Novel Probe Sonication Method for the Preparation of Meloxicam Bilosomes for Transdermal Delivery: Part One

Othman FB Al-Sawaf^* and Fatima Jalal

^*Correspondence: Othman FB Al-Sawaf, Department of pharmaceutics, college of pharmacy, Baghdad University, Iraq, Email:

Author info »

Introduction

The human’s skin which represents about 16% of the total body weight [1] is considered as the largest organ of the body [2] with main duty to protect the body against invading foreign bodies [3]. The outermost layer of the skin knowns as stratum corneum is considered as the main barrier against skin penetration due to its low permeability [4]. Transdermal drug delivery has gained interest in the last years with estimated market value of transdermal products of 9.5 billion dollars a year worldwide till 2017 [5]. The main challenge for drug delivery across the skin is how to pass through the stratum corneum; several approaches have been tested for this purpose including physical, chemical, and vesicles-based methods [6].

Physical methods including different approaches such as microneedles [7-10], jet injector, laser ablation, electroporation [11-14], sonophoresis iontophoresis and magnetophoresis [15-18]. Chemical methods involve the usage of chemical compounds which act as penetration enhancers such as ethanol [19-22].

Vesicles-based methods involve the employment of vesicle carriers to enhance skin penetration such as liposomes niosomes and bilosomes [23-25].

Bilosomes were firstly described by Conacher [26] are bilayer vesicles like niosomes in structure but with the inclusion of bile salts in the bilayer [27]. Bilosomes were firstly tested for transdermal delivery by Al-Mahallawi in a research article that concluded the potential uses of these vesicles carrier to enhance skin penetration of tenoxicam [28].

Inflammation considered as the alarm system of the body against tissue injury however, prolonged inflammation can result in tissue damage [29], inflammation involves the activation of cyclooxygenase (COX) enzymes which act as inflammatory mediators [30]. Non-steroidal anti-inflammatory drugs (NSAIDs) which act through the inhibition of COX enzymes are among the most prescribed medicines due to their wide variety of uses including anti-inflammatory, anti-pyretic and analgesic activities [31].

Meloxicam which was approved by the FDA in 2000 as 7.5 mg tablet [32] is a non-steroidal anti-inflammatory drug belong to the oxicam group and has shown selective activity for inhibition of COX-2 enzyme over COX-1 enzyme. Despite its safety, meloxicam has the unwanted gastrointestinal adverse effects of NSAIDs which make transdermal delivery of it favorable over oral route however due to its low water solubility there are obstacles against successful transdermal delivery, different approaches have been employed for enhancing meloxicam transdermal delivery [33-36]. However, based on our knowledge bilosomes have never been employed for enhancing transdermal delivery of meloxicam.

The aim of part one of these researches is to test if probe sonication method which is employed for the preparation of niosomes can be employed for bilosomes preparation. Till now almost all bilosomes formulations are prepared by using thin film hydration method which involves the usage of hazardous organic solvents. Based on our knowledge this part is the first to describe the preparation of bilosomes using probe sonication method.

Materials and Methods

Meloxicam, Sodium Deoxy Cholate (SDC), Cholesterol, Sorbitan monostearate(Span® 60), Absolute ethanol 99.8%.

Preparation of Meloxicam Bilosomes

In a beaker, a constant amount of Span® 60 (420 mg) was mixed with different amounts of meloxicam, cholesterol and sodium deoxy cholate as shown in Table 2. To the above mixture 20 ml of distilled water was added and the resultant dispersion was homogenized with a homogenizer running at 3000 RPM for 5 minutes. After that the resultant dispersion was subjected to probe sonication for 5 minutes (50 seconds on and 10 seconds off with 30% amplitude) (Q500 QSONICA Sonicator, Qsonica, LLc. USA). Finally, the resultant milky dispersion was stored at 4°C overnight to allow vesicles to mature and remained at the refrigerator until further characterization.

In vitro characterization

Light Microscopic Study

To assure the formation of vesicles, 1ml of different dispersions were tested under the light microscope using different magnifications (10X, 40X, and oil immersion 100X).

Determination of vesicles size, polydispersity index and zeta potential

1 ml of each formulation was diluted with 10 ml of distilled water to reach faint opalescence and tested for vesicles size, Poly Dispersity Index (PDI) and zeta potential using Zetasizer Ultra. The used cuvettes were made of quartz and the instrument refractive index was adjusted at 1.33.

