The document discusses the development of spectrophotometric methods for the quantitative determination of nalbuphine hydrochloride in various forms, including raw samples and spiked urine. The methods are described as simple, rapid, sensitive, precise, and accurate, utilizing bromophenol blue and chlorophenol red as coloring reagents to form colored ion associates detectable in the visible region. Key parameters such as optimum reaction conditions, absorbance maxima, and validation of methods are detailed to establish their effectiveness in determining nalbuphine hydrochloride concentrations.