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Design of cationic nanostructured heterolipid matrices for ocular delivery of methazolamide.

Youshia J, Kamel AO, El Shamy A, Mansour S - Int J Nanomedicine (2012)

Bottom Line: Solid lipid nanoparticles (SLNs) formulated from one type of lipid (homolipid) suffer from low drug encapsulation and drug bursting due to crystallization of the lipid into the more ordered β modification, which leads to decreased drug entrapment and faster drug release.The results showed that increasing the ratio of CSA to Compritol increased the EE% and PS, while increasing the concentration of Tween 80, decreased PS with no significant effect on EE%.The ZP values of all formulae were positive, and greater than 30 mV.

View Article: PubMed Central - PubMed

Affiliation: Pharmaceutics and Industrial Pharmacy Department, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt.

ABSTRACT
Solid lipid nanoparticles (SLNs) formulated from one type of lipid (homolipid) suffer from low drug encapsulation and drug bursting due to crystallization of the lipid into the more ordered β modification, which leads to decreased drug entrapment and faster drug release. This study assessed the feasibility of using nanostructured lipid matrices (NLMs) for ocular delivery of methazolamide-(MZA) adopting heterolipids composed of novel mixtures of Compritol (®) and cetostearyl alcohol (CSA), and stabilized by Tween 80(®). The systems were prepared using the modified high shear homogenization followed by ultrasonication method, which avoids the use of organic solvents. A 3(2) full factorial design was constructed to study the influence of two independent variables, namely the ratio of CSA:Compritol and the concentration of Tween 80, each in three levels. The dependent variables were the entrapment efficiency percentages (EE%), mean particle size (PS), polydispersity index (PDI), and zeta potential (ZP). In vivo intraocular pressure (IOP) lowering activity for the selected formulae was compared to that of MZA solution. The results showed that increasing the ratio of CSA to Compritol increased the EE% and PS, while increasing the concentration of Tween 80, decreased PS with no significant effect on EE%. The ZP values of all formulae were positive, and greater than 30 mV. The best formula, composed of 4% CSA, 2% Compritol, 0.15% stearylamine, and 2% Tween 80, with EE% of 25.62%, PS of 207.1 nm, PDI of 0.243, and ZP of 41.50 mV, showed in vitro sustained release properties for 8 hours and lowered the intraocular pressure by 8.3 mmHg within 3 hours, with this drop in pressure lasting for 12 hours.

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X-ray diffraction patterns for (A) MZA, (B) MZA-loaded NLM-9, (C) Compritol, and (D) CSA.Abbreviations: CSA, cetostearyl alcohol; MZA, methazolamide.
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f8-ijn-7-2483: X-ray diffraction patterns for (A) MZA, (B) MZA-loaded NLM-9, (C) Compritol, and (D) CSA.Abbreviations: CSA, cetostearyl alcohol; MZA, methazolamide.

Mentions: X-ray diffraction was carried out to evaluate the crystallinity of MZA-loaded NLM formula NLM-9 and compare it to that of pure MZA, Compritol, and CSA (see Figure 8). The MZA X-ray diffractogram shows several sharp, narrow peaks between 10° and 40° (2θ) with maximum peak intensity at 2θ = 13.87° (d = 6.37 Å), indicating its crystalline nature. The X-ray diffractogram of CSA showed four major sharp peaks with a maximum peak at 2θ = 21.29° (d = 4.16 Å), while Compritol showed only two sharp peaks with the maximum at 2θ = 21.18° (d = 4.189 Å). In the case of formula NLM-9 there was only one major peak at 2θ = 21.15° (d = 4.19 Å), which probably represented an overlapped peak of both CSA and Compritol. Also, it is clear that the peaks of MZA disappeared from the diffraction pattern of NLM-9, indicating its amorphous state and confirming the results of DSC analysis. It is known that the intensity of peaks is related to the crystallinity of the sample, with a higher peak intensity indicating that the material is more crystalline. Given that the peak intensity of NLM-9 showed a sharp decrease when compared to that of Compritol or CSA, this indicates a marked decrease in the crystallinity of NLMs and confirms previous results from the DSC analysis.


