title: Formulation study of topically applied lotion: in vitro and in vivo evaluation.
abstract: BACKGROUND
  This article presents the development and evaluation of a new topical formulation of diclofenac diethylamine (DDA) as a locally applied analgesic lotion.
  
  
  METHODS
  To this end, the lotion formulations were formulated with equal volume of varying concentrations (1%, 2%, 3%, 4%; v/v) of permeation enhancers, namely propylene glycol (PG) and turpentine oil (TO). These lotions were subjected to physical studies (pH, viscosity, spreadability, homogeneity, and accelerated stability), in vitro permeation, in vivo animal studies and sensatory perception testing. In vitro permeation of DDA from lotion formulations was evaluated across polydimethylsiloxane membrane and rabbit skin using Franz cells.
  
  
  RESULTS
  It was found that PG and TO content influenced the permeation of DDA across model membranes with the lotion containing 4% v/v PG and TO content showed maximum permeation enhancement of DDA. The flux values for L4 were 1.20±0.02 μg.cm(-2).min(-1) and 0.67 ± 0.02 μg.cm(-2).min(-1) for polydimethylsiloxane and rabbit skin, respectively. Flux values were significantly different (p < 0.05) from that of the control. The flux enhancement ratio of DDA from L4 was 31.6-fold and 4.8-fold for polydimethylsiloxane and rabbit skin, respectively. In the in vivo animal testing, lotion with 4% v/v enhancer content showed maximum anti-inflammatory and analgesic effect without inducing any irritation. Sensatory perception tests involving healthy volunteers rated the formulations between 3 and 4 (values ranging between -4 to +4, indicating a range of very bad to excellent, respectively).
  
  
  CONCLUSIONS
  It was concluded that the DDA lotion containing 4% v/v PG and TO exhibit the best performance overall and that this specific formulation should be the basis for further clinical investigations.
authors.affiliation: Faculty of Pharmacy, Bahauddin Zakariya University, Multan, Pakistan.
authors.forename: Syed Nisar
authors.initials: SN
authors.lastname: Hussain Shah
authors.forename: Talib
authors.initials: T
authors.lastname: Hussain
authors.forename: Ikram
authors.initials: I
authors.lastname: Ullah Khan
authors.forename: Sajid
authors.initials: S
authors.lastname: Asghar
authors.forename: Yasser
authors.initials: Y
authors.lastname: Shahzad
keywords: Diclofenac Diethylamine; Percutaneous Absorption; Propylene Glycol; Topical Applied Lotion; Turpentine Oil