suppository researches showed no study used a hydrophilic drug in a fatty base of suppository for prolonged action. Thus, to investigate the aim of work; different formulations of triflu suppositories composed of cocoa butter as a base and loaded with different concentrations of span 60, tween 80, and PEG 400 separately. After that, different physical tests were applied to the suppositories such as hardness, melting range, drug content, disintegration time, and melting time. Also, the effect of the addition of span 60, tween 80, and PEG 400 to the cocoa butter suppositories on the release of triflu was examined and the best addition of surfactants that achieved the aim of work was investigated for further examinations by both the FTIR to check the possible changes of the triflu molecules and the thermal analysis using differential scanning calorimetry.

2. MATERIALS:

Trifluoperazine HCl (triflu) was kindly gifted by Alforat factory for drug industries where the Cocoa butter and PEG 400 were purchased from china LTD. Also, sodium lauryl sulphate was taken from Fluka AG. The span 60 and tween 80 were brought from Sinopharm chemical lreagent Co. Ltd and CDH respectively.

3. METHODS:

3.1 Preparation of suppositories:

10 mg of the active constituent of the Triflu was weighed and mixed with cocoa butter as a fatty base and span 60, tween 80, or PEG 400 were added separately in different w/w percentages. Also, drug displacement values were defined and considered throughout the preparation using fusion method. The suppositories preparation started with melting the cocoa butter as the heating temperature was set at 40°C then followed by addition of span 60, tween 80 or PEG 400 to be mixed and fused with melted cocoa butter. A gentle, continuous stirring to the mixture to guarantee both completed mixing. Before congealing, the melted mixture was poured in a metal mould of 1gm capacity and all suppositories were preserved in a refrigerator and wrapped with aluminum foil for further evaluations.

3.2 Physicochemical characterization of triflu suppositories:

3.2.1 Hardness (fracture point):

The hardness is considered as the weight needed to destroyed the suppository and this was done using Monsanto hardness tester model. This test was carried out in triplicate.

3.2.2 Melting Range:

To apply this test, the suppository was maintained in a beaker filled with 500 ml of 0.1N sodium phosphate buffer, pH 7.4 contained 0.1% w/v sodium lauryl sulphate and incubated at 29± 0.5℃ in a water bath then the temperature was increased at a rate 2℃/ 30 minutes till reaching a completed melting to the whole suppository as the last temperature recorded for this test. This test was done in triplicate

3.2.3 Drug Content:

This was done by dissolving the whole suppository in 900 ml of the 0.1N sodium phosphate buffer, pH 7.4 that contained 0.1 % w/v sodium lauryl sulphate and warmed to 37°C by the aid of magnetic stirrer. Then a 5 ml was filtered and the triflu was quantified by measuring the absorbance at 262 nm the trifluλmax,.

3.2.4 Disintegration Test:

This test was executed using the apparatus of USP tablet disintegration as the temperature and pH were set on 37 °C and 7.4 correspondingly, using 0.1N sodium phosphate buffer that containing 0.1% w/v sodium lauryl sulphate and this study was done in triplicate.

3.2.5 Melting time:

This test was performed by immersing the suppository in a beaker contains 100 ml of the prepared buffer in a water bath at 37°C as this test run with time counting till getting a completed melting to the entire suppository and this was done in triplicate.

3.2.6 In- vitro Dissolution Study:

The dissolution of suppositories was carried out using the dissolution apparatus USP Type II (Paddle) as the temperature was set at 37±0.5°C and the rotation of paddles was 50 rpm. The jars were filled to 900 ml of the prepared sodium phosphate buffer that contained 0.1% w/w sodium lauryl sulphate. A 5 ml from the dissolution media was taken at specified periods of time and replaced with fresh 5 ml of the buffer then the samples were filtered and analysed by UV as the absorbance was read at 262 nm, the λmax of triflu.

3.2.7 FTIR:

Shimadzu FTIR-8400S was used to investigate the selected samples and the cell plate was 201-77160-20 for KBr and in case of liquid a sealed cell with KRS-5 plate was used.