Design of cationic nanostructured heterolipid matrices for ocular delivery of methazolamide.

Youshia J, Kamel AO, El Shamy A, Mansour S - Int J Nanomedicine (2012)

X-ray diffraction patterns for (A) MZA, (B) MZA-loaded NLM-9, (C) Compritol, and (D) CSA.Abbreviations: CSA, cetostearyl alcohol; MZA, methazolamide.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3367493&req=5

f8-ijn-7-2483: X-ray diffraction patterns for (A) MZA, (B) MZA-loaded NLM-9, (C) Compritol, and (D) CSA.Abbreviations: CSA, cetostearyl alcohol; MZA, methazolamide.
Mentions: X-ray diffraction was carried out to evaluate the crystallinity of MZA-loaded NLM formula NLM-9 and compare it to that of pure MZA, Compritol, and CSA (see Figure 8). The MZA X-ray diffractogram shows several sharp, narrow peaks between 10° and 40° (2θ) with maximum peak intensity at 2θ = 13.87° (d = 6.37 Å), indicating its crystalline nature. The X-ray diffractogram of CSA showed four major sharp peaks with a maximum peak at 2θ = 21.29° (d = 4.16 Å), while Compritol showed only two sharp peaks with the maximum at 2θ = 21.18° (d = 4.189 Å). In the case of formula NLM-9 there was only one major peak at 2θ = 21.15° (d = 4.19 Å), which probably represented an overlapped peak of both CSA and Compritol. Also, it is clear that the peaks of MZA disappeared from the diffraction pattern of NLM-9, indicating its amorphous state and confirming the results of DSC analysis. It is known that the intensity of peaks is related to the crystallinity of the sample, with a higher peak intensity indicating that the material is more crystalline. Given that the peak intensity of NLM-9 showed a sharp decrease when compared to that of Compritol or CSA, this indicates a marked decrease in the crystallinity of NLMs and confirms previous results from the DSC analysis.

Bottom Line: Solid lipid nanoparticles (SLNs) formulated from one type of lipid (homolipid) suffer from low drug encapsulation and drug bursting due to crystallization of the lipid into the more ordered β modification, which leads to decreased drug entrapment and faster drug release.The results showed that increasing the ratio of CSA to Compritol increased the EE% and PS, while increasing the concentration of Tween 80, decreased PS with no significant effect on EE%.The ZP values of all formulae were positive, and greater than 30 mV.

View Article: PubMed Central - PubMed

Affiliation: Pharmaceutics and Industrial Pharmacy Department, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt.

ABSTRACT
Solid lipid nanoparticles (SLNs) formulated from one type of lipid (homolipid) suffer from low drug encapsulation and drug bursting due to crystallization of the lipid into the more ordered β modification, which leads to decreased drug entrapment and faster drug release. This study assessed the feasibility of using nanostructured lipid matrices (NLMs) for ocular delivery of methazolamide-(MZA) adopting heterolipids composed of novel mixtures of Compritol (®) and cetostearyl alcohol (CSA), and stabilized by Tween 80(®). The systems were prepared using the modified high shear homogenization followed by ultrasonication method, which avoids the use of organic solvents. A 3(2) full factorial design was constructed to study the influence of two independent variables, namely the ratio of CSA:Compritol and the concentration of Tween 80, each in three levels. The dependent variables were the entrapment efficiency percentages (EE%), mean particle size (PS), polydispersity index (PDI), and zeta potential (ZP). In vivo intraocular pressure (IOP) lowering activity for the selected formulae was compared to that of MZA solution. The results showed that increasing the ratio of CSA to Compritol increased the EE% and PS, while increasing the concentration of Tween 80, decreased PS with no significant effect on EE%. The ZP values of all formulae were positive, and greater than 30 mV. The best formula, composed of 4% CSA, 2% Compritol, 0.15% stearylamine, and 2% Tween 80, with EE% of 25.62%, PS of 207.1 nm, PDI of 0.243, and ZP of 41.50 mV, showed in vitro sustained release properties for 8 hours and lowered the intraocular pressure by 8.3 mmHg within 3 hours, with this drop in pressure lasting for 12 hours.

Show MeSH
Related in: MedlinePlus