ABS	Acrylonitrile butadiene styrene
AIC	Akaike information criterion
CCD	Central composite design
CAD	Computer-aided design
DoE	Design of experiments
DF	Drug-free formulation
E2	Estradiol hemihydrate
EPHCD	Estradiol-loaded polymer-based hollow cylindrical delivery system
EC	Ethyl cellulose
FDC	Franz diffusion cell
GSM	Genitourinary syndrome of menopause
IDDS	Implantable drug delivery systems
IUD	Intrauterine device
MSC	Model selection criterion
MCDDS	Multi component drug delivery system
NETA	Norethindrone acetate
NLPM	Norethindrone acetate-loaded hollow cylindrical polymeric matrix
PBS	Phosphate-buffered saline
PCL	Polycaprolactone
PRESS	Predicted residual sum of squares
SEM	Scanning electron microscopy
SUF	Simulated uterine fluid
SD	Standard deviation