Determination of entrapment efficiency %

To determine the entrapment efficiency %( EE %) a method reported in [37] was used. Briefly, 1 ml of each bilosomes formulations was diluted with 9 ml of absolute ethanol 99.8% then actual drug content was determined spectrophotometrically using UV absorbance (CARY 100 Conc UV-Visible spectrophotometer, Varian, Australia) read at 354 nm wavelength using calibration curve of meloxicam in absolute ethanol 99.8% (R² = 0.997 n = 3) after suitable dilutions. Then the entrapped drug was determined through taking 1 ml of each bilosomes formulations and subjected to centrifuge using cold centrifuge (eppendrof centrifuge 5417 R, Eppendrof AG, Germany) running at 9000 RPM at 4oC temperature for 90 minutes, the supernatant was discarded and the precipitates were dissolved in 10 ml absolute ethanol 99.8% with the aid of sonication using bath sonicator operates at 56oC temperature for 5 minutes then entrapped drug was determined spectrophotometrically as above. Finally, the entrapment efficiency of each formulation was calculated using the equation below

Studying the influence of different formulation variables using Box-Behnken design

Box-Behnken design was employed using Design- Expert^® version 13.0.5.0 software (Stat Ease, USA). The three independent variables were: (X1: Meloxicam dose), (X2: Cholesterol amount) and (X3: SDC amount). The dependent variables or responses were (Y1: Vesicle size), (Y2: Zeta potential), (Y3: PDI) and (Y4: Entrapment efficiency%) as shown in table 1. 17 formulations with 5 center points of meloxicam bilosomes were prepared based on the above software as shown in table 2.

Table 1: Dependents and independents variables used in Box-Behnken design.

Table 2: Formulations of meloxicam bilosomes done using Box-Behnken design.

Abbreviations: SDC (Sodium deoxycholate), PDI (Polydispersity index), EE% (Entrapment efficiency %), a: experiments were done as triplicate with results represent mean ± standard deviation.

Optimization of meloxicam bilosomes

Design-Expert^® version 13.0.5.0 software (Stat Ease, USA) was used to select optimal bilosomes formulations for in vitro drug release study by applying the desirability function. The selected optimization criteria were to get formulas with least vesicle size and polydispersity index and with highest entrapment efficiency and zeta potential as absolute values.

In vitro drug release study

In vitro drug release was performed for the selected bilosomal formulations. Dialysis bag method was used to determine the amount of drug released after 6 hours, in brief an equivalent amount to 1.5 milligrams of meloxicam was taken from the selected bilosomes formulation and poured in dialysis membrane (which were soaked overnight in release media) (M.wt 8000-14000, Special products laboratory, USA) then the dialysis bags were placed in type two dissolution apparatus (paddle type) (RC-6 Dissolution tester, Faithful, China).The release media was 250 ml Phosphate puffer saline (PBS) PH 7.4 solution to achieve sink condition. The apparatus temperature was 37±0.2 and the paddle rotation speed was 100 Round Per Minute (RPM).At predetermine time (1, 2, 3, 4, 5 and 6 hours) three milliliters samples are withdrawn and replaced by fresh PBS solution to maintain sink condition. The withdrawal samples were tested for meloxicam amount spectrophotometrically using UV-Visible spectrophotometry (CARY 100 Conc UV-Visible spectrophotometer, Varian, Australia) reading the concentration at the λ max of meloxicam in PBS PH 7.4 which is 362 nm and by using the calibration curve equation of it (R² = 0.998, n = 3). The release experiments were done as triplicate [38].

Release Kinetic Modelling

The obtained in-vitro release data from different bilosomes formulations were fitted to different mathematical equations using DD-solver and Microsoft excel^® 2016 program for determining the mechanism and kinetic of meloxicam release from bilosomes formulations [39]. The used kinetic models were: zero order release kinetic model (cumulative percentage drug release vs. time), first order release kinetic model (Log cumulative percentage drug retained vs. time), Higuchi release kinetic model (cumulative percentage drug release vs. cubic root of time), and finally Korsmeyer-Peppas release kinetic model (Log cumulative percentage drug release vs. Log time), model with the highest correlation coefficient was selected to be the best fitted model [40].

Selection of the optimal bilosomes formula.

Depending on the amount of meloxicam released after 6 hours, the formula that shows the highest amount of drug release was chosen as best formula to be studied further in part two of this research.