3.2.8 DSC:

Thermal analysis was applied using Platinum evaluation V1.0.89 and around 18 mg to 20 mg of the suppository was taken and placed into T zero pan and to be covered with T zero Hermetic lids. The heating rate was 5°C / minute and started from room temperature and end at the 400 °C.

4. RESULTS AND DISCUSSION:

This work started with the physical examinations for the suppositories as the loaded suppositories with triflu were inspected visually for the following parameters such as fissuring, pitting and exudation and all formulations showed good appearance. The next step was to investigate the hardness of the suppositories which indicates the ability of the suppositories to tolerate the abrasive force of travelling and the results as shown in Table 1 were in this range 3.25- 5.15 kg. This was similar to the paracetamol suppositories that prepared byranjita and kamalinder in suppocire base and showed the same our range of hardness [13].

Also, melting range was studied which helps to evaluate the suppository permanence time to stay integral at body temperature. Usually, the melting range of cocoa butter suppositories is (33-38 °C) which indicates the purity of cocoa butter and this was close to the melting range of the whole suppositories in this work (34-39°C) as shown in Table-1. [14] Moreover, the drug content was studied and this shows the homogeneity of the drug within the single suppository and also reflects and guarantees the precise dose as this is demonstrated in Table 1 and the content range was 95.47% w/w-103.0% w/w. This range is in line with the acceptable range to the assay of triflu tablet in the British Pharmacopia which was from 92.5 to 107.5% [15]

Furthermore, the disintegration time was explored which is commonly the time needed to soften the suppository and this according to the European pharmacopeia [16]. The data of the disintegration time as demonstrated in Table 1 of plane suppository of the cocoa butter was 31 min and the addition of different surfactants gave a variable disintegration time in comparison with the plain suppository of the cocoa butter. Clearly, it was found a direct relationship between the amount of surfactant of span 60, tween 80 and PEG 400 and the disintegration time as the disintegration time range of the suppositories loaded with 2% w/w, 4% w/w and 6% w/w of tween 80 was (17-47.5 min) and the suppositories containing 2% w/w, 4% w/w and 6% w/w of span 60, their disintegration time was (43 to 47 min). Also, the disintegration time range was (23.5 to 35 min) for the suppositories containing 10% w/w, 20% w/w and 30% w/w of PEG 400. This could be explained that the increased in the quantity of surfactants leads to increase the dispersion of surfactants molecules in the whole mass of the suppository. In turn, the surfactant molecules attracted water from release media and led to fragment the suppositories. However, this suppository fragmentation did not assist in melting the cocoa butter, the main content of the suppository; and showed pieces that stayed for long time in the release medium.

Further to the above physical properties, melting time was explored to give a clue to the entire melting of the suppository in the body temperature and as shown in Table 1. The melting time of plain suppositories of cocoa butter was 20.5 min but the addition of tween 80 decreased the melting range and was (14.5- 16.5 min) while the addition of span 60 and PEG400 showed a close and a higher melting range (21-22.5 min) and (23-29 min) correspondingly as compared with the plane cocoa butter suppositories. In different study, salbutamol suppository was formulated in fatty bases the suppocire and witepsol as their melting times were also vary and wide [17].

Table 1: The physicochemical properties of the whole range of the suppositories and SD is the standard deviation and CB is the cocoa butter.

Formulations % w/w	Hardness Kg (SD)	Melting range in °C(SD)	Content Uniformity (% w/w)	Disintegration time in minutes (SD)	Melting time in minutes (SD)
cocoa butter (CB)	3.25 (0.35)	34.5 (0.7)	103.0	31.0 (1.4)	20.5 (0.7)
(CB) +Tween 80 2%	4.30 (0.14)	35.5 (0.7)	98.72	17.0 (1.4)	16.5 (2.1)
(CB) +Tween 80 4%	4.35 (0.07)	34.5 (0.7)	99.37	41.5 (2.1)	14.5 (0.7)
(CB) +Tween 80 6%	5.00 (0.28)	34.5 (0.7)	101.0	47.5 (0.7)	16.0 (1.4)
(CB) +Span 60 2%	3.75 (0.35)	34.5 (0.7)	105.0	43.0 (1.4)	21.0 (1.4)
(CB) +Span 60 4%	4.80 (0.56)	36.0 (1.4)	100.5	47.0 (2.8)	22.5 (2.1)
(CB) +Span 60 6%	4.95 (0.21)	36.5 (2.1)	99.37	49.0 (1.4)	22.5 (0.7)
(CB) +PEG400 10%	5.30 (0.28)	39.0 (1.4)	98.72	23.5 (2.1)	23.0 (1.4)
(CB) +PEG400 20%	5.30 (0.14)	39.5 (0.7)	95.47	28.5 (2.1)	24.5 (2.1)
(CB) +PEG400 30%	5.15 (0.21)	39.0 (1.4)	97.81	35.0 (2.8)	29.0 (1.4)

