Insignificant effect of all factors on PS and PDI as a quadratic model was not a good fit for these responses which might occur due to aliased factor or human error.

Significant –ve interaction between mPEG-2K-DSPE and number of cycles on EE.

Increase in concentration of mPEG-2K-DSPE increases EE for 10 cycles but at 30 cycles this effect diminishes.

At 0.1% w/v AmB, increase in amount of mPEG-2K-DSPE increases DL, and at 0.3% w/v of AmB, increase in amount of mPEG-2K-DSPE decreases DL as AmB might get saturated with total lipids.

Significant effect (+ve) of LL:TL on PS due to aggregation of higher concentration of lipids.

Increase in the concentration of SC: CSC decreases PS due to internal arrangement within NLC.

Increase in the concentration of LL:TL increases EE due to solubilization of drug inside LL.

Increase in the concentration of LL:TL decreases EE as surfactants assisted drug to remain on the surface and inside NLC.

BBD was employed to get the best experimental run with desired CQAs (size in nano, PDI < 0.5, ZP ≥ ± 30 mV, and EE > 80%).

CCD was performed using only 2 factors, i.e., CPPs to further improve CQAs.

Increased SA significantly decreases EE and LC due to expulsion of drug from NLC.

High –ve ZP was observed with increased SA resulting in higher stability of NLC. SA increases temperature of the system resulting in degradation and desorption of non-ionic surfactant which makes –ve value of ZP relatively +ve thus decreasing stability of NLC.

PS and PDI decreased with increased SA due to production of shock wave and high temperature which imparts shear force on NLC resulting in breaking of NLC in nano range.

3 CMAs for BBD was screened was ratio of surfactants, concentrations of surfactants and lipid concentration.

Quadratic model was found to be significant for size and PDI but insignificant for ZP and EE.

Increased lipid and surfactant concentration decreased PS and PDI.

Factors were insignificant for ZP and EE.

Total lipid, surfactant, and ST were screened for further optimization.

Increased lipid concentration increased PS while decreased PDI.

Increased surfactant concentration increased PDI while decreased ZP.

PS increased with an increase in surfactant concentration till the middle value, further increase in concentration decreased PS.

LL, drug, and surfactant were screened for CCD as critical factors.

Increased amount of drug increased DL resulting in increased surface tension. Thus, increased surfactant concentration was inefficient in decreasing size.

Increased PS was observed with increased amount of LL.

PDI increased with increased amount of LL and drug.

EE increased with increased amount of LL and surfactant.

Tween 80 and ST were found as critical factors for further use in CCD.

As per response surface method, amount of SL:LL and tween 80 was found to be 3:1 and 158 mg.

PS decreased with increased value of surfactant and HPH pressure while PS increased as lipid concentration increased.

On PDI, increased value of surfactant had –ve effect. Moreover, lipid concentration had +ve effect.

As HPH pressure increased till intermediate level PDI decreased but after that PDI increased due to increased collision resulting in aggregation of NLC.

All 3 factors had significant +ve effect on EE.

PS and PDI decreased with increased concentration of SL till intermediate level. Further increase, increased PS and PDI. Moreover, effect on EE was just reverse of that observed on PS and PDI.

PS and PDI decreased with increased surfactant concentrations.

PS and PDI increased with increased ST while EE decreased.

Lipid concentration had no effect on EE. Drug and surfactant concentrations were inversely related to EE and PS.

Increased surfactant concentration decreased PS but increased ZP.

TSL has highest –ve impact on PS and PDI.

Interaction of TSL × PC and TSL × TAS had significant impact on PS.

Lower concentration of P80H, decreased PS.

Significant effect of all factors and their interactions (except TSL × TAS) was observed on ZP.

ZP value increased by increased amount of TAS and PC while decreased due to increased SL.

Highest +ve significant effect of TSL was observed on EE. All other factors were insignificant.

+ve significant effect was observed with chitosan solution on EE and % yield.

EE decreased with increased concentration of SL and LL as drug was hydrophilic but interaction of SL and LL had +ve effect on EE.

All factors had significant +ve effect on PS.

On PDI SL had –ve effect while LL and chitosan had +ve effect.

Factors affecting EE was observed in the order: drug:TL > LL:TL > co-surfactant > surfactant.

Linear model was significant, R² = 89.54%.

Reduction in PS was observed due to significant interaction observed between gelucire × precirol, gelucire × miglyol, precirol × poloxamer.