Results and Discussion

Analysis of factorial design

Today, the use of experimental designs is a common method for analyzing the effect of different variables on the characteristics of the drug delivery system under study, theses variables can affect the properties of the final dosage form [41]. In this study all the selected independent variables and their levels are chosen based on preliminary data which are not shown here. In all responses studied, adequate precision value greater than 4 (the desired value) was observed indicating that the chosen model for each response can be used effectively [42].As shown in table 3 the predicted R² values for all responses except PDI are in reasonable agreement with the adjusted R² as the differences is less than 0.2. The negative predicted R² of PDI implies that the overall mean is a better predictor for the response.

Table 3: Output data of the Box- Behnken design.

Light microscope study

Results of light microscope are shown in figure 1 which indicates the formation of vesicles that support the use of probe sonication for the preparation of bilosomes.

Figure 1: Light microscope study, A under 100X oil immersion, B under 40X, and C under 10 X.

Effect of formulation variables on vesicle size

In transdermal delivery dosage form vesicles or particles size plays an important role in the penetration of vesicles or particles across the skin, that the smallest vesicles or particles penetrate the skin deeper and hence enhance transdermal delivery. The prepared bilosomes vesicles were in nano sized range with a mean diameter fluctuated from 147.933 ± 6.87 nm to 308.6 ± 109.5 nm. The effects of independent parameters on vesicle size are shown as 3D plots in figure 2. ANOVA study was used to determine the significant of independent variables on vesicle size, results indicate that both meloxicam dose (X1) and cholesterol amount (X2) have significant effects on vesicle size (P < 0.05) whereas Sodium deoxycholate amount (X3) has a non-significant effect on vesicle size (P > 0.05).Regarding the effect of meloxicam dose (X1) on vesicle size, meloxicam dose has a significant positive effect on vesicle size (P = 0.0193) those when increasing the dose, the vesicle size increased, this can be due to increasing the amount of entrapped drug when increasing meloxicam dose, that more entrapped drug resulted in larger vesicles hence increasing the vesicle size, similar results were obtained in the literature [43,44].Regarding the effect of cholesterol amount (X2) on vesicles size, increasing cholesterol amounts paradoxically resulted in smaller vesicles those cholesterol has a significant negative effect on vesicle size (P< 0.0001) this can be interrupted as the incorporation of cholesterol in bilosomes increase the bilayer hydrophobicity which resulted in decreasing surface energy and vesicles size. Similar results were obtained for the effect of cholesterol on decreasing the vesicles size of niosomes prepared from Span® 60 [45].

Figure 2: Response surface 3D plots of independent variables effects on vesicles size. (As shown that both meloxicam dose and cholesterol amount have significant effect on vesicle size whereas increasing SDC amount has no significant effect on vesicle size), (a- 5 mg SDC, b- 10 mg SDC, c-15 mg SDC).

Effect of formulation variables on zeta potential

Zeta potential can be defined as a measurement of the total surface charge of vesicles; it can be used as an indication for the stability of the system, in general large value of zeta potential as an absolute number indicates a more stable system [46].

In this research the values of zeta potential were varied from -17.16 ± 3.9 to -27.16 ± 7.47 indicating that most formulations have sufficient surface charge. The negative charge of all formulation resulted from the anionic nature of the bile salt sodium deoxy cholate (SDC).ANOVA study indicating that only the amounts of SDC (X3) has significant effect on the value of zeta potential (P < 0.05). Regarding the effect of SDC on zeta potential, a significant positive effect (P < 0.0001).As shown in figure 3, increasing the amount of SDC resulted in increasing the absolute value of zeta potential, this is due to that bile salts act as membrane stabilizers that added charge to the membrane surface and hence increasing the stability, similar results were obtained in the literature [47].

Figure 3: Response surface 3D plots of independent variables effects on zeta potential. (As the amount of SDC increased from 5 mg to 10 mg to 15 mg, the zeta potential values increased significantly) , (a- 5 mg SDC, b- 10 mg SDC, c-15 mg SDC).

Effects of formulation variables on PDI.

Polydispersity index (PDI) is a measure of the homogeneity of the formulations. A formulation with a PDI value close to 0 indicates a uniform population while those with a PDI value close to 1 indicates highly polydisperse system [48]. In our work PDI values ranged from 0.219 ± 0.033 to 0.335 ± 0.133 indicates monodisperse systems. ANOVA study indicates that none of the independent variables has a significant effect on the values of PDI. Similar results were reported by literature [49].