The in vitro release experiment was studied to find out the loading effect of different types of surfactants span 60, tween 80 and PEG 400 and different concentrations of each surfactant on the release of triflu in comparison with the plain suppository of cocoa butter. The cocoa butter suppositories as shown in Figure 1, at the beginning within the first 60 min; the triflu was released slowly and not more than 40% w/w but after that, it showed a rapid and a completed release of triflu within 100 min of the release experiment. This was considered in our study as a standard to compare the effect of addition of surfactants on the release of triflu as demonstrated in Figure 1. Clearly, the addition of 2% w/w, 4% w/w and 6% w/w of span 60 did not slow the release of triflu in comparison with the plain suppository and specifically the 2% w/w and 4% w/w of span 60 while the 6% w/w showed a better retardation to the release of triflu. Differently, the addition of tween 80 to the cocoa butter slowed the release of triflu as shown in Figure 1 but initially within the first 60 min, the release of the 3 different concentrations (2% w/w, 4% w/w and 6% w/w) of tween 80 showed the same release behaviour of the plain suppository. Then, the release of triflu stayed slow and was around 60% w/w at 200 min the end of the release experiment. It was noticed that the 3 different concentrations of tween 80 did not give different release pattern. Lastly, the 30% w/w of PEG 400 addition slowed the release of triflu and it showed similar release behaviour to tween 80 in the plane suppositories. Whilst, the 10% w/w and 20% w/w of PEG 400 slowed the release of triflu significantly (p < 0.05) and did not release more than 30% w/w of triflu within the frame time of the experiment.

Figure 1: The release of triflu from cocoa butter suppositories containing different concentrations of span 60, tween 80 and PEG400 where the release medium is 0.01 M of Na phosphate buffer, pH 7.4 with 0.1% w/v of sodium lauryl sulphate as each value represents the mean ± SD (n=3).

Generally for the last 2 surfactants, the slow release could be attributed to the presence of surfactant in the fatty base that could help in more dispersion and capturing of the triflu, the water soluble drug molecules, in the fatty base [18].

The FTIR data as shown in figure 2 might help in interpreting the release study because we have a belief of possible hydrogen interactions between the carbonyl group of the triglyceride in the cocoa butter and the hydroxyl group in the span 60, tween 80 or PEG 400 during the suppository formulations and having a chance to produce a water in oil emulsion. This emulsion could be able to catch the triflu molecules and slowing the release of these molecules (All the chemical structures of the suppository compositions are in the supplementary information). The FTIR study was executed on the suppositories of 6% w/w of span 60, 6% w/w tween 80 and 10% w/w PEG 400 in the plane suppository. The concept we think was not clear enough in the data of span 60 and tween 80 that contained in the suppositories as all the chemical structures of triglyceride (which is the main content of cocoa butter), span 60 and tween 80 have carbonyl group as shown in Figure 2A and 2C. As the peak that related to carbonyl of the suppositories that contained tween 80 showed a shift and a split to the left and to the right at 1727 cm^-1 and 1743 cm^-1 where originally the peaks related to carbonyl group of tween 80 was at 1736 cm^-1and cocoa butter was at 1732 cm^-1. However, as shown in Figure 2E; it was obvious that there was a shift to the carbonyl peak of cocoa butter from 1732 cm^-1 to 1747 cm^-1 in the spectrogram of the suppository as the PEG 400 has no carbonyl group in its chemical structure. In addition, Figures 2B, 2D and 2F showed a clear disappearance of the peaks that associated with hydroxyl groups in the spectrograms of suppositories in comparison with the peaks in the spectrograms of span 60, tween 80 and PEG 400 at 3409 cm^-1, 3453 cm^-1 and 3367 cm^-1respectively. This disappearance of hydroxyl group indicates the formation of hydrogen bonds as expected with the carbonyl group of triglyceride of cocoa butter.