Effects of formulation variables on entrapment efficiency %.

Entrapment efficiency % of the prepared bilosomes formulation was ranged from 9.3 ± 1.22% to 94.8 ± 1.76%. regarding ANOVA study only meloxicam dose (X1) has a significant effect on the entrapment efficiency % (P < 0.05), neither cholesterol (X2) nor SDC (X3) amounts have a significant effect on entrapment efficiency %.The 3D plots of the effects of independent variables on entrapment efficiency are shown in figure 4.Regarding meloxicam dose (X1) a significant positive effect was observed with (P < 0.0001), this may be due to that increasing meloxicam dose resulted in increasing media saturation with meloxicam, those forcing it to be entrapped within bilosomes, similar results were reported in the literature [50].

Figure 4: Response surface 3D plots of independent variables effects on entrapment efficiency %.

Only meloxicam dose has a significant positive effect on EE %, increasing meloxicam dose from 5 mg to 10 mg to 15 mg results in statistically significant increase in EE %, (a- 5 mg SDC, b- 10 mg SDC, c-15 mg SDC).

Selection of the optimal bilosomes formulations

By applying the desirability function design experts was used to select optimal bilosomes formulations to be studied further. The selected bilosomes formulations with their desirability values are shown in table 4, whereas table 5 compared predicted vs actual dependent variables for the selected bilosomes formulations.

In vitro drug release

Table 4: Predicted vs actual dependent variables of selected bilosomes formulations.

The release profiles of the selected bilosomes formulation are shown in figure 5. F2 shows the highest release percentage after six hours reaching 100 % release of the entrapped meloxicam. The release profiles for all tested formulations show a sustained drug release which can be interrupted as the bilosomes just like other colloidal vesicles systems act as drug reservoir that release the entrapped drug in sustained fashion, similar results were obtained in the literature [51]. To study the effects of different formulation variables on the percentage of release after six hours, F2 and F4 release was used to study the influence of cholesterol amount on the percentage of drug release since these two bilosomal formulas differ only in the amount of cholesterol F2 contains 60 mg of cholesterol while F4 contains 180 mg of cholesterol. While F6 and F8 release profiles were used to study the effect of sodium deoxycholate on the percentage of drug release after six hours as these formulas only differ in the amount of SDC they contain F6 contains five mg of SDC while F8 contains 15 mg of SDC. Regarding the effects of cholesterol amount on the amount of drug release, increasing cholesterol amount form 60 mg in F2 to 180 mg in F4 results in decreasing the amount of drug release, that cholesterol has a negative effect on the release of drug from bilosomes. This effect may be due to when increasing cholesterol amounts the wall of bilosomes becomes stiff and this hindered drug release from bilosomes, similar result was obtained in the literature. Regarding SDC amount effects on the amount of drug release, increasing SDC amount form five mg in F6 to 15mg in F8 results in increasing the amount of drug release, those SDC has a positive effect on the release of drug from bilosomes. This can be due to that bile salts act to increase bilosomes wall flexibility which facilitates release of the entrapped drug, similar result was obtained in the literature [52].

Table 5: Desirability of selected bilosomes formulations.

Figure 5: In-vitro drug release from selected bilosomes formulations, F2 formula reaches 100 % drug release after 6 hours.

Release kinetic modelling

Different mathematical models were used to simulate the release of meloxicam from different bilosomes formulations. The values of release constants and regression coefficients are listed in table 6. The best describing release model is based on the highest R² values, from the above table the Korsmeyer- Peppas model has the highest R² values for all tested formulations those it was chosen as the best fit model for describing the mechanism of meloxicam release from bilosomes formulation, similar results were obtained in the literature for the release of drug from bilosomes (52). Regarding the exponent n values, all formulas except F4 showed value larger than 0.5 meaning that the drug transport mechanism is non-Fickian anomalous transport (that both diffusion and erosion is involved in drug release mechanism), F4 with n value less than 0.5 shows quasi Fickian diffusion drug transport. Similar results regarding the exponent values were shown in the literature [53].

Table 6: release kinetics values summary.

Selection of the optimal bilosomes formula

F2 which shows the highest release amount after 6 hours was chosen for further studies in part two of this research mainly for ex-vivo permeation and in-vivo studies together with transmission electron microscope images and finally stability studies.

Conclusion

In this part of our research probe sonicator was successfully employed for the preparation of meloxicam bilosomes. This method represents an ecological friendly and simple method when compared to thin film hydration which is the one most widely used method for the preparation of bilosomes. Based on our knowledge this part is the first published article that discusses the preparation of bilosomes using novel probe sonication methods. Future studies will be conducted to study the permeation and other testes of the best selected meloxicam bilosomes formulation.

Author Contributions

Authors contribute to this research equally.

Conflicts of Interest

The authors report no conflicts of interest in this work.

References

1. Chen Z, Lv Y, Qi J, et al. Overcoming or circumventing the stratum corneum barrier for efficient transcutaneous immunization. Drug Discov Today 2018; 23:181-6.

Indexed at, Google Scholar, Cross Ref

2. Wang Y, Wang L, Wen X, et al. NF-κB signaling in skin aging. Mech Ageing Dev 2019; 184:111160.

Indexed at, Google Scholar, Cross Ref

3. Chen X. Current and future technological advances in transdermal gene delivery. Adv Drug Deliv Rev 2018; 127:85-105.

Indexed at, Google Scholar, Cross Ref

4. Eltellawy YA, El-Kayal M, Abdel-Rahman RF, et al. Optimization of transdermal atorvastatin calcium–Loaded proniosomes: Restoring lipid profile and alleviating hepatotoxicity in poloxamer 407-induced hyperlipidemia. Int J Pharm 2021; 593:120163.

Indexed at, Google Scholar, Cross Ref

5. Ramkanth S, Chetty CM, Sudhakar Y, et al. Development, characterization & invivo evaluation of proniosomal based transdermal delivery system of Atenolol. Future J Pharm Sci 2018; 4:80-7.

Indexed at, Google Scholar, Cross Ref

6. Guillot AJ, Cordeiro AS, Donnelly RF, et al. Microneedle-based delivery: An overview of current applications and trends. Pharm 2020; 12:569.

Indexed at, Google Scholar, Cross Ref

7. Singh TR, Mcmillan H, Mooney K, et al. Microneedles for drug delivery and monitoring. InMicrofluidic devices biomed app 2013; 185-230.

Indexed at, Google Scholar, Cross Ref

8. Cheung K, Das DB. Microneedles for drug delivery: Trends and progress. Drug Deliv 2016; 23:2338-54.

Indexed at, Google Scholar, Cross Ref

9. Bhatnagar S, Dave K, Venuganti VV. Microneedles in the clinic. J Control Release 2017; 260:164-82.

Indexed at, Google Scholar, Cross Ref

10. Rzhevskiy AS, Singh TR, Donnelly RF, et al. Microneedles as the technique of drug delivery enhancement in diverse organs and tissues. J Control Release 2018; 270:184-202.

Indexed at, Google Scholar, Cross Ref

11. Atkinson WL, Kroger AL, Pickering LK. General immunization practices. InVaccines 2008; 83-109.

Google Scholar

12. Trimzi MA, Ham YB. A needle-free jet injection system for controlled release and repeated biopharmaceutical delivery. Pharm 2021; 13:1770.

Indexed at, Google Scholar, Cross Ref

13. Hsiao CY, Yang SC, Alalaiwe A, et al. Laser ablation and topical drug delivery: A review of recent advances. Expert Opin Drug Deliv 2019; 16:937-52.

Indexed at, Google Scholar, Cross Ref

14. Medi BM, Layek B, Singh J. Electroporation for dermal and transdermal drug delivery. Percut penetration 2017:105-22.

Indexed at, Google Scholar, Cross Ref

15. Mishra DK, Pandey V, Maheshwari R, et al. Cutaneous and transdermal drug delivery: Techniques and delivery systems. InBasic FundDrug Del 2019; 595-650.

Google Scholar

16. Park D, Park H, Seo J, Lee S. Sonophoresis in transdermal drug deliverys. Ultrasonics 2014; 54:56-65.

Indexed at, Google Scholar, Cross Ref

17. Forrester JV, Dick AD, McMenamin P, et al. Eye 2021.

Google Scholar

18. Ita KB. Iontophoresis, magnetophoresis, and electroporation.

Indexed at, Google Scholar, Cross Ref

19. Dragicevic N, Atkinson JP, Maibach HI. Chemical penetration enhancers: classification and mode of action. Percutaneous penetration enhancers chemical methods in penetration enhancement: Modification of the stratum corneum. 2015:11-27.