Further to the FTIR results as shown in Figure 2, the same investigation was applied to the suppositories that contained the 10% w/w PEG 400 and the triflu due to the clear shift in the functional groups of cocoa butter and hydroxyl group that approving the emulsion concept. Figure 3A and 3B demonstrates the possible interactions between the CF3 of triflu and the hydroxyl group of PEG 400 which was the splitting of the triflu peak associated with CF3 at 1342 cm^-1in the spectrogram of triflu and PEG 400 compared with the individual spectrogram of PEG 400 and triflu as in Figure 3A. Also, the peak related to the hydroxyl group of PEG 400 was shifted from 3365 cm^-1 to the 3395 cm^-1 in the spectrogram of triflu and PEG 400.This was stated clearly by Kucet al, that the hydration of triflu molecules showed a splitting of peaks associated with the CF3[19]. This interaction might led the triflu molecules to be more captured within the hydrophilic phase (PEG 400) of the presumed water in oil emulsion in the fatty suppository leading to slow the release. For the same above purpose of selection the suppository that contained PEG 400, DSC study was run to probe the changes that might occur to the triflu or to the content of the suppository. Figure 4 exhibited all thermograms of triflu powder, the suppository as a base and the loaded triflu into the suppository and the results revealed distinguished peaks of triflu at 217-230 °C and at 290 °C which are completely vanished in the thermogram of the suppository loaded with the triflu and this could be attributed to the dispersion of triflu in the suppository base. This outcome is similar to the sharp peak disappearance of carbamazepine in a suppository base composed of hydrogenated vegetable oil and poloxamer 407 and this change referred to the drug dispersion in the base.

This concept of emulsion formation and specifically in the suppositories loaded with PEG 400 might harmonized with the fragmented suppository in the disintegration time study where the surfactant PEG 400 presence helped in formation of emulsion which aided to retard the melting of suppository and prolonged the disintegration time, but in the same time PEG 400 facilitated in attracting more water from release media. In turn, this led to release more triflu in the media as the concentration of PEG 400 increased in suppository because as approved in FTIR study there were bonds between PEG 400 and triflu molecules.

Figure 4: Melting thermograms of DSC of trifle alone, trifle and suppository of the whole components and the suppository component alone.

The DSC and the FTIR in the Figure 3 outcomes are consonant as both proved an interaction between triflu molecules and suppository components and this deepened that triflu molecules dispersed in the suppository body.

5. CONCLUSION:

The suppositories of cocoa butter and specifically 10% w/w and 20 % w/w with PEG 400 gave not more than 30% w/w of triflu and it was the slowest release in comparison with other types of surfactants. This slow release was explained as a possible formation of water in oil emulsion in the suppository and this emulsion was approved according to the FTIR study that showed interactions between the carbonyl of triglycerides of cocoa butter and the hydroxyl group of PEG 400. Additionally, FTIR study showed triflu molecules were bonded to the PEG 400 that assumed the triflu molecules were captured in the aqueous phase of emulsion. Also, DSC exhibited the dispersion of triflu in the suppositories compositions.

6. ACKNOWLEDGMENT:

We would like to thank Mustansiriyah University (www.uomustansiriyah.edu.iq) in Baghdad-Iraq for unconditional help that supported us throughout our work. Also, we would like to thank Dr Mohammed Al-Ameedee and DrGhaidaa S. Hameed (scholars in pharmacy school for their assistance to our work.

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Received on 10.03.2019 Modified on 15.04.2019

Research J. Pharm. and Tech 2019; 12(10):4934-4940.

DOI: 10.5958/0974-360X.2019.00856.4