Google Scholar

20. Lopes LB, J Garcia MT, LB Bentley MV. Chemical penetration enhancers. Ther Deliv 2015; 6:1053-61.

Indexed at, Google Scholar, Cross Ref

21. Karande P, Mitragotri S. Enhancement of transdermal drug delivery via synergistic action of chemicals. Biochim Biophys Acta 2009; 1788:2362-73.

Indexed at, Google Scholar, Cross Ref

22. Lane ME. Skin penetration enhancers. Int J Pharm 2013; 447:12-21.

Indexed at, Google Scholar, Cross Ref

23. Siler-Marinkovic S. Liposomes as drug delivery systems in dermal and transdermal drug delivery. Percut penetration 2016:15-38.

Indexed at, Google Scholar, Cross Ref

24. Chen S, Hanning S, Falconer J, et al. Recent advances in non-ionic surfactant vesicles (niosomes): Fabrication, characterization, pharmaceutical and cosmetic applications. Eur J Pharm Biopharm 2019; 144:18-39.

Indexed at, Google Scholar, Cross Ref

25. Aziz DE, Abdelbary AA, Elassasy AI. Investigating superiority of novel bilosomes over niosomes in the transdermal delivery of diacerein: in vitro characterization, ex vivo permeation and in vivo skin deposition study. J Liposome Res 2019; 29:73-85.

Indexed at, Google Scholar, Cross Ref

26. Conacher M, Alexander J, Brewer JM. Oral immunisation with peptide and protein antigens by formulation in lipid vesicles incorporating bile salts (bilosomes). Vaccine 2001; 19:2965-74.

Indexed at, Google Scholar, Cross Ref

27. Aburahma MH. Bile salts-containing vesicles: Promising pharmaceutical carriers for oral delivery of poorly water-soluble drugs and peptide/protein-based therapeutics or vaccines. Drug Deliv 2016; 23:1847-67.

Indexed at, Google Scholar, Cross Ref

28. Al-Mahallawi AM, Abdelbary AA, Aburahma MH. Investigating the potential of employing bilosomes as a novel vesicular carrier for transdermal delivery of tenoxicam. Int J Pharm 2015; 485:329-40.

Indexed at, Google Scholar, Cross Ref

29. Chen YC, Moseson DE, Richard CA, et al. Development of hot-melt extruded drug/polymer matrices for sustained delivery of meloxicam. J Control Release 2022; 342:189-200.

Indexed at, Google Scholar, Cross Ref

30. Jyothi VG, Pawar J, Fernandes V, et al. Film forming topical dermal spray of meloxicam attenuated pain and inflammation in carrageenan-induced paw oedema in Sprague Dawley rats. J Drug Deliv Sci Technol 2022; 70:103195.

Indexed at, Google Scholar, Cross Ref

31. Hijos-Mallada G, Sostres C, Gomollón F. NSAIDs, gastrointestinal toxicity and inflammatory bowel disease. Gastroenterol Hepatol 2022.

Indexed at, Google Scholar, Cross Ref

32. Draksiene G, Venclovaite B, Pudziuvelyte L, et al. Natural polymer chitosan as super disintegrant in fast orally disintegrating meloxicam tablets: Formulation and evaluation. Pharmaceutics 2021; 13:879.

Indexed at, Google Scholar, Cross Ref

33. Al-Hassani HR, Al-Khedairy EB. Formulation and In-Vitro Evaluation of Meloxicam Solid Dispersion using Natural Polymers. Iraqi J Pharm Sci 2021; 30:169-78.

Indexed at, Google Scholar, Cross Ref

34. POJARANİ LB, ZARİFİAZAR S. Formulation and chracterization of meloxicam loaded niosome-based hydrogel formulations for topical applications. EMU J Pharm Sci 2020; 3:194-204.

Google Scholar

35. Chen J, Gao Y. Strategies for meloxicam delivery to and across the skin: A review. Drug Deliv 2016; 23:3146-56.

Indexed at, Google Scholar, Cross Ref

36. El Taweel MM, Aboul-Einien MH, Kassem MA, et al. Intranasal zolmitriptan-loaded bilosomes with extended nasal mucociliary transit time for direct nose to brain delivery. Pharmaceutics 2021; 13:1828.

Indexed at, Google Scholar, Cross Ref

37. Albash R, El-Nabarawi MA, Refai H, et al. Tailoring of PEGylated bilosomes for promoting the transdermal delivery of olmesartan medoxomil: in-vitro characterization, ex-vivo permeation and in-vivo assessment. Int J Nanomedicine 2019; 6555-74.

Indexed at, Google Scholar, Cross Ref

38. Zhang Y, Huo M, Zhou J, et al. DDSolver: An add-in program for modeling and comparison of drug dissolution profiles. AAPS J 2010; 12:263-71.

Indexed at, Google Scholar, Cross Ref

39. Bruschi ML. Strategies to modify the drug release from pharmaceutical systems. Woodhead Publ 2015.

Google Scholar

40. Araujo J, Gonzalez-Mira E, Egea MA, et al. Optimization and physicochemical characterization of a triamcinolone acetonide-loaded NLC for ocular antiangiogenic applications. Int J Pharm 2010; 393:168-76.

Indexed at, Google Scholar, Cross Ref

41. Albash R, El-Nabarawi MA, Refai H, et al. Tailoring of PEGylated bilosomes for promoting the transdermal delivery of olmesartan medoxomil: in-vitro characterization, ex-vivo permeation and in-vivo assessment. Int J Nanomedicine 2019; 15:6555-74.

Indexed at, Google Scholar, Cross Ref

42. Raj R, Raj PM, Ram A. Preparation and characterization of solid lipid nanoparticles loaded with cytarabine via a micellar composition for leukemia. RSC adv 2016; 6:53578-86.

Indexed at, Google Scholar, Cross Ref

43. Kazi KM, Mandal AS, Biswas N, et al. Niosome: A future of targeted drug delivery systems. J Adv Pharm Technol 2010; 1:374.

Indexed at, Google Scholar, Cross Ref

44. Nowroozi F, Almasi A, Javidi J, et al. Effect of surfactant type, cholesterol content and various downsizing methods on the particle size of niosomes. Iran J Pharm Res 2018; 17:1.

Indexed at, Google Scholar, Cross Ref

45. Khalil RM, Abdelbary A, Kocova El-Arini S, Basha M, et al. Evaluation of bilosomes as nanocarriers for transdermal delivery of tizanidine hydrochloride: in vitro and ex vivo optimization. J Liposome Res 2019; 29:171-82.

Indexed at, Google Scholar, Cross Ref

46. Ammar HO, Mohamed MI, Tadros MI, et al. Transdermal delivery of ondansetron hydrochloride via bilosomal systems: in vitro, ex vivo, and in vivo characterization studies. AAPS Pharm Sci Tech 2018; 19:2276-87.

Indexed at, Google Scholar, Cross Ref

47. El Menshawe SF, Aboud HM, Elkomy MH, et al. A novel nanogel loaded with chitosan decorated bilosomes for transdermal delivery of terbutaline sulfate: Artificial neural network optimization, in vitro characterization and in vivo evaluation. Drug Deliv Transl Res 2020; 10:471-85.

Indexed at, Google Scholar, Cross Ref

48. Ahmed S, Kassem MA, Sayed S. Bilosomes as promising nanovesicular carriers for improved transdermal delivery: construction, in vitro optimization, ex vivo permeation and in vivo evaluation. Int J Nanomedicine 2020: 9783-98.

Indexed at, Google Scholar, Cross Ref

49. Usama A, Fetih G, El-Faham T. Performance of meloxicam niosomal gel formulations for transdermal drug delivery. BJPR 2016; 12:1-4.

Indexed at, Google Scholar, Cross Ref

50. Mohsen AM, Salama A, Kassem AA. Development of acetazolamide loaded bilosomes for improved ocular delivery: Preparation, characterization and in vivo evaluation. J Drug Deliv Sci Technol 2020; 59:101910.

Indexed at, Google Scholar, Cross Ref

51. Zafar A, Alruwaili NK, Imam SS, et al. Bioactive Apigenin loaded oral nano bilosomes: Formulation optimization to preclinical assessment. Saudi Pharm J 2021; 29:269-79.

Indexed at, Google Scholar, Cross Ref

52. Ismail A, Teiama M, Magdy B, et al. Development of a Novel Bilosomal System for Improved Oral Bioavailability of Sertraline Hydrochloride: Formulation Design, In Vitro Characterization, and Ex Vivo and In Vivo Studies. AAPS PharmSciTech 2022; 23:188.

Indexed at, Google Scholar, Cross Ref